Post by: Skidous on July 22, 2016, 05:06:41 pm
HSC BIOLOGY Q&A THREAD
To go straight to posts for the new syllabus, click here.
What is this thread for?
If you have general questions about the HSC Biology course or how to improve in certain areas, this is the place to ask! 👌
Who can/will answer questions?
Everyone is welcome to contribute; even if you're unsure of yourself, providing different perspectives is incredibly valuable.
Please don't be dissuaded by the fact that you haven't finished Year 12, or didn't score as highly as others, or your advice contradicts something else you've seen on this thread, or whatever; none of this disqualifies you from helping others. And if you're worried you do have some sort of misconception, put it out there and someone else can clarify and modify your understanding!
There'll be a whole bunch of other high-scoring students with their own wealths of wisdom to share with you. So you may even get multiple answers from different people offering their insights - very cool.
To ask a question or make a post, you will first need an ATAR Notes account. You probably already have one, but if you don't, it takes about four seconds to sign up - and completely free!
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* Free Biology notes
* HSC Biology Question Thread
* How to Get a Band 6 in HSC Biology
* HSC Biology - How to Get a Band 6
* HSC BIO GUIDE: BLUEPRINT OF LIFE
* HSC BIO GUIDE: THE SEARCH FOR BETTER HEALTH
* Long Responses in HSC Biology
* HSC Biology: How to Ace the 8 Marker Questions
* How to Go About Studying for Any Science
* HSC Biology Question Thread
* How to Get a Band 6 in HSC Biology
* HSC Biology - How to Get a Band 6
* HSC BIO GUIDE: BLUEPRINT OF LIFE
* HSC BIO GUIDE: THE SEARCH FOR BETTER HEALTH
* Long Responses in HSC Biology
* HSC Biology: How to Ace the 8 Marker Questions
* How to Go About Studying for Any Science
Original post.
Hello Bio Students, Whilst I may not be one of the ATARNotes legends, I noticed that there wasn't one of these threads in our section of the forums so I thought I'd start one up.
Basically this is a place where any of the Biology Students or Lecturers to come and place any questions that they need help with, or answered questions that you want marked or feedback on, or even just questions on the general concepts in Biology that you may need help with.
For me, I've done the core modules for Biology and I've gotten through a little bit of the Communications Option so feel free to ask me any questions regarding that. I'm currently first in my Biology class so I feel as though I can help some other people out, but feel free to prove me wrong and help others out with any questions. Looking forward to seeing these questions too
Let's get this thread rolling
Skidous
Basically this is a place where any of the Biology Students or Lecturers to come and place any questions that they need help with, or answered questions that you want marked or feedback on, or even just questions on the general concepts in Biology that you may need help with.
For me, I've done the core modules for Biology and I've gotten through a little bit of the Communications Option so feel free to ask me any questions regarding that. I'm currently first in my Biology class so I feel as though I can help some other people out, but feel free to prove me wrong and help others out with any questions. Looking forward to seeing these questions too
Let's get this thread rolling
Skidous
Post by: studybuddy7777 on July 22, 2016, 09:11:13 pm
(For communication, at time of writing we had just started outcome 5- sound)
I am on a Band 5 at the moment and have past siblings notes which have gotten them a Band 6, so I am able to answer most questions.
Just whatever you do, do not be afraid to ask questions! Questions are how we improve (both the one/s answering the question as well as the asker) and there is a fair chance that someone else has that question. Wouldnt it suck to not ask a question on that one achilles heel you have for a topic and then to get an 8 marker on it? So, lets ask up and then some mods can get on here with their advice too ;D
Post by: vox nihili on July 22, 2016, 09:14:52 pm
Post by: Skidous on July 22, 2016, 10:14:40 pm
Post by: studybuddy7777 on July 23, 2016, 07:22:47 am
I'll start with a question:
Treatment of water- the whole aeration to chlorination thing. I can never remember it. Is there an easy (creative?) way to remember it or do i just have to know it? Could someone also put it down below and ill try to make a mnemonic out of it or something hehe ;D
Thanks all
Post by: Skidous on July 23, 2016, 02:17:42 pm
Haha no probs :).
I'll start with a question:
Treatment of water- the whole aeration to chlorination thing. I can never remember it. Is there an easy (creative?) way to remember it or do i just have to know it? Could someone also put it down below and ill try to make a mnemonic out of it or something hehe ;D
Thanks all
Hey StudyBuddy
It starts with the SEDIMENTATION for the water (removal of large particles) from a reservoir usually through a fine screen. Then the water given a coagulant where COAGULATION occurs in order to gather tiny particles remaining in the raw water. The coagulated dirt is known as the floc, FLOCCULATION is the gathering of this floc into larger groups. FILTRATION then occurs where water is passed through Sand and crushed coal, trapping the floc and separating it from the water. Water is then disinfected through CHLORINATION where Chloramine (Chlorine and Water) is added into the water in order to kill off any bacteria present in the water (prevents to spread of waterborne diseases like giardia and cryptosporidian). After that, depending on the encatchment area, the water goes through FLUORIDATION in which fluorine is added to the water (Teeth health of the public). Then STABILIZATION occurs in which Lime or CO2 is added to the water to correct the pH of the water before it is pumped to houses for use.
The process goes
Sedimentation
Coagulation
Flocculation
Filtration
Chlorination
Fluoridation
Stabilization
if you can make a mnemonic out of that go right ahead.
The easiest thing to do for me is to try and do a flow chart which I've attached to the post. Hope this helps out
Skidous
Post by: studybuddy7777 on July 24, 2016, 09:54:39 am
Should Clinton Fall For Charismatic Flying Seagulls :D
(A suitable one for the forums ;))
I might exclude chorination and just remember that individually coz then its ffs :) or i might make it ff cakes :p
SCruFFy CaFeS also works (wtf?)
Post by: Skidous on July 24, 2016, 12:24:52 pm
Post by: dtinaa on July 24, 2016, 02:55:20 pm
Post by: HighTide on July 24, 2016, 03:07:43 pm
Does anyone understand what refraction of light has to do with myopia and hyperopia??Your eye has a lens and cornea which are responsible for refraction of light onto the rods and cones of the retina and this is at the FOCAL POINT. The rods and cones are responsible for colour and shade vision. In hyperopia and myopia, the FOCAL POINT occurs further than the retina or before the retina (respectively), and so images cannot be made properly. In order for proper images to form, the focal point must be at the retina.
Post by: vox nihili on July 24, 2016, 03:28:53 pm
Does anyone understand what refraction of light has to do with myopia and hyperopia??
(https://upload.wikimedia.org/wikipedia/commons/thumb/e/e0/Myopia_and_lens_correction.svg/220px-Myopia_and_lens_correction.svg.png)
This picture is pretty handy. Basically just shows exactly what HighTide said. In the top image, you can see that the light is being refracted into a point in front of the retina (myopia), whereas in the bottom image the light is being focused directly onto the retina.
I will add that it's really important to remember the cornea, as it actually does the majority of the refraction; not the lens as many would assume (including me!).
Post by: Skidous on July 24, 2016, 03:39:33 pm
Does anyone understand what refraction of light has to do with myopia and hyperopia??
Hi Dtinaa
Refraction of light is how light bends when entering mediums of different optical densities
In the eye, the lens, aqueous humour and vitreous humour refract light onto the retina.
When it refracts in front of the retina, myopia occurs, which means that objects that are far away are not focused properly (usually due to the eyeball being to long for accommodation to properly focus)
When it refracts behind the retina then hyperopia occurs, where the objects that are closer become blurry (usually due to the lens becoming less elastic due to age).
Hope this helps
Skidous
Post by: vox nihili on July 24, 2016, 03:45:12 pm
Hi Dtinaa
Refraction of light is how light bends when entering mediums of different optical densities
In the eye, the lens, aqueous humour and vitreous humour refract light onto the retina.
When it refracts in front of the retina, myopia occurs, which means that objects that are far away are not focused properly (usually due to the eyeball being to long for accommodation to properly focus)
When it refracts behind the retina then hyperopia occurs, where the objects that are closer become blurry (usually due to the lens becoming less elastic due to age).
Hope this helps
Skidous
Don't forget the cornea, it's the most important bit for refraction
Post by: gadeerrr on July 25, 2016, 09:15:38 pm
Thanks
Post by: HighTide on July 25, 2016, 09:37:35 pm
Can anyone please explain to me introns and exons? It's part of the option module code broken - still confused as to the difference between exons and introns.In DNA, you have introns and exons. Exons code for proteins or polypeptides, whilst the introns are just non-coding segments which interfere with coding genes and are GENERALLY useless (the reason I say generally is because there's been some research into why introns are present).
Thanks
During transcription, you make pre-mRNA then mature mRNA. pre-mRNA has introns and exons. mature mRNA only has exons which codes for only the protein. The introns are removed by splicosomes.
Idk much about your syllabus but generally it's just introns useless interrupting sequence, exons useful coding sequence.
Post by: liiz on July 26, 2016, 02:59:16 pm
Post by: studybuddy7777 on July 26, 2016, 05:07:35 pm
Gather and process information..
This means that youll need to be doing more than simply 'identifying' (soz if going all BOSTES on you :p)
The main points of malaria: (soz its a bit long got carried away :p)
Around 2700 BC - several characteristic symptoms of malaria were described in the Nei Ching, Chinese medical writings. The Greece recognised it by 4 B.C. as the cause of the decline of many city populations. Hippocrates noted the principal symptoms.
Around 18 BC- Romans discovered malaria was common in marshy areas around Rome. The name malaria is derived from the Italian for “bad air"
Quechua healers of South American tribes in the Amazon used the bark of the Cinchona shrub to treat fevers and diseases
In the 1600s, this was observed by Spanish priests, who started using it to treat fevers associated with malaria. By 1649, the bark was available in England. The active ingredient, quinine, was isolated in 1820 by Pierre Joseph Pelletier. Quinine is one of the most effective anti-malarial drugs today.
In 1880, Charles Laveran, a French army doctor, observed the malarial parasite. He was awarded the Nobel Prize for his work in 1907.
In 1886, Golgi observed asexual reproduction in the protozoan Plasmodium and identified two species.
In 1897, Ronald Ross discovered the malarial parasite in the stomach of an Anopheles mosquito. The parasite is the protozoa of the genus Plasmodium transmitted by the female Anopheles mosquito. In 1902, Ronald Ross won the Nobel Prize in Medicine for this achievement.
In 1898, Giovanni Grassi named the Anopheles mosquito as the carrier of the malarial parasite.
In 1934, Hans Andersag discovered chloroquinine, a synthetic drug. He named the compound resochin. Chloroquinine is an effective and safe antimalarial, though it was not recognised as such by British and American scientists until 1946.
In 1942, Paul Muller discovered the insecticide DDT. It was first used in Italy in 1944, and idea of global eradication of malaria seemed possible. Subsequently, widespread systematic control of the Anopheles mosquito has been used to interrupt its lifecycle, including the spraying of DDT, coating marshes with paraffin, using mosquito nets and draining stagnant water. However, mosquito populations developed resistance to DDT, making DDT have minimal or no effect
I feel like I have gone on for ages but the main points are in bold
Hope that has actually summarised rather than extended your notes! ;D
Post by: Skidous on July 26, 2016, 06:00:56 pm
You should also talk about the reduced effectiveness of quinine over the years as well as the development of plans to try and prevent malaria through controlling mosquito populations, this is another dot point but it would be good to refer to it
Post by: liiz on July 26, 2016, 08:37:34 pm
Just to add onto what StudyBuddy wroteAh okay awesome - will do! Thankyou so much :))
You should also talk about the reduced effectiveness of quinine over the years as well as the development of plans to try and prevent malaria through controlling mosquito populations, this is another dot point but it would be good to refer to it
Post by: liiz on July 26, 2016, 08:40:22 pm
Hey liizThis was super helpful, and yep - definitely summarised rather than made my notes longer!! Short but good information in there that hopefully I'll be able to remember a bit easier. Thankyou so much for helping out, really appreciate it :))
Gather and process information..
This means that youll need to be doing more than simply 'identifying' (soz if going all BOSTES on you :p)
The main points of malaria: (soz its a bit long got carried away :p)
Around 2700 BC - several characteristic symptoms of malaria were described in the Nei Ching, Chinese medical writings. The Greece recognised it by 4 B.C. as the cause of the decline of many city populations. Hippocrates noted the principal symptoms.
Around 18 BC- Romans discovered malaria was common in marshy areas around Rome. The name malaria is derived from the Italian for “bad air"
Quechua healers of South American tribes in the Amazon used the bark of the Cinchona shrub to treat fevers and diseases
In the 1600s, this was observed by Spanish priests, who started using it to treat fevers associated with malaria. By 1649, the bark was available in England. The active ingredient, quinine, was isolated in 1820 by Pierre Joseph Pelletier. Quinine is one of the most effective anti-malarial drugs today.
In 1880, Charles Laveran, a French army doctor, observed the malarial parasite. He was awarded the Nobel Prize for his work in 1907.
In 1886, Golgi observed asexual reproduction in the protozoan Plasmodium and identified two species.
In 1897, Ronald Ross discovered the malarial parasite in the stomach of an Anopheles mosquito. The parasite is the protozoa of the genus Plasmodium transmitted by the female Anopheles mosquito. In 1902, Ronald Ross won the Nobel Prize in Medicine for this achievement.
In 1898, Giovanni Grassi named the Anopheles mosquito as the carrier of the malarial parasite.
In 1934, Hans Andersag discovered chloroquinine, a synthetic drug. He named the compound resochin. Chloroquinine is an effective and safe antimalarial, though it was not recognised as such by British and American scientists until 1946.
In 1942, Paul Muller discovered the insecticide DDT. It was first used in Italy in 1944, and idea of global eradication of malaria seemed possible. Subsequently, widespread systematic control of the Anopheles mosquito has been used to interrupt its lifecycle, including the spraying of DDT, coating marshes with paraffin, using mosquito nets and draining stagnant water. However, mosquito populations developed resistance to DDT, making DDT have minimal or no effect
I feel like I have gone on for ages but the main points are in bold
Hope that has actually summarised rather than extended your notes! ;D
Post by: studybuddy7777 on July 27, 2016, 07:38:44 am
This was super helpful, and yep - definitely summarised rather than made my notes longer!! Short but good information in there that hopefully I'll be able to remember a bit easier. Thankyou so much for helping out, really appreciate it :))No worries im glad i was able to help :D nice to see that some people dont think i ramble on too much (my english teacher thinks otherwise.. :p)
Post by: Skidous on July 28, 2016, 07:05:56 pm
Macrophages introduce antigens to B Cells and T cells in the lymph nodes.
These B Cells produce antibodies that attach to the antigen to form an antibody-antigen complex, then the antibodies flag the pathogen for destruction via phagocytosis. T cells attack the pathogens via Killer T-cells (cytotoxic T-Cells) in which the T-Cells latches onto the pathogen and kills it using chemicals.
Helper T-Cells assists in the production of antibodies by promoting antibody production by plasma B Cells
Post by: vox nihili on July 28, 2016, 07:49:00 pm
Hey guys!
I'm gonna drop a few questions for Search for Better Health here. Any answers would be appreciated!
1) What were MacFarlane Burnet's contributions to our understanding of the immune response and the effectiveness of immunisation programs?
2) What are the interactions between B and T cells and what are the mechanisms that allow these interactions?
3) What are the main features of epidemiology?
Thanks!
The purpose of this forum, as I see it, is to help refine your understanding, so please to try to avoid just dumping questions and expecting people to answer them, especially when, such as in the case as question 1, you could just as easily Google it.
So before I contribute to answering any of those, what do you think? What have you found by doing your own research? Then we can help refine it.
Post by: Skidous on July 28, 2016, 08:33:01 pm
The purpose of this forum, as I see it, is to help refine your understanding, so please to try to avoid just dumping questions and expecting people to answer them, especially when, such as in the case as question 1, you could just as easily Google it.
So before I contribute to answering any of those, what do you think? What have you found by doing your own research? Then we can help refine it.
I totally agree with what Vox is saying, even though I've already attempted at answering, it's only haphazardly done so that it was there to help out, it is also a lot easier to help fill in blanks instead of answering whole questions
Post by: Sssssrr on August 01, 2016, 10:29:42 pm
thanks
Post by: Sine on August 01, 2016, 10:39:06 pm
could someone please explain to me the difference between enatiostasis and homeostasis?enatiostasis is the the maintenance of metabolic and physiological functions in response to variations in the environment.
thanks
homestasis is the maintenance of relatively stable internal environment despite fluctuations of the external environment
Post by: Skidous on August 02, 2016, 06:49:11 am
Enantiostasis: Mangroves Trees active accumulated salt on older leaves in order to prevent the salt from building up in other cells, the salt is removed when the leaves fall off.
Homeostasis: Aldosterone is activated when the blood pressure and ion concentration in blood is too low in order to actively absorb more sodium ions and stabilise blood pressure
Post by: Sssssrr on August 02, 2016, 09:50:16 am
Post by: studybuddy7777 on August 02, 2016, 05:12:00 pm
To add onto what Sine said, you should also have an example of each.
Enantiostasis: Mangroves Trees active accumulated salt on older leaves in order to prevent the salt from building up in other cells, the salt is removed when the leaves fall off.
Homeostasis: Aldosterone is activated when the blood pressure and ion concentration in blood is too low in order to actively absorb more sodium ions and stabilise blood pressure
We had this exact question ("Distinguish between homeostasis and enantiostasis") so i got full marks in the homeostasis part but when i talked about mangrove trees and the accumulation/excretion of salt for enantiostasis i ended up getting a cross right on "mangrove"l also said it was the maintenance of metabolic functions.
This was in my 1/2yearly btw. This question was out of 4. I got 2 for homeostasis and 1 for enantiostasis. What was i missing to make it a 4/4?
Post by: Skidous on August 02, 2016, 05:56:20 pm
Osmoregulators: organisms that avoid changes in their internal environment and have the ability to keep the solutes at an optimal level (‘regulate’ solute concentrations within the body), regardless of the differing external environment. i.e Mussels close their mouths in order to keep the salt levels in their tissues the same as sea water
Osmoconformers: organisms that tolerate the changes in the environment by altering the concentration of their internal solutes to match the external environment. i.e the fiddler crab accumulates salt into its tissues to match seawater and pumps out the excess when exposed to fresh water.
You should also talk what estuaries are and what change in the environment that requires enantiostasis to occur for these organisms to live in their ecosystems
Post by: studybuddy7777 on August 02, 2016, 06:50:41 pm
My guess is that you need 2 examples. These include the
Osmoregulators: organisms that avoid changes in their internal environment and have the ability to keep the solutes at an optimal level (‘regulate’ solute concentrations within the body), regardless of the differing external environment. i.e Mussels close their mouths in order to keep the salt levels in their tissues the same as sea water
Osmoconformers: organisms that tolerate the changes in the environment by altering the concentration of their internal solutes to match the external environment. i.e the fiddler crab accumulates salt into its tissues to match seawater and pumps out the excess when exposed to fresh water.
You should also talk what estuaries are and what change in the environment that requires enantiostasis to occur for these organisms to live in their ecosystems
Wow okay thanks for the information! I'll thank you now but read it later as its all going over the top of my head right now (2 trial papers does that to you, especially when one is English Adv paper 2 modules)
Post by: Skidous on August 02, 2016, 06:53:30 pm
Post by: studybuddy7777 on August 02, 2016, 06:58:42 pm
Them feels man, them feels. English trials are over though so that means only the "easy" subjects are left. Y'know, physics, chemistry, maths, SOR II and Bio
You seriously did not just put SOR II and "easy" in the same sentence.. :P
I agree that the sciences are certainly easier than english, math comes down to the mindset and level being assessed but omg i am so screwed for SOR II. Perhaps even more so than english. Section III and IV are not looking fun :-\ :'(
But its my last exam so i can relax a bit :D
Post by: Skidous on August 02, 2016, 07:00:26 pm
Post by: studybuddy7777 on August 02, 2016, 07:03:36 pm
I don't mean to brag but I'll have you know that I came third in SOR II and I barely did study for all 3 assessment tasks
I dont want sympathy but I actually tried in all my assessment tasks and are still ranked 7th (out of 20) for SOR II. Life is not fair lol.
Post by: Skidous on August 02, 2016, 07:10:27 pm
Post by: Ayyddaan on August 02, 2016, 07:34:36 pm
Post by: Skidous on August 02, 2016, 07:37:19 pm
Could someone please explain the mechanisms that allow interaction between B and T cells?? (INCLUDING MHC molecules?)
This image may be of use to you
Post by: Skidous on August 02, 2016, 07:41:00 pm
Post by: Ayyddaan on August 02, 2016, 07:42:08 pm
The major histocompatibility complex (MHC) is a set of cell surface proteins essential for the acquired immune system to recognize foreign molecules in vertebrates. so you would refer to them basically as the protein flags which determine whether a cell is self or non-self (and consequently an antigen)
Ohhhhh, thanks dude!!
Post by: Skidous on August 02, 2016, 07:42:52 pm
Ohhhhh, thanks dude!!
No problem man, always happy to help
For some extra information there are 2 types of MHC molecules
MHC II can be conditionally expressed by all cell types, but normally occurs only on professional macrophages and B cells, used primarily to assist in antibody mediated immunity (Humoral Immunity)
MHC I occurs on all nucleated cells—in essence all cells but red blood cells—and presents epitopes to killer T cells, also called cytotoxic T lymphocytes. CD8 receptor on Cytotoxic T-cells docks to MHC I molecules, if they fit together it triggers the cell to undergo programmed cell death by apoptosis, hence assisting with Cell Mediated Immunity (addressess intracellular pathogens, such as viruses and some bacteria)
Post by: Ayyddaan on August 02, 2016, 11:34:59 pm
Moderator Action: if you do have questions you'd like to ask, try to post them into the question thread to make it easier for everyone to help you out :)
Post by: Skidous on August 03, 2016, 08:37:09 am
Cell-Mediated Immunity is the immune response that occurs when T-Cells interact with antigens, resulting in the death of cells through the use of cytotoxins in order to kill the cell and the pathogen.
Antibody Mediated Immunity (AKA Humoral Immunity) is the immune response where antibodies produced by plasma cells (B-cells) attach themselves to a specific antigen to form an antibody-antigen complex, which deactivates the antigen and marks it for destruction by macrophages through phagocytosis.
Hope this helps, Skidous
Post by: vox nihili on August 03, 2016, 06:35:41 pm
No problem man, always happy to help
For some extra information there are 2 types of MHC molecules
MHC II can be conditionally expressed by all cell types, but normally occurs only on professional macrophages and B cells, used primarily to assist in antibody mediated immunity (Humoral Immunity)
MHC I occurs on all nucleated cells—in essence all cells but red blood cells—and presents epitopes to killer T cells, also called cytotoxic T lymphocytes. CD8 receptor on Cytotoxic T-cells docks to MHC I molecules, if they fit together it triggers the cell to undergo programmed cell death by apoptosis, hence assisting with Cell Mediated Immunity (addressess intracellular pathogens, such as viruses and some bacteria)
Not sure how much detail you guys go into, but I'd just add that dendritic cells are probably the most important cell that expresses MHC class II. It would also be reasonable to say that only antigen-presenting cells express MHC class II.
Also, it is probably somewhat incorrect to say that MHC class II is directed at humoral immunity and class I to cellular immunity. The role of CD4+ (helper) T-cells in cellular immunity is well-established too.
Post by: Skidous on August 03, 2016, 06:36:54 pm
Post by: vox nihili on August 03, 2016, 06:44:01 pm
That's correct I forgot to add that in, didn't know about the dendritic cells however
Given that you don't know it, I'm going to presume it's probably not part of the course, so don't worry about dendritic cells. For your interest though:
Dendritic cells pretty much just chill out in the lymph nodes, sampling the environment. So antigens drain from tissues into the lymph nodes, where they're taken up by dendritic cells and presented on MHC class II molecules. These cells are actually the most important when it comes to activating T-helper cells. The role of MHC class II molecules on macrophages and B-cells, although important, is fairly minor compared to dendritic cells.
They're not really covered on the VCE course either and ever since learning about them I've always felt a bit ripped off about that hahah
Post by: Skidous on August 03, 2016, 06:49:44 pm
Post by: vox nihili on August 03, 2016, 06:53:48 pm
So basically they're like B-Cells and Macrophages, but in the lumph and are the most important part of the specific immune response, right?
Hmmmm, kind of. B-cells, macrophages and dendritic cells are all called antigen-presenting cells, because they can present antigen on MHC class II molecules.
The role of the dendritic cell is to sit in the lymph and activate T-cells. They really are the cell responsible for activation of T-cells.
Macrophages and B-cells present antigen not so much to activate T-cells, but rather, to get help from them.
Post by: studybuddy7777 on August 03, 2016, 07:13:00 pm
Hmmmm, kind of. B-cells, macrophages and dendritic cells are all called antigen-presenting cells, because they can present antigen on MHC class II molecules.
The role of the dendritic cell is to sit in the lymph and activate T-cells. They really are the cell responsible for activation of T-cells.
Macrophages and B-cells present antigen not so much to activate T-cells, but rather, to get help from them.
Hence why they are referred to in some textbook as Helper T Cells (my teacher says this)
(Soz about that stuff up I meant to write T cells not B cells)
Post by: anotherworld2b on August 03, 2016, 08:33:27 pm
Our hypothesis was that the consumption of caffeine increases the rate of human urine production.
Our experimental group was caffeine (ice tea) and control group was cordial.
In our results the graph of the cordial spiked in the amount of urine produced before the graph of peach ice tea.
Why would this happen? Errors could have occurred? I though caffeine would increase the rate of human urine production?
I also wanted to ask for the discussion would be appropriate to explain what should have happened?
Eg ADH is involved in fluid, in the body; it causes the kidneys to reabsorb water. When ADH is not present there is decreased water reabsorption in the kidneys, which, in turn increases the need to urinate?
Could I have a answer as soon as possible? I have to finish writing my report to hand in tomorrow
Post by: Skidous on August 03, 2016, 08:53:38 pm
For the hypothesis, you need it to be longer using IF...THEN...BECAUSE
As for the experimental group, the control should've have been a plain substance such as regular water and then the variables should be something like a diuretic (like coffee) and an anti-diuretic/substance that is not as diuretic as water.
This is probably the error you are concerned about, there also may be issues with the experimental group having full bladders BEFORE consuming coffee or cordial which may have affected the results.
Caffeine IS a Diuretic so it does increase urine production (to remove the toxin from the body), as for cordial, I'm not sure of the diuretic properties so I cannot say for sure whether it is or not, but it would be safe to assume it's not a diuretic and it was an error with the experimental group when the experiment was conducted.
Your discussion should explain the validity, reliability and accuracy, indicating how you can improve upon all 3 of them, and you should DEFINITELY explain what should have happened so you acknowledge that the experiment was flawed, what the expected result was, why you didn't achieve that and how it can be improved in the future.
Hope this helps, Skidous
Post by: anotherworld2b on August 03, 2016, 09:18:10 pm
Would this be a better hypothesis?
If the concentration of caffeine consumed increases then the rate of human urine production will increase over the duration of two hours.
-2 hours is the period in which this experiment was conducted
Post by: Skidous on August 03, 2016, 09:23:18 pm
Note: You should also name the toxin/s being removed
Post by: anotherworld2b on August 03, 2016, 09:34:51 pm
For the introduction of the report what information would be required? I have info about the kidney, permeability of the tubules changing due to the different compositions of material in each respective liquid.
Would this be right for the discussion?
I wrote that
Caffeine is a diuretic that inhibits reabsorption of sodium ions and the antidiuretic hormone(ADH) causing urination. ADH is involved in selective reabsorption by acting on the permeability of the distal convoluted tubule and collecting duct preventing the production of concentrated urine. This causes dehydration because it inhibits the antidiuretic hormone(ADH).ADH is involved in fluid storage in the body; it causes the kidneys to reabsorb water. When ADH is not present there is decreased water reabsorption in the kidneys, which, in turn increases the need to urinate?
Post by: Skidous on August 03, 2016, 09:49:15 pm
As for the discussion you need to talk about
Validity: Variables (Independent, Dependent, Control) and assess whether it was a valid experiment and how it can be more valid
Reliability: Repetition (Number of trials to calculate an average in order to produce consistent results) and assess the reliability of the experiment
Accuracy: Errors (Error margins of measurement tool [such as +/- 0.5ml in a measuring cylinder or +/- 0.5ms on a stopwatch] and experimental errors or issues that may have occurred) and assess the accuracy of the experiment and how to improve that accuracy
Then you need to discuss the results of the experiment and if they showed the expected result to confirm or disprove the hypothesis. This needs to be explained and why it was confirmed/disproved.
The discussion you wrote would be better for the introduction rather than the discussion.
Hope this helps
Post by: Bparker on August 04, 2016, 01:45:46 pm
Two quick questions:
1. Could someone very simply explain what form lipids are transported in the body, and also
2. In an exam, if asked about justifying the appropriateness of an experiment - how would you go about answering that?
Thanks!
Post by: Skidous on August 04, 2016, 02:05:09 pm
1: Lipids are transported in the body in the form of Glucose, Amino acids, Fatty Acids and Glycerol, Nucleotides.. Glucose and Amino Acids enters the bloodstream through water (water soluble) and then dissolves in the plasma.
Lipids (Fatty Acids and Glycerols) Only some enter the bloodstream directly, whilst most need to be packaged into small droplets which pass the lymphatic system into the bloodstream.
2: When justifying whether an experiment is appropriate you need to consider what is being tested by the question and whether the experiment actually is trying to test the same thing. IF that is the case then you need to go into the validity, reliability and accuracy of the experiment. These points also have to be explained (using cause and effect language)
Post by: Bparker on August 04, 2016, 02:08:32 pm
Hey Bparker
1: Lipids are transported in the body in the form of Glucose, Amino acids, Fatty Acids and Glycerol, Nucleotides.. Glucose and Amino Acids enters the bloodstream through water (water soluble) and then dissolves in the plasma.
Lipids (Fatty Acids and Glycerols) Only some enter the bloodstream directly, whilst most need to be packaged into small droplets which pass the lymphatic system into the bloodstream.
2: When justifying whether an experiment is appropriate you need to consider what is being tested by the question and whether the experiment actually is trying to test the same thing. IF that is the case then you need to go into the validity, reliability and accuracy of the experiment. These points also have to be explained (using cause and effect language)
Very clear response! Thankyou Skidous!!
Post by: Skidous on August 04, 2016, 02:15:24 pm
Post by: vox nihili on August 04, 2016, 07:14:33 pm
Hey Bparker
1: Lipids are transported in the body in the form of Glucose, Amino acids, Fatty Acids and Glycerol, Nucleotides.. Glucose and Amino Acids enters the bloodstream through water (water soluble) and then dissolves in the plasma.
Lipids (Fatty Acids and Glycerols) Only some enter the bloodstream directly, whilst most need to be packaged into small droplets which pass the lymphatic system into the bloodstream.
2: When justifying whether an experiment is appropriate you need to consider what is being tested by the question and whether the experiment actually is trying to test the same thing. IF that is the case then you need to go into the validity, reliability and accuracy of the experiment. These points also have to be explained (using cause and effect language)
As usual, thanks for doing such a good job on this forum Skidous!
Just going to jump in on this one though. Lipid≠glucose≠amino acid≠nucleotide.
Lipids include things like sterols (including cholesterol), triglycerides and phospholipids. Glucose is a carbohydrate, amino acids are the building blocks of proteins and nucleotides the building blocks of nucleic acids. If you mean to say that lipids are used as substrates in the synthesis of these things, of course you would be exactly right; however, once they are turned into these things they cease to be lipids.
You did correctly identify how lipids are transported around the blood stream. They are packaged into small droplets, with proteins to hold them in together. They can, however, be directly placed into the bloodstream without having to worry about the lymph (only when lipids are absorbed do they travel in the lymph).
Post by: Bparker on August 04, 2016, 07:18:52 pm
As usual, thanks for doing such a good job on this forum Skidous!
Just going to jump in on this one though. Lipid≠glucose≠amino acid≠nucleotide.
Lipids include things like sterols (including cholesterol), triglycerides and phospholipids. Glucose is a carbohydrate, amino acids are the building blocks of proteins and nucleotides the building blocks of nucleic acids. If you mean to say that lipids are used as substrates in the synthesis of these things, of course you would be exactly right; however, once they are turned into these things they cease to be lipids.
You did correctly identify how lipids are transported around the blood stream. They are packaged into small droplets, with proteins to hold them in together. They can, however, be directly placed into the bloodstream without having to worry about the lymph (only when lipids are absorbed do they travel in the lymph).
Thankyou vox nihili! Are these droplets you're referring to called chylomicrons?
Post by: HighTide on August 04, 2016, 07:19:56 pm
Thankyou vox nihili! Are these droplets you're referring to called chylomicrons?Yeah they're chylomicrons
Post by: Bparker on August 04, 2016, 07:34:58 pm
Yeah they're chylomicrons
Mad as that makes sense now - thanks!
Post by: Skidous on August 04, 2016, 08:42:40 pm
Post by: vox nihili on August 04, 2016, 09:02:31 pm
Sorry about that, it must have gotten most up with my notes on digestive products
No worries. If you need some help on that just let us know :) It's all a bit of a minefield!
Thankyou vox nihili! Are these droplets you're referring to called chylomicrons?
Just to add on chylomicrons:
(I don't know how much detail you need for HSC).
Chylomicrons only carry lipids from the gut to the tissues/liver. LDL is responsible for carrying lipids from the liver to the tissues; whereas HDL carries lipid from the tissues to the liver.
Post by: Skidous on August 04, 2016, 09:58:21 pm
Post by: Gregs on August 08, 2016, 02:17:47 pm
Thanks
P.S. Not trying to offend anyone just wondering because I got a question that asks how to prevent someone with this disease from passing it on to further generations. If they are "allowed" to reproduce how else would they prevent the passing on of the disease to future generations
Post by: Skidous on August 08, 2016, 02:24:14 pm
Normally you wouldn't be asked if people who have a genetic disease should reproduce as that may hurt someone's feelings but I understand where you're coming from.
The best way to prevent the genetic disease from being transmitted is finding a cure for the genetic disease if the father has it.
For the mother there are reproductive technologies such as In Vitro Fertilisation (IVF) and preimplantation genetic diagnosis (PIGD or PGD) to produce an embryo and scan it for the disease before being implanted if the mother is a carrier.
When a question is asking about preventing diseases from being passed on you're more or less looking at lifestyle choices I.e diet, exercise, radiation exposure etc. and then saying how these can affect non-infectious disease from being passed on to future generations
Thanks for the question
P.S try to post questions that aren't as controversial next time :)
Post by: Gregs on August 10, 2016, 09:04:57 am
Post by: Skidous on August 10, 2016, 09:05:31 am
Post by: Elenaa on August 10, 2016, 02:13:11 pm
So i was just wondering, when we draw graphs do we need to draw a line of best fit? instead of connecting the dots because my tutor told me thats what you have to do for the HSC but i don't know if i have to do that for trials because my school teachers never said anything about it.
Thanks :)
Post by: Skidous on August 10, 2016, 02:21:33 pm
Yes you do more often than not have to use a line of best fit. Sometimes, however a line is not sufficient and a Curve of Best Fit is needed, which is similar to a line of best fit but curved.
In some situations, however, there are graphs which have a distinguished shape. Some examples include enzyme activity based upon
Temperature
(http://www.bbc.co.uk/staticarchive/3e166752332b7f16e1dd0f4efca373310e4706fc.gif)
pH
(http://www.bbc.co.uk/staticarchive/db7ba3135d8cf5ce20b58387bf6b7784436ce279.gif)
Substrate Concentration
(http://study.com/cimages/multimages/16/Figure_3.png)
The you will have to know when to use and interpret them.
Hope this helps, Skidous
Post by: Skidous on August 10, 2016, 02:44:17 pm
Does anyone know of an Australian Biologist current working in the field? and if so what work are they doing?
Post by: Ragdolls on August 10, 2016, 07:16:32 pm
Question Time!
Does anyone know of an Australian Biologist current working in the field? and if so what work are they doing?
Hey Skidoos!
Yes I know a Australian biologist. His name is George Miklos. He was the founder of Atomic Oncology. He holds a PhD in genetics and has a range of laboratory experience in biological concepts. His publications and research include genetics, developmental biology, transgenic organisms and many other biological fields.
Hope this helps! :) ;)
Post by: Skidous on August 10, 2016, 07:18:43 pm
Post by: Ragdolls on August 10, 2016, 07:28:38 pm
Thanks Ragdolls, could you maybe go into a little more depth into what exactly he does?
Hey Skidous. When I researched this in class that is all the information I found about him. So he basically works in the field of genetics and works by analysing cells. That's what I can interpret from the research I done.
Hope this helps...
Post by: Skidous on August 10, 2016, 07:29:35 pm
Post by: Ragdolls on August 10, 2016, 07:30:52 pm
Thanks that's all I needed, big help, hope to see you on the forums some more.
Thanks Skidoos! :)
Post by: Skidous on August 10, 2016, 07:31:41 pm
Post by: Ragdolls on August 10, 2016, 07:33:06 pm
Post by: Skidous on August 10, 2016, 07:34:18 pm
Hey. I just wanted to ask if anyone could please help me understand the parts of the brain from the Communications Option. I'm unsure which section of the brain is responsible for what...Unfortunately I have not covered this part in the content yet :(
Post by: vox nihili on August 10, 2016, 08:28:11 pm
Hi, I was just wondering, if a gene I'd recessively sex linked on the X chromosome (males get) are those males then encouraged not to reproduce or even perhaps the mother of the child with the disease encouraged not to reproduce again.
Thanks
P.S. Not trying to offend anyone just wondering because I got a question that asks how to prevent someone with this disease from passing it on to further generations. If they are "allowed" to reproduce how else would they prevent the passing on of the disease to future generations
Just going to jump in and say something about this.
If a male has an X-linked recessive condition, he can only pass that X chromosome onto his daughter. So if his wife is homozygous dominant, then there's actually no danger of that man passing on that condition to a child. The daughter will certainly be a carrier though.
In terms of X-linked conditions, you start to get into murkier waters when the mother has an X-linked recessive condition. In that case, there's a 50% chance that she will pass that condition onto a son. Indeed, the couple can't have a male child that doesn't have the condition.
I just wanted to say those things, because your question seems to me to belie a misunderstanding about the way X-linked inheritance works. On the ethical arguments, that's really up to you to form your own opinion. There is not any legislation in Australia that prevents someone with a genetic disease from having a child. Personally, I think it'd be abhorrent if there were, but you may disagree with me.
As Skidous mentioned, there are technologies that can help prevent these diseases from being passed on. He referenced a couple that are available to women, but I would add this clarification: they also can be used to assess the genome of the male gametes too. So, in IVF for instance, you can actually check the sperm and the egg to make sure that the egg that is implanted (i.e. given back to the woman) does not carry a genetic disease.
People with a genetic disease often do feel really anxious about having children. It's really useful for them to meet with their doctor, and hopefully then a genetic counsellor, for some testing to ascertain the risk that the child will also have the disease. Beyond that, there can also be some other potential issues. For instance, cycstic fibrosis dramatically reduces male fertility (to the point that they can't naturally conceive). Also, other genetic diseases might make it dangerous for a woman to carry the foetus (if she has the disease), or may result in the inability of a parent to care for their children when they're growing up.
These are difficult decisions that often require difficult choices. What I think is important is that these choices remain with the patient and that they be allowed to make those choices with the help of good advice. :)
Hey. I just wanted to ask if anyone could please help me understand the parts of the brain from the Communications Option. I'm unsure which section of the brain is responsible for what...
Can you give us some more deets about the option please? I'm a VCE kid but should hopefully know the content :)
Post by: Skidous on August 10, 2016, 08:30:56 pm
Post by: vox nihili on August 10, 2016, 08:37:46 pm
It's a question about what sections of the brain are responsible for each process with regards to receiving and interpreting stimuli (sound, sight, smell, taste, touch)
Thanks mate. To the OP, you can probably Google these and I would encourage you to.
Sound: auditory cortex in the temporal lobe.
Sight: visual cortex in the occipital lobe
Smell/taste: not really sure. Pretty sure they're not as well studied and not as discretely located as the other senses (Google this)
Touch: Somatosensory cortex, partietal lobe (sits right behind the central sulcus, which divides it and the motor cortex)
Also really worth remembering that even though these areas are those responsible for the first steps in interpreting sensory signals, these signals are then transmitted to different parts of the brain for higher-level analysis and integration with other senses/prior knowledge. For example, if you see an orange coloured fruit, and don't know what it is. You might smell it. You decide it smells like a tangerine or a mandarin, thereby excluding orange, grapefruit etc. To confirm, you take a bite. Low and behold it's a mandarin. Here you've used three different senses to determine what the fruit is. Obviously these three senses have to be put together, and then added to your memories of the fruit to make sense of what it is. It then follows that there are brain areas (called association areas) responsible for this kind of stuff.
Post by: Gregs on August 10, 2016, 08:48:27 pm
Post by: Skidous on August 10, 2016, 08:49:29 pm
Post by: vox nihili on August 10, 2016, 09:49:57 pm
Hi Vox, yeah sorry i should've made my understanding clearer i was more talking about the kids of the daughters he had being affected. I didn't make that clear at all, my bad. Thanks for the extra info as well
Not a worry at all!
I see what you mean there. That's a big ethical issue. With IVF, for instance, you can help someone with cystic fibrosis have a baby...but that baby is certain to be a carrier of CF. There's debate about whether that's ok, particularly given that 1 in 25 Anglo-Saxons already carry the gene.
For future notice, true just copying out the question that was asked so there is less confusion
I don't think this advice is necessary :) There's a lot to be gained in asking questions in your own word. It shows that you've actually thought about it, rather than picking them out of the book and dumping them on AN. Was really happy to give Gregs a long answer because they'd clearly put in a lot of thought to the question.
Post by: Skidous on August 11, 2016, 05:29:28 pm
Just before anyone starts posting questions about their trial exam please see the thread started by fellow mod StudyBuddy and go ask questions about your thoughts on the trial
Post by: anotherworld2b on September 03, 2016, 08:30:42 pm
But I was wondering what happens to the cycle when there is fertilization and no fertilization.
Post by: Skidous on September 03, 2016, 10:36:43 pm
I don't think this is in the Biology Syllabus since there isn't any need for bio students to know the hormonal regulation for ovulation/menstruation cycle.
I did find a video that may assist though
https://m.youtube.com/watch?v=RFDatCchpus
If this doesn't help then I'm sorry, but you may wanna head over to the Senior Science Board or another science related board for more assistance
Hope this helps
Skidous
Post by: anotherworld2b on September 03, 2016, 11:03:51 pm
Hey anotherworld2b
I don't think this is in the Biology Syllabus since there isn't any need for bio students to know the hormonal regulation for ovulation/menstruation cycle.
I did find a video that may assist though
https://m.youtube.com/watch?v=RFDatCchpus
If this doesn't help then I'm sorry, but you may wanna head over to the Senior Science Board or another science related board for more assistance
Hope this helps
Skidous
Post by: marynguyen18 on September 13, 2016, 10:03:01 pm
Post by: Skidous on September 13, 2016, 10:13:25 pm
For sections of the brain
The Frontal Lobe deals with logic and reasoning
The Temporal Lobe deals with hearing
The Occipital Lobe deals with sight
The Cerebellum deals with motor functions and balance
The Medulla Oblongata or Brain Stem is used for many functions of the autonomic system such as breathing rates and heartbeat
Action Potential is a nerve impulse that is triggered by a stimuli large enough to open voltage gated channels in the nerve cells.
If you need help with how this action potential occurs and the steps let me know
Hope this helps, Skidous
Post by: Alter on September 13, 2016, 10:15:45 pm
hey i was wondering if anyone did/does communication what are the functions of each section of the brain?Different lobes:
Frontal - higher order thinking, logical reasoning, planning, motor control
Parietal - Registering sensory information, spatial orientation, perceiving shapes and designs, reading/writing (partially)
Occipital - Receiving and processing visual information
Temporal - Memory, auditory perception, visual perception
There are also different cortices; it is very simple to google them for explanations of functions.
Quote
and whats action potential?An action potential is the changing of electrical potential in a neuron which happens as a result of neuron de/polarisation. The potential travels down the axon of a neuron and causes changes in the electrical charge/polarity. An action potential can trigger a pre-synaptic neuron to release neurotransmitters to diffuse across a synaptic gap, which bind to receptors in post-synaptic dendrites. (This is a pretty simplistic overview. I didn't do hsc or vce bio so I'm not sure what details you need to know exactly)
Post by: marynguyen18 on September 13, 2016, 10:16:48 pm
Post by: lha on September 25, 2016, 03:42:54 pm
--
How many past papers is recommended before hsc?
--
Does anyons know of any videos on youtube that explains meiosis clearly? Im so confused with the concept
Mod: Merged triple post.
Post by: marynguyen18 on September 25, 2016, 03:48:17 pm
--
I'm doing the red kangaroo and frilled neck lizard for Maintaining a balance
Mod: Merged double post.
Post by: Ayyddaan on September 27, 2016, 12:07:29 pm
How many past papers is recommended before hsc?
AS MANY AS POSSIBLE - at the bare minimum, do ALL the HSC past papers from 2010 - 2015.
Post by: jnicko989 on September 27, 2016, 04:12:37 pm
9.3.4.1 - Discuss evidence for the mutagenic nature of radiation
Can anyone help me out?
Post by: specclee on September 27, 2016, 04:26:24 pm
Having trouble with this dot-point:I have two examples for this dot point:
9.3.4.1 - Discuss evidence for the mutagenic nature of radiation
Can anyone help me out?
1) Survivors of the bombings of Hiroshima and Nagasaki (which occurred in 1945, towards the end of World War II) suffered physical mutations as a result of the radioactive output of the nuclear explosion. Children born to survivors showed many defects, in particular a microcephalic condition (development of a very small head and failure for brain to grow)
2) In 1926, H. G. Muller performed an experiment in which he irradiated the reproductive cells of fruit flies. He found that the irradiated flies had an incidence of mutation 150 times higher than control flies that had not been irradiated. If he reduced the dosage, the frequency of mutations also decreased. His experiments provided direct evidence of the link between exposure to ionising radiation and mutations.
There's a lot more evidence to prove the mutagenic nature of radiation but I just stick with these two because they're pretty easy to remember. Hope this helps!
Post by: jnicko989 on September 27, 2016, 04:31:18 pm
I have two examples for this dot point:
1) Survivors of the bombings of Hiroshima and Nagasaki (which occurred in 1945, towards the end of World War II) suffered physical mutations as a result of the radioactive output of the nuclear explosion. Children born to survivors showed many defects, in particular a microcephalic condition (development of a very small head and failure for brain to grow)
2) In 1926, H. G. Muller performed an experiment in which he irradiated the reproductive cells of fruit flies. He found that the irradiated flies had an incidence of mutation 150 times higher than control flies that had not been irradiated. If he reduced the dosage, the frequency of mutations also decreased. His experiments provided direct evidence of the link between exposure to ionising radiation and mutations.
There's a lot more evidence to prove the mutagenic nature of radiation but I just stick with these two because they're pretty easy to remember. Hope this helps!
Ugh, thank you so much. Yeah it does help, I didn't know whether we were meant to include examples of mutagens (like UV and stuff) as well. Thank you again.
Post by: Sssssrr on September 27, 2016, 05:30:41 pm
Post by: jnicko989 on September 27, 2016, 09:28:56 pm
With reference to the dot point in maintaining a balance - "Compare response of named Australian ectothermic and endothermic organisms to changes in ambient temp and explain how these response assist in temp regulation", is an adaptation the same as a response or are they different?
From what I understand, the response is a result of the adaptation. From my example, the Red Kangaroo places it's tail underneath it's body when the ambient temperature rises to reduce SA:V ratio, and decrease heat absorption from the sun - the behavioural adaptation allows for the response (placing tail under body) in order to decrease temperature and regulate temperature. So they are kind of two peas in a pod to an extent.
Happy to clarify if this doesn't make sense aha.
Post by: evey-cox on September 28, 2016, 10:23:43 am
Post by: jnicko989 on September 28, 2016, 11:05:21 am
I was doing the 2015 HSC biology paper and I was confused with Q26: sugar is transported in vascular tissue in plants and animals. Contrast the structure and workings of ONE named plant tissue and ONE named animal tissue used to transport sugar. And I'm not sure how to answer the animal tissue portion of the question and would love help, cheers :)
The wording is kind of weird, I remember doing this a few weeks ago. The animal tissue portion one is an artery - one of the key words in that was vascular which is just relating to vessels. So the answer would just be artery, the structure (three layers of muscle and elastic fibre, closed system etc), and the workings (the heart muscles forcing the blood around the body under pressure, which transports the sugar)
Hope this helps.
Post by: Sssssrr on September 28, 2016, 11:09:00 am
From what I understand, the response is a result of the adaptation. From my example, the Red Kangaroo places it's tail underneath it's body when the ambient temperature rises to reduce SA:V ratio, and decrease heat absorption from the sun - the behavioural adaptation allows for the response (placing tail under body) in order to decrease temperature and regulate temperature. So they are kind of two peas in a pod to an extent.
Happy to clarify if this doesn't make sense aha.
That helps a lot, thanks
Post by: aimbotted on September 30, 2016, 01:49:28 pm
Post by: jakesilove on September 30, 2016, 04:58:01 pm
hi guys, could someone explain to me the difference between cell mediated immunity vs anti-body mediated immunity? thanks
Anti-body
Produced by B cells, which match specific antigens. Antigens generate an anti-body response.
Cell mediated
You've got cells in your body, like natural killer cells. Cell mediated immunity doesn't get better over time. Everyone has some mediated immunity. I think. Let me check that
Answer from the Med student sitting next to me
Jake
Post by: marynguyen18 on September 30, 2016, 05:31:17 pm
Post by: jakesilove on September 30, 2016, 05:33:05 pm
whats the different between a B and T cell?
According to google: T cells can be distinguished from other lymphocytes, such as B cells and natural killer cells, by the presence of a T-cell receptor on the cell surface.
Jake
Post by: g98 on September 30, 2016, 05:51:45 pm
There are several dot points in the Biotechnology syllabus that are worded like this:
describe one example from the following applications of biotechnology in medicine:
-tissue engineering using skin transplantation as an example
-gene delivery by nasal sprays
-production of a synthetic hormone, such as insulin
Does this mean we need to know one example from each of the three or does it mean we need to know one of the three but not the others? I hope that makes sense!
Thanks
Post by: g98 on September 30, 2016, 06:35:55 pm
what are monoclonal antibodies and recombinant vaccines and what do we need to know about each?
Thanks!
Post by: Sssssrr on September 30, 2016, 09:49:08 pm
Thanks
Post by: cajama on October 01, 2016, 05:48:16 pm
I'm kind of confused by the sample answer for this question (2011 HSC Biology Q.30 b. -- sorry if the screenshot doesn't appear, it would not appear on preview):
"If the temperature of the animal is determined only by the ambient temperature, the animal would lose temperature at a similar rate to which it gained the temperature, rather than retaining the heat" - Success One | HSC Biology 2013 ed.
My own answer was basically: Body temp. is not controlled by ambient temp as the avg. body temp of the reptiles, shown in the graph, correlates with the day's temperatures where it is often highest during the early afternoon.
I can see flaws in my answer as I don't fully have evidence for the change in temperature(weather) during the day and that correlation does not always imply causation, but yeah I wasn't really sure how to answer this question + sample answer was a little confusing haha. Thankyou in advance to whoever replies! :D :D
--
Also, general question for all science exams, can we abbreviate words in the exam i.e. temperature to temp., environment to enviro., generation to gen.? It just helps to save time :-\
Post by: cajama on October 01, 2016, 06:28:42 pm
Hey can someone please help me with questions 19 and 20, I've attached them
Thanks
Hello, I'm probably wrong in these answers and I'm not really a reliable source of help but I tried the questions:
For Q.19 I chose A because basically it would take time to produce the enzyme. If it was gradual, as one enzyme denatures, another one may be on its way to be produced. If it was a rapid change, all the currently functioning enzymes would die out and as it takes time to produce enzymes, there wouldnt be any enzymes that would maintain metabolic activity and the fish would die??
For Q.20 I thought maybe it would be B: the change in temperature in the environment affects the production of the enzymes (the phenotype being the ability to produce four enzymes at different temperatures??)
Not D: because the case study doesn't really say anything about the body temperature of the fish and it only talks about the temperature of the environment, A: because the case study doesn't mention substrates, C: it's not really a limitation for the fish if they can still survive at such a wide temperature variation as long as the four enzymes can still function respective of their temperature ranges.
"idk tho"
Please correct me if I'm wrong haha I tried ;D
Post by: vox nihili on October 01, 2016, 08:37:34 pm
Hello, I'm probably wrong in these answers and I'm not really a reliable source of help but I tried the questions:
For Q.19 I chose A because basically it would take time to produce the enzyme. If it was gradual, as one enzyme denatures, another one may be on its way to be produced. If it was a rapid change, all the currently functioning enzymes would die out and as it takes time to produce enzymes, there wouldnt be any enzymes that would maintain metabolic activity and the fish would die??
For Q.20 I thought maybe it would be B: the change in temperature in the environment affects the production of the enzymes (the phenotype being the ability to produce four enzymes at different temperatures??)
Not D: because the case study doesn't really say anything about the body temperature of the fish and it only talks about the temperature of the environment, A: because the case study doesn't mention substrates, C: it's not really a limitation for the fish if they can still survive at such a wide temperature variation as long as the four enzymes can still function respective of their temperature ranges.
"idk tho"
Please correct me if I'm wrong haha I tried ;D
Well reasoned; both answers are correct imo
Post by: kevin217 on October 02, 2016, 01:06:20 pm
Post by: Skidous on October 02, 2016, 02:48:03 pm
Hey guys I got a question. When we are solving sex-linked inheritance do we always assume that the X chromosome is the one carrying condition and never the Y chromosome?
That is correct, the infection is always carried on the X chromosome, this is why males can only inherit or not inherit a condition whilst females can be carriers (condition carried on only one X-chromosome)
Post by: vox nihili on October 02, 2016, 03:06:26 pm
Hey guys I got a question. When we are solving sex-linked inheritance do we always assume that the X chromosome is the one carrying condition and never the Y chromosome?
I'm not particularly clear on what you're expected to know in HSC, but of course sex-linked inheritance could involve genes on the Y-chromosome. Pretty much as easy as it gets though. Passed from father to son to son to son to son to son to son, can't skip a generation, never seen in females blah blah
Post by: Skidous on October 02, 2016, 03:08:39 pm
I'm not particularly clear on what you're expected to know in HSC, but of course sex-linked inheritance could involve genes on the Y-chromosome. Pretty much as easy as it gets though. Passed from father to son to son to son to son to son to son, can't skip a generation, never seen in females blah blah
Yeah I got told about Y linked diseases but there isn't anything on that for the HSC so it's not exactly necessary
Post by: kevin217 on October 02, 2016, 03:15:02 pm
Post by: Skidous on October 02, 2016, 03:42:32 pm
Post by: lha on October 02, 2016, 03:49:00 pm
Post by: naomisirmai on October 02, 2016, 03:50:43 pm
- Sex-linked characteristics are ones found either on the X or the Y chromosome
- X-linked conditions are much more common than Y-linked conditions
- In X-linked conditions, females can be carriers (as they have a spare X) whilst males cannot be - they either have the disease or they don't
- You *could* be asked about Y-linked conditions. These are *impossible* for females to get as females have no Y chromosome. Furthermore, males cannot be carriers.
Post by: naomisirmai on October 02, 2016, 03:53:03 pm
For the verb "Design", for example "design an experiment", do you only provide a procedure or do you give aim, hypothesis, procedure, equipment, results and variables?
The whole thing! Not just the method. Aim, hypothesis, equipment, variables, risk assessment and method.
You might not have the results - particularly if it's an experiment that you have not done. In this case, do not include any.
Post by: lha on October 02, 2016, 03:58:04 pm
The whole thing! Not just the method. Aim, hypothesis, equipment, variables, risk assessment and method.
You might not have the results - particularly if it's an experiment that you have not done. In this case, do not include any.
Okay so for example for the question:
A new product has been developed to kill pathogens in drinking water.
Design an experiment to test the effectiveness of the product.
(4 marks)
Would I say:
Hypothesis: there will be less pathogens remaining in the sample of water after the product has been applied.
Aim: to test the effectiveness of the new product
Method: .....
Im conflicted as to what i would write for the hypothesis as the question states that it is a "new product" so how can you make an educated guess?
Also what would the method be?
Post by: Skidous on October 02, 2016, 03:59:10 pm
For the verb "Design", for example "design an experiment", do you only provide a procedure or do you give aim, hypothesis, procedure, equipment, results and variables?
There is actually a part of the syllabus right at the beginning which is all the skills for science (with regards to research and pracs) so to add onto what Naomi said you should look into those as well to make sure you answer the question properly
Post by: lha on October 02, 2016, 04:00:44 pm
There is actually a part of the syllabus right at the beginning which is all the skills for science (with regards to research and pracs) so to add onto what Naomi said you should look into those as well to make sure you answer the question properly
Okay thank you
Post by: lha on October 02, 2016, 04:01:38 pm
Post by: Skidous on October 02, 2016, 04:02:40 pm
Okay so for example for the question:
A new product has been developed to kill pathogens in drinking water.
Design an experiment to test the effectiveness of the product.
(4 marks)
Would I say:
Hypothesis: there will be less pathogens remaining in the sample of water after the product has been applied.
Aim: to test the effectiveness of the new product
Method: .....
Im conflicted as to what i would write for the hypothesis as the question states that it is a "new product" so how can you make an educated guess?
(Most Hypotheses have a format of If (independent variable) then (dependent variable) Because (explanation/reason))
Also what would the method be?
You would need to write a hypothesis such as
If this product is added to water then pathogens would be not present in the water because it is designed to work like this
Then the method would go through testing the type of pathogens and the amount of said pathogen the product removes
You also need to include variables and a risk assessment
Post by: naomisirmai on October 02, 2016, 04:06:55 pm
Also, when you write the method, can you do it in number point form or do you have to describe it?
Always number form! It's a list of steps, like cooking.
Post by: Skidous on October 02, 2016, 04:10:20 pm
Also, when you write the method, can you do it in number point form or do you have to describe it?
Also the equipment should be in dot points and include measurements
I.e if you need water for plants state 200ml of water
But if you have 5 plants and they need 200ml every day for a week then it would be
5x1000ml of water and then in the method state how much you need per day (sorta like a shopping list you state the total amount used for one and how many times you need that amount)
Hope this Helps
Post by: vox nihili on October 02, 2016, 04:12:05 pm
Post by: Skidous on October 02, 2016, 04:16:09 pm
What do you need in your method though? As in, what are the critical factors that make a good experiment?
For HSC the method just needs to describe the steps carried out in the experiment, it should have specific steps/instructions into how it should be carried out and what needs to happen there aren't any really critical factors other than making sure the experiment is reasonable and could be carried out in a laboratory of school standard (so not being something that isn't possible if done by a school like using the Large Hadron Collider)
Post by: lha on October 02, 2016, 04:21:01 pm
Also the equipment should be in dot points and include measurements
I.e if you need water for plants state 200ml of water
But if you have 5 plants and they need 200ml every day for a week then it would be
5x1000ml of water and then in the method state how much you need per day (sorta like a shopping list you state the total amount used for one and how many times you need that amount)
Hope this Helps
Yes that helps thank you!
Post by: lha on October 02, 2016, 04:22:39 pm
Always number form! It's a list of steps, like cooking.
Thank you!
Post by: lha on October 02, 2016, 04:24:07 pm
Post by: Skidous on October 02, 2016, 04:27:40 pm
Also no that there is less than a month till hsc bio exam, what do you do for study?
You should revise absolutely everything
This includes practical and Research tasks
You should also try to do as many past papers as possible
If you want some help with study check out this
http://atarnotes.com/forum/index.php?topic=161208
Post by: lha on October 02, 2016, 04:41:37 pm
You should revise absolutely everything
This includes practical and Research tasks
You should also try to do as many past papers as possible
If you want some help with study check out this
http://atarnotes.com/forum/index.php?topic=161208
Okay so are past papers enough or do I have to go and rewrite my notes ( they have said to rewrite notes in every forum so far but i want to know if it is actually necessary, arent past papers enough?)
Post by: kevin217 on October 02, 2016, 04:53:33 pm
Okay so are past papers enough or do I have to go and rewrite my notes ( they have said to rewrite notes in every forum so far but i want to know if it is actually necessary, arent past papers enough?)
I definitely don't think you should be re-writing notes now. If you are still revising notes, supplement it by practising past paper questions like me.
Post by: Skidous on October 02, 2016, 04:54:17 pm
Okay so are past papers enough or do I have to go and rewrite my notes ( they have said to rewrite notes in every forum so far but i want to know if it is actually necessary, arent past papers enough?)
Yes, definitely. By rewriting notes you can learn them better through muscle memory as well as learn where you know a lot of information and where you don't. You can also begin to summarise your notes and remember content from last year. It's a great way to consolidate the information you may not know perfectly or the stuff out really want to get right.
Post by: Skidous on October 02, 2016, 04:57:28 pm
I definitely don't think you should be re-writing notes now. If you are still revising notes, supplement it by practising past paper questions like me.
It's fine to rewrite notes now, we still have 2 weeks till the biology exam as the HSC isn't a one week set of exams it take up to 4 weeks. If you feel like you want to consolidate your information a little further then you can rewrite notes but summarise. Even if it's just the stuff you don't know quite yet it's still a good way to review.
Not to say that past papers aren't good for study, they are, but some people need that extra bit of work before they can get stuck into their work.
Also it is best to hand write these new summary notes as you will remember it better if you write it by hand
Post by: lha on October 02, 2016, 05:02:58 pm
It's fine to rewrite notes now, we still have 2 weeks till the biology exam as the HSC isn't a one week set of exams it take up to 4 weeks. If you feel like you want to consolidate your information a little further then you can rewrite notes but summarise. Even if it's just the stuff you don't know quite yet it's still a good way to review.
Not to say that past papers aren't good for study, they are, but some people need that extra bit of work before they can get stuck into their work.
Also it is best to hand write these new summary notes as you will remember it better if you write it by hand
Alright thank you! I procrastinated way too much during the year and as a result am entirely not prepared for the hsc so i guess whatever happens, happens. But thanks for the help!
Post by: lha on October 02, 2016, 05:03:47 pm
I definitely don't think you should be re-writing notes now. If you are still revising notes, supplement it by practising past paper questions like me.
Alright, thank you!
Post by: Skidous on October 02, 2016, 05:05:56 pm
Alright thank you! I procrastinated way too much during the year and as a result am entirely not prepared for the hsc so i guess whatever happens, happens. But thanks for the help!
I get that procrastination happens (trust me I did my last 2 bio assessments (that weren't trials) in 2 days before they were due and I still topped) but what matters now is putting in heaps of effort to get the best mark possible, that includes asking for help like on these forums
Post by: vox nihili on October 02, 2016, 05:06:37 pm
For HSC the method just needs to describe the steps carried out in the experiment, it should have specific steps/instructions into how it should be carried out and what needs to happen there aren't any really critical factors other than making sure the experiment is reasonable and could be carried out in a laboratory of school standard (so not being something that isn't possible if done by a school like using the Large Hadron Collider)
I disagree. The HSC syllabus really clearly sets out some critical things they expect you to cover when designing an experiment. It's not simply enough to design an experiment that can be performed with x materials; you're being tested on whether or not you can design a good experiment. I was asking about what those factors are that make an experiment workable.
Post by: lha on October 02, 2016, 05:09:18 pm
I get that procrastination happens (trust me I did my last 2 bio assessments (that weren't trials) in 2 days before they were due and I still topped) but what matters now is putting in heaps of effort to get the best mark possible, that includes asking for help like on these forums
Thats true, well goodluck!
Post by: Zaynab on October 02, 2016, 11:22:30 pm
Post by: Skidous on October 02, 2016, 11:25:16 pm
Essentials in regards to an experiment? Usually BOS get an experiment question about plants, etc. How can I, under 10 minutes figure out a procedure??That will depend on the question being asked, with pracs it is usually related to one of the Dot points in the syllabus so the method would be very similar to an experiment you've probably already done in class. If you haven't done an experiment like the one given in class then make one up that seems appropriate and can test what is being asked of you.
Hope this helps
Post by: Zaynab on October 03, 2016, 09:46:24 am
Post by: Skidous on October 03, 2016, 10:02:53 am
What are some key scientific words that should be used consistently in short answers/long responses
That will depend on the question that is being asked, each question will be different so it is difficult to give exact types of words. Using sophisticated language is a good way to start then using content words based on the question is good.
Some easy ones to remember
Homeostasis
Action Potential (communication)
Stimuli
Response
Enzyme
Tolerance
Just use words that have been used in textbooks based on what the question is asking
Post by: lha on October 03, 2016, 03:01:13 pm
Describe the occurrence, symptoms, cause and treatment/management of a named non-infectious disease. (5 marks)
For the occurrence part, is it enough to say, "lung cancer is the leading cause of death due to cancer in Australia"? Or do I have to give more stats?
Also, what would the mark distribution be for this questions?
Post by: Skidous on October 03, 2016, 03:07:21 pm
For a question like:You would need to talk about the cause of lung cancer and then link it to cancer deaths in Australia.
Describe the occurrence, symptoms, cause and treatment/management of a named non-infectious disease. (5 marks)
For the occurrence part, is it enough to say, "lung cancer is the leading cause of death due to cancer in Australia"? Or do I have to give more stats?
Also, what would the mark distribution be for this questions?
You will need to know statistics for occurrence as that is the purpose for understanding occurrence, this will include numbers and demographic of the infection (age, gender, socio-economic status etc.)
As for mark allocation
1mrk for Name of Disease
1mrk for correct occurance
1mrk for correct description of symptoms
1mrk for Correct description of cause
1mrk for correct description of treatment and management
Potentially 1mrk for coherent and concise response
Hope this Helps
Post by: lha on October 03, 2016, 04:17:03 pm
You would need to talk about the cause of lung cancer and then link it to cancer deaths in Australia.
You will need to know statistics for occurrence as that is the purpose for understanding occurrence, this will include numbers and demographic of the infection (age, gender, socio-economic status etc.)
As for mark allocation
1mrk for Name of Disease
1mrk for correct occurance
1mrk for correct description of symptoms
1mrk for Correct description of cause
1mrk for correct description of treatment and management
Potentially 1mrk for coherent and concise response
Hope this Helps
Yes, thank you!
Post by: julia.wilson3 on October 03, 2016, 08:36:13 pm
Post by: vox nihili on October 03, 2016, 08:48:16 pm
Hey I was just wondering how exactly Burnet discovered immunological tolerance, like did he inject fetuses with diseases? I can't really find much info and I'm so confused haha, Question 2: How does the creation of hybridisation and transgenic species reduce genetic diversity, aren't you essentially making a new species? Thanks !!
Pretty sure he didn't do the experiments to prove it, funnily enough. He just theorised about its existence. Peter Medawar, with whom Burnet shared the Nobel prize in 1960, was the person who managed to do the experiments to prove it. Pretty sure he used mouse and chick embryos to prove that you can induce tolerance.
Post by: Skidous on October 03, 2016, 08:49:28 pm
Hey I was just wondering how exactly Burnet discovered immunological tolerance, like did he inject fetuses with diseases? I can't really find much info and I'm so confused haha, Question 2: How does the creation of hybridisation and transgenic species reduce genetic diversity, aren't you essentially making a new species? Thanks !!Immunology tolerance wasn't discovered by Burnet, it was him that discovered the method by which humans gain their acquired immunity, I don't know the logistics of this but he did research into the 3 lines of defence.
For question 2 hybridisation creates species through artificial insemination/pollination which effectively breeds organisms selectively with favourable characteristics, over time these organism will become abundant and therefore reduce the diversity from natural variation through regular breeding methods.
Transgenic Species have the same type of genetic material to produce genetically modified organisms which have no variation as they are artificially created, hence no genetic variation.
Both Hybrid Organisms and Transgenic Species are normally sterile and hence not able to reproduce to promote variation
Hope this Helps
Post by: Skidous on October 03, 2016, 08:59:59 pm
Post by: vox nihili on October 03, 2016, 09:26:48 pm
Immunology tolerance wasn't discovered by Burnet, it was him that discovered the method by which humans gain their acquired immunity, I don't know the logistics of this but he did research into the 3 lines of defence.
He wasn't the first to observe tolerance, no doubt; but he was certainly the one to describe it, and as I said, Medawar provided the evidence to support Burnet's theorising.
Burnet's research was very broad. He started off as a microbiologist, with a particular interest in viruses. In fact, he is credited with the discovery of the causative agent of so-called Q fever, which is named after him (Coxiella burnetii). If I remember correctly, he was initially very interested in influenza, but decided to make the switch to immunology. Obviously he won the Nobel for describing immunological tolerance; however, arguably his biggest contribution to the field was the discovery of clonal selection/expansion (which I presume you guys probably learn about?). If not, his theory described the way by which cells of the third line of defence—T-cells and B-cells—respond specifically to pathogens.
PS: given this is an HSC biology thread it would remiss of me to not remind you that Macfarlane Burnet was born, educated and worked all of his life in Victoria :p
Post by: Skidous on October 03, 2016, 09:30:09 pm
PS: given this is an HSC biology thread it would remiss of me to not remind you that Macfarlane Burnet was born, educated and worked all of his life in Victoria :p
I know but we unfortunately can't use him as an example for an Australian biologist.
Speaking of which, I have a question. What is your Male and Female Named Scientist working in the field of biology? I would really like a name and the work they have done in biology
Post by: kevin217 on October 03, 2016, 10:08:54 pm
I know but we unfortunately can't use him as an example for an Australian biologist.I don't have one yet. When was the last time they asked for a male or female scientist in the HSC?
Speaking of which, I have a question. What is your Male and Female Named Scientist working in the field of biology? I would really like a name and the work they have done in biology
Post by: Skidous on October 03, 2016, 10:10:58 pm
I don't have one yet. When was the last time they asked for a male or female scientist in the HSC?
It doesn't matter, since it's in the syllabus it can be asked. And you need both male AND female not or.
Post by: kevin217 on October 03, 2016, 10:25:08 pm
Post by: Skidous on October 03, 2016, 10:27:55 pm
Post by: zaayxo on October 03, 2016, 11:19:05 pm
Post by: :3 on October 04, 2016, 10:23:30 am
ADH and adolsterone. Please, I need this to be explained in a more alleviated form!
Basically, both hormones are involved in osmoregulation (salt/water levels):
- ADH (Anti-diuretic hormones): decrease in water levels detected --> this is secreted into the bloodstream --> upon contact with the kidney, it increases the permeability of the membrane to water --> more water conserved
- Adolsterone: decrease in sodium levels detected --> this is secreted into the bloodstream --> upon contact with the kidney, it increases the permeability of the membrane, particularly at the ascending loop of Henle, to sodium --> sodium retained.
Post by: lha on October 04, 2016, 11:05:15 am
Post by: vox nihili on October 04, 2016, 07:48:07 pm
What diseases are caused by lack of adh or aldosterone?
Aldosterone: Conn syndrome or death. If you have a complete absence of aldosterone, you'll die within days
Post by: lha on October 05, 2016, 07:46:19 am
Aldosterone: Conn syndrome or death. If you have a complete absence of aldosterone, you'll die within days
I think lack of aldosterone can also lead to Addison's disease
Post by: lha on October 05, 2016, 07:49:31 am
Post by: Skidous on October 05, 2016, 10:58:50 am
Have there been any productions in artifical blood in australia?Not entirely sure but I know that you don't need an Australian example, just an example of artificial blood and what it does, why it's important and what it doesn't do that real blood does
Post by: lha on October 05, 2016, 11:01:20 am
Not entirely sure but I know that you don't need an Australian example, just an example of artificial blood and what it does, why it's important and what it doesn't do that real blood does
Could you please give me an example?
Post by: Skidous on October 05, 2016, 12:05:29 pm
Could you please give me an example?
Abstract
This report will examine the production of artificial blood. Including its advantages/ disadvantages, clinical trials of a chosen blood substitute as well as the reasoning as to why the blood substitute could potentially be an effective substitute and why blood substitutes are needed in the first place.
Introduction
Artificial blood is the name given to a substance used to mimic and fulfill some functions of biological blood, although it cannot carry out all functions of blood, for example it cannot, help clotting, immune defence or coagulation. Although it can carry carbon dioxide and oxygen.
Blood substitutes are designed to carry oxygen and carbon dioxide. An ideal blood substitute should lack antigenicity and eliminate, or at least substantially reduce, the ability to transmit infections. In addition, it should be readily available, should have a long half-life, and should be capable of being stored at room temperature. The biologic properties of an ideal blood substitute should include a reasonable amount of oxygen delivery, when compared to normal human red blood cells.
Example of Blood Substitutes
An example of blood substitutes is maleimide-polyethylene glycol hemoglobin (MP4). MP4 is currently under development in the UK and is a blood substitute made of Haemoglobin obtained from out-of-date human blood and modified using maleimide-polyethylene glycol in order to make the molecule bulkier as well as altering shape of the molecule. By doing this MP4 has a great oxygen affinity which is essential for a blood substitute. MP4 being a blood substitute does not, however, provide many other functionings of blood such as the clotting and immune defence.
Clinical Trials
MP4 has undergone many clinical trials on pigs and some humans in order to test its effectiveness of transporting oxygen as well as its ability to assist in the recovery of hemorrhaging without causing vasoconstriction. These trials have shown successful results in the ability of MP4, however more research is needed in order to prove whether or not it is ready to be used on humans as an effective blood substitute.
Why is it needed?
Blood substitutes such as MP4 are needed due to the fact that there are many obstacles that need to be overcome that are associated with blood donation. Donors of blood are required in order for a supply of blood to be given to those who need it. There is a deficit of people willing to donate their blood and thus a substitute is needed due to the fact that more blood is needed in hospitals to treat patients as a result of blood having a relatively short shelf life and there not being as many donors to replace all the unused blood donations. The development of MP4 allows for the blood to be in ready supply to treat patients such as providing blood to those who are extremely anaemic with blood transfusions. With the development of and eventual use of MP4, there would not be an issue with the amount of blood received from blood donations as it can be synthetically produced in labs to provide treatment to those who need it as well as MP4 having a relatively long shelf life so that it can be ready to use even after an extended period of time.
Blood received from donors goes through a screening process in order to ensure that there are not antigens and other possible diseases that are present within the blood. There is a risk that some of the blood may contain blood-borne pathogens such as HIV, AIDS and Hepatitis-C when donated. As a result of this, the development of MP4 is essential for society in order to reduce the risk of pathogens such as HIV from being unintentionally passed on due to screening of donor blood missing pathogens within them and thus providing safe blood transfusion and blood usage during surgery for patients.
Conclusion
Artificial Blood is better known as Blood substitutes as they only perform some of the functions of blood such as the transportation of oxygen and carbon dioxide. The development of the blood substitute MP4 has shown promising potential due to its high affinity for oxygen shown through clinical trials. This development is beneficial for society as it allows for potential use for the blood substitute as a means of providing doctors and patients with a ready to supply source of blood for surgeries and transfusion without running the risk of possible blood-borne pathogens being present within the sample.
My class got given a research project for this as an activity
Post by: lha on October 05, 2016, 01:35:51 pm
Abstract
This report will examine the production of artificial blood. Including its advantages/ disadvantages, clinical trials of a chosen blood substitute as well as the reasoning as to why the blood substitute could potentially be an effective substitute and why blood substitutes are needed in the first place.
Introduction
Artificial blood is the name given to a substance used to mimic and fulfill some functions of biological blood, although it cannot carry out all functions of blood, for example it cannot, help clotting, immune defence or coagulation. Although it can carry carbon dioxide and oxygen.
Blood substitutes are designed to carry oxygen and carbon dioxide. An ideal blood substitute should lack antigenicity and eliminate, or at least substantially reduce, the ability to transmit infections. In addition, it should be readily available, should have a long half-life, and should be capable of being stored at room temperature. The biologic properties of an ideal blood substitute should include a reasonable amount of oxygen delivery, when compared to normal human red blood cells.
Example of Blood Substitutes
An example of blood substitutes is maleimide-polyethylene glycol hemoglobin (MP4). MP4 is currently under development in the UK and is a blood substitute made of Haemoglobin obtained from out-of-date human blood and modified using maleimide-polyethylene glycol in order to make the molecule bulkier as well as altering shape of the molecule. By doing this MP4 has a great oxygen affinity which is essential for a blood substitute. MP4 being a blood substitute does not, however, provide many other functionings of blood such as the clotting and immune defence.
Clinical Trials
MP4 has undergone many clinical trials on pigs and some humans in order to test its effectiveness of transporting oxygen as well as its ability to assist in the recovery of hemorrhaging without causing vasoconstriction. These trials have shown successful results in the ability of MP4, however more research is needed in order to prove whether or not it is ready to be used on humans as an effective blood substitute.
Why is it needed?
Blood substitutes such as MP4 are needed due to the fact that there are many obstacles that need to be overcome that are associated with blood donation. Donors of blood are required in order for a supply of blood to be given to those who need it. There is a deficit of people willing to donate their blood and thus a substitute is needed due to the fact that more blood is needed in hospitals to treat patients as a result of blood having a relatively short shelf life and there not being as many donors to replace all the unused blood donations. The development of MP4 allows for the blood to be in ready supply to treat patients such as providing blood to those who are extremely anaemic with blood transfusions. With the development of and eventual use of MP4, there would not be an issue with the amount of blood received from blood donations as it can be synthetically produced in labs to provide treatment to those who need it as well as MP4 having a relatively long shelf life so that it can be ready to use even after an extended period of time.
Blood received from donors goes through a screening process in order to ensure that there are not antigens and other possible diseases that are present within the blood. There is a risk that some of the blood may contain blood-borne pathogens such as HIV, AIDS and Hepatitis-C when donated. As a result of this, the development of MP4 is essential for society in order to reduce the risk of pathogens such as HIV from being unintentionally passed on due to screening of donor blood missing pathogens within them and thus providing safe blood transfusion and blood usage during surgery for patients.
Conclusion
Artificial Blood is better known as Blood substitutes as they only perform some of the functions of blood such as the transportation of oxygen and carbon dioxide. The development of the blood substitute MP4 has shown promising potential due to its high affinity for oxygen shown through clinical trials. This development is beneficial for society as it allows for potential use for the blood substitute as a means of providing doctors and patients with a ready to supply source of blood for surgeries and transfusion without running the risk of possible blood-borne pathogens being present within the sample.
My class got given a research project for this as an activity
THANK YOU
Post by: vox nihili on October 05, 2016, 02:47:03 pm
I think lack of aldosterone can also lead to Addison's disease
Other way round. Addison's disease is a problem with the adrenal glands, that usually leads to low aldosterone (but more prominently, leads to low cortisol).
Post by: lha on October 05, 2016, 02:50:20 pm
Other way round. Addison's disease is a problem with the adrenal glands, that usually leads to low aldosterone (but more prominently, leads to low cortisol).
Ohh so addisons disease causes lack of aldosterone...got it, thanks!
Post by: lha on October 05, 2016, 05:59:39 pm
Post by: kevin217 on October 05, 2016, 06:10:04 pm
What is the control used in the pasteur swanneck flask experiment?I believe it would be the flask that is open to the air and microbes.
Post by: :3 on October 05, 2016, 06:36:17 pm
What is the control used in the pasteur swanneck flask experiment?
The control is essentially one where the broth is exposed to air (i.e. no swan flask neck; using a straight flask neck).
Post by: Daliaradosevic on October 05, 2016, 07:23:07 pm
Post by: :3 on October 05, 2016, 07:44:53 pm
Hey guys so i'm that confused with the difference b/w meiosis and mitosis, could someone please explain it? :)
Mitosis: refers to the duplication of cells; involved in the repair, growth and replacement of cells.
- Parent cell differentiates --> two genetically identical, diploid daughter cells formed.
Meisos: refers to the differentiation of cells to form sex cells, which are involved in the production of offsprings (and heredity).
- Parent cell differentiates --> 4 genetically different, haploid daughter cells formed.
Post by: lha on October 05, 2016, 07:55:04 pm
I believe it would be the flask that is open to the air and microbes.
Alright so when i write the method, do i say "have one straight necked flask as a control"?
Post by: Daliaradosevic on October 05, 2016, 08:02:01 pm
Mitosis: refers to the duplication of cells; involved in the repair, growth and replacement of cells.THANK YOU SO MUCH!
- Parent cell differentiates --> two genetically identical, diploid daughter cells formed.
Meisos: refers to the differentiation of cells to form sex cells, which are involved in the production of offsprings (and heredity).
- Parent cell differentiates --> 4 genetically different, haploid daughter cells formed.
Post by: :3 on October 05, 2016, 08:12:51 pm
Alright so when i write the method, do i say "have one straight necked flask as a control"?
Precisely; just talk about preparing two flasks followed by the insertion of a swan glass 'tube' in one flask's stopper and a straight glass 'tube' (control) in the other.
Post by: lha on October 05, 2016, 08:24:47 pm
Precisely; just talk about preparing two flasks followed by the insertion of a swan glass 'tube' in one flask's stopper and a straight glass 'tube' (control) in the other.
Okay but what is the reasoning behind the straight necked flask being the control?
Post by: :3 on October 05, 2016, 08:26:17 pm
Okay but what is the reasoning behind the straight necked flask being the control?
To basically prove that your experiment is working; it shows that microbes ARE carried by dust particles.
Post by: Skidous on October 05, 2016, 09:16:43 pm
Mitosis: refers to the duplication of cells; involved in the repair, growth and replacement of cells.
- Parent cell differentiates --> two genetically identical, diploid daughter cells formed.
Meisos: refers to the differentiation of cells to form sex cells, which are involved in the production of offsprings (and heredity).
- Parent cell differentiates --> 4 genetically different, haploid daughter cells formed.
Just to further this point
Meiosis begins when the chromosomes of the parent cell quadruple their chromosomes (haploid (23) --> Double Diploid (46 pairs)
Meiosis is also important for genetic diversity in 3 steps
1: Chromosomes cross over with their homologous pairs at a chiasmata and trade genetic information (this creates new alleles)
2: Independent alignment: The chromosomes themselves randomly align along the equatorial plate (there is no order in which the diploid chromosomes align on one side AND they do not have to match up with their homologous pairs) when they separate into 2 DIPLOID Cells
3: Random Segregation: The Chromosomes randomly segregate into different halves of the cell when the 4 HAPLOID cells are formed.
Since these gametes are all random when they are formed, there is also the benefit of random fertilization as there no NATURAL way to ensure one gamete fertilizes another gamete to produce a specific offspring, this furthers genetic diversity
NB There are reproductive technologies such as In Vitro Fertilization (IVF) and Pre-Implantation Genetic Diagnosis (PIGD/PGD) that can ensure that one games fertilizes another and produces an offspring that is healthy or without any genetic disorders or illnesses
Post by: vox nihili on October 05, 2016, 10:00:08 pm
Just to further this point
Meiosis begins when the chromosomes of the parent cell quadruple their chromosomes (haploid (23) --> Double Diploid (46 pairs)
Meiosis is also important for genetic diversity in 3 steps
1: Chromosomes cross over with their homologous pairs at a chiasmata and trade genetic information (this creates new alleles)
2: Independent alignment: The chromosomes themselves randomly align along the equatorial plate (there is no order in which the diploid chromosomes align on one side AND they do not have to match up with their homologous pairs) when they separate into 2 DIPLOID Cells
3: Random Segregation: The Chromosomes randomly segregate into different halves of the cell when the 4 HAPLOID cells are formed.
Since these gametes are all random when they are formed, there is also the benefit of random fertilization as there no NATURAL way to ensure one gamete fertilizes another gamete to produce a specific offspring, this furthers genetic diversity
NB There are reproductive technologies such as In Vitro Fertilization (IVF) and Pre-Implantation Genetic Diagnosis (PIGD/PGD) that can ensure that one games fertilizes another and produces an offspring that is healthy or without any genetic disorders or illnesses
Just gonna jump in and clear up a couple of minor points. As normal you know your stuff well, but meiosis is a little bit tricky.
That the parent cell quadruples its chromosomes seems to imply that the parents start off with a haploid set of chromosomes. This is obviously not the case.
The parent cell starts off with 46 pairs of chromosomes. It then undergoes replication. It does not, however, double the number of chromosomes. It doubles the number of chromatids. This distinction is really critical.
3. as you've described is not a source of variation. Only the first meiotic division generates variation. You correctly identified independent assortment, during prophase I, as a means of generating variation. Independent alignment just means that the chromosomes line up in the middle randomly, from which they are segregated into the daughter cells randomly as well. After that there are no other sources of variation; so all the variation exists after the first division. The second operates just like mitosis.
Post by: Skidous on October 05, 2016, 10:10:17 pm
Just gonna jump in and clear up a couple of minor points. As normal you know your stuff well, but meiosis is a little bit tricky.Isn't the parent cell for a gamete just another gamete? Or is it another type of cell?
That the parent cell quadruples its chromosomes seems to imply that the parents start off with a haploid set of chromosomes. This is obviously not the case.
The parent cell starts off with 46 pairs of chromosomes. It then undergoes replication. It does not, however, double the number of chromosomes. It doubles the number of chromatids. This distinction is really critical.
3. as you've described is not a source of variation. Only the first meiotic division generates variation. You correctly identified independent assortment, during prophase I, as a means of generating variation. Independent alignment just means that the chromosomes line up in the middle randomly, from which they are segregated into the daughter cells randomly as well. After that there are no other sources of variation; so all the variation exists after the first division. The second operates just like mitosis.
Post by: vox nihili on October 05, 2016, 10:18:09 pm
Isn't the parent cell for a gamete just another gamete? Or is it another type of cell?
Nope, it can't be. If you think about it, if the parent cell were a gamete, where does the variation come from? Gametes only have one copy of each chromosome, so you can't mix and match copies like you can if you start off with a diploid cell. A cell that forms gametes is called a gametocyte.
Post by: marynguyen18 on October 05, 2016, 10:20:48 pm
1. what's the difference between ADH and Aldosterone?
2. what is the role and function of the kidney?
3. what is the hormone replacement dot point about?
thank you in advanced
Post by: :3 on October 05, 2016, 10:43:50 pm
i have three questions:
1. what's the difference between ADH and Aldosterone?
2. what is the role and function of the kidney?
3. what is the hormone replacement dot point about?
thank you in advanced
Most of the questions I'm answering can be easily found in the textbook or internet.
Anyways:
1. Both are hormones, except ADH (anti-duretic hormone) is involved in water retention, whilst aldosterone is involved in salt (e.g. sodium) retention.
2. The kidney is generally involved in homeostasis - it removes excess substances and waste (i.e. nitrogenous waste) and is involved in osmoregulation (salt/water levels).
3. Basically talk about the detrimental effects it has upon those without such hormones (due to glands not functioning properly and secreting it), followed up by why it is needed (i.e. to address the detrimental effects mentioned)
Post by: Skidous on October 05, 2016, 10:46:25 pm
Most of the questions I'm answering can be easily found in the textbook or internet.Just to add onto this for 3 you need to also talk about what the hormone replacement is for those who have Addison's disease or when they cannot produce ADH
Anyways:
1. Both are hormones, except ADH (anti-duretic hormone) is involved in water retention, whilst aldosterone is involved in salt (e.g. sodium) retention.
2. The kidney is generally involved in homeostasis - it removes excess substances and waste (i.e. nitrogenous waste) and is involved in osmoregulation (salt/water levels).
3. Basically talk about the importance of each hormone and the negative effects it has on an individual if missing (e.g. No ADH = dehydration, No aldosterone = addison's disease).
Post by: vox nihili on October 05, 2016, 10:48:58 pm
(VCE is full of these too unfortunately!).
Post by: Skidous on October 05, 2016, 10:51:40 pm
Post by: vox nihili on October 05, 2016, 11:03:25 pm
It's an oversimplification we are supposed to know what Addison's disease actually is but some people simplify it to mean there is no aldosterone
Thanks :)
So there you go everyone: Addison's is an adrenal insufficiency, it also involves cortisol!
Loss of aldosterone alone is called Conn syndrome
Post by: amina_98 on October 06, 2016, 02:30:27 pm
Right so a couple of marks in the marking guidelines are allocated for "relates understanding of genetic change to the use of genetic technology"
Could someone shed some light here I got stuck there in terms of formulating my "knowledge" to respond to what they're asking
cheers
Post by: aimbotted on October 06, 2016, 02:52:36 pm
Identify the role of genes in embryonic development
i can't really understand it besides the fact that there are structural and regulating genes.
Post by: studybuddy7777 on October 06, 2016, 03:44:21 pm
I personally didnt do genetics (did communication instead) but a quick google turned this up:
Homeotic gene, any of a group of genes that control the pattern of body formation during early embryonic development of organisms. These genes encode proteins called transcription factors that direct cells to form various parts of the body.
For example, in fruit flies (Drosophila), mutation of a particular homeotic gene results in altered transcription, leading to the growth of legs on the head instead of antenna; this is known as the antennapedia mutation.
(Source: Britannica)
Hope this helps and sorry I couldnt do more for you!
Post by: studybuddy7777 on October 06, 2016, 03:51:47 pm
I came across this question in 2013 paper from genetics section "analyse how the understanding of mechanisms of genetic change has influenced the use of genetic technology in society"
Right so a couple of marks in the marking guidelines are allocated for "relates understanding of genetic change to the use of genetic technology"
Could someone shed some light here I got stuck there in terms of formulating my "knowledge" to respond to what they're asking
cheers
Not that I have done genetics (maybe aimbotted could help?) but this is how i would structure it (assuming 7 or 8 marks)
First, topic sentence. This is basically rewording the question (not always needed but imho i think dump statements are good)
Next, What are the mechanisms of genetic change? What causes a change in the genes?
Then bring in your genetic technology. Define GT1. Then say GT1 has influenced society by... (Advances in technology yada yada yada)
This has led to.. (Increased/decreased genetic diversity and changes to genes and gene technology)
Wouldnt hurt to talk about ethical issues either :)
Sorry I could not help more, but hopefully you (or someone else) can fill the gaps of knowledge where mine is so evidently lacking.
Post by: Blissfulmelodii on October 07, 2016, 12:47:14 pm
"Scientists have tried to achieve a viable embryo by fusing two ova (eggs) from the same female.
Explain whether the offspring produced using this process would be a clone of the female whose two ova were used. Use your knowledge of gamete formation and sexual reproduction to support your answer."
Also I am pretty hopeless at the Kidney stuff so I would greatly appreciate if someone could explain the role of the kidney in the excretory system of fish and mammals and how it all works in simple terms?
Thank you in advanced!! :) :)
Post by: marynguyen18 on October 07, 2016, 01:15:30 pm
Thank you in advanced
Post by: aimbotted on October 07, 2016, 01:22:53 pm
i was looking at the 2004 HSC question and was unsure on how to answer q24. "JUSTIFY CONTINUED RESEARCH INTO THE DEVELOPMENT OF ARTIFICIAL BLOOD." Can anyone please explain to me what exactly is artificial blood and how it can be incorporated into this kind of question. I looked at the answers and didn't like the way it was explained.
Thank you in advanced
artificial blood is blood that is created, not donated. it is important to develop artificial blood as sometimes donated blood may not be readily available, as opposed to where you can create blood in a laboratory there will always be a constant supply of blood. another reasoning for artificial blood is that it does not require cross matching for the type of blood, this will remove the necessity of finding the correct type of blood in situations such as transfusions basically saving lives.
there are more dotpoints but this is just what i could think of from the top of my head (god help me if i'm totally wrong)
you can further elaborate on those points as to how it saves lives and is more effective than relying on donated blood.
Post by: aimbotted on October 07, 2016, 01:37:03 pm
I came across this question in 2013 paper from genetics section "analyse how the understanding of mechanisms of genetic change has influenced the use of genetic technology in society"
Right so a couple of marks in the marking guidelines are allocated for "relates understanding of genetic change to the use of genetic technology"
Could someone shed some light here I got stuck there in terms of formulating my "knowledge" to respond to what they're asking
cheers
i'm not entirely sure if i'm answering this question correct but i'll give it a go
what i think the question is asking for is the mechanics of genetic change and how we use those mechanisms in society
the mechanics of genetic change are technologies such as recombinant dna (snipping dna and inserting into another organism) and selective breeding. i think both are mechanisms to change the genetic composition in an organism.
we use technologies such as recombinant DNA in society to create necessary proteins such as insulin to treat diabetes in humans, effectively helping to treat or cure a disease. another use of a mechanism of genetic change is selective breeding in which we choose organisms with desirable traits and breed them for their benefits, such as higher yields better quality better suitability
benefits of these technologies involve having the ability to treat a disease, another benefit is having the ability to solve world issues such as world hunger (transgenic species)
disadvantages of this technology include ethical issues and which you are disrupting nature and evolution
Post by: Ayyddaan on October 07, 2016, 01:37:51 pm
i was looking at the 2004 HSC question and was unsure on how to answer q24. "JUSTIFY CONTINUED RESEARCH INTO THE DEVELOPMENT OF ARTIFICIAL BLOOD." Can anyone please explain to me what exactly is artificial blood and how it can be incorporated into this kind of question. I looked at the answers and didn't like the way it was explained.
Thank you in advanced
So artificial blood is an alternative for actual blood, that is 'man-made'; it carries out some of the functions of real blood. Hemerythrin is an example of artificial blood - it is a protein extracted from sea worms and mixed with water & salt; could lead to 'instant blood' as it is like a 'just add water' thing.
So, now that you know what Artificial Blood is, you need to know why it is good (in order to justify the continued research into the development of it). Artificial blood has heaps of benefits:
- It can be sterilised. Therefore, it can prevent the spread of diseases like HIV - if you sterilise biological blood, it will kill the cells.
- AB doesn't have a membrane, therefore there is no need for cross matching - 'universal blood type'.
- Shelf-life of up to 3 years, unlike biological blood which can only be stored for a few weeks.
- Since it does not contain other human cells, it is safe for use by religious groups that cannot use biological blood due to beliefs.
- Does not cause any side-effects
Now, why do we need to conduct more research?
- the population is rising, but not enough people are donating - more blood is needed!
- Useful in emergencies - no time to test for blood type.
Therefore, to answer this question, you need to, using this information, support the idea of continuing research in AB.
Post by: Skidous on October 07, 2016, 04:03:37 pm
Post by: marynguyen18 on October 07, 2016, 09:34:57 pm
Post by: Lottie99 on October 07, 2016, 09:39:40 pm
I really struggle with those 7 or 8 mark questions at the end of the code broken that have vague mentions of technology and genetics and genetic change and development. What kind of things are really core to understanding gene homologues and gene cascades and how they fit within all those 8 mark questions?
Post by: :3 on October 07, 2016, 09:47:04 pm
hey, I was hoping someone could explain to me how to go about answering this question. Essentially how to structure the response and what details are exactly needed to satisfactorily answer it?
"Scientists have tried to achieve a viable embryo by fusing two ova (eggs) from the same female.
Explain whether the offspring produced using this process would be a clone of the female whose two ova were used. Use your knowledge of gamete formation and sexual reproduction to support your answer."
Also I am pretty hopeless at the Kidney stuff so I would greatly appreciate if someone could explain the role of the kidney in the excretory system of fish and mammals and how it all works in simple terms?
Thank you in advanced!! :) :)
First question: the answer is basically that it does not produce a clone of the female whose ovaries were combined.
- Refer to Boveri's experiment with sea urchins: he discovered that if only the nucleus of one parent was present, it would result in abnormalities (not 100% sure why but probably due to chromosomes not being transferred properly).
- Refer to how crossing over, independent assortment and random segregation during meisos results in a different and unique genetic makeup to that of the parent cell within each daughter cell produced.
Second question:
- the kidney is fundamentally involved in homeostasis; it removes excess substances and nitrogenous waste that is either not needed by or toxic to the body, or reabsorps substances needed by the body for optimal functiong (e.g. salt and water).
- For how it works, are there any specific areas/concepts you are unsure about? The process itself can't be simplified other than the fact that blood enters it, reabsorption occurs throughout and the left over bits are excreted as urine.
Hopefully this helps :).
Post by: Lottie99 on October 07, 2016, 09:47:18 pm
can anyone explain chromosomes to me i always get confused with it
Chromosomes as in do they exist? Or their function? Or how they came about? Or their structure? Or our understanding?
Post by: marynguyen18 on October 07, 2016, 09:48:41 pm
Post by: :3 on October 07, 2016, 09:51:41 pm
chromosomes in general
Chromosomes basically carry the genetic information needed to carry out certain roles within the body and also contributes to one's characteristics.
Post by: Lottie99 on October 07, 2016, 09:51:53 pm
chromosomes in general
They're the things that carry our genetic information pretty much. Most things about you are going to be defined by your chromosomes and how each gene is expressed (Except for stuff like impact of environment on the expression of the phenotype and nature v. nature)
Chromosomes never leave the nucleus. How they code for proteins is all under 'polypeptide synthesis'
Depending on what option you're doing you may need to know really in depth things about them e.g in the code broken.
The main thing is to know that its just DNA (all that stuff about Watson and Crick is the history) but its the basis of pretty much all life.
Post by: aimbotted on October 07, 2016, 09:54:22 pm
Gene homologues and gene cascades. Why. Just why.
I really struggle with those 7 or 8 mark questions at the end of the code broken that have vague mentions of technology and genetics and genetic change and development. What kind of things are really core to understanding gene homologues and gene cascades and how they fit within all those 8 mark questions?
i feel your pain, i have no clue as to how i should be answering any 5-6-7 questions
Post by: Lottie99 on October 07, 2016, 09:55:54 pm
i feel your pain, i have no clue as to how i should be answering any 5-6-7 questions
Really hoping for a recombinant DNA/Human genome question. Anything but the last dotpoint :(
Post by: marynguyen18 on October 07, 2016, 09:56:00 pm
Post by: aimbotted on October 07, 2016, 09:57:20 pm
Really hoping for a recombinant DNA/Human genome question. Anything but the last dotpoint :(
gene expression is absolutely terrifying too haha
Post by: aimbotted on October 07, 2016, 09:58:29 pm
then how does the chromosome study relate to Boveri and Sutton? is it because they discovered that chromosomes are required for the normal production of DNA in the body?
well one of them discovered that they must have 2 set of chromosomes for an organism to function properly ( i think) and the other found that inheritance of characteristics is due to chromosomes
Post by: marynguyen18 on October 07, 2016, 09:59:33 pm
Post by: Lottie99 on October 07, 2016, 10:00:39 pm
then how does the chromosome study relate to Boveri and Sutton? is it because they discovered that chromosomes are required for the normal production of DNA in the body?
Pretty much the main thing that Sutton and Boveri did is show that you have to inherit an exact amount of chromosomes from your father and an exact amount from your mother, otherwise the embryo will not function properly or may not be viable at all.
Post by: marynguyen18 on October 07, 2016, 10:01:59 pm
Post by: marynguyen18 on October 07, 2016, 10:09:24 pm
Post by: Skidous on October 07, 2016, 10:09:30 pm
i feel your pain, i have no clue as to how i should be answering any 5-6-7 questionsFor any 5-8mrk question you should be analysing the question and breaking it down to be see what they're asking of you and then writing your response. Question that ask to discuss, assess, evaluate should make sure your points are explained.
Discuss says points AND/OR against so you can do all for and all against but you should try to do both sides of the argue me that
Assess/Evaluate you need to make a judgement and make it clear
Post by: Skidous on October 07, 2016, 10:14:21 pm
Hey Skidoos, do you think you could re upload that report you did on Artificial Blood?Artificial Blood Report
Abstract
This report will examine the production of artificial blood. Including its advantages/ disadvantages, clinical trials of a chosen blood substitute as well as the reasoning as to why the blood substitute could potentially be an effective substitute and why blood substitutes are needed in the first place.
Introduction
Artificial blood is the name given to a substance used to mimic and fulfill some functions of biological blood, although it cannot carry out all functions of blood, for example it cannot, help clotting, immune defence or coagulation. Although it can carry carbon dioxide and oxygen.
Blood substitutes are designed to carry oxygen and carbon dioxide. An ideal blood substitute should lack antigenicity and eliminate, or at least substantially reduce, the ability to transmit infections. In addition, it should be readily available, should have a long half-life, and should be capable of being stored at room temperature. The biologic properties of an ideal blood substitute should include a reasonable amount of oxygen delivery, when compared to normal human red blood cells.
Example of Blood Substitutes
An example of blood substitutes is maleimide-polyethylene glycol hemoglobin (MP4). MP4 is currently under development in the UK and is a blood substitute made of Haemoglobin obtained from out-of-date human blood and modified using maleimide-polyethylene glycol in order to make the molecule bulkier as well as altering shape of the molecule. By doing this MP4 has a great oxygen affinity which is essential for a blood substitute. MP4 being a blood substitute does not, however, provide many other functionings of blood such as the clotting and immune defence.
Clinical Trials
MP4 has undergone many clinical trials on pigs and some humans in order to test its effectiveness of transporting oxygen as well as its ability to assist in the recovery of hemorrhaging without causing vasoconstriction. These trials have shown successful results in the ability of MP4, however more research is needed in order to prove whether or not it is ready to be used on humans as an effective blood substitute.
Why is it needed?
Blood substitutes such as MP4 are needed due to the fact that there are many obstacles that need to be overcome that are associated with blood donation. Donors of blood are required in order for a supply of blood to be given to those who need it. There is a deficit of people willing to donate their blood and thus a substitute is needed due to the fact that more blood is needed in hospitals to treat patients as a result of blood having a relatively short shelf life and there not being as many donors to replace all the unused blood donations. The development of MP4 allows for the blood to be in ready supply to treat patients such as providing blood to those who are extremely anaemic with blood transfusions. With the development of and eventual use of MP4, there would not be an issue with the amount of blood received from blood donations as it can be synthetically produced in labs to provide treatment to those who need it as well as MP4 having a relatively long shelf life so that it can be ready to use even after an extended period of time.
Blood received from donors goes through a screening process in order to ensure that there are not antigens and other possible diseases that are present within the blood. There is a risk that some of the blood may contain blood-borne pathogens such as HIV, AIDS and Hepatitis-C when donated. As a result of this, the development of MP4 is essential for society in order to reduce the risk of pathogens such as HIV from being unintentionally passed on due to screening of donor blood missing pathogens within them and thus providing safe blood transfusion and blood usage during surgery for patients.
Conclusion
Artificial Blood is better known as Blood substitutes as they only perform some of the functions of blood such as the transportation of oxygen and carbon dioxide. The development of the blood substitute MP4 has shown promising potential due to its high affinity for oxygen shown through clinical trials. This development is beneficial for society as it allows for potential use for the blood substitute as a means of providing doctors and patients with a ready to supply source of blood for surgeries and transfusion without running the risk of possible blood-borne pathogens being present within the sample.
Post by: Skidous on October 07, 2016, 10:15:10 pm
Post by: marynguyen18 on October 07, 2016, 10:17:07 pm
Post by: Skidous on October 07, 2016, 10:18:39 pm
im so sorry Skidous, my computer must have autocorrected your name to Skidoos instead i apologise profusely but thank you so much for the report.No problem I've had it happen before :)
Post by: Essej on October 07, 2016, 10:48:02 pm
No problem I've had it happen before :)
On behalf of all of the atarnotes community, we sincerely hope you can recover from this mispronunciation - all hail king skidous! ;D ;D ;D
Post by: Skidous on October 07, 2016, 10:51:26 pm
On behalf of all of the atarnotes community, we sincerely hope you can recover from this mispronunciation - all hail king skidous! ;D ;D ;D
Thank you legal man
Post by: Neutron on October 08, 2016, 11:03:12 am
Didn't know there was a bio thread on ATAR notes hahaha but I'm happy there is! I was wondering whether one of you guys know how to answer the horrific 8 marker from 2007? Here's the question :)
Scientists at a climate research unit estimate that global land areas have warmed at an average rate of 0.07°C per decade from 1901 to 2000.
Analyse the possible effects of temperature change on Australian plants and animals with regard to the short-term survival of individuals and long-term survival of species.
Perhaps maybe a dot point outline of what I really need to talk about? So the question is quite evidently in two parts, short-term and long-term. Would you say that for short-term, you discuss the adaptive features of the plant that assist with excessive heat? And then for long-term go into evolution? Cheers
Neutron
Post by: studybuddy7777 on October 08, 2016, 11:56:36 am
The notes from the marking centre are below in the spoiler.
Spoiler
In better responses, candidates explained the consequences of temperature change using correct biological terminology for specific examples of both animals and plants, and demonstrated a sound understanding of natural selection.
In weaker responses, candidates simply stated some generalised animal and/or plant responses. Weaker responses incorrectly described the process of organisms adapting to climate change in a Lamarckian way. Some responses described responses to water loss in terms of the structural features of plants, without linking it to a rise in temperature.
In weaker responses, candidates simply stated some generalised animal and/or plant responses. Weaker responses incorrectly described the process of organisms adapting to climate change in a Lamarckian way. Some responses described responses to water loss in terms of the structural features of plants, without linking it to a rise in temperature.
These are the dot points covered: 9.2.3.2.9, 9.3.4.3.4, 9.3.1.2.1, 9.3.4.2.6, 9.2.1.2.7/8/9, 9.2.1.3.3. Anyone trouble with deciphering these dot points let me know :D
Also the marking guidelines in the spoiler for a 7-8
Spoiler
just bear with the lack of spaces please :) if you can't it can be found here
http://www.boardofstudies.nsw.edu.au/hsc_exams/exam-papers-2007/pdf_doc/biology-notes-07.pdf
Explainspossibleconsequencesoftemperaturechangeforplantsand animals using examples of individuals and species
• Relatesimplicationsofchangesinsurvivalofindividualstosurvivalof species
• Demonstratescoherenceandlogicalprogressionandincludescorrectuseof scientific principles and ideas
http://www.boardofstudies.nsw.edu.au/hsc_exams/exam-papers-2007/pdf_doc/biology-notes-07.pdf
Explainspossibleconsequencesoftemperaturechangeforplantsand animals using examples of individuals and species
• Relatesimplicationsofchangesinsurvivalofindividualstosurvivalof species
• Demonstratescoherenceandlogicalprogressionandincludescorrectuseof scientific principles and ideas
Post by: lha on October 08, 2016, 02:43:56 pm
People can have problems with communication because of difficulties in the sending, receiving or interpretation of some signals. How has an increased understanding of sight and hearing led to improved assistance for people with difficulties in communicating? 7 marks
Actually my problem doesnt lie within what to write but how to make it concise. My answer for this goes for way too long and i think for 7 markers the average should be 1-1.5 pages right? Anyways if anyone could show me a band 6 response to show me how to include all the relevant info for 7 marks while keeping it in a concise form, that would be great!
Post by: Blissfulmelodii on October 08, 2016, 02:48:31 pm
First question: the answer is basically that it does not produce a clone of the female whose ovaries were combined.
- Refer to Boveri's experiment with sea urchins: he discovered that if only the nucleus of one parent was present, it would result in abnormalities (not 100% sure why but probably due to chromosomes not being transferred properly).
- Refer to how crossing over, independent assortment and random segregation during meisos results in a different and unique genetic makeup to that of the parent cell within each daughter cell produced.
Second question:
- the kidney is fundamentally involved in homeostasis; it removes excess substances and nitrogenous waste that is either not needed by or toxic to the body, or reabsorps substances needed by the body for optimal functiong (e.g. salt and water).
- For how it works, are there any specific areas/concepts you are unsure about? The process itself can't be simplified other than the fact that blood enters it, reabsorption occurs throughout and the left over bits are excreted as urine.
Hopefully this helps :).
Thanks so much!
In terms of the kidney I just don't understand what the steps are i guess, in terms of the mammalian kidney. I've read over some content on it but i guess it just isn't sticking. Is there anyway of remembering the steps and each part of the nephron that it occurs in?
Post by: kevin217 on October 08, 2016, 02:59:21 pm
Thanks so much!What year is this question from?
In terms of the kidney I just don't understand what the steps are i guess, in terms of the mammalian kidney. I've read over some content on it but i guess it just isn't sticking. Is there anyway of remembering the steps and each part of the nephron that it occurs in?
Post by: Blissfulmelodii on October 08, 2016, 03:04:58 pm
What year is this question from?
HSC 2014. Question 29 (5 marks)
Post by: Skidous on October 08, 2016, 03:30:26 pm
Im having trouble with answering this question:
People can have problems with communication because of difficulties in the sending, receiving or interpretation of some signals. How has an increased understanding of sight and hearing led to improved assistance for people with difficulties in communicating? 7 marks
Actually my problem doesnt lie within what to write but how to make it concise. My answer for this goes for way too long and i think for 7 markers the average should be 1-1.5 pages right? Anyways if anyone could show me a band 6 response to show me how to include all the relevant info for 7 marks while keeping it in a concise form, that would be great!
Well to be concise you would tackle each of these responses separately and only include very necessary information. There really isn't much else other than ensuring that the info you write is really necessary and using specific examples to get your point across
Hope this helps
Post by: :3 on October 08, 2016, 04:01:41 pm
Thanks so much!
In terms of the kidney I just don't understand what the steps are i guess, in terms of the mammalian kidney. I've read over some content on it but i guess it just isn't sticking. Is there anyway of remembering the steps and each part of the nephron that it occurs in?
This diagram had really helped me out when it came to understanding the kidney:
(https://i.gyazo.com/b97c7f4d8971d518f96809ead4e8d368.png)
Picturing/memorising the kidney like this and following the movement of blood through it can really help.
Post by: Blissfulmelodii on October 08, 2016, 04:09:20 pm
This diagram had really helped me out when it came to understanding the kidney:
(https://i.gyazo.com/b97c7f4d8971d518f96809ead4e8d368.png)
Picturing/memorising the kidney like this and following the movement of blood through it can really help.
I will definitely try that. Thank you!
Post by: lha on October 08, 2016, 05:37:22 pm
Well to be concise you would tackle each of these responses separately and only include very necessary information. There really isn't much else other than ensuring that the info you write is really necessary and using specific examples to get your point across
Hope this helps
But what is relevant or necessary to put in?
Post by: Skidous on October 08, 2016, 06:00:17 pm
But what is relevant or necessary to put in?That will come down to the question itself
If you're doing a question on the importance of accommodation (for the communication option) you wouldn't necessarily need to take about the refractive powers of the vitreous or aqueous humour. Whilst it is relevant to the refraction of light to hit the retina it isn't necessary for the question as all you would need to talk about is the ciliary body, suspensory ligaments and the changing in curvature of the lens with regards to the light hitting the retina.
It takes practice but you should try to break down the question and look at what absolutely must be included and whether other bits of information that may tie in with the question are suitable to add in or will just take up valuable writing space. It's better to answer the question than add useless information just because you know it.
Hope this helps
Post by: aimbotted on October 08, 2016, 07:53:10 pm
Post by: :3 on October 08, 2016, 08:01:19 pm
would you guys recommend knowing the meiosis diagram? or any particular diagrams?I highly recommend it (the diagrams on page 168 from the Chidrawi biology textbook are pretty decent).
You may be asked to examine a diagram showing one of the stages of meiosis and describe/explain what is happening.
Also, it helps with understanding what is happening during each of the stages of meiosis.
Post by: Skidous on October 08, 2016, 09:04:58 pm
would you guys recommend knowing the meiosis diagram? or any particular diagrams?Here are a few from my textbook that I used, they're pretty good
Post by: aimbotted on October 08, 2016, 09:11:52 pm
Here are a few from my textbook that I used, they're pretty good
legend! thanks skidoos :p
Post by: Skidous on October 08, 2016, 09:14:15 pm
legend! thanks skidoos :pNP
Don't get mad at the spelling, it was a mistake
Post by: Skidous on October 09, 2016, 02:22:39 pm
THE HSC REQUIRES YOU TO USE BLACK PENS
If any of you guys who still have to buy pens and other materials for the exam please keep this in mind to make sure you don't waste your moneys
Good luck to all for the English Exams coming up and then the Bio exam after that :)
Post by: Blissfulmelodii on October 09, 2016, 02:34:43 pm
Not a question but just a reminder
THE HSC REQUIRES YOU TO USE BLACK PENS
If any of you guys who still have to buy pens and other materials for the exam please keep this in mind to make sure you don't waste your moneys
Good luck to all for the English Exams coming up and then the Bio exam after that :)
Thanks for the reminder!! I actually forgot that new rule. Does anyone know now that they are scanning exam whether we still draw diagrams in pencil or do we have to do them all in pen now??
Post by: studybuddy7777 on October 09, 2016, 02:48:10 pm
Thanks for the reminder!! I actually forgot that new rule. Does anyone know now that they are scanning exam whether we still draw diagrams in pencil or do we have to do them all in pen now??I am pretty sure it said on the trials "Draw diagrams using pencil" but who knows. I would pack a pencil in your little clear ziplock bag or whatever you do (and an eraser, a sharpener and another pencil- no use spending half the exam trying to sharpen up a pencil thats snapped)
If it doesnt say it on the front, then draw using pen. If it does, draw it using pencil. My biology teacher said you actually dont get penalised for doing diagrams in pen, but if you make a mistake, it is much easier to rub out pencil rather than leaving the marker scrambling all over the exam to see where you did in pen and crossed it out.
Just a word of advice from one bio student to another, and good luck everyone! (May the odds be ever in your favour :D)
Post by: Skidous on October 09, 2016, 03:02:14 pm
I am pretty sure it said on the trials "Draw diagrams using pencil" but who knows. I would pack a pencil in your little clear ziplock bag or whatever you do (and an eraser, a sharpener and another pencil- no use spending half the exam trying to sharpen up a pencil thats snapped)
If it doesnt say it on the front, then draw using pen. If it does, draw it using pencil. My biology teacher said you actually dont get penalised for doing diagrams in pen, but if you make a mistake, it is much easier to rub out pencil rather than leaving the marker scrambling all over the exam to see where you did in pen and crossed it out.
Just a word of advice from one bio student to another, and good luck everyone! (May the odds be ever in your favour :D)
You should draw diagrams in pencil yes but everything else should be black pens
Post by: studybuddy7777 on October 09, 2016, 03:04:09 pm
You should draw diagrams in pencil yes but everything else should be black pensEverything else HAS to be in black pen. No excuses. If it gets scanned in to the markers and they cant read it because you have put it in pencil, you dont get marked. That simple.
Post by: Skidous on October 09, 2016, 05:15:19 pm
Australian Biologists
Male
George L Gabor Miklos, PhD: Founder of Atomic Oncology, Sydney, Australia
Holds a PhD in Genetics and has extensive laboratory experience in diverse biological disciplines. He has provided advice to international firms and individuals in the areas of advanced molecular technologies and clinical trials, including being an advisor to the Human Genome Project conducted at CELERA.
His current interests take in the multiple uses of laser ablation-based diagnostics in various neoplasms, clinical trials of prostate cancer screening, detection and drug treatments of breast cancer, the mechanisms of radioresistance in different organisms, and the stability of Attractor Basins in normal versus tumorous tissues. He is an outspoken advocate for complete data release and transparency in clinical trials. George Miklos’ disclosures of potential conflicts of interest relating to Atomic Oncology.
Female
Denisse Leyton: PhD in Microbiology
She studied at Monash University on autotransporters, a superfamily of bacterial outer membrane proteins typically found in bacterial pathogens responsible for infectious diseases such as diarrhea, whooping cough, cholera, chlamydia, and bacterial meningitis. Here she identified two novel autotransporter proteins and determined how their function contributed to bacterial virulence. Denisse then moved to the University of Birmingham (UK) for a post-doctoral position where her research efforts focused on the mechanisms underpinning autotransporter secretion
At The ANU, Denisse and her research group will focus on understanding the mechanisms of autotransporter assembly, their function, and on their reengineering for biotechnological applications.
Hopefully this information can be useful and assist in your studies and get you out of a tight pinch if it turns up in this years HSC
Hope this Helps
Post by: studybuddy7777 on October 09, 2016, 05:24:58 pm
I thought that there weren't many people asking this question except me and there wasn't much response to it I'd help everyone out
Australian Biologists
Male
George L Gabor Miklos, PhD: Founder of Atomic Oncology, Sydney, Australia
Holds a PhD in Genetics and has extensive laboratory experience in diverse biological disciplines. He has provided advice to international firms and individuals in the areas of advanced molecular technologies and clinical trials, including being an advisor to the Human Genome Project conducted at CELERA.
His current interests take in the multiple uses of laser ablation-based diagnostics in various neoplasms, clinical trials of prostate cancer screening, detection and drug treatments of breast cancer, the mechanisms of radioresistance in different organisms, and the stability of Attractor Basins in normal versus tumorous tissues. He is an outspoken advocate for complete data release and transparency in clinical trials. George Miklos’ disclosures of potential conflicts of interest relating to Atomic Oncology.
Female
Denisse Leyton: PhD in Microbiology
She studied at Monash University on autotransporters, a superfamily of bacterial outer membrane proteins typically found in bacterial pathogens responsible for infectious diseases such as diarrhea, whooping cough, cholera, chlamydia, and bacterial meningitis. Here she identified two novel autotransporter proteins and determined how their function contributed to bacterial virulence. Denisse then moved to the University of Birmingham (UK) for a post-doctoral position where her research efforts focused on the mechanisms underpinning autotransporter secretion
At The ANU, Denisse and her research group will focus on understanding the mechanisms of autotransporter assembly, their function, and on their reengineering for biotechnological applications.
Hopefully this information can be useful and assist in your studies and get you out of a tight pinch if it turns up in this years HSC
Hope this Helps
Lol thanks :D now i just have remember it all as well 160 or so other dot points in eleven days. (Not meaning to be sarcastic at all)
Should get me a few marks though just knowing the names :P
Post by: aimbotted on October 09, 2016, 05:50:54 pm
Lol thanks :D now i just have remember it all as well 160 or so other dot points in eleven days. (Not meaning to be sarcastic at all)
Should get me a few marks though just knowing the names :P
hey there bud, what dot point requires australian biologists? i don't recall any
Post by: Skidous on October 09, 2016, 06:11:03 pm
hey there bud, what dot point requires australian biologists? i don't recall any
It is some dot point right at the beginning of the syllabus where all the skills are (I think it's 9.1 or something like that) and it's in one of the research sections so it can turn up.
Another similar thing is even though there is not dot point referring to Macfarlane Burnett you can get asked a question on him as his name is in the title of the dotpoint for search for better health
Hope this helps
Post by: studybuddy7777 on October 09, 2016, 06:53:53 pm
hey there bud, what dot point requires australian biologists? i don't recall any
Hey,
Be careful to look at the Biology skills (9.1) section of the syllabus!
12.3 e) explicitly states "identify practising male and female scientists, the areas they currently working in and their research"
They can ask anything from 9.1 as this is all assumed knowledge. I would be kicking myself quite hard if i didnt study this and it turned out to be an 8 marker.
Only 11 days till the Bio exam, so get cracking on this section now :D
Best of luck everyone and hope this helps
Post by: kevin217 on October 09, 2016, 09:18:05 pm
Post by: aimbotted on October 09, 2016, 09:22:11 pm
Hey guys could someone simplify the move of materials in xylem and phloem. I'm having trouble understanding this dotpoint.
is this the pressure flow theory and the transpiration stream theory?
Post by: marynguyen18 on October 09, 2016, 09:23:00 pm
Hey guys could someone simplify the move of materials in xylem and phloem. I'm having trouble understanding this dotpoint.
xylem is dead and transports water and dissolved ions it only goes down towards the roots, whilst phloem is alive and transports water and minerals and travels both up and down. I hope that made sense
Post by: Skidous on October 09, 2016, 09:40:25 pm
Hey guys could someone simplify the move of materials in xylem and phloem. I'm having trouble understanding this dotpoint.Xylem: Cohesion-Adhesion-Tension Theory
Step 1: Water enters the plant through the root hairs via osmosis
Step 2: As a water molecule transpires in the leaves, another one is ‘pulled up’ the column of water in the xylem by the negative pressure (tension) created to replace it.
Step 3: Another water molecule enters the plant by osmosis at the bottom of the xylem to replace the one that was lost through transpiration.
Cohesion is prevalent through the water molecules sticking together, adhesion is the water molecules adhering to the cellulose molecules of the xylem wall.
Phloem: The Pressure-Flow Theory
Step 1: Loading at the Source
Amino acids, sucrose and other mineral nutrients are loaded into the phloem in the leaves. There are two theories as to how this may occur:
1. symplastic loading—sugars and other nutrients move in the cytoplasm from the mesophyll cells to the sieve elements through plasmodesmata (strands of cytoplasm that pass through pits in the cell walls)
2. apoplastic loading—sugars and nutrients move along a pathway through the cell walls until they reach the sieve element. They then cross the cell membrane to enter the phloem tube. These sugars pass into the sieve cell by active transport.
As sugars enter the phloem, the phloem sap becomes more concentrated and so the osmotic pressure at the source end is high. This draws water into the phloem, from the adjacent xylem tissue, by osmosis
Step 2: Offloading at the sinks
Materials flow to the sink. At the sink (for example roots, flowers or any other parts of the plant that need nutrients), sugars and materials are removed from the phloem by active transport.As sugars move out of the phloem, they draw water out with them (by osmosis). This results in a lower osmotic pressure (due to the higher water concentration) in the phloem at the sink region.
Step 3: Pressure Flow
This difference in osmotic pressure between the source and the sink in the phloem drives the phloem sap to flow. The direction of flow depends on where the sink areas (roots or flowers) of the plant are, in relation to the source (leaves). Water can move into the phloem by osmosis at any point along the gradient. The flow is continuous, because sucrose is continually being added at one end and removed at the other
Hope this helps
Post by: Justina Shehata on October 09, 2016, 10:16:16 pm
Post by: Skidous on October 09, 2016, 10:19:50 pm
How well does someone have to perform in Biology to hit band 6's because a previous student was getting band 6's all year and performed really well in the HSC but did not get band 6 at the end of the yearThat shifts around year to year but a scaled mark of around 90 is a band 6 but that mark of 90 can change depending on how every student does on that particular exam that year and then the marks are shifted. I.e. 2014 band 6 may be 95 but 2015 band 6 may be 87.
The best way to get band 6 is to aim for the highest mark you could possible get and then it's decided from there
Post by: Justina Shehata on October 09, 2016, 10:58:58 pm
Thank you
Post by: Skidous on October 09, 2016, 11:10:36 pm
Can anyone help me with myopia and hyperopia. Im quite confused because from what I understand is that myopia results from an elongated eyeball but I thought to see long distance objects you needed a elongated eyeball and for close objects a more rounded eyeball? So if it results from an elongated eyeball, shouldn't there be a longer focal length and thus the image would fall behind the retina not in front?If your eyeball is elongated the the refractive powers of the relaxed lens would not be sufficient to refract the light into the retina but just in front of it (the lens is only part of the eyeball) and thus causing the image to be blurry when light from an object enters the eye from a far distance which I known as myopia (short-sightedness)
Thank you
When dealing to looking at objects close up and far away it is actually the lens that changes shape not the eyeball. This is known as Accommodation
When an object is closer, the light scatters more from that object, hence the ciliary body contracts which causes the suspensory ligaments to loosen and thus cause the lens to increase in curvature and achieving maximum accommodation.
When an object is further away, the light from the objects are more parallel, therefore the ciliary body relaxes, causing the suspensory ligaments to tighten and thus decreasing the curvature of the eye and minimum accommodation.
Hope this helps
Post by: kevin217 on October 10, 2016, 08:46:12 am
Xylem: Cohesion-Adhesion-Tension TheoryI'm still confused on the phloem part. Is sugar still being moved in step 3? In step 2 the sugars are already actively transported to the areas of the plant where they are needed. Shouldn't the theory end here?
Step 1: Water enters the plant through the root hairs via osmosis
Step 2: As a water molecule transpires in the leaves, another one is ‘pulled up’ the column of water in the xylem by the negative pressure (tension) created to replace it.
Step 3: Another water molecule enters the plant by osmosis at the bottom of the xylem to replace the one that was lost through transpiration.
Cohesion is prevalent through the water molecules sticking together, adhesion is the water molecules adhering to the cellulose molecules of the xylem wall.
Phloem: The Pressure-Flow Theory
Step 1: Loading at the Source
Amino acids, sucrose and other mineral nutrients are loaded into the phloem in the leaves. There are two theories as to how this may occur:
1. symplastic loading—sugars and other nutrients move in the cytoplasm from the mesophyll cells to the sieve elements through plasmodesmata (strands of cytoplasm that pass through pits in the cell walls)
2. apoplastic loading—sugars and nutrients move along a pathway through the cell walls until they reach the sieve element. They then cross the cell membrane to enter the phloem tube. These sugars pass into the sieve cell by active transport.
As sugars enter the phloem, the phloem sap becomes more concentrated and so the osmotic pressure at the source end is high. This draws water into the phloem, from the adjacent xylem tissue, by osmosis
Step 2: Offloading at the sinks
Materials flow to the sink. At the sink (for example roots, flowers or any other parts of the plant that need nutrients), sugars and materials are removed from the phloem by active transport.As sugars move out of the phloem, they draw water out with them (by osmosis). This results in a lower osmotic pressure (due to the higher water concentration) in the phloem at the sink region.
Step 3: Pressure Flow
This difference in osmotic pressure between the source and the sink in the phloem drives the phloem sap to flow. The direction of flow depends on where the sink areas (roots or flowers) of the plant are, in relation to the source (leaves). Water can move into the phloem by osmosis at any point along the gradient. The flow is continuous, because sucrose is continually being added at one end and removed at the other
Hope this helps
Post by: RuiAce on October 10, 2016, 08:56:27 am
Not a question but just a reminderShould post that impact size 36 font elsewhere so that EVERYONE can see it, not just biologists.
THE HSC REQUIRES YOU TO USE BLACK PENS
If any of you guys who still have to buy pens and other materials for the exam please keep this in mind to make sure you don't waste your moneys
Good luck to all for the English Exams coming up and then the Bio exam after that :)
Post by: Skidous on October 10, 2016, 08:58:53 am
Should post that impact size 36 font elsewhere so that EVERYONE can see it, not just biologists.
Yes it should be I just didn't know where that place was
Post by: RuiAce on October 10, 2016, 09:00:50 am
Yes it should be I just didn't know where that place wasHSC discussion thread will do lol
Because it applies to every subject and not just science, that's perhaps your best bet.
Post by: AngelicOnyx on October 10, 2016, 10:08:28 am
I'm still confused on the phloem part. Is sugar still being moved in step 3? In step 2 the sugars are already actively transported to the areas of the plant where they are needed. Shouldn't the theory end here?
Hmm I'm not excellent at Biology, but isn't the pressure flow theory a continuous process in the plant? Sugar is still being continuously added and removed, which also affects the water pressure
Post by: melprocrastinator on October 10, 2016, 10:23:27 am
Hey what did you mean by 'lose marks for things i didnt even know i needed'?
Hey!
For example it would be a four mark question, and 2 of the marks were allocated to an example... but the question never said provide or give an example.
There was also a two marker in trials about "IDENTIFYING" Darwins impact on evolution or something, and i talked about natural selection and survival of the fiitest blah blah blah, yet i only got one mark because i didnt mention his journey/ work with the darwin finches. Like i knew what that was, but i didnt think it was neccessary for a two mark identify question.
Does that make sense? hahaha
Moderator Action: Moved from the How to Get Band 6 in Biology Thread to Biology Question Thread to make it easier for other forum users to see the question and get the answer as it may assist them in their studies. Thanks for asking the question though :)
Post by: Skidous on October 10, 2016, 10:46:27 am
Hey!
For example it would be a four mark question, and 2 of the marks were allocated to an example... but the question never said provide or give an example.
There was also a two marker in trials about "IDENTIFYING" Darwins impact on evolution or something, and i talked about natural selection and survival of the fiitest blah blah blah, yet i only got one mark because i didnt mention his journey/ work with the darwin finches. Like i knew what that was, but i didnt think it was neccessary for a two mark identify question.
Does that make sense? hahaha
Hey melprocrastinator
Your questions is sorta hard to understand, do you happen to have a copy of the question or maybe what paper it is from so I can help you out?
Post by: studybuddy7777 on October 10, 2016, 12:22:07 pm
Hey!
For example it would be a four mark question, and 2 of the marks were allocated to an example... but the question never said provide or give an example.
There was also a two marker in trials about "IDENTIFYING" Darwins impact on evolution or something, and i talked about natural selection and survival of the fiitest blah blah blah, yet i only got one mark because i didnt mention his journey/ work with the darwin finches. Like i knew what that was, but i didnt think it was neccessary for a two mark identify question.
Does that make sense? hahaha
Was this the question?
Question 27 (5 marks)
a) Outline the contributions of Charles Darwin to the theory of evolution. (2)
or this one?
Question 27 (5 marks)
a) Identify such a scientist and their theory of evolution (2)
In the case of the second one, you could basically draw up a table saying
"Scientist" (Darwin/Wallace or Lamarck or Gould) and "Theory of Evolution" (Evolution by Natural Selection or Acquired characterisitcs or punctuated equilibrium)
To be safe for D/W you could say, his work with his finches on the galapagos islands led to him producing the "origins of species" reporting his findings in 1850. This led to the theory of evolution by natural selection.
Could you please explain the question where you "lost marks for things you didnt know you needed?"
Thanks and hope this helps
Post by: Justina Shehata on October 10, 2016, 03:49:04 pm
If your eyeball is elongated the the refractive powers of the relaxed lens would not be sufficient to refract the light into the retina but just in front of it (the lens is only part of the eyeball) and thus causing the image to be blurry when light from an object enters the eye from a far distance which I known as myopia (short-sightedness)
When dealing to looking at objects close up and far away it is actually the lens that changes shape not the eyeball. This is known as Accommodation
When an object is closer, the light scatters more from that object, hence the ciliary body contracts which causes the suspensory ligaments to loosen and thus cause the lens to increase in curvature and achieving maximum accommodation.
When an object is further away, the light from the objects are more parallel, therefore the ciliary body relaxes, causing the suspensory ligaments to tighten and thus decreasing the curvature of the eye and minimum accommodation.
Hope this helps
Thank you so much! This was very helpful!
Post by: Skidous on October 10, 2016, 03:56:06 pm
I'm still confused on the phloem part. Is sugar still being moved in step 3? In step 2 the sugars are already actively transported to the areas of the plant where they are needed. Shouldn't the theory end here?No as the sugar is describing how it enters one sink not other sinks
Hmm I'm not excellent at Biology, but isn't the pressure flow theory a continuous process in the plant? Sugar is still being continuously added and removed, which also affects the water pressure
Yes that is correct, this process is ongoing as sugar enters one sink, another is produced and sugar is added to the source and is constantly flowed throughout the organism. Similar to human blood, your blood doesn't stop flowing when it has dropped off its products and taken the waste, the blood is flowed through the rest of your body back towards the heart and excretory organs and the lungs etc.
So it doesn't end at one step it's a process
Step two is the Source of the sugars, step 2 is sugar in those sinks and step 3 involves the movement of said sugars from the sources to the sinks
Post by: Nialllovespie on October 10, 2016, 08:17:40 pm
Also,
Any tips for how to prepare for/do well in a biology practical Assessment task?
Thank you!!
Moderator Action: Merged topic with the question thread to make it easier for all bio students to access the information. Please post any more questions you may have to this thread, we're always happy to help here :)
Post by: studybuddy7777 on October 10, 2016, 08:24:47 pm
Does anyone have any Maintaining A Balance HSC exam questions or practice papers?
Also,
Any tips for how to prepare for/do well in a biology practical Assessment task?
Thank you!!
Hey Niall,
I'm assuming you are a HSC 2017 student?
Firstly, I will upload (soon) a topic guide for all HSC's 2001-2015 so you will be able to see what questions are applicable for the Maintaining A Balance module.
Secondly, you probably already know that you can find all past HSC exams for Bio on the BOSTES website, but are you aware you can look at past/exemplar responses? Look through these and distinguish what the difference is between a Band 4/5 and a Band 5/6.
Best of luck and for the practical assessment just make sure to control all variables and just get familiar with practical (first hand investigations)
Hope i helped! :)
Moderator Action: Merged topic with the question thread to make it easier for all bio students to access the information :)
Post by: Skidous on October 11, 2016, 12:54:41 pm
Does anyone have any Maintaining A Balance HSC exam questions or practice papers?Hi there,
Also,
Any tips for how to prepare for/do well in a biology practical Assessment task?
Thank you!!
For the practical task there are 2 things you will need to do to prepare
1: Know how to perform the practical task - This may be a no brainer to some but it would be wise to have a practical written up as if you were doing the experiment yourself (aim, hypothesis, equipment/aparatus, variables, safety, method, results (or expected results), discussion[validity, reliability and accuracy]) and then make sure that when you get into the assessment room you perform the experiment quickly as there will more than likely be written questions about the prac and about other information which brings me to the next thing
2: Know background information about your prac - I assume that this task will be an enzyme prac, so you should try to know background information about the enzyme you're using, the substrate it reacts to along with the theories behind enzyme-substrate interactions (Lock and Key Model and the Induced Fit Model) and other things about what the enzyme is, what happens to the enzymes when they are outside their specific optimum ranges (for temperature and pH which you should know for that specific enzyme that is being used in the experiment), the role of enzymes in homeostasis and then any information that could assist with answering short answer questions in the exam
In the exam room, time is of the essence so you'll need to manage your time and wanting to get the experiment done quickly and efficiently (you wanna get 2 trials of the experiment done, maybe 3 if you're lucky) and even if you only get one trial done or the results contradict the theory, state that in your short answers and relate it back to the validity, reliability and accuracy of your experiment. Then you will need to be managing your time well in the short answers so you have time to look over the experiment and any of the short answers that may be wrong.
Don't forget to check the back page of the exam in case you may have missed a question which you don't want
Hope this Helps
Moderator Action: Merged topic with the question thread to make it easier for all bio students to access the information :)
Post by: lha on October 15, 2016, 04:13:53 pm
Explain the relationship between replication of DNA and evolution.
Do I have to describe the process of DNA replication (helicase etc.) or no?
Post by: Skidous on October 15, 2016, 04:53:54 pm
For this question (5 marks):
Explain the relationship between replication of DNA and evolution.
Do I have to describe the process of DNA replication (helicase etc.) or no?
You would probably refer to some of the DNA replication process but then link that to the meiosis process because it talks about DNA and evolution
Post by: imtrying on October 15, 2016, 04:55:49 pm
So I was just doing a past paper where it said that Mendel's monohybrid cross was of tall pea plants x short pea plants. we were always taught that it was smooth peas x wrinkled peas. if i were to get a question that didnt specify what cross mendel did, and asked me to outline his experiment, what should i do? is it ok to just go with what i was originally taught?
Post by: aimbotted on October 15, 2016, 04:56:04 pm
You would probably refer to some of the DNA replication process but then link that to the meiosis process because it talks about DNA and evolution
hmm would you not talk about evolution as in mutations which changes the dna, which then gets replicated aswell?
Post by: lha on October 15, 2016, 04:57:21 pm
hmm would you not talk about evolution as in mutations which changes the dna, which then gets replicated aswell?
Yeah thats what i thought... but also, why would you talk about meiosis? Its asking about dna replication, not just dna itself
Post by: Skidous on October 15, 2016, 04:57:36 pm
hmm would you not talk about evolution as in mutations which changes the dna, which then gets replicated aswell?
Yes you are also correct with that knowledge but you would then need to link that to the replication process AND explain how some mutations are not always beneficial
Post by: Skidous on October 15, 2016, 05:02:23 pm
Hey:)
So I was just doing a past paper where it said that Mendel's monohybrid cross was of tall pea plants x short pea plants. we were always taught that it was smooth peas x wrinkled peas. if i were to get a question that didnt specify what cross mendel did, and asked me to outline his experiment, what should i do? is it ok to just go with what i was originally taught?
Mendel actually did several experiments not just those 2. They were
Pea Shape (smooth or wrinkled)
Pea Colour (yellow and green)
Pea Pod Colour (Yellow and green)
Pea Pod Shape (Smooth or constricted)
Stem Length (tall or short)
Flower Colour (white or pink)
Pea/Flower (not too sure of which one) positioning (Axial [along the whole stem] or Terminal [just the top])
If asked to outline his experiment you would choose on of the traits, preferably the one you know the best. Then proceed to describe the experiment. Always do what you know best if it was what you were taught. You don't need to stress about knowing all 7 traits but knowing the experiment and knowing which trait was dominant and recessive should suffice.
Hope this helps
Post by: Skidous on October 15, 2016, 05:04:05 pm
Yeah thats what i thought... but also, why would you talk about meiosis? Its asking about dna replication, not just dna itself
Before meiosis takes place, the DNA replicated within the cells to produce the increased number of chromosomes within the nucleus before the meiosis begins, hence why you can talk about it and you can then talk about the different types of alleles that are made and how those are then replicated to promote variations and therefore evolution
Post by: lha on October 15, 2016, 05:05:28 pm
Before meiosis takes place, the DNA replicated within the cells to produce the increased number of chromosomes within the nucleus before the meiosis begins, hence why you can talk about it and you can then talk about the different types of alleles that are made and how those are then replicated to promote variations and therefore evolution
Ohh thanks!
Post by: imtrying on October 15, 2016, 05:05:42 pm
Mendel actually did several experiments not just those 2. They were
Pea Shape (smooth or wrinkled)
Pea Colour (yellow and green)
Pea Pod Colour (Yellow and green)
Pea Pod Shape (Smooth or constricted)
Stem Length (tall or short)
Flower Colour (white or pink)
Pea/Flower (not too sure of which one) positioning (Axial [along the whole stem] or Terminal [just the top])
If asked to outline his experiment you would choose on of the traits, preferably the one you know the best. Then proceed to describe the experiment. Always do what you know best if it was what you were taught. You don't need to stress about knowing all 7 traits but knowing the experiment and knowing which trait was dominant and recessive should suffice.
Hope this helps
Thank you!! This helps heaps:)
Post by: kevin217 on October 15, 2016, 05:24:08 pm
Also could you guys explain what the control would be? My excel book says "Temperature/volume medium" so I think they are getting it mixed up with controlled variables. The Bostes answers say "sterilised water" which I'm not exactly too sure why.
Post by: Skidous on October 15, 2016, 05:47:25 pm
For dependent variable is "characteristics of microbe colony growth on agar plate" an acceptable answer?
Also could you guys explain what the control would be? My excel book says "Temperature/volume medium" so I think they are getting it mixed up with controlled variables. The Bostes answers say "sterilised water" which I'm not exactly too sure why.
For dependent variable you would be looking at microbial growth in general not necessarily the characteristics of it.
The control for this experiment would be sterilised water as you want to confirm whether or not the agar plates were contaminated.
What your textbook described was a controlled VARIABLE and not a controlled experiment where no independent variable is added (sterilised water would not promote microbial growth)
Hope this helps
Post by: kevin217 on October 15, 2016, 07:06:20 pm
For dependent variable you would be looking at microbial growth in general not necessarily the characteristics of it.Thanks for the insight. But for the control, you said it is to confirm whether or not there are contaminants on the agar plate that produce microbes. Could an agar plate just by itself be a control as well?
The control for this experiment would be sterilised water as you want to confirm whether or not the agar plates were contaminated.
What your textbook described was a controlled VARIABLE and not a controlled experiment where no independent variable is added (sterilised water would not promote microbial growth)
Hope this helps
Post by: Skidous on October 15, 2016, 07:10:02 pm
Thanks for the insight. But for the control, you said it is to confirm whether or not there are contaminants on the agar plate that produce microbes. Could an agar plate just by itself be a control as well?
Yes it could be, but since this question asks about food or water it'll be easier to use one of those that has no bacteria.
(Also to express control experiments its to show what the independent variable does within the experiment (which then produces the dependent variable) and then allows for comparison)
Post by: aimbotted on October 15, 2016, 08:41:15 pm
Post by: Skidous on October 15, 2016, 09:20:07 pm
skidoos! talking about meiosis can you help me out with this question?
You would need to draw all the different types of daughter cells
EBG/EBg/EbG/Ebg
Each of these have equal opportunities to be daughter cells so their expected frequency should be 1/4 for each
This is because each of these pairs have 4 chromatids and this have a 2/8 chance of becoming gametes and hence an expected frequency of 1/4
Post by: Justina Shehata on October 15, 2016, 10:29:48 pm
Post by: kevin217 on October 15, 2016, 10:32:10 pm
What are the sizes of the red and white blood cells and the units we measure them in?They're measured in micrometres (μm). Red blood cell is approx 6-8 μm and white blood cells are approx 10-12 μm
Post by: Skidous on October 15, 2016, 10:33:07 pm
What are the sizes of the red and white blood cells and the units we measure them in?
Red Blood Cells (RBC) are approximately 8 micrometers
White Blood Cells (leukocytes) are 12-15 micrometers
Don't forget about the biconvex shape of RBC
Post by: Skidous on October 15, 2016, 10:35:02 pm
They're measured in micrometres (μm). Red blood cell is approx 6-8 μm and white blood cells are approx 10-12 μm
White blood cells (more specifically neutrophils which make up 70% of the white blood cells in our body) are 12-15 μm
Post by: kevin217 on October 15, 2016, 11:14:40 pm
White blood cells (more specifically neutrophils which make up 70% of the white blood cells in our body) are 12-15 μmI guess so but I was taught WBC were 10-12 μm
Post by: melprocrastinator on October 16, 2016, 10:13:49 am
see my problem, which one is correct??
THANK YOU x
Post by: lha on October 16, 2016, 11:06:32 am
Post by: kevin217 on October 16, 2016, 11:19:17 am
Hey, i have a contradicting set of notes. The ones i wrote earlier this year, have that the blood becomes de-oxygnated at the Kidney, but my other sets says there is an increase of oxygen in the blood around the kidney...Oxygen levels in blood will decrease after it passes the kidney. Your first set of notes are correct. According to my notes, carbon dioxide is the only chemical that increases after blood passes through the kidney.
see my problem, which one is correct??
THANK YOU x
Post by: Skidous on October 16, 2016, 11:26:56 am
How many pages should you be writing for 7 and 8 markers in the exam? I know in the core topic, it gives you one page usually for the 7/8 marker but usually for all of the questions you need more lines, so how many pages is the optimal number? Also for the option topic, where there is no line indication, how many pages should we write for the long responses?
For the core topics you should actually stick to the number of lines given as they give an indication to the length of the responses in an exam, a couple lines over is ok but you want to answer the question in a concise and succinct manner.
As for the option topic I would recommend 2 pages for the 7-8 markers depending on what they are asking for the question. If it is a table it should be approximately 1 page with maybe 1/2 a page for some discussion if need be.
I hope this helps
Post by: Skidous on October 16, 2016, 11:28:25 am
Oxygen levels in blood will decrease after it passes the kidney. Your first set of notes are correct. According to my notes, carbon dioxide is the only chemical that increases after blood passes through the kidney.
Just to add onto this the only place where oxygen should increase in blood, according to my knowledge, is in the lungs where the oxygen mixes with the blood and removes CO2. Everywhere else in the body oxygen in the blood should be decreasing as cells take oxygen for respiration
Post by: Skidous on October 16, 2016, 11:29:51 am
I guess so but I was taught WBC were 10-12 μm
Some text books have this but if you do some research using google you can find different answers, 12 μm is not incorrect but 10 may be too small, just as 15 may be too large so it would be wise to remember that WBC are at least 12μm in diameter
Post by: melprocrastinator on October 16, 2016, 12:55:33 pm
Oxygen levels in blood will decrease after it passes the kidney. Your first set of notes are correct. According to my notes, carbon dioxide is the only chemical that increases after blood passes through the kidney.
Ok, cool, thanks.
Just to add onto this the only place where oxygen should increase in blood, according to my knowledge, is in the lungs where the oxygen mixes with the blood and removes CO2. Everywhere else in the body oxygen in the blood should be decreasing as cells take oxygen for respiration
does that mean Co2 rises in the blood when it goes past the lungs??
Post by: Skidous on October 16, 2016, 12:59:11 pm
Ok, cool, thanks.
does that mean Co2 rises in the blood when it goes past the lungs??
The CO2 lowers when it goes past the lungs and increases when it passes through all other organs
Post by: melprocrastinator on October 16, 2016, 05:00:17 pm
The CO2 lowers when it goes past the lungs and increases when it passes through all other organs
ah ok, Thankyou!
Post by: melprocrastinator on October 17, 2016, 04:15:40 pm
Post by: imtrying on October 17, 2016, 04:23:05 pm
Are the marker molecules on the surface of transplanted organs which cause an immune response referred to as antigens or is it that they have a different MCHI molecule?
Also, one of the focus areas for the search for better health topic refer to a scientist called Macfarlane Burnet but I dont seem to have any notes on him. Is there anything specific we need to know about him?
Post by: Blissfulmelodii on October 17, 2016, 04:37:15 pm
Hey:)
Are the marker molecules on the surface of transplanted organs which cause an immune response referred to as antigens or is it that they have a different MCHI molecule?
Also, one of the focus areas for the search for better health topic refer to a scientist called Macfarlane Burnet but I dont seem to have any notes on him. Is there anything specific we need to know about him?
I'm not 100% about that first part but I can try and answer your second question. There is technically no dot point on Burnet which is probably why you don't have any notes on him, i myself only got a short paragraph intro into him when my class went through search for better health but i guess all you would really need to know about him is that he made a significant contribution to the understanding of the immune response. He investigated the reason why the immune system can respond to foreign substances without destroying its own cells in the process and concluded that immunity is gradually acquired over the course of foetal development. He did this by introducing foreign cells to foetus in utero and noted that these foreign cells were not rejected.
He also used chicken eggs to develop a way to isolate spcific viruses - allowing for creation of vaccines like the influenza vaccine
Post by: imtrying on October 17, 2016, 04:49:42 pm
I'm not 100% about that first part but I can try and answer your second question. There is technically no dot point on Burnet which is probably why you don't have any notes on him, i myself only got a short paragraph intro into him when my class went through search for better health but i guess all you would really need to know about him is that he made a significant contribution to the understanding of the immune response. He investigated the reason why the immune system can respond to foreign substances without destroying its own cells in the process and concluded that immunity is gradually acquired over the course of foetal development. He did this by introducing foreign cells to foetus in utero and noted that these foreign cells were not rejected.
He also used chicken eggs to develop a way to isolate spcific viruses - allowing for creation of vaccines like the influenza vaccine
Thanks so much! :)
Post by: Skidous on October 17, 2016, 04:52:23 pm
Hey, i have another question. I know fish produce ammonia. However, im not sure if ammonia needs a loy of water to be produced?
Ammonia readily dissolves in water so as long as there is water nearby it dilutes very easily, you just have to be concerned with the concentration of the secretion based up freshwater and marine fish
Post by: Skidous on October 17, 2016, 04:55:59 pm
Hey:)
Are the marker molecules on the surface of transplanted organs which cause an immune response referred to as antigens or is it that they have a different MCHI molecule?
Also, one of the focus areas for the search for better health topic refer to a scientist called Macfarlane Burnet but I dont seem to have any notes on him. Is there anything specific we need to know about him?
Marker molecules are actually protein flags on all of the tissues within the body. The reason why an immune response occurs is due to the fact that invading foreign bodies (not necessarily pathogens) have different sets of these flags (different types, too many, too little or none at all) and that triggers an immune response as the body detects the antigen as 'Non-Self'
When an organ is transplanted that isn't similar to the patient's tissue type or when a person who has had a transplant stops taking immunosuppressants then the immune response attacks the organ.
The protein flags themselves are not antigens but the human immune system recognises them as non-self and will treat the organ as though it is an antigen.
Hope this helps
Post by: Blissfulmelodii on October 17, 2016, 04:59:57 pm
Marker molecules are actually protein flags on all of the tissues within the body. The reason why an immune response occurs is due to the fact that invading foreign bodies (not necessarily pathogens) have different sets of these flags (different types, too many, too little or none at all) and that triggers an immune response as the body detects the antigen as 'Non-Self'
When an organ is transplanted that isn't similar to the patient's tissue type or when a person who has had a transplant stops taking immunosuppressants then the immune response attacks the organ.
The protein flags themselves are not antigens but the human immune system recognises them as non-self and will treat the organ as though it is an antigen.
Hope this helps
Though i did not ask the question, that actually really helped me understand. Thank you for responding!
Post by: imtrying on October 17, 2016, 05:03:08 pm
Marker molecules are actually protein flags on all of the tissues within the body. The reason why an immune response occurs is due to the fact that invading foreign bodies (not necessarily pathogens) have different sets of these flags (different types, too many, too little or none at all) and that triggers an immune response as the body detects the antigen as 'Non-Self'Thanks! That helped heaps:)
When an organ is transplanted that isn't similar to the patient's tissue type or when a person who has had a transplant stops taking immunosuppressants then the immune response attacks the organ.
The protein flags themselves are not antigens but the human immune system recognises them as non-self and will treat the organ as though it is an antigen.
Hope this helps
Post by: imtrying on October 17, 2016, 06:34:54 pm
In the Communication topic there's a dot point that says a nerve is a bundle of neuronal fibres. Are neuronal fibres just neurones?
Post by: studybuddy7777 on October 17, 2016, 06:41:52 pm
Hi again:)Hey imtrying,
In the Communication topic there's a dot point that says a nerve is a bundle of neuronal fibres. Are neuronal fibres just neurones?
These are sometimes also called axons, but in essence neuronal fibres and neurones are the same thing.
If we want to get specific: a neurone consist of axons, cell body and dendrites. So a neurone consists of neuronal fibres.
This may lead to the question: what is an axon? Simply put axons take information away from the cell body.
Post by: imtrying on October 17, 2016, 06:47:12 pm
Hey imtrying,Thanks!
These are sometimes also called axons, but in essence neuronal fibres and neurones are the same thing.
If we want to get specific: a neurone consist of axons, cell body and dendrites. So a neurone consists of neuronal fibres.
This may lead to the question: what is an axon? Simply put axons take information away from the cell body.
Post by: 006609 on October 17, 2016, 06:54:16 pm
I was wondering if you could explain the difference between prevention and control in terms of malaria?
I personally believe prevention has to do with vaccines and control with other measures such as mosquito nets and appropriate clothing. But
couldn't some control measures be regarded as prevention as well? Sorry, I've just gotten confused...
Thanks in advance!!
Post by: Skidous on October 17, 2016, 07:03:28 pm
Hi!
I was wondering if you could explain the difference between prevention and control in terms of malaria?
I personally believe prevention has to do with vaccines and control with other measures such as mosquito nets and appropriate clothing. But
couldn't some control measures be regarded as prevention as well? Sorry, I've just gotten confused...
Thanks in advance!!
Hey, so prevention is the use of antimalarial drugs (since there is not a vaccine for malaria yet) and other forms of protections such as repellents and long clothing (long-sleeves on shirts and pants)
Control has to deal with the maintenance of the vectors or causes for the disease. This in the past has been DDT and removal of swamps that promote mosquito growth but has changed to other methods such as the IRS as a preventative also seeks to help control malarial infections in Africa. Vector management plans are also set in place to control the spread of malaria by Anopheles
Post by: Blissfulmelodii on October 17, 2016, 07:05:20 pm
Hi!
I was wondering if you could explain the difference between prevention and control in terms of malaria?
I personally believe prevention has to do with vaccines and control with other measures such as mosquito nets and appropriate clothing. But
couldn't some control measures be regarded as prevention as well? Sorry, I've just gotten confused...
Thanks in advance!!
For malaria prevention would be not allowing mosquito's to bite humans (and that's your mosquito nets, protective clothing, insect repellent etc) and the control would be breaking the plasmodium's life cycle (so draining swamps, killing mosquito's with insecticides etc)
As for the actual terms of prevention and control don't take my word for it but I think that has more to do with short term vs long term fixes... Prevention is looking at an immediate way to stop from catching the disease while control is looking at long term measures to stop the spread
Post by: Skidous on October 17, 2016, 07:06:46 pm
"Hi, I just answered Q31 of 2011 HSC. I included biological understanding surrounding the mutagenic nature of radiation through Beadle and Tatum, knowledge of polypeptide sequences and bacterial/microflora imbalances - when I checked sample answers only polypeptides were mentioned. The marking criteria did not give specific examples - Am I technically correct? Because these advancements were the most obvious at the time for me, does it matter what scientists or what historical advancements I include?
Thanks for your time"
(http://uploads.tapatalk-cdn.com/20161017/fe01865e54538b994470f96ec48c775b.jpg)
My response to this was
Well you are not incorrect with the first 2 but what you should base it around is not Beadle and Tatum and other scientists such as Pasteur and Koch who discovered that microbes and pathogens caused diseases and not spontaneous generation/miasma theory. And you could also talk about the discovery of penicillin by Alexander Fleming to the development of other antibiotics as well as how their misuse has lead to antibiotic resistant bacteria such as MRSA and VRSA.
Hope this helps you guys
Post by: Skidous on October 17, 2016, 07:09:37 pm
Hey imtrying,
These are sometimes also called axons, but in essence neuronal fibres and neurones are the same thing.
If we want to get specific: a neurone consist of axons, cell body and dendrites. So a neurone consists of neuronal fibres.
This may lead to the question: what is an axon? Simply put axons take information away from the cell body.
Actually no, that is incorrect
A NERUONE is a single nerve cell containing the soma, axon and dendrites
A Neruonal Fibre is a collection of axons from many nerones. This what a Nerve is.
To simplify it: Neuron-Nerve Cell
Neuronal Fibres- Many Neurons
Post by: imtrying on October 17, 2016, 07:21:35 pm
also, i noticed that extra clarification on my last question, thanks:)
Post by: Sssssrr on October 17, 2016, 07:25:32 pm
when a dotpoint say 'process information from secondary sources', does that mean that they'll provide information in the exam which we interpret, or do we have to go in with info already memorised to answer the question?
thanks!
Post by: Skidous on October 17, 2016, 07:27:10 pm
when it comes to the electrochemical changes that occur in the membranes of neurons, what initially stimulates the movement of ions?
also, i noticed that extra clarification on my last question, thanks:)
There are actually 3 channels on a neuron that allows Na to enter the membrane
Ligand-Gated Channels: Respond to neurotransmitters
Mechanically-Gated Channels: They open to physically motion such as stretching it
Voltage-Gated Channels: These open once the membrane threshold is reached (-55mV)
Once one part of the membrane reaches peak depolarisation (40mV) this stimulates other voltage gated channels along the neuron to also open and then move that change along the neuron to the synapses
After this the sodium channels close and the Potassium channels open letting out too much of the Potassium where the membrane is in hyperpolarisation (-75mv) and the Sodium Potassium pump brings the membrane back to resting potential (-70mV)
Nb action potential is a all-or-none effect where if the stimuli does not cause the membrane to reach -55mV then a graded potential occurs where it is only in the localised area and the membrane quickly returns to its resting potential
Another NB this all takes place in the span of 4 MILLOSECONDS! Now if only wifi was that fast
Hope this helps
Post by: Blissfulmelodii on October 17, 2016, 07:30:02 pm
hi,
when a dotpoint say 'process information from secondary sources', does that mean that they'll provide information in the exam which we interpret, or do we have to go in with info already memorised to answer the question?
thanks!
Usually when they say something about secondary sources it means you need to go and do your own research. In the exam they would have specific questions for you to integrate that knowledge. For example blood testing technology is something that you go and research about and i have seen questions asking about pulse oximeter etc.
Post by: Skidous on October 17, 2016, 07:30:33 pm
hi,
when a dotpoint say 'process information from secondary sources', does that mean that they'll provide information in the exam which we interpret, or do we have to go in with info already memorised to answer the question?
thanks!
When it talks about processing secondary sources you will normally relate it to 2 parts
1: The actual research (so your own knowledge from past research tasks or assessments/exams)
2: The analysis of that secondary source (validity, reliability and accuracy)
Validity: is who has written the secondary source (qualifications- do they work in the field you are researching, do they have bias, are they well known)
Reliability: Cross-Referencing the info gathered with other valid sources (if it's the same then the source is valid)
Accuracy: Relevance to the task (is it helpful, does it answer your question, is it recent data [usually gathered within the last 5-10 years] and is it reliable and valid)
Hope this helps
Post by: imtrying on October 17, 2016, 07:39:09 pm
Whats the go with synapses and neurotransmitters? Would i be right in saying that when the impulse reaches the synapse at the end of the axon, a neurotransmitter is released and this allows the electrical impulse to be changed to a chemical one as it crosses the synapse and then back to electrical impulse at the dendrites?
Post by: :3 on October 17, 2016, 07:43:16 pm
Very sorry to keep asking questions in different posts...im finding the neuron thing a bit confusing.
Whats the go with synapses and neurotransmitters? Would i be right in saying that when the impulse reaches the synapse at the end of the axon, a neurotransmitter is released and this allows the electrical impulse to be changed to a chemical one as it crosses the synapse and then back to electrical impulse at the dendrites?
Precisely. Except, that the neurotransmitter diffuses to the next dendrite and stimulates a new, but same electrical impulse at the dendrites.
Post by: Blissfulmelodii on October 17, 2016, 07:46:09 pm
Precisely. Except, that the neurotransmitter diffuses to the next dendrite and stimulates a new, but same electrical impulse at the dendrites.
Is it concerning that my class is also doing communication yet I am not understanding any of this?? Honestly the only thing that makes sense to me from that topic is the eye and ear stuff...
Post by: Skidous on October 17, 2016, 07:47:18 pm
Very sorry to keep asking questions in different posts...im finding the neuron thing a bit confusing.
Whats the go with synapses and neurotransmitters? Would i be right in saying that when the impulse reaches the synapse at the end of the axon, a neurotransmitter is released and this allows the electrical impulse to be changed to a chemical one as it crosses the synapse and then back to electrical impulse at the dendrites?
This would be corrects, however there are 2 types of this transmission
Sometimes the signal stays electrical which allows for fast communication to all other associated neurons
Other synapses are chemically based which, when an action potential occurs, causes the release of specific neurotransmitters to open ligand gates channels to promote the action potential in the next neuron and so on.
This vid could help you understand them a little better: https://m.youtube.com/watch?v=VitFvNvRIIY
Hope this helps
Post by: Skidous on October 17, 2016, 07:48:45 pm
Is it concerning that my class is also doing communication yet I am not understanding any of this?? Honestly the only thing that makes sense to me from that topic is the eye and ear stuff...
That's ok, we all have our weaknesses and strength in subjects, you just need to focus more on the stuff you do not understand or remember rather than on what you do know. If you don't understand something ask a classmate, a teacher, or even post it here, IM sure I can help
Hope to see you soon :)
Post by: justdoit on October 17, 2016, 07:58:23 pm
I have a few bio MC questions to ask, i dont understand why i got them wrong so here goes ...
An extremely high concentration of carbon dioxide is undesirable in active muscle tissue
because it will
(A) increase the pH.
(B) cause enzymes to denature.
(C) increase cellular reaction rates.
(D) cause haemoglobin to release oxygen.
My answer was D, which im pretty sure is right BUT the answers said B???
The following measures could be used to prevent the spread of this fruit fly across
Australia.
1. Australia-wide release of infertile fruit flies
2. Aerial spraying of orchards throughout the country
3. Spot spraying of newly affected orchards in Western Australia
4. Stopping the transport of fruit from Western Australia to other states
To prevent the spread of this fruit fly across Australia, which combination of measures
would be most practical to use?
(A) 1 and 2
(B) 1 and 4
(C) 2 and 3
(D) 3 and 4
I put B because I though of prevention, which includes the use of genetic engineering... doesnt it? but the answers says D
If someone can help differentiate between control, prevention and treatment. That would be great :)
Why might epidemiology be considered more essential for the study of non‑infectious
diseases than for the study of infectious diseases?
(A) The causes of infectious diseases have already been determined.
(B) Only non‑infectious diseases are affected by patterns of behaviour.
(C) Epidemiology cannot be used to find the causes of infectious diseases.
(D) Koch’s postulates are not useful in finding the causes of non‑infectious disease
How the hell is it D ???
Students conducted a large first-hand investigation into enzyme activity.
The aim in the report is shown.
Aim: To determine the optimum pH of four different enzymes.
How many independent variables were in this first-hand investigation?
(A) 1
(B) 2
(C) 4
(D) 5
For an experiment to be valid shouldnt it change ONE variable at a time, then how come the answer is B
Also q. 17 from the 2015 paper, how is C not D
VERY MUCH APPRECIATE ANY HELP :)
Post by: aimbotted on October 17, 2016, 08:08:18 pm
HEYY GUYS!
I have a few bio MC questions to ask, i dont understand why i got them wrong so here goes ...
An extremely high concentration of carbon dioxide is undesirable in active muscle tissue
because it will
(A) increase the pH.
(B) cause enzymes to denature.
(C) increase cellular reaction rates.
(D) cause haemoglobin to release oxygen.
My answer was D, which im pretty sure is right BUT the answers said B???
The following measures could be used to prevent the spread of this fruit fly across
Australia.
1. Australia-wide release of infertile fruit flies
2. Aerial spraying of orchards throughout the country
3. Spot spraying of newly affected orchards in Western Australia
4. Stopping the transport of fruit from Western Australia to other states
To prevent the spread of this fruit fly across Australia, which combination of measures
would be most practical to use?
(A) 1 and 2
(B) 1 and 4
(C) 2 and 3
(D) 3 and 4
I put B because I though of prevention, which includes the use of genetic engineering... doesnt it? but the answers says D
If someone can help differentiate between control, prevention and treatment. That would be great :)
Why might epidemiology be considered more essential for the study of non‑infectious
diseases than for the study of infectious diseases?
(A) The causes of infectious diseases have already been determined.
(B) Only non‑infectious diseases are affected by patterns of behaviour.
(C) Epidemiology cannot be used to find the causes of infectious diseases.
(D) Koch’s postulates are not useful in finding the causes of non‑infectious disease
How the hell is it D ???
Students conducted a large first-hand investigation into enzyme activity.
The aim in the report is shown.
Aim: To determine the optimum pH of four different enzymes.
How many independent variables were in this first-hand investigation?
(A) 1
(B) 2
(C) 4
(D) 5
For an experiment to be valid shouldnt it change ONE variable at a time, then how come the answer is B
Also q. 17 from the 2015 paper, how is C not D
VERY MUCH APPRECIATE ANY HELP :)
well for the first one, we know that an abundance of carbon dioxide in cells will lead to carbonic acid which leads to a decrease in pH = denature
the flies one its because using infertile flies takes time for flies to die, and spraying every orchid in australia is very costly and time consuming
no idea about the epidimology one
the question says determine the optimum PH of FOUR different enzymes. so you are changing the enzyme and the ph
not sure if i'm correct though
Post by: Skidous on October 17, 2016, 08:09:36 pm
HEYY GUYS!
I have a few bio MC questions to ask, i dont understand why i got them wrong so here goes ...
An extremely high concentration of carbon dioxide is undesirable in active muscle tissue
because it will
(A) increase the pH.
(B) cause enzymes to denature.
(C) increase cellular reaction rates.
(D) cause haemoglobin to release oxygen.
My answer was D, which im pretty sure is right BUT the answers said B???
The following measures could be used to prevent the spread of this fruit fly across
Australia.
1. Australia-wide release of infertile fruit flies
2. Aerial spraying of orchards throughout the country
3. Spot spraying of newly affected orchards in Western Australia
4. Stopping the transport of fruit from Western Australia to other states
To prevent the spread of this fruit fly across Australia, which combination of measures
would be most practical to use?
(A) 1 and 2
(B) 1 and 4
(C) 2 and 3
(D) 3 and 4
I put B because I though of prevention, which includes the use of genetic engineering... doesnt it? but the answers says D
If someone can help differentiate between control, prevention and treatment. That would be great :)
Why might epidemiology be considered more essential for the study of non‑infectious
diseases than for the study of infectious diseases?
(A) The causes of infectious diseases have already been determined.
(B) Only non‑infectious diseases are affected by patterns of behaviour.
(C) Epidemiology cannot be used to find the causes of infectious diseases.
(D) Koch’s postulates are not useful in finding the causes of non‑infectious disease
How the hell is it D ???
Students conducted a large first-hand investigation into enzyme activity.
The aim in the report is shown.
Aim: To determine the optimum pH of four different enzymes.
How many independent variables were in this first-hand investigation?
(A) 1
(B) 2
(C) 4
(D) 5
For an experiment to be valid shouldnt it change ONE variable at a time, then how come the answer is B
Also q. 17 from the 2015 paper, how is C not D
VERY MUCH APPRECIATE ANY HELP :)
For the first question
CO2 cause an increase in acidity, decreasing the pH of the blood and the surrounding environment, which results in enzymes being out of their optimum and tolerance range causing them to denature which is why it is B. Whilst D DOES occur in the blood the reason why it does that is actually beneficial as it supplies organs with oxygen whilst sending CO2 to the lungs to be excreted.
2nd Question
The question asks for prevention of spread of the flies. 1 would not be very efficient as there would still be fertile flies to mate with whilst the infertile ones would die out.
2 is incredibly costly and ineffective
That leaves 3 and 4. 3 allows for a more cost effective way of treating infected plants whilst 4 prevents flies using fruit as a means of transport from getting into areas with unaffected orchids which is why it's D
3rd Question
Koch'a Postulates only work for infectious diseases as they rely on specific pathogens.
Non-infectious disease are cause by environmental, lifestyle and genetics that cannot be passed between people (excluding hereditary) and therefore there is no pathogen to identify, hence why D is correct
4th question
It is 2 because it says 4 DIFFERENT enzymes so 1 of them is the pH and the other is the type of enzymes
Hope this helps
Post by: Skidous on October 17, 2016, 08:13:53 pm
HEYY GUYS!
I have a few bio MC questions to ask, i dont understand why i got them wrong so here goes ...
An extremely high concentration of carbon dioxide is undesirable in active muscle tissue
because it will
(A) increase the pH.
(B) cause enzymes to denature.
(C) increase cellular reaction rates.
(D) cause haemoglobin to release oxygen.
My answer was D, which im pretty sure is right BUT the answers said B???
The following measures could be used to prevent the spread of this fruit fly across
Australia.
1. Australia-wide release of infertile fruit flies
2. Aerial spraying of orchards throughout the country
3. Spot spraying of newly affected orchards in Western Australia
4. Stopping the transport of fruit from Western Australia to other states
To prevent the spread of this fruit fly across Australia, which combination of measures
would be most practical to use?
(A) 1 and 2
(B) 1 and 4
(C) 2 and 3
(D) 3 and 4
I put B because I though of prevention, which includes the use of genetic engineering... doesnt it? but the answers says D
If someone can help differentiate between control, prevention and treatment. That would be great :)
Why might epidemiology be considered more essential for the study of non‑infectious
diseases than for the study of infectious diseases?
(A) The causes of infectious diseases have already been determined.
(B) Only non‑infectious diseases are affected by patterns of behaviour.
(C) Epidemiology cannot be used to find the causes of infectious diseases.
(D) Koch’s postulates are not useful in finding the causes of non‑infectious disease
How the hell is it D ???
Students conducted a large first-hand investigation into enzyme activity.
The aim in the report is shown.
Aim: To determine the optimum pH of four different enzymes.
How many independent variables were in this first-hand investigation?
(A) 1
(B) 2
(C) 4
(D) 5
For an experiment to be valid shouldnt it change ONE variable at a time, then how come the answer is B
Also q. 17 from the 2015 paper, how is C not D
VERY MUCH APPRECIATE ANY HELP :)
As for the HSC question
(http://uploads.tapatalk-cdn.com/20161017/5e31535fa29b7b0ea7ddfc040b346910.jpg)
The reason why it is C as the antigen is displayed on a MHC molecule, it is being Presented to the specific T-Cell (in this case a T-Helper Cell) which is providing support through cytokines to turn into plasma cells
It is not D as there is no antigen within the cell and it is not giving cytoTOXINS.
An easy mistake
Hope this helps
Post by: justdoit on October 17, 2016, 08:19:38 pm
But still have 1 q. how does pH lead to denaturing, i thought it was only temperature...
Post by: Skidous on October 17, 2016, 08:23:43 pm
ohhhh, thank you so much!!!!!!!!!
But still have 1 q. how does pH lead to denaturing, i thought it was only temperature...
No it is not just temperature
Back when we got taught homeostasis, everything about the internally environment has an optimum and tolerance range. Water balance, salt balance, gases, temperature AND pH.
When these exceed this tolerance range the body does not perform at its optimum. These functions occur through the reactions between enzymes and substrate, if pH is not correct this can lead to the breakdown of proteins in enzymes and effectively making them dysfunctional and ineffective.
Think of it like dropping meat into a vat of acid, it would melt into nothing so if the pH is too low the enzymes would also denature
Hope this helps
Post by: aimbotted on October 17, 2016, 08:24:07 pm
ohhhh, thank you so much!!!!!!!!!
But still have 1 q. how does pH lead to denaturing, i thought it was only temperature...
disrupts the hydrogen bonds
Post by: Skidous on October 17, 2016, 08:25:44 pm
disrupts the hydrogen bonds
Just to expand on that, acids like to 'accept' hydrogens so they will rip them off of anything with with hydrogen in it such as proteins.
The answer suffices but just a little further explanation
Post by: Skidous on October 17, 2016, 08:35:58 pm
70 questions were answered, if you would like to take a look the link is here
https://docs.google.com/document/d/1HoR4MRbEpI-cYOfF3Hygs_kd69kjJrhs7MzsLVxevfg/preview
Post by: melprocrastinator on October 18, 2016, 07:10:27 am
Post by: Skidous on October 18, 2016, 07:35:11 am
Thanks for answering my previous question. Im wondering now, if Mendel's "factors" reffered to the 'gene' or the 'allele'. Different websites seem to be saying different things...
Mendels 'Factors' are referring to genes on chromosomes. What he was test is the dominant and recessive alleles of those genes which is how we get those Mendelian ratios
Post by: hannah11111 on October 18, 2016, 08:45:57 am
I know its really simple but I just don't understand haha, cause I keep getting multiple choice questions wrong for it
Thanks
Post by: Skidous on October 18, 2016, 08:48:59 am
Hi guys, just having a bit of trouble understanding the difference between hybridisation and transgenic species?
I know its really simple but I just don't understand haha, cause I keep getting multiple choice questions wrong for it
Thanks
Hybridisation is the breeding between different species to produce a new species (like Ligers or Mules) which are usually infertile and bred for their favourable characteristics
Transgenic Species are Species which have been genetically modified to have favourable characteristics (Bt Cotton) and these are also usually infertile.
Hope this helps
Post by: Blissfulmelodii on October 18, 2016, 02:32:24 pm
Quick question. Is comparative DNA sequencing the same thing as DNA hybridisation??
Post by: kimmie on October 18, 2016, 03:21:49 pm
Post by: Skidous on October 18, 2016, 03:32:33 pm
Hey guys
Quick question. Is comparative DNA sequencing the same thing as DNA hybridisation??
No, DNA Sequencing is just the sequencing of the base pairs.
DNA Hybridisation is matching up the DNA from 2 different species and testing the matches and mismatches (less=closely related) and the difficulty in separation (increased difficulty = closely related)
Post by: kevin217 on October 18, 2016, 03:35:11 pm
No, DNA Sequencing is just the sequencing of the base pairs.Wait aren't you describing DNA sequencing still?
DNA Hybridisation is matching up the DNA from 2 different species and testing the matches and mismatches (less=closely related) and the difficulty in separation (increased difficulty = closely related)
Post by: Skidous on October 18, 2016, 03:38:10 pm
Hey guys so I have always been confused on how to draw transverse and longitudinal sections of phloem and xylem tissue. Can someone please show me how to draw them? Because I always get them wrong :-X
Transverse
(http://uploads.tapatalk-cdn.com/20161017/427c6d523e21e6f4688baeaba01a9bd0.jpg)
Longitudinal
(http://uploads.tapatalk-cdn.com/20161017/0742dd2b824fc2774de7bec4259fbba6.jpg)
Both
(http://uploads.tapatalk-cdn.com/20161017/b3e658b9ffd0b8b5b61bdf5e9310cae7.jpg)
An easy way to remember
Transverse is circular
Longitudinal is rectangular
Post by: kevin217 on October 18, 2016, 03:38:33 pm
Hey guysFYI DNA sequencing can be part of BP1 where you have to analyse how advances in technology have changed scientific thinking about evolution. It allowed scientists to find similarities between humans and apes, thus a closer evolutionary relationship.
Quick question. Is comparative DNA sequencing the same thing as DNA hybridisation??
Post by: Skidous on October 18, 2016, 03:39:57 pm
Wait aren't you describing DNA sequencing still?
No DNA sequencing only talks about the base pairs on a single organism. So you can compare just base pairs
DNA Hybridisation actually combines 2 strands of DNA from DIFFERENT species and then tested to see how difficult it is to separate them.
I made a mistake in the first one my apologies
Post by: Blissfulmelodii on October 18, 2016, 03:41:23 pm
Wait aren't you describing DNA sequencing still?
Okay that makes sense but then how is comparative DNA sequencing used in biochemistry to show evolution?
Post by: kevin217 on October 18, 2016, 03:45:37 pm
Okay that makes sense but then how is comparative DNA sequencing used in biochemistry to show evolution?I don't know if you saw my other post. But scientists will compare the bases of DNA strands from two different species. The more similar the bases are, the more closely related the two organisms are with each other. This supports common ancestry and thus evolution.
Post by: Blissfulmelodii on October 18, 2016, 04:40:32 pm
I don't know if you saw my other post. But scientists will compare the bases of DNA strands from two different species. The more similar the bases are, the more closely related the two organisms are with each other. This supports common ancestry and thus evolution.
Yeah that's DNA hybidisation right?
So what is Comparative DNA sequencing? Isn't it the same thing?
Sorry I'm so confused right now
Post by: kimmie on October 18, 2016, 04:49:11 pm
Transverse
(http://uploads.tapatalk-cdn.com/20161017/427c6d523e21e6f4688baeaba01a9bd0.jpg)
Longitudinal
(http://uploads.tapatalk-cdn.com/20161017/0742dd2b824fc2774de7bec4259fbba6.jpg)
Both
(http://uploads.tapatalk-cdn.com/20161017/b3e658b9ffd0b8b5b61bdf5e9310cae7.jpg)
An easy way to remember
Transverse is circular
Longitudinal is rectangular
Post by: Blissfulmelodii on October 18, 2016, 04:52:00 pm
So which parts are the xylem and phloem?
The xylem is always the bit that is in the inside and the phloem is on the outside. Looking at a transverse cutting the xylem always makes an x shape in the centre.
Post by: kevin217 on October 18, 2016, 05:07:52 pm
Yeah that's DNA hybidisation right?Oh I see what you mean, I've been taught DNA sequencing involves the comparison. In that case, I would think they're the same thing.
So what is Comparative DNA sequencing? Isn't it the same thing?
Sorry I'm so confused right now
Post by: Blissfulmelodii on October 18, 2016, 05:12:53 pm
Oh I see what you mean, I've been taught DNA sequencing involves the comparison. In that case, I would think they're the same thing.
That's okay. Thanks :)
Post by: Skidous on October 18, 2016, 05:20:05 pm
Oh I see what you mean, I've been taught DNA sequencing involves the comparison. In that case, I would think they're the same thing.No they're different
Comparative DNA sequencing does not include the combination of DNA Strands, just looking at the differences in the sequencing themselves. So I just looks at the base pairs
Post by: Blissfulmelodii on October 18, 2016, 05:40:02 pm
No they're different
Comparative DNA sequencing does not include the combination of DNA Strands, just looking at the differences in the sequencing themselves. So I just looks at the base pairs
Oh okay so how is that used in biochemistry as evidence for evolution?
Post by: nibblez16 on October 18, 2016, 05:42:03 pm
:)
Post by: Skidous on October 18, 2016, 05:42:38 pm
Oh okay so how is that used in biochemistry as evidence for evolution?
Is biochemistry an option or is it a technology
As a technology if the sequenced chemicals are similar then that shows that they will exhibit similar traits and thus show evolutionary links between organisms
Post by: Skidous on October 18, 2016, 05:43:52 pm
Hello, can you please explain the answer to this question. The answer is D.
:)
Hey
So the reason it's D is because the movement of ions is AGAINST the concentration gradient (should be high to low concentrations when this one goes from low to high) which requires energy, hence it's active transport
Post by: Blissfulmelodii on October 18, 2016, 05:45:46 pm
Is biochemistry an option or is it a technology
As a technology if the sequenced chemicals are similar then that shows that they will exhibit similar traits and thus show evolutionary links between organisms
Okay thanks. Biochemistry is a branch of scientific study which is used to support evolution, so DNA sequencing would be a technology.
Thanks again!
Post by: Skidous on October 18, 2016, 05:46:53 pm
Okay thanks. Biochemistry is a branch of scientific study which is used to support evolution, so DNA sequencing would be a technology.
Thanks again!
I know it's the technology just weren't sure if it was an option topic
Post by: Elenaa on October 18, 2016, 05:48:49 pm
So i'm kinda confused on the concept of DNA replication. I don't get why it happens in meiosis, i know its for heredity and for genetic information to be passed on, but i don't understand the concept behind it, like all the chromosome and chromatid stuff.
Thanks :)
Post by: nibblez16 on October 18, 2016, 05:54:02 pm
Hey
So the reason it's D is because the movement of ions is AGAINST the concentration gradient (should be high to low concentrations when this one goes from low to high) which requires energy, hence it's active transport
Thank You! I got a little confused with osmosis and active transport :)
Post by: Skidous on October 18, 2016, 05:58:14 pm
Hi!Chromatids contain DNA and Chromosomes are comprised of 2 chromatids joined at the centromere
So i'm kinda confused on the concept of DNA replication. I don't get why it happens in meiosis, i know its for heredity and for genetic information to be passed on, but i don't understand the concept behind it, like all the chromosome and chromatid stuff.
Thanks :)
When a cell replicates it needs a copy of DNA in order to stay alive and perform respiration
In meiosis it needs half that copy of that DNA to allow the genetic information from one person to be passed into future generations and stuff like that
Post by: katnisschung on October 18, 2016, 06:15:36 pm
looking for hsc biology past papers organised by questions according to the topics
i know there are some available online but would anyone have just a list?
thanks
Post by: Skidous on October 18, 2016, 06:18:37 pm
Hi everyone
looking for hsc biology past papers organised by questions according to the topics
i know there are some available online but would anyone have just a list?
thanks
I don't think you can find them organised by biology topics as in the HSC they appear in random order so you're better off practising papers like that.
If you need a collection of past papers you can go to Board of Studies or aceHSC.net and there will be past papers there
Post by: Blissfulmelodii on October 18, 2016, 06:26:02 pm
I know it's the technology just weren't sure if it was an option topic
ohh no it comes under Blueprint of Life
Post by: Skidous on October 18, 2016, 06:27:41 pm
ohh no it comes under Blueprint of Life
Yeah i know it does just wanted to clarify
Post by: Blissfulmelodii on October 18, 2016, 06:28:21 pm
Yeah i know it does just wanted to clarify
all good. Thanks for your help!!!
Post by: Gregs on October 18, 2016, 06:38:57 pm
Post by: Blissfulmelodii on October 18, 2016, 06:40:56 pm
Whats stopping BOSTES from asking a question worth more than 8 marks??? :'(
honestly nothing however stressing over the what ifs is not going to help, so you may as well just prepare as much as you can and not overthink the paper
Post by: Gregs on October 18, 2016, 06:44:07 pm
Post by: Skidous on October 18, 2016, 06:45:23 pm
Whats stopping BOSTES from asking a question worth more than 8 marks??? :'(
Anything above 8 marks would be an essay which is not something required of a bio student. They don't ask anything above that so you have nothing to worry about. There is nothing STOPPING them but there is also no reason FOR THEM to give a 9 or 10 mark question
Post by: Gregs on October 18, 2016, 06:46:22 pm
Post by: Skidous on October 18, 2016, 06:46:44 pm
okay cheers, was just imagining the HSC discussion group post an exam with a 20 marker in it ;D
20 markers are essays, those subjects could be SOR, English, business, legal
Basically any of the humanities subjects
Post by: Blissfulmelodii on October 18, 2016, 06:46:53 pm
okay cheers, was just imagining the HSC discussion group post an exam with a 20 marker in it ;D
Hahaha the memes and posts on that group can be hilarious at times but can also be terrifying lol just gotta filter out the irrelevant stuff sometimes
Post by: Skidous on October 18, 2016, 07:22:40 pm
Hahaha the memes and posts on that group can be hilarious at times but can also be terrifying lol just gotta filter out the irrelevant stuff sometimes
Yeah but it's a good way to relieve stress
Post by: Blissfulmelodii on October 18, 2016, 07:30:49 pm
Yeah but it's a good way to relieve stress
100% agree! It's the reason I did not give up after paper 1 hahaha
Post by: Skidous on October 18, 2016, 07:32:11 pm
Post by: Blissfulmelodii on October 18, 2016, 07:33:25 pm
True, #WhaleBoats #ButterflyDarts #FiveThousandLightYearsAway
LOL never going to look at a boat or whale the same way ;D
#walkingforpleasure
Post by: Skidous on October 18, 2016, 07:35:58 pm
LOL never going to look at a boat or whale the same way ;DSad thing is I actually don't mind walking, but I would never write an article about it.
#walkingforpleasure
Especially since the guy was named Sam Wright who is a COMEDIAN
Post by: Blissfulmelodii on October 18, 2016, 07:41:14 pm
Sad thing is I actually don't mind walking, but I would never write an article about it.
Especially since the guy was named Sam Wright who is a COMEDIAN
I feel like BOSTES always manage to find the most wacky texts for us to look at
Post by: Skidous on October 18, 2016, 07:42:03 pm
Post by: Blissfulmelodii on October 18, 2016, 07:45:00 pm
True and no visual :O
I KNOW!!! That threw me so much! and the stimulus for the creative was so highly specific. I actually had to just write a story on the sport because there was no way to adapt my prepared story
Post by: atar27 on October 18, 2016, 07:49:44 pm
can someone please helpThanks in advance!!
Post by: Skidous on October 18, 2016, 07:54:46 pm
Does anyone understand the polypeptide and how it's formed!! I get extremely confused with this aspect!! I know that there is a ribosome which 'sticks' the amino acids together to form a polypeptide. I don't even think that's right!
Thanks in advance!!
The ribosomes can bring in chains for anticodons with correspond to the codons with produce polypeptides, the chain begins with an STA amino acid and ends with a TER amino acid (terminate)
mRNA is produced when the RNA helicase unravels the DNA one rung at a time, then RNA polymerase transcribes it into mRNA
This leaves the nucleus and heads to the ribosome where it translates the mRNA into polypeptides in codons (groups of 3 base pairs) with corresponding anticodons which are free floating and release a specific polypeptide when the codon and anticodon reacts.
There are some codons that code for the same polypeptide as well.
Hope this helps
Post by: g98 on October 18, 2016, 07:56:13 pm
Thank you
Post by: Skidous on October 18, 2016, 08:00:55 pm
Hi, I was wondering if we need to know all the scientific names for animals/plants etc that we use for examples?
Thank you
That depends on the question
If it's just a plant or animal then no not really
If it's an important organism such as the fruit fly (Drosophila will suffice) in Morgans work or a vector (Anopheles mosquito for Malaria) or a bacteria used in genetic modification (Bacillus thuringiensis for Bt Cotton) you should know the scientific name for that
If you do want to know the scientific name then that's ok as well just make sure you put the binomial name written correctly (capital genus, lower cases species and italics/bold/underlined) and the common name of the organism
Hope it helps
Post by: vox nihili on October 18, 2016, 08:03:41 pm
The ribosomes can bring in chains for anticodons with correspond to the codons with produce polypeptides, the chain begins with an STA amino acid and ends with a TER amino acid (terminate)
mRNA is produced when the RNA helicase unravels the DNA one rung at a time, then RNA polymerase transcribes it into mRNA
This leaves the nucleus and heads to the ribosome where it translates the mRNA into polypeptides in codons (groups of 3 base pairs) with corresponding anticodons which are free floating and release a specific polypeptide when the codon and anticodon reacts.
There are some codons that code for the same polypeptide as well.
Hope this helps
Super picky: DNA helicase (it's the DNA being unraveled)
Post by: atar27 on October 18, 2016, 08:04:36 pm
The ribosomes can bring in chains for anticodons with correspond to the codons with produce polypeptides, the chain begins with an STA amino acid and ends with a TER amino acid (terminate)
mRNA is produced when the RNA helicase unravels the DNA one rung at a time, then RNA polymerase transcribes it into mRNA
This leaves the nucleus and heads to the ribosome where it translates the mRNA into polypeptides in codons (groups of 3 base pairs) with corresponding anticodons which are free floating and release a specific polypeptide when the codon and anticodon reacts.
There are some codons that code for the same polypeptide as well.
Hope this helps
Thank you!! But is there an easier way by any chance! Sorry I know I am a pain atm
Post by: Skidous on October 18, 2016, 08:05:29 pm
Super picky: DNA helicase (it's the DNA being unraveled)
Actually no, DNA Helicase unravels the ENTIRE DNA strand where as RNA Helicase only unravels a small section of DNA rung by rung, at least that is what we're taught
Edit: RNA Helicase is used for splicing DNA pre-mRNA
Post by: Blissfulmelodii on October 18, 2016, 08:09:23 pm
Thank you!! But is there an easier way by any chance! Sorry I know I am a pain atm
This may not be the best use of scientific language but i basically remember it as the DNA unwinds by an enzyme called helicase leaving 2 single strands. One strand is used as a template where nucleotides in the nucleus will match up with so C-G and A-T (this becomes your mRNA strand). Once it is done copying it is released from the nucleus through nuclear pores into the cytoplasm where it attaches to the ribosome and the original DNA will wind back up. tRNA then matches in groups of three to its complementary pair remembering that T is replaced with U. The released strand is your polypeptide.
Post by: Skidous on October 18, 2016, 08:09:33 pm
Post by: :3 on October 18, 2016, 08:12:34 pm
Ok, after some further research I've discovered I may be wrong and it may be the RNA polymerase that actually separates the DNA and created the mRNA at the same time. Now I'm just confused
RNA polymerase unzips the DNA (Note: does not separate the DNA completely).
Then it starts pairing up the bases with spare nucleotide to form the mRNA (Note: does not attach to the DNA).
For DNA replication:
1. Enzyme helicase unwinds and separates it.
2. Enzyme polymerase pairs the bases up of each strand with spare nucleotide.
Post by: kevin217 on October 18, 2016, 08:17:57 pm
Thank you!! But is there an easier way by any chance! Sorry I know I am a pain atmIf you're still having trouble understanding polypeptide synthesis, I recommend watching some youtube videos. They're very helpful for simplifying complicated biological processes.
Post by: Skidous on October 18, 2016, 08:18:33 pm
RNA polymerase unzips the DNA (Note: does not separate the DNA completely).
Then it starts pairing up the bases with spare nucleotide to form the mRNA (Note: does not attach to the DNA).
For DNA replication:
1. Enzyme helicase unwinds and separates it.
2. Enzyme polymerase pairs the bases up of each strand with spare nucleotide.
Yeah that's what I thought cause i remember it being opposite for RNA where in DNA polymerase adds on bases where for RNA it splits
Post by: vox nihili on October 18, 2016, 09:56:01 pm
There's clearly some confusion about helicases. I'm not familiar with the HSC course and I don't know what you guys learn and are expected to know. But the reality:
- A single DNA helicase molecule does not unwind the entire molecule of DNA. The reality is that DNA replication takes place at multiple sites along the same molecule; and these smaller strands are then ligated together after replication.
- There is a lot of information out there suggesting that RNA polymerase has helicase activity (i.e. is capable of unwinding DNA). In the case of eukaryotic RNA polymerase, this is simply not true. There are three RNA polymerases in eukaryotes—the one responsible for transcription of mRNA does not contain a helicase domain
- In transcription of mRNA, DNA is unwound by a helicase called TFIIH, which forms part of the pre-initiation complex. Before RNA polymerase can bind to DNA, a host of other proteins have to bind to prepare it; one of these proteins unwinds the DNA, ready for RNA pol
- RNA helicases unwind RNA, DNA helicases unwind DNA; ipso facto an RNA polymerase will not unwind DNA
EDIT: you don't need to know this level of detail obviously, but it seemed to turn into a bit of a shit fight and it was worthwhile stating the facts so that we can put the issue to bed. DNA is unwound by helicase (just call it that) and RNA pol gets in and smashes out a new mRNA
Post by: aimbotted on October 18, 2016, 10:09:33 pm
Post by: lha on October 19, 2016, 09:34:37 am
And also, how do we do line of best fits? What are the rules? Because everyone tells me something different
Post by: kevin217 on October 19, 2016, 09:45:32 am
In graphing questions, even if it doesnt ask for a line of best fit, do we still do it? And do we do the normal line and the line of best fit as well, and then label it as "line if best fit"?From doing past papers. If they say draw a CURVE of best fit, your line must be curved. So by saying that, if they ask for a LINE of best fit, your line must be straight. If there isn't any clear instruction then you plot the graph normally.
And also, how do we do line of best fits? What are the rules? Because everyone tells me something different
Post by: Elenaa on October 19, 2016, 10:32:28 am
Just wondering, roughly how long should we be spending on each section of the bio paper?
Thanks!
Post by: Skidous on October 19, 2016, 10:39:18 am
Hi!
Just wondering, roughly how long should we be spending on each section of the bio paper?
Thanks!
In an exam the paper will say how long on each section
For section 1
Multiple choice should be 25minutes
Short Answers should be 1hr40minutes
For Section 2 (Option Topic)
45 minutes should be allotted
Post by: christopherk8 on October 19, 2016, 11:52:42 am
is hybridisation (e.g. CSIRO Mandarins created from Ellendale Tangor and Imperial mandarins) the same this as selective breeding (Mating Freisian Cows with Jersey cows to get the best combination)????????????????
thanks
Post by: Skidous on October 19, 2016, 12:10:34 pm
hi could someone please answer this question that is really confusing me......
is hybridisation (e.g. CSIRO Mandarins created from Ellendale Tangor and Imperial mandarins) the same this as selective breeding (Mating Freisian Cows with Jersey cows to get the best combination)????????????????
thanks
No, Hybridisation is the artificial pollination between different specifies to produce a new species with favourable traits from both
Selective Breeding just takes 2 organisms from the same species to produce another organism with favourable traits
Hope this helps
Post by: lha on October 19, 2016, 01:11:08 pm
And i meant, does the line of best fit have to pass through as many points as possible? Or does jithave to have equal amount of points on top and below the line? Etc.
Post by: Gregs on October 19, 2016, 02:10:11 pm
Post by: Skidous on October 19, 2016, 02:25:24 pm
So unless it asks for a line of best fit, we just do a normal line connecting the points?
And i meant, does the line of best fit have to pass through as many points as possible? Or does jithave to have equal amount of points on top and below the line? Etc.
It has to pass through as many points as possible and it should ALWAYS be a line/curve of best fit
You are allowed to draw the line of best fit and the connected points on the same graph
Post by: Skidous on October 19, 2016, 02:27:31 pm
Has anyone seen any questions about the timeline on malaria or anything where we need to know the history of malaria? Do we even need to know it?
I have seen questions on the history of malaria but you could be asked a question on the change of nature and direction of scientific thinking and use it as well
Since it is a dot point in the syllabus you have to know It as they can ask a question from any part of the syllabus
Post by: lha on October 19, 2016, 02:29:59 pm
Do we label it as line of best fit or not?
And does the line of best fit start at the first point and end at the last point?
Post by: Skidous on October 19, 2016, 02:32:32 pm
So even if it doesnt ask for a line of best fit, we draw the normal connected dots graph AND a line of best fit?
Do we label it as line of best fit or not?
And does the line of best fit start at the first point and end at the last point?
Yes
If you do label it you need a key
And it stars at your first point and ends at the end of the graph (not necessarily your last point )
Post by: imtrying on October 19, 2016, 02:44:35 pm
Post by: Skidous on October 19, 2016, 02:45:52 pm
if asked a question about models for enzyme specificity, would I just talk about the induced fit model because its the more correct one or would I need to mention the lock and key as well?
If it asked about just a model then use induced fit but if it asks about the change in models then you need to refer to both
Post by: imtrying on October 19, 2016, 03:04:34 pm
Post by: Skidous on October 19, 2016, 03:06:26 pm
Just checking if my info in my notes is right - oxygen is carried 95% in oxyhaemoglobin? I don't know if this is the same as just haemoglobin or not oops
Yes, oxyhaemoglobin is the molecule that carries oxygen in blood (it's just the molecule created when oxygen bonds to haemoglobin)
Post by: imtrying on October 19, 2016, 03:08:04 pm
Yes, oxyhaemoglobin is the molecule that carries oxygen in blood (it's just the molecule created when oxygen bonds to haemoglobin)Thanks!
Post by: kimmie on October 19, 2016, 03:52:48 pm
Post by: christinebelista on October 19, 2016, 04:21:57 pm
Hey guys quick question you know how transgenes are made using bacterial plasmids, I am a bit confused about how it is inserted into a species? For example how do they insert the anti-freeze gene from salmon into strawberries?
The process of transferring genetic material requires the use of enzymes. Basically they're scissors to cut out the required genetic material, and glue when the foreign genetic material is inserted into the recipient's genetic material, = gene splicing.
You could also do this by microinjection and particle gun. I hope they don't ask about this tomorrow thougH HAHA it's a weird question
How would you guys set up your answer for this question?
(http://i64.tinypic.com/303e25i.jpg)
Post by: Elenaa on October 19, 2016, 04:27:21 pm
Just wondering how much do you have to write for an 8 marker?
and also what do you guys do during reading time? like do you answer the multiple questions straight away first? or read the short answers and stuff? what would be the most effective approach for the reading time
Thankyou !
Post by: christopherk8 on October 19, 2016, 04:40:19 pm
Hello !
Just wondering how much do you have to write for an 8 marker?
and also what do you guys do during reading time? like do you answer the multiple questions straight away first? or read the short answers and stuff? what would be the most effective approach for the reading time
Thankyou !
in my opinion for an eight marker you should be filling up the whole lines given and go beyond them if you have to....just to be sure that you are covering all parts of the question especially since a lot of detail is required......and i always to multiple choice first just because there are sometimes questions that trigger pieces of information that you can use in the short answers and it eases you into the exam
Post by: Ragdolls on October 19, 2016, 04:47:52 pm
Hello !
Just wondering how much do you have to write for an 8 marker?
and also what do you guys do during reading time? like do you answer the multiple questions straight away first? or read the short answers and stuff? what would be the most effective approach for the reading time
Thankyou !
During reading time I usually try to read as many short answer questions as possible and attempt to plan them in my head. Also, if I have any time left I go over my option questions so my mind is set on the content. Apparently you shouldn't read multiple choice, especially considering it is the easiest section a lot of the time and you have enough time to complete it. You usually don't need all the allocated time to complete the M.C questions so you have time to read the question and options carefully in the allocated multiple choice time. Hope that helps!
Post by: imtrying on October 19, 2016, 04:52:04 pm
Post by: smile123 on October 19, 2016, 05:30:09 pm
I was wondering if some one can tell me what Is the guanine bases in human DNA
Post by: justdoit on October 19, 2016, 05:31:45 pm
They will ask questions about the process by which minerals and sugars are transported in the phloem, so it is better to know the exact process. Since you do know that phloem actively loads at the source through apoploastic and symplastic loading,its really good but in case it becomes a 5 marker instead of a 3 or 4.
You can write that
symplostic loading:. sugars move into the cytoplasm from the mesophyll cells to sieve tube via the plasmodesmata
apoplastic: sugars move to the cell wall to the cell membrane into the sieve tube by active transport
Post by: imtrying on October 19, 2016, 05:39:01 pm
Heyy, Imtrying :)
They will ask questions about the process by which minerals and sugars are transported in the phloem, so it is better to know the exact process. Since you do know that phloem actively loads at the source through apoploastic and symplastic loading,its really good but in case it becomes a 5 marker instead of a 3 or 4.
You can write that
symplostic loading:. sugars move into the cytoplasm from the mesophyll cells to sieve tube via the plasmodesmata
apoplastic: sugars move to the cell wall to the cell membrane into the sieve tube by active transport
Thank you!!!
Post by: justdoit on October 19, 2016, 05:59:40 pm
Post by: Elenaa on October 19, 2016, 06:01:52 pm
During reading time I usually try to read as many short answer questions as possible and attempt to plan them in my head. Also, if I have any time left I go over my option questions so my mind is set on the content. Apparently you shouldn't read multiple choice, especially considering it is the easiest section a lot of the time and you have enough time to complete it. You usually don't need all the allocated time to complete the M.C questions so you have time to read the question and options carefully in the allocated multiple choice time. Hope that helps!
in my opinion for an eight marker you should be filling up the whole lines given and go beyond them if you have to....just to be sure that you are covering all parts of the question especially since a lot of detail is required......and i always to multiple choice first just because there are sometimes questions that trigger pieces of information that you can use in the short answers and it eases you into the exam
Thanks guys !! :)
Post by: stephanieazzopardi on October 19, 2016, 06:31:08 pm
hey :)
I was wondering if some one can tell me what Is the guanine bases in human DNA
Guanine is a purine containing 2 carbon chains, and pairs with cytosine in the formation of a DNA strand. If you were asked to calculate the number of guanine bases in a sample of human DNA, the number of guanine bases would always equal the number of cytosine bases. Likewise, the number of adenine bases would always equal the number of thymine bases in a DNA strand. Hope this helped! :)
Post by: aaron_solomon on October 19, 2016, 08:06:13 pm
thanks :)
Post by: Sssssrr on October 19, 2016, 08:36:29 pm
Post by: Elenaa on October 19, 2016, 09:24:37 pm
I'm kinda confused on the larynx and the pitch it produces. When its a high pitch will the vocal chords be longer and the gap between the vocal fold is smaller? and vice versa for low pitch?
thankkksss
Post by: Sanaz on October 19, 2016, 09:26:59 pm
is random segregation and independent assortment the same thing?
nope :P
1. Segregation: Alleles separate during meiosis and random go into a gamete. Then they randomly combine during fertilisation.
2. Independent assortment: Traits in an organism independently get passed onto the successive generation. So just because the F1 generation has a tall yellow plant and a short green plant, it doesn't mean that the offspring, will be either tall and yellow or short and green. It could be short and yellow for example. Each gene for each trait gets inherited independently.
Post by: kevin217 on October 19, 2016, 09:29:54 pm
Hi!I don't know about the vocal chords being longer, but they are more stretched/tighter and yes there is a smaller gap. Also important to know that when air is pushed from the lungs, the vocal chords will vibrate quickly to produce a high pitch sound.
I'm kinda confused on the larynx and the pitch it produces. When its a high pitch will the vocal chords be longer and the gap between the vocal fold is smaller? and vice versa for low pitch?
thankkksss
Post by: Skidous on October 19, 2016, 09:30:36 pm
Hi!
I'm kinda confused on the larynx and the pitch it produces. When its a high pitch will the vocal chords be longer and the gap between the vocal fold is smaller? and vice versa for low pitch?
thankkksss
It's easier to not think about the gap but the actual vocal chords themselves
When the vocal cords are stretched tight, a higher pitch is created as the air that rushes past them from the lungs vibrates them at a higher frequency and vice versa for low pitch. If the vocal cords are not being stretched there is no vibration and hence No sound
Post by: atar27 on October 19, 2016, 09:30:54 pm
if asked a question about models for enzyme specificity, would I just talk about the induced fit model because its the more correct one or would I need to mention the lock and key as well?
If it asks for one example of an enzyme model then you talk about the one you want but if it asks about both then you need to talk about both the induced for and the lock and key model.
Hope this helps :)
Post by: atar27 on October 19, 2016, 09:34:30 pm
Post by: Skidous on October 19, 2016, 09:36:27 pm
SLEEP
if you don't get a good nights rest you will be very tired the next morning, half the exam is actually performing well in the exam room whilst the other half is preparation
Also your brain retains information better if you get some rest the day before a big test.
Don't be one of those people who crams the whole night up until 3am, get to sleep and wake up heaps early to do study before then
Good Luck to all you guys, I know we can all smash out these exams and show the HSC whose boss
Post by: :3 on October 19, 2016, 09:37:10 pm
By the way do we need to know the diagrams for meiosis and mitosis?
Its possible they may show you a diagram of meiosis and ask you a question relating to what is happening.
_______________________________________________________________________________________________________________________
Also, what are the features of an epidemiological study? :P
Post by: Skidous on October 19, 2016, 09:37:43 pm
By the way do we need to know the diagrams for meiosis and mitosis?
If you need a diagram then it would be good to know one but as long as you know the process you should be ok.
The only diagram question I saw in the past was one where you had to fill in the step on crossing over during meiosis and the end gametes of the daughter cells
Post by: Skidous on October 19, 2016, 09:40:56 pm
Its possible they may show you a diagram of meiosis and ask you a question relating to what is happening.
_______________________________________________________________________________________________________________________
Also, what are the features of an epidemiological study? :P
The features of an epidemiological study is
1. Long time span
2. Large Sample size
3. Demographics (Age, Sex, Religion, Socio-economic status etc)
4. Nutrition/Lifestyle of the participants
5. A potential cause for a non-infectious disease
6. A notable change in rate of infection and deaths after removal of potential cause
7. A cause and effect link being established
Post by: Sanaz on October 19, 2016, 09:45:29 pm
Post by: Skidous on October 19, 2016, 09:48:03 pm
Its possible they may show you a diagram of meiosis and ask you a question relating to what is happening.
_______________________________________________________________________________________________________________________
Also, what are the features of an epidemiological study? :P
To better my response
Epidemiology: is the study of the incidence of diseases or risk factors involved in its occurrence, prevalence and spread within a population.The main features of epidemiology include:» The cause of the disease» How it is transmitted» Who is at risk» Method of treatment and control» Long-term measures of prevention» Virulence of the strain and whether itchanges over time
Post by: :3 on October 19, 2016, 09:49:23 pm
What is the trend for long response questions (the one at the end) ?
Often they ask you about either: technologies and increased understandings (i.e. scientist's contributions) and the implications it has for society and the environment.
Note: they may be specific in regards to the technologies/understandings that should be included (i.e. 2015 = kidney, other ones about reproductive technologies/genetic diversity, natural selection etc).
Also, cheers Skidous.
Post by: Skidous on October 19, 2016, 09:50:23 pm
What is the trend for long response questions (the one at the end) ?
The trend usually lend to heavy content dot points such as the work of scientist on a specific part of the syllabus, a Prescribed Focus Area, a development within fields or technologies
Sometimes a table may appear which can be worth 8-marks
Sometimes they will be describe but you're generally going to get Explain, discuss, analyse, evaluate or assess questions
Just remember to deconstruct the question and see what it is asking you before you begin to brain dump all the information you have
Post by: :3 on October 19, 2016, 09:50:42 pm
Post by: Skidous on October 19, 2016, 09:53:16 pm
Often they ask you about either: technologies and increased understandings (i.e. scientist's contributions) and the implications it has for society and the environment.
Note: they may be specific in regards to the technologies/understandings that should be included (i.e. 2015 = kidney, other ones about reproductive technologies/genetic diversity, natural selection etc).
Also, cheers Skidous.
Whilst this is true you can always get a PFA such as the nature and practice of biology which can lead you to a massive loss in marks (like the question some people got in trials for CSSA papers)
Post by: Skidous on October 20, 2016, 12:44:08 pm
Post by: naomisirmai on October 20, 2016, 12:47:26 pm
Now that the exams are done I would like to say congrats to all you bio student, we did jt
Well done!! How did it go? :D
Post by: Skidous on October 20, 2016, 12:48:54 pm
Well done!! How did it go? :D
I found it pretty easy, then again I won't know how well I did till December and I finished with an hour left on the time
Post by: naomisirmai on October 20, 2016, 12:50:10 pm
I found it pretty easy, then again I won't know how well I did till December and I finished with an hour left on the time
Legendary. What's next on the exam-menu for you?
Post by: Skidous on October 20, 2016, 12:51:26 pm
Legendary. What's next on the exam-menu for you?
Good ol' Mathematics. As my maths teacher told us 'Maths is a wonderful and beautiful thing'
Post by: naomisirmai on October 20, 2016, 12:53:07 pm
Good ol' Mathematics. As my maths teacher told us 'Maths is a wonderful and beautiful thing'
My maths teacher told us "Maths is like god; you just have to believe." ???
Post by: Skidous on October 20, 2016, 12:56:56 pm
My maths teacher told us "Maths is like god; you just have to believe." ???
But what about the atheists :o
Post by: naomisirmai on October 20, 2016, 01:01:36 pm
But what about the atheists :o
I think that's why I'm so bad at maths.
Post by: Skidous on October 20, 2016, 01:02:45 pm
I think that's why I'm so bad at maths.
Same, except I'm not an atheist :/
Post by: aimbotted on October 20, 2016, 01:27:21 pm
Post by: jakesilove on October 20, 2016, 01:31:02 pm
multiple choice was one of the hardest ive ever encountered
We've already got some sample solutions up for MC! Come chat about the Biology exam here :)
Post by: Blissfulmelodii on October 20, 2016, 02:30:24 pm
I finished with an hour left on the time
Wow that's amazing! I only has 10 minutes left which was just enough to recheck everything. Then again I spent quite a bit of time planning my response and over thinking half the questions lol
Glad bio is ever now to switch on the math brain 😔
Post by: lmnop on October 21, 2016, 11:32:58 am
Post by: studybuddy7777 on October 21, 2016, 03:24:32 pm
guys OmG i just realised that throughout the bio exam i used shorthand like a triangle to symbolsie the word change and like arrows to show increasing and decreasing if that makes sense.... i know in economics thats alright to use but is it ok in bio exams to use that or am i screwed?!
Hey imnop,
As long as it is a recognised abbreviation for science (like it is in physics im pretty sure) then you should be sweet!
Things like delta to symbolise change should be okay, arrows for increasing and decreasing definitely are because my bio teacher uses them all the time!!
Dont stress im sure itll be fine :)
Post by: lmnop on October 21, 2016, 06:27:49 pm
Post by: studybuddy7777 on October 21, 2016, 07:53:38 pm
oh ok thanks!! I was really worried about that! :) thats relief!
Thats ok :)
Just remember, as ruthless as bostes may appear (and the exam preparers are :D) the markers are genuinely nice people who are trying to give you ad many marks as they can without being locked out for being "too nice"
Most of my teachers have been markers, so if you think about it that way it doesnt seem so bad. A teacher is marking my responses I have done, not some BOSTES head honcho official ;D
Glad i helped :)
Post by: katnisschung on November 15, 2016, 01:35:07 pm
question
many capillaries are only 6-8 micrometre wide which means
that many red blood cells dirstort into a bell shape (forced to flow in single file)
discuss the advantages of this behaviour?
Post by: vox nihili on November 15, 2016, 01:46:33 pm
hi guys
question
many capillaries are only 6-8 micrometre wide which means
that many red blood cells dirstort into a bell shape (forced to flow in single file)
discuss the advantages of this behaviour?
What are your ideas first?
Post by: Skidous on November 15, 2016, 01:47:05 pm
hi guys
question
many capillaries are only 6-8 micrometre wide which means
that many red blood cells dirstort into a bell shape (forced to flow in single file)
discuss the advantages of this behaviour?
The capillaries has a wall that is one cell thick and forces the RBC to form in single file. These promote closeness to the tissues and the thinness of the wall promotes efficient exchange of products (gases and nutrients in/waste products out)
Post by: khitnay on November 15, 2016, 10:33:29 pm
Post by: Skidous on November 16, 2016, 12:24:36 am
Hey guys. I have an assessment task report coming up. We did a prac on testing enzyme activity with changes in temperature. (amino acids in egg whites with pepsin to be exact). The assignment asks for the usual scientific report, but there's a separate section for presenting the report in some way; powerpoint or video format or whatever, but it's worth 10 marks based on creativity. Any ideas on how to present a prac such as this creatively? Thanks in advance
For creativity try using analogies on how enzymes work and maybe try to make it very vibrant in colour and add in animations to help present your report. If you plan on doing a video you could set it out in the form of a news report where you interview things in your experiment (I.e the egg whites, the Pipettes, the enzyme and substrate etc) and then proceed through the report that way. You need to balance the creativity with the authenticity and concise nature of the information presented so that it is still a formal report that gives the correct information whilst being equally creative. If they are out of homeostasis then it will be to the detriment to the project ;)
Hope this helps
Post by: khitnay on November 16, 2016, 07:15:13 pm
Post by: Aussie1Italia2 on November 26, 2016, 05:50:59 pm
If you can! Please and thank you!
Post by: Skidous on November 26, 2016, 06:17:14 pm
I'm just wondering how you would approach the question 'what can you conclude from your results and the control experiment?', it's for my bio assignment and the experiment was about the effects of carbon dioxide on the pH of water. I just need some help tackling the question.
If you can! Please and thank you!
If the control would be the pH water before CO2 and then the result would be the pH of the water after CO2 and the conclusion would be the change in the pH from normal water to CO2 water
And example would be 'The result showed the pH of the water has decreased with the addition of CO2, this change can be determined through a comparison between the pH of normal water compared to the experimental water, which is (insert change in pH)"
Hope this Helps
Post by: katnisschung on December 05, 2016, 05:39:31 pm
direct evidence that sugar is transported in the sieve tubes of the phloem was obtained using radioactive tracers.
eg. plants can be exposed to co2 which contain C14
the plants photosynthesise and the radioactive carbon is incorporated into the
sugars of the plant.
halting the process and taking fine sections which are then covered with fine photographic film
shows the location of the radioactive sugars.
Draw a diagram to show where the autoradiograph would show fogging due to radioactivity
in the stem of the plant..
isn't it just the phloem?
seems to simple for such as a long question...
also i was thinking the source and sink cells but they're not really part of the stem....
any ideas?maybe i'm overthinking it
Post by: Skidous on December 05, 2016, 05:58:47 pm
hi i'm stuck on this question
direct evidence that sugar is transported in the sieve tubes of the phloem was obtained using radioactive tracers.
eg. plants can be exposed to co2 which contain C14
the plants photosynthesise and the radioactive carbon is incorporated into the
sugars of the plant.
halting the process and taking fine sections which are then covered with fine photographic film
shows the location of the radioactive sugars.
Draw a diagram to show where the autoradiograph would show fogging due to radioactivity
in the stem of the plant..
isn't it just the phloem?
seems to simple for such as a long question...
also i was thinking the source and sink cells but they're not really part of the stem....
any ideas?maybe i'm overthinking it
Well the thing is the stem of the plant is vascular tissue, meaning it is a bundle of both xylem and phloem cells. Source and Sink cells are just names for the places where sugar is stored or produced (source) and where sugar is needed (sinks) in the plant (this can be in roots of the plant as well)
Your explanation for the radioactive tracers is correct but what you should do is a comparison between a control and a test sample to help assist the results
Your diagram should show a vascular bundle where the xylem and phloem are located and fogging appears in the phloem.
Hope this helps
Post by: katnisschung on December 05, 2016, 06:03:31 pm
thanks Skidous
Post by: jamesq on December 08, 2016, 08:52:57 pm
Post by: Blissfulmelodii on December 09, 2016, 08:55:57 am
Hey guys, I have a student research project that is to be conducted through the holiday period. I'm finding it quite difficult to find something i'm interested in. I certainly don't want to grow a plant but I was wondering if you guys have any ideas.
What's the reasearch task about? Is it where you have to create your own experiment based on a hypothesis that you yourself make?
If so, then I actually did mine on shampoo. My aim was to determine which brand of shampoo actually made your hair stronger and so I got fresh samples of my own hair and soaked them in different brands of shampoo's (i.e. Garnier, schwarzkopf etc) and then tested how much strength I used to pulled them until they snapped.
Post by: Skidous on December 09, 2016, 09:03:10 am
What's the reasearch task about? Is it where you have to create your own experiment based on a hypothesis that you yourself make?
If so, then I actually did mine on shampoo. My aim was to determine which brand of shampoo actually made your hair stronger and so I got fresh samples of my own hair and soaked them in different brands of shampoo's (i.e. Garnier, schwarzkopf etc) and then tested how much strength I used to pulled them until they snapped.
I think it may be but since this is biology I'm not sure if that relates to anything in the biology syllabus.
Post by: Blissfulmelodii on December 09, 2016, 09:04:12 am
I think it may be but since this is biology I'm not sure if that relates to anything in the biology syllabus.
Ahh that's true, I did that in year 10.
I did find this website that has some pretty cool Ideas (and they are bio related)
https://askabiologist.asu.edu/activities/experiments
Post by: Skidous on December 09, 2016, 09:05:51 am
I think it may be but since this is biology I'm not sure if that relates to anything in the biology syllabus.
[/quote
Ahh that's true, I did that in year 10.
Yeah most SRP are done in year 10 so I'm not sure whether or not there is an experiment you can do as an SRP for bio cause most of my ideas use plants
Post by: jamesq on December 09, 2016, 09:45:12 pm
Post by: Skidous on December 09, 2016, 10:11:35 pm
The SRP is the same as the one in yr10 but in this case it has to be biology related :) It can be anything just as long as it relates to biology
You may want to look at the syllabus and on the 3rd column there will be a bunch of practical tasks (look for first hand) and use one of those
Post by: anotherworld2b on December 10, 2016, 04:09:45 pm
I wanted to ask is there a way that enables someone to easily identify a tissue?
Does anyone have any tips?
I have seen a few questions that requires me to identify the tissue and explain why I think so. However, I am quite bad at answering this type of question
Post by: Blissfulmelodii on December 10, 2016, 05:49:31 pm
Hi,
I wanted to ask is there a way that enables someone to easily identify a tissue?
Does anyone have any tips?
I have seen a few questions that requires me to identify the tissue and explain why I think so. However, I am quite bad at answering this type of question
I found this video on YouTube that I think explains it all pretty well and answers your question
https://www.youtube.com/watch?v=NDWYZdow87I
Post by: vox nihili on December 10, 2016, 06:47:01 pm
Hi,
I wanted to ask is there a way that enables someone to easily identify a tissue?
Does anyone have any tips?
I have seen a few questions that requires me to identify the tissue and explain why I think so. However, I am quite bad at answering this type of question
Not entirely sure what kind of stuff you need to be able to do, but I learn most of my histology by having a play around with some tissue slices.
This is a really good database for them: https://www.best.edu.au/s/featured
Post by: J.B on December 12, 2016, 03:34:55 pm
I was just wondering in relation to the dot point "explain how mutations in DNA may lead to the generation of new alleles."
I am just a bit confused. Is it just because mutations change the DNA base sequence which changes the gene. And since alleles are genes they are therefore different? How would this work in relation to the dominant and recessive alleles?
Thank you
Post by: Skidous on December 12, 2016, 04:21:15 pm
Hi I am studying the Blueprint of Life topic at the moment.
I was just wondering in relation to the dot point "explain how mutations in DNA may lead to the generation of new alleles."
I am just a bit confused. Is it just because mutations change the DNA base sequence which changes the gene. And since alleles are genes they are therefore different? How would this work in relation to the dominant and recessive alleles?
Thank you
That's sorta right. Since mutations changes the structure of the DNA, it changes how that part of the DNA (the gene) is experessed and thus changing something about the organism (either physiologically or physically). These changes aren't always beneficial and could be very detrimental if not lethal.
As for dominant and recessive traits that will depend upon how the mutated gene is experessed in further generations (if asked a question on dominant/recessive traits you will more than likely be given a pedigree to draw or fill in)
Hope this Helps
Post by: katnisschung on January 15, 2017, 04:30:30 pm
why are freshwater fish considered hypertonic to their surroundings?
my textbook says this and I am having trouble understanding
Post by: Skidous on January 15, 2017, 04:37:43 pm
Question,
why are freshwater fish considered hypertonic to their surroundings?
my textbook says this and I am having trouble understanding
Hey Kat
Freshwater fish contain a larger concentration of solute (salts) compared to the surrounding water, therefore water will enter the fish's body through osmosis to balance the concentrations, hence the fish is considered hypertonic (more salt)
Post by: katnisschung on January 15, 2017, 05:35:46 pm
hypotonic pls
Post by: Rathin on January 15, 2017, 05:41:01 pm
hmmm.. could u please explain the difference between hypertonic and
hypotonic pls
A hypotonic solution is one in which the concentration of solutes is greater inside the cell than outside of it, and a hypertonic solution is one where the concentration of solutes is greater outside the cell than inside it. Isotonic solution is when the concentration outside and inside are in an equilibrium.
Post by: vcestressed on January 15, 2017, 06:05:27 pm
https://www.khanacademy.org/science/biology/membranes-and-transport/diffusion-and-osmosis/v/hypotonic-isotonic-and-hypertonic-solutions-tonicity
;)
Post by: shreya_ajoshi on January 22, 2017, 05:50:43 pm
Anyone have any links to videos that cover the Biology Syllabus?
Thank you :)
Post by: Skidous on January 22, 2017, 05:57:30 pm
Hello!
Anyone have any links to videos that cover the Biology Syllabus?
Thank you :)
Hey Shreya
There won't be many videos that cover the WHOLE syllabus but there are some notes in this website that do.
You should really realistically try to look at the parts of the syllabus that you are struggling and looking for videos about that
For example: if you struggling with the kidney then you could use this video
https://m.youtube.com/watch?v=l128tW1H5a8
If you do the communication option and have trouble with the parts of the brain then there's another video
https://m.youtube.com/watch?v=q8NtmDrb_qo
Hope This Helps
Post by: shreya_ajoshi on January 22, 2017, 10:02:05 pm
The video about kidneys definitely helped.
I did find one website that uploads HSC Bio Videos. It's called HSC Hero
Post by: Skidous on January 22, 2017, 10:07:13 pm
Thank you so much :)
The video about kidneys definitely helped.
I did find one website that uploads HSC Bio Videos. It's called HSC Hero
That's cool, videos are a great way to consolidate information, but you shouldn't use them as your only form of study. Study notes are still one of the best ways to study due to muscle memory when you physically write down notes.
Nothing wrong with videos just use them in tandem with your other forms of study
Post by: shreya_ajoshi on January 23, 2017, 11:34:55 am
That's cool, videos are a great way to consolidate information, but you shouldn't use them as your only form of study. Study notes are still one of the best ways to study due to muscle memory when you physically write down notes.
Nothing wrong with videos just use them in tandem with your other forms of study
Yeah I definitely agree! I'm just using them to consolidate information. It's also because my teacher isn't the greatest, so I often have to go home and teach myself the content.
Post by: vox nihili on January 23, 2017, 12:01:55 pm
Yeah I definitely agree! I'm just using them to consolidate information. It's also because my teacher isn't the greatest, so I often have to go home and teach myself the content.
I really like your attitude :) It's easy to fall into the trap of blaming your teacher for everything and spending the year whinging about it. Unfortunately, very few just accept the fact and do what's needed to do well (i.e. teach yourself!). :)
Post by: shreya_ajoshi on January 23, 2017, 12:18:33 pm
I really like your attitude :) It's easy to fall into the trap of blaming your teacher for everything and spending the year whinging about it. Unfortunately, very few just accept the fact and do what's needed to do well (i.e. teach yourself!). :)
Haha yes thank you!! Hopefully my marks will improve :)
Post by: anotherworld2b on January 25, 2017, 12:59:16 am
1. What chemicals/digestive enzymes are secreted by the liver, stomach, intestine (basically the alimentary canal)
2. Tips to deal with pedigrees
Post by: Skidous on January 25, 2017, 01:11:56 am
Hi :) I was wondering if anyone had tips to remember
1. What chemicals/digestive enzymes are secreted by the liver, stomach, intestine (basically the alimentary canal)
2. Tips to deal with pedigrees
Hey anotherworld,
For 1 I know that the liver has catalase which can break down peroxides into oxygen, as for the stomach it contain sulfuric acid, I'm not quite sure about the intestines
For 2 you should remember a few things
1: Write down Generations (I, II, III, etc.)
2: Have a key (Square for Male, Circle for Female, patterns/coloured in shape for affected)
3: Analyse the relationship between the affected people and the pedigree (i.e. Does it skip a generation, does it only affect men, is it more apparent than the unaffected, can 2 non-affected parents produce and affected offspring etc)
4: Sometimes there will be a question with a paragraph and you have to construct the pedigree, read the question very carefully so you get the right relationships between people and who is affected.
5: Always use a ruler for the lines in a pedigree
6: It may help to write the Genotypes of each person in the pedigree to better grasp how the disease/disorder is passed down generations
Hope this helps
Post by: anotherworld2b on January 25, 2017, 01:33:38 am
I found this flow chart on youtube for pedigrees. I just wanted to know opinions on whether or not it would be effective to use
Hey anotherworld,
For 1 I know that the liver has catalase which can break down peroxides into oxygen, as for the stomach it contain sulfuric acid, I'm not quite sure about the intestines
For 2 you should remember a few things
1: Write down Generations (I, II, III, etc.)
2: Have a key (Square for Male, Circle for Female, patterns/coloured in shape for affected)
3: Analyse the relationship between the affected people and the pedigree (i.e. Does it skip a generation, does it only affect men, is it more apparent than the unaffected, can 2 non-affected parents produce and affected offspring etc)
4: Sometimes there will be a question with a paragraph and you have to construct the pedigree, read the question very carefully so you get the right relationships between people and who is affected.
5: Always use a ruler for the lines in a pedigree
6: It may help to write the Genotypes of each person in the pedigree to better grasp how the disease/disorder is passed down generations
Hope this helps
Post by: sirecg02 on January 26, 2017, 08:24:30 pm
Post by: Skidous on January 26, 2017, 08:46:48 pm
Ok so I am having trouble writing summary notes on the pracs and studying my bio pracs...I just don't know where to start. Any suggestions?? I am currently doing notes for maintaining a balance. Thanks in advance.
Hey sirecg
I would start with making sure you have all the equipment and method written down.
You should then remember the key content related to the experiment (i.e. The enzyme pracs are about how enzymes interact with substrates and how other factor impact upon enzyme activity).
After that you should write up the reliability, validity and accuracy about each experiment along with how effective of an experiment was with assisting you knowledge of the content.
Post by: sirecg02 on January 27, 2017, 12:38:57 pm
Post by: bigsweetpotato2000 on January 27, 2017, 02:04:03 pm
I have decided to rewrite my biology notes for some random reason (don't ask) and I got a little lost with the first dot point. I know, I'm a genius.
So for 'Identify the role of enzymes in metabolism, describe their chemical composition and use a simple model to describe their specificity on substrates', the worksheet says 'Enzymes are proteins made out of amino acids.' I was very happy with such a simple description until I read the next line. 'Proteins are made up of C,N, H, O'
So my question is (after a paragraph of ranting) are amino acids made up of C, N, H, O or are amino acids = C, N, H, O?
Thanks for reading :D
Post by: Quantum44 on January 27, 2017, 02:41:09 pm
Story time.
I have decided to rewrite my biology notes for some random reason (don't ask) and I got a little lost with the first dot point. I know, I'm a genius.
So for 'Identify the role of enzymes in metabolism, describe their chemical composition and use a simple model to describe their specificity on substrates', the worksheet says 'Enzymes are proteins made out of amino acids.' I was very happy with such a simple description until I read the next line. 'Proteins are made up of C,N, H, O'
So my question is (after a paragraph of ranting) are amino acids made up of C, N, H, O or are amino acids = C, N, H, O?
Thanks for reading :D
Amino acids are the monomers/building blocks of proteins. So basically proteins are made of long chains of amino acids. Amino acids are made of the elements Carbon, Hydrogen, Oxygen and Nitrogen due to the specific functional groups they are composed of (amine and carboxyl). There are 20 different amino acids that exist so the amino acids do not equal Carbon, Nitrogen, Hydrogen and Oxygen, they are composed of those elements. Amino acids can also contain Sulfur and Phosphorus but all of them must contain C, H, O and N. I'd suggest searching up amino acid on google images so you can visualise the structure.
Post by: bigsweetpotato2000 on January 27, 2017, 03:37:35 pm
Amino acids are the monomers/building blocks of proteins. So basically proteins are made of long chains of amino acids. Amino acids are made of the elements Carbon, Hydrogen, Oxygen and Nitrogen due to the specific functional groups they are composed of (amine and carboxyl). There are 20 different amino acids that exist so the amino acids do not equal Carbon, Nitrogen, Hydrogen and Oxygen, they are composed of those elements. Amino acids can also contain Sulfur and Phosphorus but all of them must contain C, H, O and N. I'd suggest searching up amino acid on google images so you can visualise the structure.
That is amazing. Thanks! ;D
Post by: trainstation on January 28, 2017, 11:55:27 am
Post by: Rathin on January 28, 2017, 04:32:15 pm
I'm having trouble understanding T cells and B cells in Search for better health. How do they interact, what happens when they do, what do these cells do and what are the processes involved?
- Helper T cells help B cells to produce more antibodies by secreting INTERLEUKIN
- Suppressor T cells stop the production of Cytotoxic (killer) T cells and B cells
- The secretion of INTERLEUKIN by helper T cells also helps differentiate the change from a B cell to a Plasma B cell in response to an antigen to produce antibodies.
Post by: sophiegmaher on January 29, 2017, 06:14:04 pm
1. Explain how the colour of each region relates to its blood supply
2. Demonstrate, using an analogy, how the kidney functions to excrete waste
Post by: jabuibui on January 31, 2017, 01:27:49 am
Thanks :)
Post by: Quantum44 on January 31, 2017, 07:31:34 am
What are actually adenine, guanine, cytosine and thymine? I know together they are codes and together they make nitrogen bases for nucleotides. Are they individual amino acids that comes together to make a bigger amino acids? or like bases?
Thanks :)
Adenine, guanine, cytosine and thymine are nitrogenous bases that form part of a nucleotide. The other parts of a nucleotide are the phosphate group and pentose sugar which is deoxyribose in the case of DNA. DNA is a polymer and hence each DNA strand is formed from a long chain of nucleotides. Since DNA is a double helix, there must be two strands of DNA with the nucleotides in each strand being complementary and able to bond via hydrogen bonding. In DNA, adenine bonds with thymine and cytosine bonds with guanine. So in DNA, if one strand is ATTCCG, the complementary strand must be TAAGGC.
Post by: sophiegmaher on January 31, 2017, 09:04:06 pm
1. Explain how the colour of each region relates to its blood supply (cortex, medulla, pelvis)
2. Demonstrate, using an analogy, how the kidney functions to excrete waste
Post by: geminii on January 31, 2017, 09:09:54 pm
Hey guys! I'm not sure about the answers to these discussion questions from the kidney dissection prac. Any ideas?
1. Explain how the colour of each region relates to its blood supply (cortex, medulla, pelvis)
2. Demonstrate, using an analogy, how the kidney functions to excrete waste
All I know for 1, is that the darker the colour of the region, the greater the blood supply to that area. I'm not too familiar with the parts of the kidney (since it wasn't part of last year's biology study design), but I think for this question you need to say that '(name of region) is a darker shade of red, therefore it has a greater blood supply.'
Post by: vox nihili on February 01, 2017, 09:18:11 pm
Hey guys! I'm not sure about the answers to these discussion questions from the kidney dissection prac. Any ideas?
1. Explain how the colour of each region relates to its blood supply (cortex, medulla, pelvis)
2. Demonstrate, using an analogy, how the kidney functions to excrete waste
All I know for 1, is that the darker the colour of the region, the greater the blood supply to that area. I'm not too familiar with the parts of the kidney (since it wasn't part of last year's biology study design), but I think for this question you need to say that '(name of region) is a darker shade of red, therefore it has a greater blood supply.'
1. I'd be interested to hear other people's thoughts, as I don't know the answer to #1 myself, but I don't think it has to do with the blood supply. The cortex of the kidney contains the glomeruli, which are—at least macroscopically—vast spaces filled with blood; whereas the majority of the cross-sectional area of the medulla is dominated by tubules, namely the LOH and the CD.
2. Would love to hear your thoughts on this first, give it a crack :)
Post by: Aussie1Italia2 on February 02, 2017, 04:52:26 pm
I pleading for some help with Enantiostasis and more specifically Osmoconformers and Osmoregulators. I just don't understand the difference between the two.
So some help would be much appreciated, thank you!
Arrivederci!
Post by: sweetcheeks on February 02, 2017, 05:07:14 pm
Hello!
I pleading for some help with Enantiostasis and more specifically Osmoconformers and Osmoregulators. I just don't understand the difference between the two.
So some help would be much appreciated, thank you!
Arrivederci!
Osmoconformers will have an internal osmotic pressure that is the same as their external environment. This means that they will be isotonic compared to the environment. If the osmoconformer enters an environment that has a higher salinity, its body will become isotonic with the environment. As the environment changes, osmoconformers will change with it
Osmoregulators will maintain tight tolerances of their internal environment rather than go with the changing environment. If an osmoregulator enters an environment with higher salinity, it will actively attempt to oppose the osmotic pressure of the environment. It will actively pump out salts. Osmoregulators attempt to keep stable conditions in the face of changing environments.
Conformers accept and embrace the osmotic change, whilst regulators actively oppose the change.
Post by: janemurray on February 02, 2017, 09:00:26 pm
Post by: Skidous on February 02, 2017, 10:46:00 pm
Good model of a feedback system (MAB module)?? PLEASE & THANKYOU(http://uploads.tapatalk-cdn.com/20170202/93d0977961a0681a68918f74f14657c2.jpg)
Hope this image helps
Post by: stephjones on February 04, 2017, 02:19:50 pm
List the advantages of excreting nitrogenous wastes as each of the following: ammonia, urea, uric acid, guanine.
i've been stuck on it for hours haha
Post by: stephanieazzopardi on February 06, 2017, 02:31:31 pm
could someone help me with this question?
List the advantages of excreting nitrogenous wastes as each of the following: ammonia, urea, uric acid, guanine.
i've been stuck on it for hours haha
Hi Steph!
So this isn't a direct syllabus dot point so it requires you to think a little bit about what you have learned about each of the different nitrogenous waste products. Here is what I think:
- Ammonia: can be excreted by some aquatic animals into their surroundings extremely fast in order to avoid a lethal accumulation of the toxic waste in their tissue. It can be excreted fast due to its simple formation from amino acids through deamination
- Urea: is far less toxic than ammonia and can accumulate in high concentrations without becoming toxic and causing tissue damage. Thus, It can also be excreted in a more concentrated form to allow for water retention depending on the organisms needs
- Uric acid: low toxicity, no water lost when excreted
- Guanine: similar to uric acid, it is the major nitrogenous waste product in arachnids
I hope this helps :)
Post by: stephjones on February 06, 2017, 05:42:35 pm
Post by: phebsh on February 07, 2017, 01:25:37 pm
Post by: Paul.I on February 08, 2017, 08:29:51 pm
Hi all, what is an experiment that models natural selection? One which is not the basic peppered moth example... Thanks! :)
An experiment that models natural selection:
Have two peaces of paper (different, but similar enough to make it realistic e.g. yellow and green)
Consider the green to be your grass/environment
From here cut up a sheet of the yellow paper and a sheet of green paper into equal sizes and scrunch then up and place into a beaker. (these are your animals/insects)
On your green peace of paper spread the crumpled 'insects'
Using a timer, time 20s and pick up as many peaces of paper as possible and place into the beaker using tweezers
Record your result (how many green picked and how many yellow)
Place back the peaces of paper from the beaker onto the green paper and repeat a further 9 times
Take an average of your 10 results.
You will notice that the yellow is picked up a lot more frequently than the green because it doesn't have the desirable trait of being able to camouflage into the background like the green can. Same thing happens in real life as you know with the peppered moth.
You can talk about limitations how the papers don't move like real animals do, not equal populations of each etc..
Post by: Snew on February 09, 2017, 11:18:45 am
Post by: sweetcheeks on February 09, 2017, 12:11:46 pm
Question: compare the role of haemoglobin in transporting oxygen and carbon dioxide. Having trouble pulling together a succinct answer. Thanks :D
For oxygen to be able to circulate around the body, it needs to bind to the haemoglobin, as oxygen gas by itself has a low solubility in plasma. Carbon dioxide on the other hand, is much more soluble in the plasma, where it forms carbonic acid (and some free CO2). Only a small percentage of the CO2 circulating around the body is bound to haemoglobin.
From this information, are you able to put together a sufficient answer? Perhaps compare the importance of haemoglobin in the transport of both substances?
Post by: Wren on February 09, 2017, 03:00:14 pm
Compare the chemical composition of blood arriving at the glomerulus with the composition of glomerular filtrate?
Post by: phebsh on February 09, 2017, 06:49:25 pm
Post by: sweetcheeks on February 09, 2017, 07:04:45 pm
Hey! I'm struggling with this issue in regards to Biology; I can understand the content that is taught to me, and while studying, but find it difficult to answer exam-style questions. How do I overcome this? Thanks :)
Practice. I had the same difficulty, I knew the content but I was unable to clearly and concisely state a point. You have to keep doing questions to build up the skill to be able to do so. Look at some of the key words that are used in answers, as these can be used in your answer allowing it to be better understood and more concise.
Post by: jabuibui on February 13, 2017, 11:14:52 pm
Post by: Kirri Rule on February 16, 2017, 10:41:28 am
Post by: jamonwindeyer on February 16, 2017, 10:45:18 am
Hi thanks in advanced but i am currently really struggling with studying and remembering all the little details in the course that always seem to show up on practice papers. Does anyone have any pointers??
Hey Kirri! I didn't do Bio, but I thought I'd recommend this guide! Hopefully it has a few ideas you can use ;D
Post by: Mathew587 on February 19, 2017, 04:47:42 pm
The only thing I can recommend is to make better notes that cover these points and repeatedly revise these points. Also do more questions on whatever you dont understand. Its better to go through the difficulty now and get it wrong than go through the difficulty and get it wrong in the actual HSC exam :P
Post by: bananna on February 19, 2017, 08:57:22 pm
I'm making notes for 'blueprint' and was wondering if you could check my table I'm wanting to study off
Is there anything I should add or remove/ is anything inaccurate?
Also, how would I go about answering a question regarding this dotpoint?
thank you!!!!
Post by: Kirri Rule on February 21, 2017, 08:44:30 pm
Hey Kirri! I didn't do Bio, but I thought I'd recommend this guide! Hopefully it has a few ideas you can use ;DWow thank you so much i didn't see that before that has some really good points thanks!
Post by: Kirri Rule on February 21, 2017, 08:46:14 pm
Hey Kirri,Thank you, do you normally go through the questions then mark them with your teacher or by yourself?
The only thing I can recommend is to make better notes that cover these points and repeatedly revise these points. Also do more questions on whatever you dont understand. Its better to go through the difficulty now and get it wrong than go through the difficulty and get it wrong in the actual HSC exam :P
Post by: stephanieazzopardi on February 22, 2017, 01:48:41 pm
hihi!
I'm making notes for 'blueprint' and was wondering if you could check my table I'm wanting to study off
Is there anything I should add or remove/ is anything inaccurate?
Also, how would I go about answering a question regarding this dotpoint?
thank you!!!!
Hi there!
Your table is great and very detailed and you have included all the right scientists :)
In terms of how the development of their respective theories were influenced by society and politics, you could add these points to Darwin's theory:
- 1920's: Protestants campaigned against anti-biblical ideas of evolution
- Several US States: passed legislation which banned the teaching of evolution in public schools
[/li][/list]
In terms of answering a question on this dot point, I would do a paragraph for each of the three theories of evolution you have listed or a paragraph for each person (1. Lamarck 2. Darwin 3. Wallace). You would start of each by explaining the theories, their evidence and then the social and political influences.
Hope this helped! :)
Post by: bananna on February 22, 2017, 03:52:21 pm
Hi there!
Your table is great and very detailed and you have included all the right scientists :)
In terms of how the development of their respective theories were influenced by society and politics, you could add these points to Darwin's theory:[li]1925: teacher from Tennessee arrested and put on trial for teaching the theory of evolution
- 1920's: Protestants campaigned against anti-biblical ideas of evolution
- Several US States: passed legislation which banned the teaching of evolution in public schools
[/li][/list]
In terms of answering a question on this dot point, I would do a paragraph for each of the three theories of evolution you have listed or a paragraph for each person (1. Lamarck 2. Darwin 3. Wallace). You would start of each by explaining the theories, their evidence and then the social and political influences.
Hope this helped! :)
awesome!!
thank you so much :)
Post by: Shania.k on February 25, 2017, 02:08:11 pm
I was wondering if there was a simple way to remember the Nephron and all its components and what they do, I've drawn it so many times but can never get the labels right!!
Post by: kiiaaa on February 25, 2017, 07:12:10 pm
could you please explain me the difference between ADH and aldostrone and any tips and tricks to remember the two what they do and the differences. im a pro and confusing the two
Thank you!
Post by: Sukakadonkadonk on February 25, 2017, 07:42:05 pm
Hello,
could you please explain me the difference between ADH and aldostrone and any tips and tricks to remember the two what they do and the differences. im a pro and confusing the two
Thank you!
Ok so basically, these are both hormones and both act on the kidneys. And also, I think that they both restabilise the blood pressure.
ADH - Antidiuretic hormone
- released from the hypothalamus in the brain
- response to low water levels in the blood
- increases permeability of tubule walls in nephron
- low water -> release of ADH -> more water reabsorbed into the blood
Aldosterone
- released from adrenal glands
- response to drop in blood pressure and low water levels
- also controls reabsorption of solutes (sodium)
- low water/minerals in blood -> release of Aldosterone -> more solutes and water reabsorbed into blood
I guess a way to remember which is which is to recall that 'Aldosterone' has more words, hence it causes the absorption or more things into the blood.
Please correct me, anyone, if I'm wrong.
Hope this helped!
Post by: DalvinT on February 25, 2017, 11:11:57 pm
Hello,
could you please explain me the difference between ADH and aldostrone and any tips and tricks to remember the two what they do and the differences. im a pro and confusing the two
Thank you!
The way I remember it is that:
ADH - fills in THREE spaces with letters
H20 - also fills up with three spaces.
So therefore, I know that ADH has got to do with the water reabsorption...
Leaving:
Aldosterone that involves salt and water reabsoprtion...
Post by: bananna on March 01, 2017, 07:17:57 am
with pedigrees, what is a quick way to determine if the affected trait is dominant or recessive?
thank you! :)
Post by: Quantum44 on March 01, 2017, 07:36:29 am
Hi,
with pedigrees, what is a quick way to determine if the affected trait is dominant or recessive?
thank you! :)
If the trait is recessive they will always show it skipping a generation whereas if the trait is dominant they will always show it being inherited by every generation. Thus you can pretty much tell in a few seconds whether it is dominant or recessive.
For example with recessive two unaffected parents can have affected children but for dominant an affected child must have at least one affected parent.
Post by: anotherworld2b on March 05, 2017, 05:59:04 pm
does that mean the heat that is released is due to both the build up and breaking of molecules?
I was wondering when would thyroxine secretion be triggered? when there is a low body temperature? (to maintain homeostasis maybe?)
I am a bit confused about thyroxin being secreted in response to thyroid stimulating hormone. Is it because TSH stimulates the production and release of hormones from the thyroid gland and thyroxine is one of these hormones? Is thyoxine the only thyroid hormone? does it include parathyroid hormones?
I am quite confused about thyroxine and thyroid stimulating hormone. Help is greatly appreciated
Post by: vox nihili on March 06, 2017, 07:34:24 pm
thyroxine is secreted by the thyroid gland and controls metabolism (breakdown/build up of molecules)
does that mean the heat that is released is due to both the build up and breaking of molecules?
I was wondering when would thyroxine secretion be triggered? when there is a low body temperature? (to maintain homeostasis maybe?)
I am a bit confused about thyroxin being secreted in response to thyroid stimulating hormone. Is it because TSH stimulates the production and release of hormones from the thyroid gland and thyroxine is one of these hormones? Is thyoxine the only thyroid hormone? does it include parathyroid hormones?
I am quite confused about thyroxine and thyroid stimulating hormone. Help is greatly appreciated
Thyroid hormone does influence metabolism, but it typically favours catabolism (i.e. breakdown of molecules). So the net effect of thyroid hormone is to increase breakdown of molecules, and thus energy production. Build up of molecules almost never produces energy.
Secretion of thyroid hormone is constitutive (meaning always secreted). This is because it is required to maintain your basal metabolic rate. If memory serves, thyroxine production does increase if you're really cold, but this isn't really your traditional homeostatic mechanism. It's more or less an option in crisis.
You're right about the role of TSH. It tells the thyroid to produce and secrete thyroid hormone.
THere are probably plenty of thyroid hormones, but the two we often talk about are thyroxine and triiodothyronine. The one that is actually active is triiodothyronine, hence why I've avoided using the term thyroxine and replacing it with thyroid hormone. The details of these hormones is pretty tricky, but the short and sweet is that thyroxine is a precursor of triiodothyronine.
Parathyroid hormones are distinct to thyroid hormones. The parathyroid glands are completely different structures.
Post by: annablackledge on March 07, 2017, 05:03:41 pm
Post by: sophiegmaher on March 09, 2017, 11:19:14 pm
Post by: sophiegmaher on March 09, 2017, 11:59:14 pm
Post by: kiiaaa on March 12, 2017, 06:43:24 pm
i was wondering if anyone knew any good sites or places to get past papers for half yearlies. my school doenst release any and i dont know where else to find them
thank you so much!
Post by: annablackledge on March 12, 2017, 07:17:19 pm
Hello everybody
i was wondering if anyone knew any good sites or places to get past papers for half yearlies. my school doenst release any and i dont know where else to find them
thank you so much!
I personally recommend purchasing the paper copy books of past papers from Excel. But they are big and heavy I use http://www.pasthsc.com.au/HSC.html
and
https://thsconline.github.io/s/yr12/
you can find some on ATAR Notes or Bored of studies
Post by: ajajaj on March 18, 2017, 07:40:38 pm
Is a line of best fit curved or straight?? In what cases would you do that in comparison to joining the dots on a graph?
Post by: Sukakadonkadonk on March 18, 2017, 08:56:06 pm
Hey guys,
Is a line of best fit curved or straight?? In what cases would you do that in comparison to joining the dots on a graph?
I remember I got marked up for drawing a straight line of best fit. I asked my teacher and she said that it should be a curve NOT a straight line, pretty much contradicts what I've learned for the past few years.
But I would ask your teacher to make sure. Did you get deducted marks or something?
Post by: ajajaj on March 18, 2017, 10:31:55 pm
I remember I got marked up for drawing a straight line of best fit. I asked my teacher and she said that it should be a curve NOT a straight line, pretty much contradicts what I've learned for the past few years.
But I would ask your teacher to make sure. Did you get deducted marks or something?
Yeah, it does happen quite often. Whenever I ask the answer isn't always concrete - it varies between teachers.
Post by: sophiemacpherso on March 19, 2017, 09:08:29 am
Post by: 1937jk on March 19, 2017, 11:51:51 pm
Hey, I'm really confused with the difference between a pair of homologous chromosomes and chromatids?
Hey! How I think of it is you have an X shape for your chromosome in which is made up of two chromatids after cell division (If you think of each line of an X being a chromatid) so then x2 chromatids = 1 chromosome. The chromatids are joined together via the centromere where there are two identical copies of the DNA and each copy being a chromatid.
Before a chromosome undergoes cell division there is one chromosome that is made up of one chromatid. After cell division you get two copies hence where the X shape comes from :)
Post by: kiiaaa on March 21, 2017, 01:46:40 pm
I have a biology test on Thursday and when doing last minute revision, i realised i don't know or remember anything about the kidney for Maintaining a Balance. Does anyone have any tricks to remember where filtration, re-absorption etc occurs and stuff on those lines please? thanks you so so so much
Post by: 1937jk on March 21, 2017, 02:35:12 pm
"Analyse information from secondary sources to identify the products extracted from donated blood and discuss the uses of these products"
With the platelets and plasma derived from donated blood, can anyone please explain what the difference is in terms of their uses?
Post by: kiiaaa on March 21, 2017, 03:19:02 pm
Post by: cookiedream on March 21, 2017, 03:58:08 pm
hi im extremely confused about random segregation and homologous pairs and lining up all that stuff. could some one help me out please?
Hello!
In meiosis, random segregation basically describes that when homologous chromosomes separate and go into different gametes, you can't tell which chromosome ends up in which gamete (i.e. the allocation of chromosomes is random).
Homologous pairs are two chromosomes which have very similar sizes and the place where the centromere is on the chromosome is pretty much the same for both chromosomes. During prophase 1 of meiosis, they come together side by side (they align) and when metaphase 1 starts, these aligned pairs formed a straight line down the centre of the cell.
Post by: kiiaaa on March 21, 2017, 04:25:59 pm
Hello!
In meiosis, random segregation basically describes that when homologous chromosomes separate and go into different gametes, you can't tell which chromosome ends up in which gamete (i.e. the allocation of chromosomes is random).
Homologous pairs are two chromosomes which have very similar sizes and the place where the centromere is on the chromosome is pretty much the same for both chromosomes. During prophase 1 of meiosis, they come together side by side (they align) and when metaphase 1 starts, these aligned pairs formed a straight line down the centre of the cell.
THNK YOU SO MUCH! that makes much more sense now.
Post by: annablackledge on March 22, 2017, 11:55:15 am
Hey, I'm really confused with the difference between a pair of homologous chromosomes and chromatids?Homologous Chromosomes are Maternal and Paternal versions of the same chromosome. That code for the same genes
Chromatids are each of the 'arms' of a chromosome.
Post by: bananna on March 27, 2017, 05:27:08 pm
Thanks !
Post by: Quantum44 on March 27, 2017, 06:36:47 pm
Hi wondering what's the best way to determine if a condition is sexlinked dom/recessive/non sex linked Dom/recessive.
Thanks !
First you determine if the condition is dominant or recessive. This can easily be discovered by checking if all affected individuals have at least one affected parent. If the condition skips a generation, it must be recessive and if it is shown to never skip a generation it is dominant.
Then you can move into X-linked and autosomal. You have to do some trial and error here using mental Punnett squares.
If recessive:
X-linked will definitely favour males over females and an affected mother must pass it onto her son. The gender ratios will be roughly equal in autosomal so the key is to try and rule out X-linked by seeing if an affected mother doesn't pass it onto her son.
If dominant:
X-linked will favour females and an affected father must pass it onto his daughter and an unaffected mother cannot have an affected son. As with recessive, proving the condition is autosomal relies on ruling out X-linked, such as the fact that two affected parents can only have an unaffected child if the condition is autosomal.
Post by: Youssk on March 28, 2017, 12:25:29 pm
I just have a question on antibiotic resistance and natural selection. Is the selection/ environmental pressure placed on the bacteria the antibiotic?
thanks :)
Post by: annablackledge on March 28, 2017, 02:56:21 pm
Hi guys,Antibiotics act on bacteria in various ways such as damaging the cell wall or disrupting functioning inside the cell. This is a pressure on the bacteria, this is the factor that determines which bacteria will live and reproduce or die; whether bacteria that has mutated to resit the damage or not.
I just have a question on antibiotic resistance and natural selection. Is the selection/ environmental pressure placed on the bacteria the antibiotic?
thanks :)
Post by: DalvinT on March 30, 2017, 08:45:52 pm
I'm not sure on how to answer questions with the verb "Critically evaulate"... I searched it up on what it means in HSC terms... And it seems like there's so much to discuss and I'm not sure where/how to start answering the quesiton..
Post by: julia_warren13 on April 05, 2017, 01:18:45 pm
Post by: Snew on April 06, 2017, 08:05:51 pm
Hey! I'm just having a bit of trouble with this MAB dotpoint: Explain why the concentration of water in cells should be maintained within a narrow range for optimal function What are the main things that I need to know for this dotpoint?? Thankyouu
Hey fellow 2017er :) this is what Naomi's notes (one of the awesome atar notes hsc lecturers) has so definitely check that out! super helpful
Enzymes work best when water is at its optimal concentration, and any variation from this negatively impacts cell metabolism
Cells work best in an isotonic environment - the solute concentration is the same both inside and outside the cell
Example:
When water concentration in red blood cells is optimal, they are said to be at an 'isotonic state' they are the right shape and size and can function effectively.
When RBC have too little water (due to there being to much salt in the fluid around them) RCB shrivel up as water moves out, attempting to recreate balance between the inside of the cell and the outside.
When RBC have too much water (due to there being too little water in the fluid around them) RBC swell up as water moves in, attempting to recreate balance between the inside of the cell and the outside
Post by: Rathin on April 08, 2017, 12:21:26 pm
Hey! I'm just having a bit of trouble with this MAB dotpoint: Explain why the concentration of water in cells should be maintained within a narrow range for optimal function What are the main things that I need to know for this dotpoint?? Thankyouu
Firstly we need to know WHY water should be maintained:
- It is a medium that transports and distributes substances between cells.
- It is a universal solvent it acts as a medium where all metabolic reactions can occur in water.
- It provides osmotic pressure for movement of materials depending on the solutes dissolved in water.
So new we need to know why the concentration of water is only maintained in a narrow range for optimum function.
- For a cell to perform at its optimum level the water concentration outside the cell and inside the same. This is known as an Isotonic state. If there is too much water the cell will burst and if there is too little water the cell will shrivel, where in both cases due to the unbalanced water concentration the functioning of the cell is not at its optimum.
Post by: pikachu975 on April 08, 2017, 01:04:40 pm
Hey! I'm just having a bit of trouble with this MAB dotpoint: Explain why the concentration of water in cells should be maintained within a narrow range for optimal function What are the main things that I need to know for this dotpoint?? Thankyouu
To add on, here's some key terms for this dot point:
Animals/Humans:
Hypotonic - too much water in the cells (bursting/swelling of the cell)
Isotonic - balance between water inside and outside (good for humans/animals)
Hypertonic - too little water (shrivelling)
Plants:
Turgid - too much water in the plant cells (good for plants)
Flaccid - same amount inside and outside (not enough water)
Plasmolysed - too little water (death due to no photosynthesis)
Post by: bananna on April 13, 2017, 05:20:33 pm
Is the peppered moth of the industrial revolution considered a modern example of natural selection ?
Thank u :)
Post by: pikachu975 on April 13, 2017, 09:39:33 pm
Hi
Is the peppered moth of the industrial revolution considered a modern example of natural selection ?
Thank u :)
The peppered moth should be good to use.
Post by: Rathin on April 14, 2017, 09:45:04 am
Hi
Is the peppered moth of the industrial revolution considered a modern example of natural selection ?
Thank u :)
Yes Peppered Moth is an example of a physical change in the environment and DDT on mosquitoes is a chemical change in the environment which has led to the mechanism of Natural Selection.
Post by: Thebarman on April 21, 2017, 09:55:12 am
Post by: diesxel on April 27, 2017, 01:15:33 am
Exam's in only a few days so any help is appreciated!!
Thanks so much :D
Post by: pikachu975 on April 27, 2017, 08:15:31 pm
Hello, I have an assessed biology exam coming up for module 1 and 2, and I was wondering if anyone had any links to good past papers or exams that I can use to study from?? I really really need to do well in this exam, I'm good with content but I need to apply it as well.
Exam's in only a few days so any help is appreciated!!
Thanks so much :D
Just some general tips to study for how to write answers:
- Use dot points! Markers will already be sighing if they see a large slab of a whole page answer with no dot points or structure whatsoever and using dot points can make it easier to read at least.
- Adding on to the first dot point, subheadings and underlining can give a lot of structure to answers.
- Writing important words in capital letters or underlining them could help the marker instantly see that you know your content because they may skip over it on a tiring night when they've read 20 other papers!
- Plan 4+ mark responses because often a logical and coherent answer is essential for the full marks, ESPECIALLY the 8 marker.
- Always look at the key verb and key terms and keep them in your mind. If it says compare, it could be useful to draw a table, etc. Alongside this, highlighting the key terms could help you remember to keep on track.
- Read marking criterias of HSC and trial papers to see the expectation of what they're looking for, but before that, try and predict the mark allocation so that in the exam you can easily tell what you need to include. Reading sample answers off of ARC or bostes examplar responses helps heaps.
Post by: DalvinT on May 01, 2017, 07:47:15 pm
So I've a question on how exams are marked in Biology. So the marking guidelines, gives points in which students can include in there responses and also has standards for each range. Now, I said "can", does that mean that if we didn't include those specific points they suggested, would we be disadvantaged? Even if the points mentioned, were valid and correct.
For example,
The question is, "Explain the advantage adaptations of haemoglobin" 2 marks
Marking guidelines:
- 4 oxygen molecules per haemoglobin, Approx. 200 haemoglobin. Large quantity (1)
- Able to transfer gases and other products efficiently to cells. (1)
- Allows proper functioning and maintains pH as well. (1)
And let's say that the answer did not include "transfer gases efficiently" but instead wrote "transfer chemicals efficiently"... would they still get a mark?
To me, I think they should cause gases are chemicals ... lol. Or does marking responses requires SPECIFIC details, in order to earn marks...
Post by: Youssk on May 02, 2017, 10:15:34 pm
Describe the importance of protein production for maintaining and repairing body tissue?
Thanks :)
Post by: vox nihili on May 03, 2017, 10:54:14 am
Hi, I'm just confused on how to answer this question from 'the search for better health)
Describe the importance of protein production for maintaining and repairing body tissue?
Thanks :)
-tissues sometimes get damaged and break down
-tissues are made out of protein
-to make new tissue to replace the damaged/old tissue, one needs to make protein
Post by: pikachu975 on May 04, 2017, 12:56:17 am
Hello,
So I've a question on how exams are marked in Biology. So the marking guidelines, gives points in which students can include in there responses and also has standards for each range. Now, I said "can", does that mean that if we didn't include those specific points they suggested, would we be disadvantaged? Even if the points mentioned, were valid and correct.
For example,
The question is, "Explain the advantage adaptations of haemoglobin" 2 marks
Marking guidelines:
- 4 oxygen molecules per haemoglobin, Approx. 200 haemoglobin. Large quantity (1)
- Able to transfer gases and other products efficiently to cells. (1)
- Allows proper functioning and maintains pH as well. (1)
And let's say that the answer did not include "transfer gases efficiently" but instead wrote "transfer chemicals efficiently"... would they still get a mark?
To me, I think they should cause gases are chemicals ... lol. Or does marking responses requires SPECIFIC details, in order to earn marks...
I think for that example chemicals is a broad/vague term and if I saw it I'd think they don't know what haemoglobin is for, and are trying to write a vague term to hope for the best.
Post by: DalvinT on May 04, 2017, 05:45:27 pm
I think for that example chemicals is a broad/vague term and if I saw it I'd think they don't know what haemoglobin is for, and are trying to write a vague term to hope for the best.
Ahh I see, good point.
Post by: Aaron12038488 on May 04, 2017, 07:44:26 pm
Post by: arunasva on May 13, 2017, 09:12:19 pm
are grasslands, deserts examples of biomes or ecosystems?
certainly. Eco systems are everywhere. Your body is an ecosystem.
Post by: sophiemacpherso on May 17, 2017, 09:46:34 pm
Post by: pikachu975 on May 18, 2017, 09:41:06 pm
Hey! How do I ace the 8 markers?? They encompass such a broad section of the syllabus and honestly they just intimidate me a lot ...
Definitely write more than the page they provide but make sure all content you write relates to the question.
Don't just content dump.
PLAN OUT THE RESPONSE which will make your response coherent and logical which is REQUIRED to get 8/8 and make sure all parts link to the question.
Post by: samsclaire on June 06, 2017, 07:30:02 pm
vaccination: vaccine --> exposure --> immune response --> immunity
immunisation is the process of getting immunity, through an immune answer
is this right?
Post by: Diala on June 08, 2017, 06:50:13 pm
Post by: Thebarman on June 08, 2017, 07:20:00 pm
Evaluate the effectiveness of quarantine in preventing the spread of plant and animal diseases into Australia or across regions of Australia.
Post by: jamonwindeyer on June 08, 2017, 07:41:29 pm
What are your best study tips for bio? Do you think it's best to start re-learning the content from now? There's about 2 months until trials!
Check out this Band 6 Bio Guide!!
Sorry guys, I'm definitely not a biologist - Would love for someone to help answer these questions ;D
Post by: pikachu975 on June 10, 2017, 12:51:54 am
What are your best study tips for bio? Do you think it's best to start re-learning the content from now? There's about 2 months until trials!
Don't "re-learn" it because I'm sure you've learnt it already just go over your notes and revise. If you don't have any notes use someone's b6 notes and revise that then do past papers.
Read marking guidelines so you know what the general idea is of what to write for responses, i.e. learn mark allocation.
Do questions and hand it in to your teacher for feedback and improve <- most important one.
Post by: phebsh on June 12, 2017, 08:35:17 pm
Produce a table for both the disease and the microflora imbalance using the following headings:
- name
- pathogen
- cause
- symptoms
- treatment
What I'm understanding is that a microflora imbalance causes a disease, so then how do I answer this question?
Post by: phebsh on June 12, 2017, 08:44:35 pm
What are your best study tips for bio? Do you think it's best to start re-learning the content from now? There's about 2 months until trials!
Hey! We had a talk at school on how to prep for exams and the technique they gave us was to first finish your notes, then memorise your notes and finally do as many practice papers as you can.
Post by: samsclaire on June 12, 2017, 09:17:23 pm
Hey, I'm struggling with this question on my assignment;
Produce a table for both the disease and the microflora imbalance using the following headings:
- name
- pathogen
- cause
- symptoms
- treatment
What I'm understanding is that a microflora imbalance causes a disease, so then how do I answer this question?
hey! we did this a couple of weeks ago, as a research task, and one of the questions was:
"If the pathogen that causes candidiasis is in the body’s microflora all the time, explain why the disease is not always present, and describe the conditions under which the disease could develop.
Candida albicans is present in the body’s microflora already. However, it is kept in low numbers as the result of other microorganisms in the microflora. These low numbers mean that Candidiasis is unable to develop. However, if this balance is undermined or changed, than C. albicans could begin to multiply at a higher rate. As the balance (of microorganisms) would be changed, it could possibly be unable to control the growth of the pathogen. Eventually, this could allow the disease (Candidiasis) to develop."
basically, the pathogen/antigen is present in the body’s microflora, but it’s kept ‘under control’ so disease doesn’t develop; if that balance is changed (for whatever reason), the disease is free to develop. the microflora in the body (as a whole) doesn’t cause the disease. the pathogen does, and it just happens to exist in the microflora.
i don’t feel like i've explained this well, so feel free to ask again if this is just confusing you more!
Post by: bigsweetpotato2000 on June 13, 2017, 09:35:47 pm
Currently we are doing Epidemiological studies right now but there is large confusion between the terms Morbidity and Prevalence.
Morbidity is the number of ill at a given time, and morality is the number of deaths but I don't understand because the definition for prevalence is number of cases at a given time.....So are they different or the same or do they even have correlation?
Confused,
Sweetpotato Farms :D
Post by: jamesq on June 14, 2017, 11:56:25 am
Post by: bethr on June 14, 2017, 06:49:56 pm
Heyyss!
Currently we are doing Epidemiological studies right now but there is large confusion between the terms Morbidity and Prevalence.
Morbidity is the number of ill at a given time, and morality is the number of deaths but I don't understand because the definition for prevalence is number of cases at a given time.....So are they different or the same or do they even have correlation?
Confused,
Sweetpotato Farms :D
I think you mean mortality? And what it means by number of cases given at a time means that say, in 2016 there were 17,000 people with lung cancer in Australia. That would be its prevalence. Incidence, I know isn't relevant, but just to hopefully create a clearer understanding, is the number of NEW cases. So of those 17,000 people, 2,000 were diagnosed in that year. Essentially prevalence: total at one time Incidence: Newly diagnosed.
Post by: vox nihili on June 14, 2017, 08:38:56 pm
Heyyss!
Currently we are doing Epidemiological studies right now but there is large confusion between the terms Morbidity and Prevalence.
Morbidity is the number of ill at a given time, and morality is the number of deaths but I don't understand because the definition for prevalence is number of cases at a given time.....So are they different or the same or do they even have correlation?
Confused,
Sweetpotato Farms :D
Good question.
Mortality is pretty straightforward. It's the number of people who die over a given period. Mortality is an expression of the incidence of death (see above for definition of incidence).
Morbidity on the other hand is a little trickier, because it can be expressed as a prevalence or incidence. As above, prevalence is the number of people with a particular disease, whereas incidence is the number of new cases of the disease in a fixed time period.
Post by: bigsweetpotato2000 on June 14, 2017, 10:24:57 pm
Good question.
Mortality is pretty straightforward. It's the number of people who die over a given period. Mortality is an expression of the incidence of death (see above for definition of incidence).
Morbidity on the other hand is a little trickier, because it can be expressed as a prevalence or incidence. As above, prevalence is the number of people with a particular disease, whereas incidence is the number of new cases of the disease in a fixed time period.
I'm really truly extremely most devotedly sorry but....
I don't get it.
Is there any difference between Morbidity and Prevalence then?
Post by: bigsweetpotato2000 on June 14, 2017, 10:26:51 pm
I think you mean mortality? And what it means by number of cases given at a time means that say, in 2016 there were 17,000 people with lung cancer in Australia. That would be its prevalence. Incidence, I know isn't relevant, but just to hopefully create a clearer understanding, is the number of NEW cases. So of those 17,000 people, 2,000 were diagnosed in that year. Essentially prevalence: total at one time Incidence: Newly diagnosed.
Wait so what is the difference between morbidity and prevalence then?
Im so confused!!!
Also I'm realllyy sorry but I'm so slow at understanding this stuff O.o
Post by: bethr on June 15, 2017, 08:54:13 am
Wait so what is the difference between morbidity and prevalence then?
Im so confused!!!
Also I'm realllyy sorry but I'm so slow at understanding this stuff O.o
Morbidity is just a fancy definition for illness. Prevalence is the number of illnesses. I know I didn't explain it very well. But does that make sense?
Post by: bigsweetpotato2000 on June 16, 2017, 09:56:27 pm
Morbidity is just a fancy definition for illness. Prevalence is the number of illnesses. I know I didn't explain it very well. But does that make sense?
Ooooooohh Okays yep!
Thank you so much HAHAH I should invest in some Biology for Dummies books :P
Post by: bethr on June 18, 2017, 10:17:57 pm
Post by: julia_warren13 on June 20, 2017, 09:35:59 pm
Post by: bethr on June 20, 2017, 10:36:56 pm
I've heard that some HSC markers may not read answers written below the given lines for section II of the paper. Is this true?? Also any tips on how to answer these short answer questions more concisely would be appreciated :) :)
Where did you hear that from? I can't see how it could be true. Even though marking a subject like biology would be a pain it is the markers job to mark. Maybe this is different, but for French I know, they mark everything written on your page. If it is true, I have massive writing and I'm a very wordy person so I'm screwed
Post by: pikachu975 on June 21, 2017, 09:44:23 pm
Where did you hear that from? I can't see how it could be true. Even though marking a subject like biology would be a pain it is the markers job to mark. Maybe this is different, but for French I know, they mark everything written on your page. If it is true, I have massive writing and I'm a very wordy person so I'm screwed
They scan the whole page. Pretty sure I read somewhere that even though it has borders and stuff they still scan the entire page. If you run out of space you can ask for extra booklets :)
Post by: itssona on June 25, 2017, 12:32:49 pm
2. How was the experiment of Miller and Urey important in illustrating the nature and practice of
science?
(A) Urey and Miller’s experiment was based upon several different hypothesises about the
origin of life.
(B) The experiments were designed so that other scientists could not replicate them.
(C) Urey and Miller’s experiments were designed to test one hypothesis about the origin of
life.
(D) Urey and Miller proved they could do an experiment that no one else wanted to do.
Post by: leighshapiro on June 28, 2017, 08:20:29 am
Post by: Youssk on July 01, 2017, 02:14:55 pm
What is the pathogen that causes Giardiasis?
Thanks
Post by: vox nihili on July 01, 2017, 10:30:06 pm
Hi,
What is the pathogen that causes Giardiasis?
Thanks
Hey there! Giardiasis is a really interesting topic. You can find all the details about the pathogen that causes it at this link :)
Post by: Opengangs on July 05, 2017, 06:50:23 pm
help plssHi, sssona09!
2. How was the experiment of Miller and Urey important in illustrating the nature and practice of
science?
(A) Urey and Miller’s experiment was based upon several different hypothesises about the
origin of life.
(B) The experiments were designed so that other scientists could not replicate them.
(C) Urey and Miller’s experiments were designed to test one hypothesis about the origin of
life.
(D) Urey and Miller proved they could do an experiment that no one else wanted to do.
In these multiple choice questions, a good tactic is to disregard two completely incorrect options. This will make it easier to distinguish which answers you're looking for.
As for the Urey-Miller experiment, the significant feature of the Urey-Miller experiment was that it confirmed Haldane and Oparin's theory about the origin of life. By simulating the conditions that they found on the primitive earth, they decided to test the theory in the 1950's using hypothesis that complex organic molecules could have been created using inorganic molecules through slow reactions.
Thus, we can conclude that the correct answer is (C) as they only performed the experiment to prove Haldane and Oparin's hypothesis.
Is anyone able to help me in differentiating xylem and phloem? just like key points or any links to good diagrams? for some reason i have so much trouble with thisHi, leighshapiro!
The defining features of the xylem and phloem are in its structure and mechanisms. I recommend drawing up a table; it should include the structure (living v dead cells, defining features), mechanism (and what they are called), as well as what they transport. This will give you an idea as to what you need to include when differentiating the two.
Xylem:
The xylem is composed of dead cells that lie end to end. A good way to remember this is the connotation of the 'x' eyes (x_x) as dead. Xylem = dead cells.
The structure of the xylem involves the dead cells disintegrating and producing continuous, hollow, fluid filled tbues.
Another defining feature about the xylem is what it transports: water and mineral ions, which travel only in an upward motion.
The best model that scientists have hypothesised about the movement of water and mineral ions around the xylem is the Transpiration-Adhesion-Cohesion-Tension model. You can remember the acronym (TACT)!! ;D
The movement of water and mineral ions start from the soil. Water and mineral ions diffuse from the soil into the plants via the plant roots. Water movement is referred to as osmosis, which is passive transport, whereas the mineral ions are both active and passive.
Since the transport in the xylem is uni-directional, meaning the flow of materials occurs in one direction only, the only way to get to the leaves is upwards. This process covers both, adhesion and cohesion.
Adhesion: refers to the process where water molecules are bound to the walls of the xylem.
Cohesion: refers to the process where water molecules are bound to one another.
The way I'd like to remember this concept is the whole notion of cohesion. When we have cohesion in a classroom, everything makes sense. We work together to understand. This means that they are 'helping' each other (ie binding to one other).
The stream of movement then transpires in the leaves and into the open air. The notion of water and mineral ions moving up to the leaves is referred to as: transpiration pull. I'd like to remember this as: our end result is the transpiration into the leaves, but in order to do this, we need to be pulled up (ie. transpiration pull).
Finally, water is lost due to evaporation through tiny pores, called stomates.
That's the process of the transportation of the materials inside the xylem!!
Phloem:
Unlike the xylem, the phloem consists of living and connected cells that run from leaves to roots. Their defining structures are: sieve tubes and companion cells.
Sieve tubes: series of cells joined end to end with perforated cross walls between cells (sieve plates) that transport the sugars throughout the plant.
Companion cells: specialised cells with a nucleus that always appear with the sieve tube element and serve to assist in the active loading and unloading of nutrients into and out of the sieve elements.
The mechanism used is: pressure-flow hypothesis. Some schools like to use 'source-to-sink theory'. The HSC, afaik, don't mind which you use, so long as you describe their mechanisms.
This describes the processes responsible for the movement of sugars through the phloem tissues.
Glucose that is produced in the leaves need to be converted into sucrose. Glucose is a monosaccharide (single sugar), whereas sucrose is a disaccharide (double sugar), which is composed of glucose and fructose.
Sucrose is then loaded from the leaves (the 'source', so to speak) into sieve tubes via active transport. The energy used to carry sucrose down the phloem tube comes from the companion cells. Water then follows the sucrose, moving into the phloem tissue via osmosis via passive transport. This water comes from the xylem tissue which lies adjacent to the phloem.
Now, the presence of water increases the pressure inside the sieve tubes, forcing sucrose to flow from one sieve tube cell to another. In this way, sucrose flows down the phloem. When sucrose reaches the tissues that require it (like the roots), it is 'unloaded' from the sieve tubes via active transport. At this point, water molecules leave the phloem via osmosis.
I personally think the pressure-flow is harder than the TACT model, just because there's a lot more going on. But these are the distinctive elements of the two. Another thing you need to note is that: xylem transports materials via transpiration, while the phloem transports nutrients via translocation.
If you're still confused, watch these videos to understand more about the models and tissues.
Cohesion, Adhesion & Surface Tensionl[1]
Pressure Flow Hypothesis[2]
Sources:
[1] Cohesion, Adhesion & Surface Tension. (2014). [video] bionerdery.
[2] Pressure Flow Hypothesis. (2017). [video] Directed by D. Weber. Biogene.
Post by: AimeeO on July 11, 2017, 03:43:49 pm
I am wondering when to use a line of best fit in biology, all the teachers tell something different.
On a practise exam the questions asks to graph the data from an experiment comparing pH to enzyme reaction rates. Obviously, the graph becomes almost like an upright triangle, so it isn't linear.
So, do you do a line of best fit here, or connect the dots?
Post by: Rachelh7 on July 11, 2017, 04:02:39 pm
Post by: pikachu975 on July 11, 2017, 04:04:08 pm
Hi,
I am wondering when to use a line of best fit in biology, all the teachers tell something different.
On a practise exam the questions asks to graph the data from an experiment comparing pH to enzyme reaction rates. Obviously, the graph becomes almost like an upright triangle, so it isn't linear.
So, do you do a line of best fit here, or connect the dots?
For pH vs enzyme activity it should be 1/clotting time vs pH which would be a bell curve, so either join the dots or do a curve of best fit! Make sure you label it 'line of best fit' or 'curve of best fit'. Usually do a line or curve of best fit if you EXPECT a perfect line or curve but some points are a bit off.
Post by: AimeeO on July 12, 2017, 10:07:00 am
For pH vs enzyme activity it should be 1/clotting time vs pH which would be a bell curve, so either join the dots or do a curve of best fit! Make sure you label it 'line of best fit' or 'curve of best fit'. Usually do a line or curve of best fit if you EXPECT a perfect line or curve but some points are a bit off.
Thank you, I wasn't sure what to do but I will give it a go!
Post by: bimberfairy on July 15, 2017, 01:33:49 am
Hey, I'm struggling with this question on my assignment;
Produce a table for both the disease and the microflora imbalance using the following headings:
- name
- pathogen
- cause
- symptoms
- treatment
What I'm understanding is that a microflora imbalance causes a disease, so then how do I answer this question?
I did something similar to this recently, so I'll try to put in my two cents + contribute to the previous reply to your question!
Microflora's all over your body and covers surfaces that are exposed to the outside. So basically, it prevents and protects your body from disease, but if the conditions of your body changes, the environment that the microflora is in can also change, therefore affecting the effectiveness of your microflora in doing what it's meant to do. As a result, diseases can be generated from it.
A really good example that you can use in your table for your assignment is "Candidiasis" which, in everyday lingo, is thrush, and it results from this microflora imbalance (generated from an environmental change in your body!)
An imbalance of microflora allows the fungus to grow out of control, causing "Candidiasis" (Candida albicans is the fungus that causes this) and the cause of this is usually through the intake of antibiotics which destroy harmful AND beneficial bacteria in the body, allowing more of the candida albicans fungus to grow and multiply, resulting in..... badum tiss! THRUUUSHHHH
I hope this helps!! I tried my best to explain how microflora imbalance relates to a particular disease, and the rest of the table can be filled out through some research online for the particular disease you plan to use (:
Post by: maddiewainwright on July 15, 2017, 05:34:06 pm
Hi can anyone answer this biology question i found in a trial. Describe the historical role that models played in determining the structure of DNA as the 'chemical of life'. (4 MARKS). Not sure where to start....
Hi Rachelh7,
For a 4m question, probably start off with a definition, so explain what DNA is and what it does:
'Deoxyribose Nucleic Acid is the molecule which carries genetic information within organisms. It is composed of nucleotides, arranged in a specific order to generate a 'code', telling the body which proteins to produce, and therefore influencing phenotype.'
Then, I think what the question wants you to talk about is the Watson and Crick discovery of DNA structure, and how they used models to test their hypothesis:
'Watson and Crick were responsible for proposing the now commonly accepted model of how DNA is structured. By collating findings of Chargaff (complementary nature of nitrogen bases) and Franklin/Wilkins (x-ray crystallography images of DNA strands), they proposed that DNA had a double helix structure, with a sugar-phosphate backbone on the outside, and nucleotide bases facing inwards to bind purine - pyrimidine (A-T, G-C). They came up with this hypothesis without conducting any formal experiments, but by constructing a 3D metal model, they measured the dimensions, and compared them to Franklin's 'photograph 51', to ultimately determine DNA structure.'
This would probably be a good place to begin, however potentially worth conducting a little more research into whether other models were proposed (as the question asks for models, plural), but is was the main one that you're likely to have a question on for the HSC.
Post by: maddiewainwright on July 15, 2017, 05:40:10 pm
Hi,
I am wondering when to use a line of best fit in biology, all the teachers tell something different.
On a practise exam the questions asks to graph the data from an experiment comparing pH to enzyme reaction rates. Obviously, the graph becomes almost like an upright triangle, so it isn't linear.
So, do you do a line of best fit here, or connect the dots?
Hi AimeeO,
For Bio it's best to connect your data points in a smooth curve (always do this for the enzyme rate of reaction questions), unless they explicitly ask for a line of best fit. For comparing pH, your line should look like a bell curve if plotted correctly.
Post by: maddiewainwright on July 15, 2017, 05:48:51 pm
For anyone doing the option Genetics Code Broken could you explain the outcome: identify the role of genes in embryonic development. I'm finding it really difficult to understand
Hi bethr,
When talking about embryonic development they specifically want you to understand that genes are switched on in a 'cascade'. So firstly, our homeobox genes are switched on to generate differentiation of cells, allowing development of bodily structures. For example, to develop an arm, first the genes which encode development of an arm 'bud' are translated, and then those which extend the arm, and so on so forth.
Post by: mixel on July 17, 2017, 10:39:13 am
I often hear suggestions to answer compare questions with a table, but I feel like it takes me too long to rule out a table that's neat enough to justify the amount of time it takes. Are there any ways I can cut corners?
Post by: pikachu975 on July 17, 2017, 07:15:18 pm
Hi all, just wondering if there's a quick way to draw tables?
I often hear suggestions to answer compare questions with a table, but I feel like it takes me too long to rule out a table that's neat enough to justify the amount of time it takes. Are there any ways I can cut corners?
Pretty simple for compare just draw a line down the middle and rule a horizontal line for the headings of each column. Once done, just quickly rule lines that enclose the box or just don't even close it.
Post by: olr1999 on July 17, 2017, 07:29:34 pm
Some people believe that transgenic organisms may play a large part in food production in the future.
Describe the genetic make-up of ONE transgenic organism you have studied. 1m
It's probably straightforward but I don't understand what it means by 'genetic make-up'
Thank you in advance :)
Post by: maddiewainwright on July 17, 2017, 07:38:49 pm
Hi! Can I please have some help with this question?:
Some people believe that transgenic organisms may play a large part in food production in the future.
Describe the genetic make-up of ONE transgenic organism you have studied. 1m
It's probably straightforward but I don't understand what it means by 'genetic make-up'
Thank you in advance :)
Hi orl1999!
An example of a transgenic organism which would be great for this question would be BT Wheat. This is a genetically modified wheat crop which has a bacterium gene (from the Bacillus thuringiensis) encoding a toxin inserted into its genome. This makes it naturally resistant to pests, so that farmers don't need to use pesticides/insecticides.
Basically when the question asks for 'genetic make-up', it's just asking what genes are added, encoding what specific characteristics.
Post by: olr1999 on July 17, 2017, 08:06:15 pm
Hi orl1999!
An example of a transgenic organism which would be great for this question would be BT Wheat. This is a genetically modified wheat crop which has a bacterium gene (from the Bacillus thuringiensis) encoding a toxin inserted into its genome. This makes it naturally resistant to pests, so that farmers don't need to use pesticides/insecticides.
Basically when the question asks for 'genetic make-up', it's just asking what genes are added, encoding what specific characteristics.
That's an amazing help, thank you so much!
Post by: michelleh on July 18, 2017, 06:13:36 pm
There was a particular question in my Biology test paper that was marked down. The question was: 'Link the structure and function of a feature of the mammalian eye'.
My answer was this: 'The choroid is a layer of the eye that consists of blood vessels near the outer surface of the layer. The blood vessels transports oxygenated blood around to the choroid layer which maintains the functioning of the eye as the eye requires cellular respiration and thus the need for oxygen to carry out the functioning of the eye'.
The feedback was simply that it did not link the structure to the function... but I'm not convinced since I did state the feature ('choroid') with its function ('blood vessels near the outer surface layer') and the function ('transports oxygenated blood to mantain functioning of eye')?
Would like to know your opinion on this, please!
Thank you!
Post by: mixel on July 18, 2017, 06:31:14 pm
Help!
There was a particular question in my Biology test paper that was marked down. The question was: 'Link the structure and function of a feature of the mammalian eye'.
My answer was this: 'The choroid is a layer of the eye that consists of blood vessels near the outer surface of the layer. The blood vessels transports oxygenated blood around to the choroid layer which maintains the functioning of the eye as the eye requires cellular respiration and thus the need for oxygen to carry out the functioning of the eye'.
The feedback was simply that it did not link the structure to the function... but I'm not convinced since I did state the feature ('choroid') with its function ('blood vessels near the outer surface layer') and the function ('transports oxygenated blood to mantain functioning of eye')?
Would like to know your opinion on this, please!
Thank you!
Hey, I don't have my textbook on me so I'm not sure, but iirc what you described is the function of the sclera. I think the choroid layer is more specifically a darkly pigmented layer between the retina and the sclera (structure) that's meant to reduce reflections of incoming light to prevent internal scattering and outward reflection of light, which would interfere with detection of light by the retina (function). I'm not sure though, and from your teacher's explanation it sounds like they pinged you for something else.
Post by: pikachu975 on July 18, 2017, 06:37:52 pm
Help!
There was a particular question in my Biology test paper that was marked down. The question was: 'Link the structure and function of a feature of the mammalian eye'.
My answer was this: 'The choroid is a layer of the eye that consists of blood vessels near the outer surface of the layer. The blood vessels transports oxygenated blood around to the choroid layer which maintains the functioning of the eye as the eye requires cellular respiration and thus the need for oxygen to carry out the functioning of the eye'.
The feedback was simply that it did not link the structure to the function... but I'm not convinced since I did state the feature ('choroid') with its function ('blood vessels near the outer surface layer') and the function ('transports oxygenated blood to mantain functioning of eye')?
Would like to know your opinion on this, please!
Thank you!
The structure of the choroid is a thin sheet of densely packed blood vessels. The function is to prevent stray light from hitting the retina to prevent stray images from being seen, which is possible as the blood vessels cause a dark pigment to absorb the stray light.
Post by: bigsweetpotato2000 on July 18, 2017, 07:31:03 pm
For the dot point:
Process information from secondary sources to describe and analyse the relatively importance of the work of:
James Watson
Francis Crick
Rosalind Franklin
Maurice Wilkins
in determining the structure of DNA and the impact of the quality of collaboration and communication on their scientific research
What sort of information are we to learn under this dotpoint? Because in my midyears I received a 3 out of 7 for the question in regards to this dotpoint and the marking said that I didn't specify their collaboration well enough...However i did actually mention how the collaboration was bad leading to the success of Rosalind and Wilkins being jeopardised and how good collaboration between Watson and Crick eventually got them the Nobel Peace Prize.
Any suggestions?
Bigsweetpotato Farm
Post by: pikachu975 on July 18, 2017, 07:35:05 pm
Holla,
For the dot point:
Process information from secondary sources to describe and analyse the relatively importance of the work of:
James Watson
Francis Crick
Rosalind Franklin
Maurice Wilkins
in determining the structure of DNA and the impact of the quality of collaboration and communication on their scientific research
What sort of information are we to learn under this dotpoint? Because in my midyears I received a 3 out of 7 for the question in regards to this dotpoint and the marking said that I didn't specify their collaboration well enough...However i did actually mention how the collaboration was bad leading to the success of Rosalind and Wilkins being jeopardised and how good collaboration between Watson and Crick eventually got them the Nobel Peace Prize.
Any suggestions?
Bigsweetpotato Farm
The collaboration between Rosalind and Wilkins was ineffective, which meant their work was not efficiently researched and they had a lack of communication. This lack of effective communication led to Wilkins leaking Rosalind's research from x-ray crystallography to Watson and Crick. Because Watson and Crick had great communication, they worked well and communicated well. This meant that even though they were told to stop after they failed numerous times, they continued to persevere and work together to produce the current model of DNA.
Post by: maddiewainwright on July 18, 2017, 07:43:16 pm
Holla,
For the dot point:
Process information from secondary sources to describe and analyse the relatively importance of the work of:
James Watson
Francis Crick
Rosalind Franklin
Maurice Wilkins
in determining the structure of DNA and the impact of the quality of collaboration and communication on their scientific research
What sort of information are we to learn under this dotpoint? Because in my midyears I received a 3 out of 7 for the question in regards to this dotpoint and the marking said that I didn't specify their collaboration well enough...However i did actually mention how the collaboration was bad leading to the success of Rosalind and Wilkins being jeopardised and how good collaboration between Watson and Crick eventually got them the Nobel Peace Prize.
Any suggestions?
Bigsweetpotato Farm
Hi Bigsweetpotato2000,
Just adding to the great points pikachu975 made, another important thing that Watson and Crick did in terms of collaboration was that they built upon other people's ideas. They took information from other scientists (Chargaff's rules of nitrogen pairing, and Franklin's 'photograph 51'), and synthesised them in a creative way, collaborating to come to a solution. This enables more effective scientific practice, and evidently betters the scientific community when people are working together.
Hope this helps!
Post by: bigsweetpotato2000 on July 18, 2017, 07:49:42 pm
The collaboration between Rosalind and Wilkins was ineffective, which meant their work was not efficiently researched and they had a lack of communication. This lack of effective communication led to Wilkins leaking Rosalind's research from x-ray crystallography to Watson and Crick. Because Watson and Crick had great communication, they worked well and communicated well. This meant that even though they were told to stop after they failed numerous times, they continued to persevere and work together to produce the current model of DNA.
Hi Bigsweetpotato2000,
Just adding to the great points pikachu975 made, another important thing that Watson and Crick did in terms of collaboration was that they built upon other people's ideas. They took information from other scientists (Chargaff's rules of nitrogen pairing, and Franklin's 'photograph 51'), and synthesised them in a creative way, collaborating to come to a solution. This enables more effective scientific practice, and evidently betters the scientific community when people are working together.
Hope this helps!
Legendss!!! Thanks so much!
Post by: olr1999 on July 18, 2017, 08:24:23 pm
I'm a little unsure about how to answer this question, any help is muchly appreciated!:
'The Black Plague was an infectious disease devastating Europe between the 14th and 19th centuries. The disease was caused by the bacteria Yersinia pestis
Yersinia pestis usually infects the intestines, but during the Black Plague it infected the lungs, causing pneumonia-like symptoms and killing millions of people.
Recently published research on the bacteria indicates that a small genetic change in the bacteria as far back as 2500 years ago may have caused it to go from a treatable infection of the intestines to a fatal lung infection.
Using your knowledge of Darwin's Theory of Natural Selection, explain how Yersinia pestis may have changed from being an intestinal infection to become a much more severe lung infection.' 3marks
Thank you!
Post by: bigsweetpotato2000 on July 18, 2017, 08:50:34 pm
Hey!
I'm a little unsure about how to answer this question, any help is muchly appreciated!:
'The Black Plague was an infectious disease devastating Europe between the 14th and 19th centuries. The disease was caused by the bacteria Yersinia pestis
Yersinia pestis usually infects the intestines, but during the Black Plague it infected the lungs, causing pneumonia-like symptoms and killing millions of people.
Recently published research on the bacteria indicates that a small genetic change in the bacteria as far back as 2500 years ago may have caused it to go from a treatable infection of the intestines to a fatal lung infection.
Using your knowledge of Darwin's Theory of Natural Selection, explain how Yersinia pestis may have changed from being an intestinal infection to become a much more severe lung infection.' 3marks
Thank you!
Oooh I'll give it a try :D
First Up! Define Evolution
Charles Darwin in the 19th century proposed the Theory of Evolution by natural selection as a process in which organisms change over time as a result of new environments, allowing the organism to better adapt to its new habitat.
2nd - Relate the case study to the three aspects of evolution: Variation, Heritability and Over Reproduction.
The Yersinia pestis's evolution from a intestinal infection to a more severe lung infection was potentially due to the variations in the population that survived the treatment 2500 years ago. The certain bacteria with a random genetic difference survived the treatment provided during the contemporary time and continued to survive, slowly reproducing over time to increase the chance of the new species survival. This resulted in the evolution of the Yersinia pestis, which became a more severe lung infection.
Hope that works :D
Bigsweetpotato Farm
Post by: bigsweetpotato2000 on July 18, 2017, 09:29:07 pm
Bigsweetpotato Farm
Post by: maddiewainwright on July 18, 2017, 09:46:56 pm
What's microflora in humans? - Search for a better health section :D
Bigsweetpotato Farm
Hi Bigsweetpotato2000,
Microflora simply refers to all the naturally occurring micro-organisms that cover/are in our bodies. This can be bacteria, fungi, all different types of microorganisms. Microflora is important for human health (there have been recent studies linking healthy gut bacteria and mental health), but can cause disease when the balance of microorganisms is disrupted (for example, thrush, when Candida albicans is allowed to grow in excess).
Post by: bigsweetpotato2000 on July 18, 2017, 09:57:46 pm
Hi Bigsweetpotato2000,
Microflora simply refers to all the naturally occurring micro-organisms that cover/are in our bodies. This can be bacteria, fungi, all different types of microorganisms. Microflora is important for human health (there have been recent studies linking healthy gut bacteria and mental health), but can cause disease when the balance of microorganisms is disrupted (for example, thrush, when Candida albicans is allowed to grow in excess).
Ahhhh... So how does Thrush develop from the imbalance? I think I was to use that as my example but I can't find it in my notes....
Thanks!
Bigsweetpotato Farm
Post by: maddiewainwright on July 18, 2017, 10:05:25 pm
Ahhhh... So how does Thrush develop from the imbalance? I think I was to use that as my example but I can't find it in my notes....
Thanks!
Bigsweetpotato Farm
Basically when you take antibiotics, it gets rid not only of bad bacteria but some of the good bacteria as well. Our natural microflora has the right balance of different microorganisms, growing at consistent rates, kind of keeping each others populations in check. So when one of the microorganisms is removed, the other is able to grow more, because of less competition and more resources. For thrush, the fungi Candida albicans will grow in excess (as it is not killed by antibiotics), generating symptoms as it becomes an irritant.
Hope that makes sense
Post by: bigsweetpotato2000 on July 18, 2017, 10:15:56 pm
Basically when you take antibiotics, it gets rid not only of bad bacteria but some of the good bacteria as well. Our natural microflora has the right balance of different microorganisms, growing at consistent rates, kind of keeping each others populations in check. So when one of the microorganisms is removed, the other is able to grow more, because of less competition and more resources. For thrush, the fungi Candida albicans will grow in excess (as it is not killed by antibiotics), generating symptoms as it becomes an irritant.
Hope that makes sense
Amazzzzing! Thanks <3
Post by: vox nihili on July 18, 2017, 10:39:12 pm
Oooh I'll give it a try :D
First Up! Define Evolution
Charles Darwin in the 19th century proposed the Theory of Evolution by natural selection as a process in which organisms change over time as a result of new environments, allowing the organism to better adapt to its new habitat.
2nd - Relate the case study to the three aspects of evolution: Variation, Heritability and Over Reproduction.
The Yersinia pestis's evolution from a intestinal infection to a more severe lung infection was potentially due to the variations in the population that survived the treatment 2500 years ago. The certain bacteria with a random genetic difference survived the treatment provided during the contemporary time and continued to survive, slowly reproducing over time to increase the chance of the new species survival. This resulted in the evolution of the Yersinia pestis, which became a more severe lung infection.
Hope that works :D
Bigsweetpotato Farm
This is a good start, and I particularly like how you've broken down the question. You might consider the potential survival advantage of transitioning to a respiratory infection for Y.pestis.
The question specifically asks about Darwinian evolution, which actually rests on four principles:
1. Heritability of traits
2. Variation in the population
3. Limited resources therefore struggle for existence
4. Some better adapted than others
Post by: vox nihili on July 18, 2017, 10:39:52 pm
Oooh I'll give it a try :D
First Up! Define Evolution
Charles Darwin in the 19th century proposed the Theory of Evolution by natural selection as a process in which organisms change over time as a result of new environments, allowing the organism to better adapt to its new habitat.
2nd - Relate the case study to the three aspects of evolution: Variation, Heritability and Over Reproduction.
The Yersinia pestis's evolution from a intestinal infection to a more severe lung infection was potentially due to the variations in the population that survived the treatment 2500 years ago. The certain bacteria with a random genetic difference survived the treatment provided during the contemporary time and continued to survive, slowly reproducing over time to increase the chance of the new species survival. This resulted in the evolution of the Yersinia pestis, which became a more severe lung infection.
Hope that works :D
Bigsweetpotato Farm
This is a good start, and I particularly like how you've broken down the question. You might consider the potential survival advantage of transitioning to a respiratory infection for Y.pestis.
The question specifically asks about Darwinian evolution, which actually rests on four principles:
1. Heritability of traits
2. Variation in the population
3. Limited resources therefore struggle for existence
4. Some better adapted than others
Post by: bigsweetpotato2000 on July 18, 2017, 11:46:05 pm
This is a good start, and I particularly like how you've broken down the question. You might consider the potential survival advantage of transitioning to a respiratory infection for Y.pestis.
The question specifically asks about Darwinian evolution, which actually rests on four principles:
1. Heritability of traits
2. Variation in the population
3. Limited resources therefore struggle for existence
4. Some better adapted than others
HAHHA Whooooops
I knew my answer was lacking something - Thanks!
Going to change my notes now
However, isn't over reproduction in the evolution theory? Since reproduction is required in order to increase the chance of the evolved species survival?
Post by: vox nihili on July 19, 2017, 07:37:50 am
HAHHA Whooooops
I knew my answer was lacking something - Thanks!
Going to change my notes now
However, isn't over reproduction in the evolution theory? Since reproduction is required in order to increase the chance of the evolved species survival?
Really good question :)
It's captured under the limited resources heading. Resources can be limited by lowering the amount of resources OR by producing too many things trying to use all of those resources. In simpler terms, a big population (over-reproduction) makes the resources limited.
Post by: Aaron12038488 on July 19, 2017, 05:52:14 pm
Post by: Potatohater on July 19, 2017, 06:33:27 pm
can anybody clarify what EPOCH means. This is relating to an assessment on 'Life on Earth', for which I have to create an accurate geological timeline.
This is part of the preliminary course right? It rings a bell but can't quite recall what it is.
Post by: blasonduo on July 19, 2017, 06:39:30 pm
can anybody clarify what EPOCH means. This is relating to an assessment on 'Life on Earth', for which I have to create an accurate geological timeline.
This is part of the preliminary course right? It rings a bell but can't quite recall what it is.Yes this is the prelim course. If you are looking for the definition, its particular period of time marked by distinctive events, which makes sense with the life on earth topic.
Post by: bigsweetpotato2000 on July 19, 2017, 10:27:35 pm
Really good question :)
It's captured under the limited resources heading. Resources can be limited by lowering the amount of resources OR by producing too many things trying to use all of those resources. In simpler terms, a big population (over-reproduction) makes the resources limited.
Ahhh- so it can sort of be treated as a sub heading :D
Okay thank you!
Post by: olr1999 on July 20, 2017, 05:15:35 pm
Post by: Potatohater on July 20, 2017, 09:09:25 pm
I've stayed on top of my syllabus summaries all throughout year 12 and I'm wondering about any quick and easy way to remind myself of the content for namely MAB and BOL... thanks!
To what extent do you need to recall information? I find that summing up the topics and the main ideas in them to a few words to trigger my recollection of information eg. MAB - enzymes, homeostasis, blood, kidneys, however you may need to go into more depth and try any other methods people suggest depending on how much you have trouble recalling the content
Post by: adelaidecruz on July 20, 2017, 09:23:34 pm
Post by: geminii on July 20, 2017, 09:30:39 pm
What are your best study tips for bio? Do you think it's best to start re-learning the content from now? There's about 2 months until trials!
I did Biology last year. By far my best study tip, which I found the most useful throughout the year is:
DON'T MEMORISE.
I tried to memorise everything in 1/2 (year 10 for me) because I couldn't be bothered to understand how the actual processes worked. That didn't turn out well - for my midyear (Unit 1) exam, I got 56%.
I tried to UNDERSTAND the processes from then on - why each step happens, and how it happens. Then I used to draw them in a notebook. For my Unit 2 exam, I got 80%, which was a huge improvement.
When I came to 3/4 Bio in Yr 11 last year, I made sure to understand all the processes rather than memorise them. You can't memorise everything in Bio - it's simply too content heavy. There's so much you would have to remember. So I just made sure I knew how to draw each process and explain the steps in each. And I came out with a pretty good study score :)
So overall, my best tip is UNDERSTAND, not MEMORISE.
Hope this helps!!
Post by: pikachu975 on July 21, 2017, 12:56:34 am
Hey guys, is it necessary to know the steps of deamination? Or just the gist of it?
Just know that it's the breakdown of amino acids
Post by: Daniyahasan on July 22, 2017, 02:31:50 pm
Post by: maddiewainwright on July 22, 2017, 03:45:31 pm
So for the HSC do we still need to know premlim topics such as protein synthesis in detail
Hi Daniyahasan,
You definitely need to understand how polypeptides are formed by transcription and translation, and then understand that polypeptides are folded into proteins. If you need a brief overview of what steps are essential, and what enzymes you need to know, I've got an overview in the powerpoint slides I presented for lectures here!
Post by: Daniyahasan on July 22, 2017, 04:16:25 pm
Hi Daniyahasan,
You definitely need to understand how polypeptides are formed by transcription and translation, and then understand that polypeptides are folded into proteins. If you need a brief overview of what steps are essential, and what enzymes you need to know, I've got an overview in the powerpoint slides I presented for lectures here!
Thank you Maddie, i came to your lecture it was really good :)
Post by: arunasva on July 22, 2017, 07:08:28 pm
Post by: maddiewainwright on July 22, 2017, 07:22:14 pm
Hey can someone please help me with this ? What is the type of inheritance shown ? I can't differentiate between dominant and recessive inheritance by looking at the pedigree, please help.
Hi arunasva,
The trick for pedigree questions is to look at whether there are any traits which skip a generation (i.e. The parents aren't affected but the child is). We can see in this pedigree that A and B are not affected, but their child is. Therefore, the trait must be recessive, as the alleles have skipped a generation.
This means that the correct answer for that multiple choice is 25%, because if we construct the punnet square where both parents have recessive alleles, there is a 25% expression probability.
Hope this helps!
Post by: pikachu975 on July 22, 2017, 09:46:42 pm
Hey can someone please help me with this ? What is the type of inheritance shown ? I can't differentiate between dominant and recessive inheritance by looking at the pedigree, please help.
It's clearly not dominant because if you consider the trait as dominant, then at least one of A or B should have the trait, but none of them have it since it's not expressed. Hence they're both aa and aa so if you do a punnett square it's 25%
Post by: Daniyahasan on July 24, 2017, 06:50:32 pm
Post by: Mounica on July 24, 2017, 07:31:37 pm
Post by: Daniyahasan on July 24, 2017, 07:33:34 pm
this question is really confusing me, can someone please explain it to me
Im pretty sure the answer is B because the lower the pH the higher the acidity :)
Post by: Mounica on July 24, 2017, 07:37:07 pm
Im pretty sure the answer is B because the lower the pH the higher the acidity :)makes sense, thank you!
Post by: Mounica on July 24, 2017, 07:38:24 pm
I dont remember doing this in class, so im really confused to as what i should be doing for this question
Post by: Daniyahasan on July 24, 2017, 07:44:08 pm
one more questionohh i love these types of questions haha
I dont remember doing this in class, so im really confused to as what i should be doing for this question
its really easy so what you basically need to do is follow the boxes, so you look at your code, the first letter is U, so on the 1st base column you find U, then you look at the next letter and find it in the second base column , same goes for the third. By then you've got the name of you first codon
and then you just do the same with the others
The answer to that question is C
hope that helped! ( i probably makes no senses but i tried haha)
Post by: Mathew587 on July 24, 2017, 07:44:50 pm
Post by: Daniyahasan on July 24, 2017, 07:48:44 pm
TBH this looks like a bs questions. Codons are in triplets therefore id guess uua, ccg and acu were the three pairs. so for uua, look at the first base axes, find u and do the same for the other two axes. it's probs c)
yeah the answer is C, its a pretty straigh forward question but the table and all makes it look hard lol
Post by: Natasha.97 on July 24, 2017, 08:22:36 pm
Hey guys, can somone pls help me with this question
Hi!
When a stimulus is introduced, a receptor (A) detects the change, which is then passed along a sensory neuron (X) to the CNS. After the brain receives and interprets the information, it passes down a signal along a motor neuron (B) to the effector muscle/gland, which then carries out the response.
Therefore, the answer would be C: A = receptor, B = motor neuron.
Hope this helps!
Post by: Daniyahasan on July 24, 2017, 08:27:51 pm
Hi!
When a stimulus is introduced, a receptor (A) detects the change, which is then passed along a sensory neuron (X) to the CNS. After the brain receives and interprets the information, it passes down a signal along a motor neuron (B) to the effector muscle/gland, which then carries out the response.
Therefore, the answer would be C: A = receptor, B = motor neuron.
Hope this helps!
it does! thank youu, i was just really confused
Post by: SwarnikaR on July 24, 2017, 08:44:13 pm
Post by: Daniyahasan on July 24, 2017, 08:48:53 pm
what are gametestheyre sex cells
Post by: gillv2017 on July 25, 2017, 05:40:22 pm
Post by: Aaron12038488 on July 25, 2017, 05:45:12 pm
how would i be going about this question.
Post by: blasonduo on July 25, 2017, 06:34:18 pm
Thanks
Post by: Potatohater on July 25, 2017, 06:49:57 pm
Hello, just a short question, when giving your answers, could you explain why the others are incorrect please?The answer would be A. This is because the wale lives in a salty environment and is constanly losing water via osmosis, so it needs to excrete concentrated urine in order to maintain water levels.
Thanks
B is incorrect as whales excrete salt rather than store it as they need to get it out of their system.
C is incorrect since whales excret small amounts of very concentrated urine to preserve water, where as humans excrete urine that is still concentrated but just a little more dilute depending on environment and water intake.
D. Is correct in a way but it wouldn't be the answer to this question. The reason why the humans need to excrete more to remove the same amount of salt comes down to the concentration rather than the amount. Since whale urine is saltier it will take less urine to excrete the same level of salt as the human which has more dilute urine and needs to excrete more.
Hope this makes sense! (I know what I mean but not sure if I have articulated it well)
Post by: blasonduo on July 25, 2017, 06:59:51 pm
The answer would be A. This is because the wale lives in a salty environment and is constanly losing water via osmosis, so it needs to excrete concentrated urine in order to maintain water levels.
B is incorrect as whales excrete salt rather than store it as they need to get it out of their system.
C is incorrect since whales excret small amounts of very concentrated urine to preserve water, where as humans excrete urine that is still concentrated but just a little more dilute depending on environment and water intake.
D. Is correct in a way but it wouldn't be the answer to this question. The reason why the humans need to excrete more to remove the same amount of salt comes down to the concentration rather than the amount. Since whale urine is saltier it will take less urine to excrete the same level of salt as the human which has more dilute urine and needs to excrete more.
Hope this makes sense! (I know what I mean but not sure if I have articulated it well)
Hey! Thanks for the answer, I also put A, but the answers say it is D.
I thought I must have missed something.
Thank you for the clearup :)
Post by: Potatohater on July 26, 2017, 05:58:14 am
Hey! Thanks for the answer, I also put A, but the answers say it is D.
I thought I must have missed something.
Thank you for the clearup :)
So the Answer is D? I'm really doubting myself now, can anyone explain why we are wrong?
Post by: vox nihili on July 26, 2017, 02:15:07 pm
Post by: maddiewainwright on July 26, 2017, 05:15:06 pm
Can someone please explain to me the concept of sex-linkage?? I understand it, but when given a question always mess it up thxxx
Hi gillv2017,
Basically, sex linkage is the concept that certain genes are located on either the X or Y chromosome exclusively (i.e. the gene for haemophilia is only located on the X chromosome). This can mean that patterns of inheritance are slightly different to typical Mendelian inheritance. For recessive genes linked to the X chromosome, males in a population will be affected at a higher rate. This is because males (XY) only inherit one X chromosomes from their mothers, and therefore will not have two alleles for the gene. This means they must express whatever allele is inherited, even if they only inherit one recessive trait.
For a question on sex-linkage I always liked to draw a punnet square because it's a really simple way to demonstrate this concept.
Hope this helps!
Post by: blasonduo on July 26, 2017, 09:27:41 pm
Where's the question from? My suspicion is that they've just stuffed up and that A is correct.
It was the 2013 Sydney tech trial paper Question 3
http://www.acehsc.net/wp-content/uploads/TrialPapers/2013/Biology/2013_Biology_-_Sydney_Tech_Trial_with_Solutions.pdf
Post by: DalvinT on July 27, 2017, 08:17:49 pm
For example, in the attachment, I wouldn't even think of writing about the problems engaged initially...
Post by: caitlinlddouglas on July 28, 2017, 07:59:03 pm
Post by: Mounica on July 29, 2017, 07:02:20 pm
can someone please explain to me what introns and exons are??
thanks
Post by: Opengangs on July 30, 2017, 11:14:34 am
Hey, GuysExons are the coding regions of DNA. That is, they encode proteins and express genes.
can someone please explain to me what introns and exons are??
thanks
Introns are the non-coding regions of DNA found between the exons. They do not specialise in encoding proteins, but some introns help with the expression of genes. Some introns contain hypervariable strands or Variable Number Tandem Repeats (VNTR) which is basically the way forensic scientists discover one's DNA fingerprints.
Post by: Opengangs on July 30, 2017, 11:20:29 am
Hey! I'm struggling to answer the higher order questions like the 7 marker questions!!! Like when I go to the marking guideline, I didn't even think of including some of the things that must've been incorporated in our response to gain the marks.The key section is its directive term, justify
For example, in the attachment, I wouldn't even think of writing about the problems engaged initially...
It's a good idea to get used to what BOSTES wants with these directive terms.
So, to justify something means to support an argument or conclusion.
My personal marking breakdown:
1 mark -- Define DNA-DNA hybridisation.
1 mark -- Define karyotype analysis
2 marks -- Outline the uses of DNA-DNA hybridisation
2 marks -- Outline the uses of karyotype analysis
1 mark -- Relate these uses back to the stimulus (ie how are they used to solve these problems)
The breaking down of marks just comes back to practice and practice!!
The more you understand what they want, the better you'll be at it.
Post by: DalvinT on August 03, 2017, 05:09:41 pm
The key section is its directive term, justify
It's a good idea to get used to what BOSTES wants with these directive terms.
So, to justify something means to support an argument or conclusion.
My personal marking breakdown:
1 mark -- Define DNA-DNA hybridisation.
1 mark -- Define karyotype analysis
2 marks -- Outline the uses of DNA-DNA hybridisation
2 marks -- Outline the uses of karyotype analysis
1 mark -- Relate these uses back to the stimulus (ie how are they used to solve these problems)
The breaking down of marks just comes back to practice and practice!!
The more you understand what they want, the better you'll be at it.
Ahh I see! THANK YOU SO MUCH! :) It really has helped!!
Post by: stephjones on August 09, 2017, 12:21:20 am
Post by: Natasha.97 on August 09, 2017, 12:33:39 am
Hey guys, how do you go about answering the "How would you improve this experiment?" questions?
Hi!
I think those types of questions are usually looking for the following 3 things:
1) Reliability: Repeating the experiment numerous times (and getting similar results), or have 2 groups follow the same experimental procedure (and getting similar results), then the results are reliable
2) Accuracy: Using precise equipment to reduce uncertainty, e.g. using a pH probe instead of pH paper + chart, a measuring cylinder rather than a beaker
3) Validity: Making sure that the results obtained stem from ONLY the change in the independent variable (the one you vary). This is ensured by keeping all variables the same, e.g. effect of substrate concentration on enzymes: control temperature, pH, volume of enzyme etc.
Hope this helps!
Post by: mjorfian on August 09, 2017, 12:37:44 am
Post by: Natasha.97 on August 09, 2017, 12:55:40 am
most important (or most commonly asked) concepts to nail down in bio core? I have two days to prepare #ragrets :-[ :-[ :-[
Hi! imo there is a lot of things that could be asked, here is my suggested list:
Blueprint of Life
- Natural selection + Theories of evolution
- Transcription + Translation
- Transgenic species
- Scientists: Mendel (peas), Morgan (fly), Beadle/Tatum (one gene-one polypeptide), Watson/Crick/Franklin/Wilkins (DNA structure)
Maintaining a Balance
- Enzymes (essentially the entire topic evolves around them)
- Xylem/phloem mechanisms, technologies for O2 saturation/CO2 concentration
- Artificial blood (progress + reasons why it's needed)
- Kidney (Aldosterone/ADH, what substance is absorbed [and where it's absorbed on the nephron], hormone replacement therapy, dialysis)
- Different types of nitrogenous wastes and which insect mammal uses which (ammonia/urea/uric acid)
Search for Better Health
- Practices assisting in disease control
- Difference b/n types of pathogens
- Description of infectious disease (name, cause, transmission, symptoms, host response etc.)
- Defence barriers and adaptations
- Scientists: Pasteur (swan v straight-neck), Koch (particular micro-org. to particular disease)
(Haven't finished SBH yet so not sure about the rest)
Hope this helps! Use these 2 days for past-papers, they're a more effective way to learn than just highlighting your notes imo :)
Post by: pikachu975 on August 09, 2017, 10:33:09 am
most important (or most commonly asked) concepts to nail down in bio core? I have two days to prepare #ragrets :-[ :-[ :-[
Hello!
I'd definitely recommend spending the 2 days memorising your notes only, forget about past papers you can do those for HSC.
I've got mine tomorrow so I'm memorising the entire course today but knowing the content is DEFINITELY more important than practising some questions, which you can't do anyway if you don't know the content!
Good luck, post here if you need any questions about the content answered.
Post by: mjorfian on August 09, 2017, 10:56:24 am
Hi! imo there is a lot of things that could be asked, here is my suggested list:
Blueprint of Life
- Natural selection + Theories of evolution
- Transcription + Translation
- Transgenic species
- Scientists: Mendel (peas), Morgan (fly), Beadle/Tatum (one gene-one polypeptide), Watson/Crick/Franklin/Wilkins (DNA structure)
Maintaining a Balance
- Enzymes (essentially the entire topic evolves around them)
- Xylem/phloem mechanisms, technologies for O2 saturation/CO2 concentration
- Artificial blood (progress + reasons why it's needed)
- Kidney (Aldosterone/ADH, what substance is absorbed [and where it's absorbed on the nephron], hormone replacement therapy, dialysis)
- Different types of nitrogenous wastes and which insect mammal uses which (ammonia/urea/uric acid)
Search for Better Health
- Practices assisting in disease control
- Difference b/n types of pathogens
- Description of infectious disease (name, cause, transmission, symptoms, host response etc.)
- Defence barriers and adaptations
- Scientists: Pasteur (swan v straight-neck), Koch (particular micro-org. to particular disease)
(Haven't finished SBH yet so not sure about the rest)
Hope this helps! Use these 2 days for past-papers, they're a more effective way to learn than just highlighting your notes imo :)
bless you!! I will definitely. I'm hoping my excellent winging skills will pull thru this time D: But do you think I should do HSC past papers or trial past papers?
Post by: pikachu975 on August 09, 2017, 11:03:38 am
bless you!! I will definitely. I'm hoping my excellent winging skills will pull thru this time D: But do you think I should do HSC past papers or trial past papers?
Memorise the content first if you don't know it. You can't rely on winging skills in biology you get marked down if you don't have specific terminology or sufficient detail.
Post by: Natasha.97 on August 09, 2017, 04:16:08 pm
bless you!! I will definitely. I'm hoping my excellent winging skills will pull thru this time D: But do you think I should do HSC past papers or trial past papers?
For me, doing past-papers (although open book) really helped in terms of pinning down the content (I learned more that way versus just reading notes) but everyone learns differently! I did trial past papers :)
Post by: caitlinlddouglas on August 09, 2017, 06:25:20 pm
Thanks! :)
Post by: Natasha.97 on August 09, 2017, 06:53:29 pm
Hi i'm doing communication and i was wondering that even though light is directed by the lens onto the retina, is it always trying to principally direct it onto the fovea even it was dark?
Thanks! :)
Hi!
Not 100% sure on this, but I think rods would be the type of photoreceptor stimulated. They are usually in charge of night vision, detection of movement, and light/shadow contrasts, forming a broad band around the edge of the retina. In terms of vision in bright light, the fovea is directed to whatever object is studied closely.
Hope this helps! :)
Post by: idontlikeschool on August 09, 2017, 11:29:53 pm
to all bio students sitting the cssa trial tomorrow, i just want to wish you all the best of luck. Don't be stressed.
Post by: mjorfian on August 10, 2017, 10:59:22 am
Memorise the content first if you don't know it. You can't rely on winging skills in biology you get marked down if you don't have specific terminology or sufficient detail.
Decided on a happy medium and have been doing both together with the Edrolo videos - which basically cover dot points and ask you short answer/ multiple choice questions directed at the dot point right afterwards :) So far I've gotten through half of SFBH and communications. Ahhhh.
Post by: sidzeman on August 13, 2017, 01:33:19 pm
I'm getting confused about the difference between cell specialisation and differentiation and how both actually assist in the maintenance of health
Post by: pikachu975 on August 13, 2017, 02:23:47 pm
There's a dotpoint in SFBH - Outline how the function of genes, mitosis, cell differentiation and specialisation assist in the maintenance of health
I'm getting confused about the difference between cell specialisation and differentiation and how both actually assist in the maintenance of health
The terms are used together, so cells "differentiate then specialise into a ___ cell". They assist in maintenance of health because with mitosis the following occurs:
1) Gene responsible for mitosis is expressed/"switched on".
2) Mitosis occurs in cells.
3) The cells differentiate and specialise into skin/epidermal cells.
So this helps with growth and repair as cells can differentiate and specialise into required cells such as skin.
Post by: Opengangs on August 13, 2017, 02:24:31 pm
There's a dotpoint in SFBH - Outline how the function of genes, mitosis, cell differentiation and specialisation assist in the maintenance of healthHi, sidzeman!
I'm getting confused about the difference between cell specialisation and differentiation and how both actually assist in the maintenance of health
Cell differentiation occurs during mitosis. When stem cells divide (undergo mitosis), they divide into specialised cells, as well as another stem cell. This process during mitosis is referred to as cell differentiation.
Cell specialisation can be seen as the result of cell differentiation. That is, they will have a specific function to perform within the body.
In terms of its assistance, cell differentiation allows an undifferentiated cell to become specialised. Because specialised cells do not perform mitosis and division itself, this is the role of cell differentiation; to undergo division, in order to become specialised.
On the other hand, specialised cells have a specific function to perform. Upon cell division, specialised cells will express the genes of a particular function (such as skin cells for repair), and thus, they have specific functions.
Hopefully, this has cleared things up! Differentiation and specialisation go hand in hand, because differentiation has a very minute part in cell division.
Post by: sidzeman on August 13, 2017, 02:59:17 pm
Also, could you please explain the difference between Boveri's and Sutton's work - it seems to me like they did the same thing, but Sutton just took it further and linked chromosomal division to Mendel's traits
Post by: Natasha.97 on August 13, 2017, 03:08:41 pm
Thanks!
Also, could you please explain the difference between Boveri's and Sutton's work - it seems to me like they did the same thing, but Sutton just took it further and linked chromosomal division to Mendel's traits
Hi!
Walter Sutton : Studied meiosis in grasshoppers, noted similarities between chromosomal behaviour and laws of segregation/independent assortment
- Segregation: During meiosis, each gamete cell receives one chromosome of each pair
- Independent Assortment: Chromosomes arrange themselves independently along the middle of the cell just before it divides
- Genes would segregate independently if they were on different homologous chromosomes
- Suggested that all characteristics followed Mendel’s law of independent assortment
- Several Mendelian factors are present in 1 chromosome, could be inherited as a unit
- Concluded that chromosomes were carriers of hereditary information
Theodore Boveri: Experimented with sea urchins, provided evidence for the halving of chromosome numbers during the process of meiosis and that a definite set of chromosomes is required to produce normal development
- Zygote chromosomes: 50% egg, 50% sperm
- If the nucleus of only one parent was present, the larvae resembled that parent, but with some abnormalities
- When a normal egg and sperm fused, the resulting offspring showed characteristics of both parents
Hope this helps :)
Post by: pikachu975 on August 13, 2017, 03:11:00 pm
Hi!
Walter Sutton : Studied meiosis in grasshoppers, noted similarities between chromosomal behaviour and laws of segregation/independent assortment
- Segregation: During meiosis, each gamete cell receives one chromosome of each pair
- Independent Assortment: Chromosomes arrange themselves independently along the middle of the cell just before it divides
- Genes would segregate independently if they were on different homologous chromosomes
- Suggested that not all characteristics followed Mendel’s law of independent assortment
- Several Mendelian factors are present in 1 chromosome, could be inherited as a unit
- Concluded that chromosomes were carriers of hereditary information
Theodore Boveri: Experimented with sea urchins, provided evidence for the halving of chromosome numbers during the process of meiosis and that a definite set of chromosomes is required to produce normal development
- Zygote chromosomes: 50% egg, 50% sperm
- If the nucleus of only one parent was present, the larvae resembled that parent, but with some abnormalities
- When a normal egg and sperm fused, the resulting offspring showed characteristics of both parents
Hope this helps :)
Note that both of their works led to the "Chromosomal theory of inheritance" which means chromosomes carry genetic information (DNA) which is the means for inheritance
Post by: sidzeman on August 13, 2017, 04:41:56 pm
Also how did Sutton infer that not all characteristics followed Mendel's law of independent assortment?
Post by: Natasha.97 on August 13, 2017, 05:34:00 pm
Ohhhh so Boveri didn't link chromosomes to carriers of inheritance - he only observed offspring get one from each parent? I had it written down as part of Boveri's work
Also how did Sutton infer that not all characteristics followed Mendel's law of independent assortment?
Hi!
For Boveri, the chromosomes are the carriers to inheritance (the offspring inherited the chromosomes, and therefore the characteristics from each parent) and the latter statement should be the other way round (i.e. Sutton did infer that they followed independent assortment).
Sorry for any confusion :/
Post by: bigsweetpotato2000 on August 14, 2017, 06:32:54 pm
Can someone explain this question to me why it's answer B?
Thanks
Post by: Opengangs on August 14, 2017, 06:50:01 pm
Hey!Hi, bigweetpotato2000!
Can someone explain this question to me why it's answer B?
Thanks
When we're exposed to changes within the ambient environment, our body attempts to maintain constant homeostasis (important to note from MAB). Thus, blood circulation (vasodilation and vasoconstriction) become the essential elements to homeostasis. In penguins, they are no different.
When penguins are exposed to the cold air, their core body attempts to maintain that level of constant stability, meaning that vasoconstriction is taking place outside of that core body (ie there will be less blood flow to the extremes, such as hands and feet).
Conversely, when penguins are exposed to the hot air, their core body will still attempt to maintain that level of homeostasis, which means there will be a rush of blood flow towards the extremities (vasodilation).
Post by: bigsweetpotato2000 on August 14, 2017, 07:06:17 pm
Hi, bigweetpotato2000!
When we're exposed to changes within the ambient environment, our body attempts to maintain constant homeostasis (important to note from MAB). Thus, blood circulation (vasodilation and vasoconstriction) become the essential elements to homeostasis. In penguins, they are no different.
When penguins are exposed to the cold air, their core body attempts to maintain that level of constant stability, meaning that vasoconstriction is taking place outside of that core body (ie there will be less blood flow to the extremes, such as hands and feet).
Conversely, when penguins are exposed to the hot air, their core body will still attempt to maintain that level of homeostasis, which means there will be a rush of blood flow towards the extremities (vasodilation).
Ahhhhhhhhhh.... But isn't blood flow linked to metabolic processes? I thought increase of metabolic processes increases heat production?
Post by: bigsweetpotato2000 on August 14, 2017, 07:20:34 pm
Would Question 14, would it be C or D
C could be a potential answer if the heart suddenly gets rejected a long time after operation then the person dies pretty damn quickly?
D is the normal answer if the immune system is weak after the antibiotics right?
Bigsweetpotato Farm
Post by: blasonduo on August 14, 2017, 07:37:51 pm
Biological Familia,
Would Question 14, would it be C or D
C could be a potential answer if the heart suddenly gets rejected a long time after operation then the person dies pretty damn quickly?
D is the normal answer if the immune system is weak after the antibiotics right?
Bigsweetpotato Farm
Hello!
Your answer for C is absolutely correct! If these suppressor drugs weren't used, the body will continue to attack the patient!
D is wrong because Anti-biotics aren't needed until a disease is present. Suppressor drugs do lower immune defence, but it does not mean that there is a constant threat of an infectious disease. Also, most antibiotics are specific to certain bacteria, so applying before any symptoms is a very bad idea. Also, this constant use will cause an imbalance of microflora in the body and can cause thrush. ALSO ALSO, the constant feed of antibiotics is a bad idea due to natural selection, where the constant intake of antibiotics can cause a strain of bacteria to be resistant.
So for the best answer, I would go C
Hope this helps :)
Post by: bigsweetpotato2000 on August 14, 2017, 08:07:22 pm
Hello!
Your answer for C is absolutely correct! If these suppressor drugs weren't used, the body will continue to attack the patient!
D is wrong because Anti-biotics aren't needed until a disease is present. Suppressor drugs do lower immune defence, but it does not mean that there is a constant threat of an infectious disease. Also, most antibiotics are specific to certain bacteria, so applying before any symptoms is a very bad idea. Also, this constant use will cause an imbalance of microflora in the body and can cause thrush. ALSO ALSO, the constant feed of antibiotics is a bad idea due to natural selection, where the constant intake of antibiotics can cause a strain of bacteria to be resistant.
So for the best answer, I would go C
Hope this helps :)
Ya legennnndd - Thanks blasonduo!
Post by: caitlinlddouglas on August 14, 2017, 09:02:23 pm
THANKS:)
Post by: Opengangs on August 14, 2017, 09:14:21 pm
Biological Familia,It'd be wise to note what immunosuppressive drugs actually do to prevent rejection of organ transplant.
Would Question 14, would it be C or D
C could be a potential answer if the heart suddenly gets rejected a long time after operation then the person dies pretty damn quickly?
D is the normal answer if the immune system is weak after the antibiotics right?
Bigsweetpotato Farm
Recall that blood groups require constant monitoring, because of the structures between each blood type.
For instance, the A blood type will develop Anti-B antibodies, and will have the A antigen. So, transplanting blood or organs with blood type B will be marked as foreign.
To counter this, doctors will usually prescribe the transplanted patient with immunosuppressant drugs to prevent further rejection. This is done by "suppressing" the production of both, B and T cells, which would usually attack the foreign particle. As such, this prevents rejection that would have been encountered without immunosuppressive drugs. However, this means that the patient is prone to pathogens.
Post by: soha.rizvi1 on August 19, 2017, 09:06:11 am
Post by: Natasha.97 on August 19, 2017, 09:53:29 am
Hey, can someone please explain Mitosis to me?
Hi :)
Mitosis is the process of producing 2 identical daughter cells. There is a division of the genetic material within the nucleus (nuclear division)
Role:
- Growth of organism
- Repair of dead/damaged cells
- Ensures that daughter cells have the same number/kind of chromosomes to the parent cell
I've attached a table outlining the different stages.
Hope this helps :)
Post by: Opengangs on August 19, 2017, 10:54:09 am
Further research on stem cells allow scientists to further investigate on the processes of mitosis.
Post by: soha.rizvi1 on August 20, 2017, 01:20:18 pm
What is the difference between Divergetn and convergent evolution?
Post by: Sine on August 20, 2017, 01:25:25 pm
Hey,divergent evolution is where there is a single common ancestor where differences in the population arise due to chance, no gene flow between populations. As a result a new speices is formed.
What is the difference between Divergetn and convergent evolution?
Convergent is different species develop similar traits usually due to having to live in very similar environements.
Post by: Natasha.97 on August 20, 2017, 01:38:59 pm
Hey,
What is the difference between Divergetn and convergent evolution?
Hi :)
Just adding onto the above answer with examples:
- Convergent Evolution: Dolphins (Mammals) and Sharks (Fish)
- Purpose: Propulsion and stability for movement in a viscous environment
- Divergent Evolution: Pentadactyl limb (Mammals)
- The limb is found on humans/cats/bats/whales, but perform different functions depending on their environment
Hope this helps ;D
Post by: vox nihili on August 20, 2017, 02:12:16 pm
Hi :)
Just adding onto the above answer with examples:- Analogous structure: Streamlined shape and fins
- Convergent Evolution: Dolphins (Mammals) and Sharks (Fish)
- Purpose: Propulsion and stability for movement in a viscous environment- Homologous structure: Five digit limb
- Divergent Evolution: Pentadactyl limb (Mammals)
- The limb is found on humans/cats/bats/whales, but perform different functions depending on their environment
Hope this helps ;D
Are you sure that sharks and dolphins' body types are an example of convergent evolution? The earliest mammals developed in the ocean as I understand it, therefore they probably started off with a structure that they inherited from fish. They subsequently diverged.
Analogous structures imply that they both independently evolved the same thing, but I'm not sure that's the case?
Post by: Natasha.97 on August 20, 2017, 02:39:07 pm
Are you sure that sharks and dolphins' body types are an example of convergent evolution? The earliest mammals developed in the ocean as I understand it, therefore they probably started off with a structure that they inherited from fish. They subsequently diverged.
Analogous structures imply that they both independently evolved the same thing, but I'm not sure that's the case?
Hi :)
From what I have been taught in class and a browse through Google to make sure, dolphins evolved from land-based animals :)
Post by: vox nihili on August 20, 2017, 03:18:06 pm
Hi :)
From what I have been taught in class and a browse through Google to make sure, dolphins evolved from land-based animals :)
Well there you go. That's really odd! :)
Post by: Mymy409 on August 26, 2017, 09:17:13 pm
Post by: Natasha.97 on August 26, 2017, 09:36:27 pm
Hi! In Communication, will we ever have to draw the structure of an entire eye?
Hi!
I've seen past questions on this before (attached image from 2009 HSC)
(http://i.imgur.com/wCDzRUz.png)
It helps in memorising the relationship between the different structures of the eye and their functions.
Hope this helps!
EDIT: Contradicted myself when I said "It may not be asked", when I attached an example of a previous question...
Post by: Mymy409 on August 26, 2017, 10:10:07 pm
Hi!
I've seen past questions on this before (attached image from 2009 HSC)
(http://i.imgur.com/wCDzRUz.png)
Even if it may not be asked, it helps in memorising the relationship between the different structures of the eye and their functions.
Hope this helps!
Oh, yikes, it was actually asked, lol. Thanks!
Post by: Daniyahasan on August 27, 2017, 09:21:10 pm
Hi! In Communication, will we ever have to draw the structure of an entire eye?
Yep they can ask you that, and its a pretty simple diagram so dont stress too much:)
Post by: Daniyahasan on August 28, 2017, 12:06:38 pm
Can someone pls explain how I would structure my answer for this question
Thanks
Post by: Opengangs on August 28, 2017, 02:52:22 pm
Hey guysIt's a six marker, so it requires you to have an extensive knowledge behind the reproductive techniques and genetic diversity. So, to help us break down the six marks, we need to locate appropriate and relevant information and then break these information down into its components.
Can someone pls explain how I would structure my answer for this question
Thanks
So, breaking down the marks can look something like this:
1 mark -- briefly outlines what modern reproductive techniques are and how they can limit genetic diversity.
2 marks -- identifies and discusses the use of modern reproductive techniques in animals. (I would probably choose 4, but mingled with plants)
2 marks -- identifies and discusses the use of modern reproductive techniques in plants. (I would probably choose 4, but mingled with animals)
1 mark -- sustains a logical response / terminology.
Some more pointers:
Here are the list of possible reproductive techniques you can talk about.
Techniques
Artificial insemination
Artificial pollination
Cloning
Transgenic species
Examples
Bt cotton
GloWorm fish
Transgenic salmon
Dolly (through Somatic Cell Nuclear Transfer)
If you need, I can provide you a sample answer that I may have written and I'll walk you through why I did it.
Post by: itssona on August 28, 2017, 07:32:06 pm
a) Bacteria
b) Oxygen
c) Glucose
d) Water
thank youuu
Post by: Aaron12038488 on August 28, 2017, 07:43:23 pm
Post by: Natasha.97 on August 28, 2017, 07:45:32 pm
1. Which of the following was present in abundance when organic molecules first developed on earth?
a) Bacteria
b) Oxygen
c) Glucose
d) Water
thank youuu
Hi!
Not A: Bacteria were formed after organic molecules first developed (first appeared 2.5bya e.g. cyanobacteria)
Not B: There was a lack of O2 in the early earth, only volcanic gases were present
Not C: No organisms were present to produce glucose as a source of energy
Therefore, the answer is D.
Hope this helps
Post by: laura.akkari on August 28, 2017, 08:34:25 pm
Post by: itssona on August 28, 2017, 10:11:54 pm
Hi!thank you!! :)
Not A: Bacteria were formed after organic molecules first developed (first appeared 2.5bya e.g. cyanobacteria)
Not B: There was a lack of O2 in the early earth, only volcanic gases were present
Not C: No organisms were present to produce glucose as a source of energy
Therefore, the answer is D.
Hope this helps
Post by: itssona on September 04, 2017, 01:57:52 pm
Post by: Natasha.97 on September 04, 2017, 02:16:11 pm
heeey :) help pls
Hi,
Not 100% sure, but I think the answer is C:
- Autotrophs make their own food by converting inorganic molecules to organic compounds (e.g. through photosynthesis)
- Heterotrophs have to consume autotrophs to produce energy, and they respire (which provides CO2 for the autotrophs)
Hope this helps
Post by: itssona on September 04, 2017, 03:34:14 pm
Hi,
Not 100% sure, but I think the answer is C:
- Autotrophs make their own food by converting inorganic molecules to organic compounds (e.g. through photosynthesis)
- Heterotrophs have to consume autotrophs to produce energy, and they respire (which provides CO2 for the autotrophs)
Hope this helps
thank you!!!
Post by: sidzeman on September 04, 2017, 06:43:10 pm
- can someone please explain the difference between homeotic and homeobox and hox genes?
Post by: pikachu975 on September 10, 2017, 02:40:11 pm
Post by: Mathew587 on September 13, 2017, 09:52:58 pm
For ectotherms and endotherms how do their metabolism AND enzyme rates differ at different temperatures?
Endotherm
At a low temp,
- Metabolism increases to maintain body temp and function
Enzyme rates stay contstant due to a regulated internal environment- homeostasis. However, extreme temps will result in denaturing (obv)
- Metabolism is normal
Enzyme rate is normal
- Metabolism is higher once again as body needs to work harder to maintain homeostasis
Enzyme rate stays constant due to homeostasis. However, extreme temps will result in denaturing (once again obv)
Ectotherm
At a low temp,
- metabolism is low cos unable to do shit
Enzyme rate is low cos of dependency on ext temp for function. will result in denaturing if extreme temps
- metabolism is normal
enzyme rate is normal
- Metablosim is way higher as activity correlates with temperature increase
Enzyme rate is higher till peak is reached followed by drops and eventual denaturing.
you could have just thought about it...
Post by: vanessa mbogo on September 15, 2017, 11:35:46 am
Post by: vox nihili on September 15, 2017, 02:32:27 pm
Use your understanding of genetics and evolution to explain why some charcteristics becomes more common in a population than others please help
You need to have a crack at this first then we'll help :)
Post by: gh971 on September 16, 2017, 11:27:41 am
Compare the way mammals transport oxygen and carbon dioxide in the blood. (4 MARKS)
This is my answer but I'm worried I'm missing things:
Mammalian blood transports oxygen and carbon dioxide between the lungs and other tissues throughout the body.These gases are carried in various forms such as dissolved in the plasma or chemically combined with haemoglobin. For oxygen transport, oxygen binds with haemoglobin in the lungs, where the oxygen concentration in the blood is low, and transports it to where the oxygen is needed. Once it reaches the desired location the oxygen bond easily breaks and the oxygen is used for processes such a respiration. However, for carbon dioxide transport it is carried in the blood in in two forms; dissolved in plasma and travels as bicarbonate ions resulting from the dissociation of carbonic acid.
Post by: Natasha.97 on September 16, 2017, 12:03:35 pm
Could someone please help me with how to best answer this question??
Compare the way mammals transport oxygen and carbon dioxide in the blood. (4 MARKS)
Hi!
I'm sitting the HSC this year (so not entirely sure if I'm correct), but I've included some comments below:
Quote
Mammalian blood transports oxygen and carbon dioxide between the lungs and other tissues throughout the body.Good introductory sentence :) These gases are carried in various forms such as dissolved in the plasma or chemically combined with haemoglobin. For oxygen transport, oxygen binds with haemoglobin in the lungs, where the oxygen concentration in the blood is low, and transports it to where the oxygen is needed. Once it reaches the desired location the oxygen bond easily breaks and the oxygen is used for processes such a respiration Not entirely sure about the relevance of this sentence to the question. However, for carbon dioxide transport it is carried in the blood in in two forms; dissolved in plasma and travels as bicarbonate ions resulting from the dissociation of carbonic acid.You've talked about the similarities and differences between these two gases, which directly addresses the question :)
Could include statistics for both of the gases:
CO2:
- HCO32- = 70%
- Carbamino-haemoglobin molecules in red blood cells = 23%
- Dissolved directly in the plasma = 7%
O2:
- Carried by red blood cells in the form of oxyhaemoglobin = 98.5%
- Dissolved in plasma = 1.5%
Hope this helps
Post by: pikachu975 on September 16, 2017, 12:18:05 pm
Endotherm
At a low temp,At a normal temp,
- Metabolism increases to maintain body temp and function
Enzyme rates stay contstant due to a regulated internal environment- homeostasis. However, extreme temps will result in denaturing (obv)At a high temp,
- Metabolism is normal
Enzyme rate is normal
- Metabolism is higher once again as body needs to work harder to maintain homeostasis
Enzyme rate stays constant due to homeostasis. However, extreme temps will result in denaturing (once again obv)
Ectotherm
At a low temp,At a normal temp,
- metabolism is low cos unable to do shit
Enzyme rate is low cos of dependency on ext temp for function. will result in denaturing if extreme tempsAt a high temp,
- metabolism is normal
enzyme rate is normal
- Metablosim is way higher as activity correlates with temperature increase
Enzyme rate is higher till peak is reached followed by drops and eventual denaturing.
you could have just thought about it...
Thanks for this, but pretty sure metabolism decreases at high temps for endotherm cause it produces heat
Post by: Opengangs on September 16, 2017, 12:47:33 pm
Could someone please help me with how to best answer this question??Hey!
Compare the way mammals transport oxygen and carbon dioxide in the blood. (4 MARKS)
This is my answer but I'm worried I'm missing things:
Mammalian blood transports oxygen and carbon dioxide between the lungs and other tissues throughout the body.These gases are carried in various forms such as dissolved in the plasma or chemically combined with haemoglobin. For oxygen transport, oxygen binds with haemoglobin in the lungs, where the oxygen concentration in the blood is low, and transports it to where the oxygen is needed. Once it reaches the desired location the oxygen bond easily breaks and the oxygen is used for processes such a respiration. However, for carbon dioxide transport it is carried in the blood in in two forms; dissolved in plasma and travels as bicarbonate ions resulting from the dissociation of carbonic acid.
When we're dealing with 4-5-6 mark questions, the best way to approach them is to create a plan or to break down how these marks may be obtained. Remember that these 4 mark questions can actually be asked in four separate 1 mark questions, so always try to break them down to its simplest form.
Compare the way mammals transport oxygen and carbon dioxide in the blood.
So, obviously we need to describe how mammals transport oxygen in the blood, which constitutes one mark.
We then need to describe how they transport carbon dioxide in the blood, which constitutes another mark.
Since the question is a compare question, we need to identify the similarities (1 mark) and the differences (1 mark) between the processes.
This will give you your 4 marks, so using this scaffold as the basis of your answer, let's compare how you may have been marked in an actual exam.
Mammalian blood transports oxygen and carbon dioxide between the lungs and other tissues throughout the body. These gases are carried in various forms such as dissolved in the plasma or chemically combined with haemoglobin. For oxygen transport, oxygen binds with haemoglobin in the lungs, where the oxygen concentration in the blood is low, and transports it to where the oxygen is needed. (1) Once it reaches the desired location the oxygen bond easily breaks and the oxygen is used for processes such a respiration. However, for carbon dioxide transport it is carried in the blood in in two forms; dissolved in plasma and travels as bicarbonate ions resulting from the dissociation of carbonic acid. (1)
You may scrape three marks, but it's a very risky three marks. You'll definitely get at least two since you've described the process for both oxygen and carbon dioxide, but explore the similarities and differences a bit more when comparing the two. Let me know if you have any more trouble.
Post by: angelahchan on September 18, 2017, 09:43:51 am
Hi I've really struggled with graphs like no matter how hard I try I always seem to stuff them up (maths has never been my strong point). I just wanted to clarify a few things bc I've gotten different responses from different teachers about certain things. Firstly I don't understand when you are supposed to join the dots or draw a line of best fit (I lost a mark in trials for drawing a LOBF). Also I get confused over whether you are supposed to connect the first dot to 0 or not ? Thirdly, I find I always have doubt over whether to use a bar or line graph and I always end up picking the wrong one, I understand that line is usually continuous data and discrete for bar (I think), but I still get confused about it all like in one of my exams they wanted a bar graph for an experiment involving time?? Anyway, some clarification would be super helpful as the graph in trials seriously stuffed up the majority of my exam after I did the entire thing wrong after spending 15 mins on it and had to start all over again (leaving me with 5 mins to do the 7 marker which was not ideal haha).
1) Usually you join the dots freehand- I don't think I've done a hsc question which asks you for line of best fit, but if the points seem really scattered e.g. you can't draw a clean curve/line with it you may have to do best fit
2) I think that depends on the question, but start at the first value they give you e.g. if you have to a graph an experiment and it starts at room temp of, say, 28 degrees then start at 28 rather than 0 (and if the experiment is based on time then obviously time has to start at 0)
3) sorry I've never done a past hsc with bar graphs before so I can't really give advice here- maybe if you have the question with you you can post it here to get clarification?
idk if this is helpful, but here's a few tips for line graphs:
1) have a title
2)put independent on x axis, dependent on y
3) remember to label axis with units
Post by: Daniyahasan on September 18, 2017, 10:08:59 am
Use your understanding of genetics and evolution to explain why some characteristics become more common in a population than others please help
According to Darwin/Wallace's theory of natural selection, the organisms with traits best suited to their environment will survive and reproduce, passing on the favourable trait to their offspring, while the ones without the favourable trait will eventually die out in the population. Hence favourable traits will become more common in population
shit answer sorry, but i tried, hope it helps:)
Post by: Sine on September 18, 2017, 11:27:50 am
Use your understanding of genetics and evolution to explain why some charcteristics becomes more common in a population than others please help-genetic variation exists in a population
-Selection pressure may exist
-some phenotypes are more favourable than others under this selection pressure hence more likely to survive and reproduce
-allele frequencies change
-Hence over time the favourable characteristics are more common in the population
Post by: Diala on September 19, 2017, 09:41:55 pm
Post by: Opengangs on September 19, 2017, 09:53:47 pm
Hi, I'm still finding it so confusing to differentiate between prevention and control. Different sites say different things... I was hoping to clear it all up. Do you have any suggestions as to how to remember the difference?Hey there!
Prevention and controlling disease are very similar by nature, but they're also very distinguishing aspects of disease! But the distinguishable aspect comes from its definition.
Preventing disease means that we stop the spread of disease. In the case of malaria, a preventative measure is that we wear long sleeves to avoid exposure from the Anopheles female mosquitoes. Prevention is usually done individually, so what can you do to avoid catching the disease?
Controlling, on the other hand, means that we regulate the spread of disease. This is usually done in favour of more than one person, so in order to regulate the spread of malaria (as our case study), we drain the mosquito breeding sites.
In summary: the main difference is that controlling includes prevention, but it covers a lot more than simply prevention. Prevention is just the personal protection side of controlling disease.
Post by: Daniyahasan on September 19, 2017, 10:34:16 pm
i find it a difficult concept to grasp on
Post by: Opengangs on September 19, 2017, 10:54:39 pm
can someone please explain how renal dialysis worksHey there!
i find it a difficult concept to grasp on
Renal dialysis is the artificial process of removing excess water and waste from the blood. It acts as a replacement to faulty kidneys, since people with faulty kidneys cannot perform the necessary actions needed to remove these excess water and waste. As a result, the use of renal dialysis is extremely important to this process.
Before understanding why this process is important, however, we need to consider how important of a role a kidney plays in our everyday lives. As we consume increased volumes of water, the role of the kidney is to "balance" out the mineral ions of potassium, calcium, sodium, and many more and maintain its equilibrium point. The acidic waste products are excreted by the kidneys. So, it is in your best interest to have functioning kidneys. Else, the internal pH of the blood decreases, leading to a denaturation of enzymes (remember that enzymes work at narrow pH levels).
In the case of kidney failures then, we need to develop some artificial process that works the same way a regular kidney does. This is known as renal dialysis. This works by diffusing solutes across a semi-permeable membrane. As a result, smaller solutes are able to pass through, leaving the larger solutes unfiltered (much like the glomerulus and Bowman's Capsule).
There are two types of dialysis:
Hemodialysis works by removing excess water and waste by circulating the blood from an external filter. This is called a dialyser, and it contains the semi-permeable membrane. As a result, the blood flow is one directional.
Peritoneal dialysis work by removing excess water and waste from the blood internally. The peritoneum acts as the semi-permeable membrane, and the waste is moved from the blood across the peritoneum into a dialysate.
Post by: caitlinlddouglas on September 20, 2017, 07:26:52 pm
Post by: angelahchan on September 20, 2017, 07:38:37 pm
hey i was wondering how having thick bark and sunken stomata reduces water loss in plants? THanks :DSunken stomata creates an area where water leaving the leaf can pool, keeping water in the leaf longer and decreasing the rate of transpiration, an example being the casuarina. Sorry, I don't have anything about thick bark in my notes, but from a quick google it seems thick bark is for fire prevention or something, e.g. during a fire the outer layer burns off protecting the cells inside. I'm not entirely sure though
Post by: caitlinlddouglas on September 20, 2017, 07:53:23 pm
Sunken stomata creates an area where water leaving the leaf can pool, keeping water in the leaf longer and decreasing the rate of transpiration, an example being the casuarina. Sorry, I don't have anything about thick bark in my notes, but from a quick google it seems thick bark is for fire prevention or something, e.g. during a fire the outer layer burns off protecting the cells inside. I'm not entirely sure though
Post by: Daniyahasan on September 20, 2017, 09:23:00 pm
Hey there!Oh wow thanks soo muchh
Renal dialysis is the artificial process of removing excess water and waste from the blood. It acts as a replacement to faulty kidneys, since people with faulty kidneys cannot perform the necessary actions needed to remove these excess water and waste. As a result, the use of renal dialysis is extremely important to this process.
Before understanding why this process is important, however, we need to consider how important of a role a kidney plays in our everyday lives. As we consume increased volumes of water, the role of the kidney is to "balance" out the mineral ions of potassium, calcium, sodium, and many more and maintain its equilibrium point. The acidic waste products are excreted by the kidneys. So, it is in your best interest to have functioning kidneys. Else, the internal pH of the blood decreases, leading to a denaturation of enzymes (remember that enzymes work at narrow pH levels).
In the case of kidney failures then, we need to develop some artificial process that works the same way a regular kidney does. This is known as renal dialysis. This works by diffusing solutes across a semi-permeable membrane. As a result, smaller solutes are able to pass through, leaving the larger solutes unfiltered (much like the glomerulus and Bowman's Capsule).
There are two types of dialysis:
Hemodialysis works by removing excess water and waste by circulating the blood from an external filter. This is called a dialyser, and it contains the semi-permeable membrane. As a result, the blood flow is one directional.
Peritoneal dialysis work by removing excess water and waste from the blood internally. The peritoneum acts as the semi-permeable membrane, and the waste is moved from the blood across the peritoneum into a dialysate.
Post by: Mounica on September 23, 2017, 10:44:29 am
Post by: Natasha.97 on September 23, 2017, 11:06:22 am
can someone please explain action potential and threshold i do not understand that at all
Hi!
Threshold: Minimum strength of a stimulus needed to begin an action potential (-55mV). If it is not reached, then the stimulus is not strong enough to generate it
Action potential: Generation of electrical impulses
Summary:
• At rest (-70mV): Cl- and K+ ions are inside axon, Na+ ions are outside, protein channels are closed
• Strong nervous impulse: Na+ channels open, ions enter.
• Threshold (-55mV) reached: Remaining Na+ ions flow into the axon through channels (depolarisation)
• Na+ and K+ are pumped back out of the axon, potential is becoming negative (repolarisation)
• Loss of both positive ions results in a potential less than -70mV
• Na+ channels close, K+ ions move back into the axon and their channels close, reaching resting potential (-70mV)
Hope this helps
Post by: Daniyahasan on September 23, 2017, 11:20:39 am
does anyone know any websites that has topic tests for search for better health?
Post by: angelahchan on September 23, 2017, 12:11:52 pm
hey,hscninja.com used to have a consolidated quiz mode where you could select a topic and they'd pick past questions for you to do. unfortunately bostes made them take it down because copyright, but they still have past questions sorted by topic. If you want, you can buy the success one HSC biology book which has the 2001-2005 sorted by topic rather than by paper
does anyone know any websites that has topic tests for search for better health?
Post by: pikachu975 on September 23, 2017, 12:39:19 pm
can someone please explain action potential and threshold i do not understand that at all
1) Resting membrane potential of -70 mV.
2) A stimulus occurs which causes depolarisation if the threshold of -55 mV is met, i.e. voltage-gated sodium ion channels open so sodium ions rush in the axon which causes membrane potential to change to around +40 mV.
3) Repolarisation occurs where sodium ion channels close and potassium ion channels open, causing potassium to rush out. This makes the membrane potential down to -75 mV.
4) Since it is too negative, repolarisation occurs which means that all ion channels close and the sodium-potassium pump balances the membrane potential to -70 mV, also known as the refractory period.
Post by: caitlinlddouglas on September 23, 2017, 02:53:39 pm
Post by: Mathew587 on September 23, 2017, 07:06:23 pm
Hey for Communication, I didn't really understand what it means by rods having high retinal convergence causing them to have poor visual clarity. Thanks :)Rod cells are found in bunches of thousands and are attached to a single nerve cell, resulting in high retinal convergence, consequently also resulting in poorer vision acuity. This coupled with the ability of rod cells to only distinguish between dark and light results in them to have poor visual acuity. In contrast, cone cells are each attached to a single nerve cell which coupled with their ability to distinguish colour results in them having higher visual acuity.
Post by: caitlinlddouglas on September 23, 2017, 09:51:44 pm
Rod cells are found in bunches of thousands and are attached to a single nerve cell, resulting in high retinal convergence, consequently also resulting in poorer vision acuity. This coupled with the ability of rod cells to only distinguish between dark and light results in them to have poor visual acuity. In contrast, cone cells are each attached to a single nerve cell which coupled with their ability to distinguish colour results in them having higher visual acuity.thanks!
Post by: Daniyahasan on September 24, 2017, 08:25:45 am
1) Resting membrane potential of -70 mV.
2) A stimulus occurs which causes depolarisation if the threshold of -55 mV is met, i.e. voltage-gated sodium ion channels open so sodium ions rush in the axon which causes membrane potential to change to around +40 mV.
3) Repolarisation occurs where sodium ion channels close and potassium ion channels open, causing potassium to rush out. This makes the membrane potential down to -75 mV.
4) Since it is too negative, repolarisation occurs which means that all ion channels close and the sodium-potassium pump balances the membrane potential to -70 mV, also known as the refractory period.
Makes sense thank you!!
Post by: justwannawish on September 27, 2017, 07:18:38 am
I'm not doing that great in biology. My main concerns are that I don't include the exact word or two that the teachers are looking for, and am not very concise. Any ways to help with this?
Post by: Daniyahasan on September 27, 2017, 08:51:03 am
Hey,Memorising is KEY. if you have your notes memorised, then when you respond to questions, the syllabus metalanguage with flow automactically, but you need to have written with that kind of language in the first place :)
I'm not doing that great in biology. My main concerns are that I don't include the exact word or two that the teachers are looking for, and am not very concise. Any ways to help with this?
Post by: inescelic on September 27, 2017, 09:22:08 am
-> identify those areas of the cerebrum involved in the perception and interpretation of light and sound
->perform a first-hand investigation to examine an appropriate mammalian brain or model of a human brain to gather information to distinguish the cerebrum, cerebellum and medulla oblongata and locate the regions involved in speech, sight and sound perception
Post by: Natasha.97 on September 27, 2017, 10:48:16 am
Hi, can someone please summarise the following communication dot points for me? I am super confused as all the information in the textbooks and other notes I've seen is super convoluted :(
-> identify those areas of the cerebrum involved in the perception and interpretation of light and sound
->perform a first-hand investigation to examine an appropriate mammalian brain or model of a human brain to gather information to distinguish the cerebrum, cerebellum and medulla oblongata and locate the regions involved in speech, sight and sound perception
Hi!
- Light/Sight (Occipital Lobe)
- Visual cortex: Where signals are sent from the retina via the optic nerve to the brain
- Visual association area: Processes and interprets visual information)
- Sound (Temporal Lobe)
- Auditory area: Where signals are sent from the hair cells in the organ of Corti via the auditory nerve to the brain
- Auditory association area: Processes and interprets auditory information
- Speech:
- Wernicke's Area: Sensory speech
- Broca's Area: Motor speech
(https://i.imgur.com/r8KXYVE.png)
Hope this helps
Post by: Daniyahasan on September 27, 2017, 10:56:02 am
Hi!
- Light/Sight (Occipital Lobe)
- Visual cortex: Where signals are sent from the retina via the optic nerve to the brain
- Visual association area: Processes and interprets visual information)
- Sound (Temporal Lobe)
- Auditory area: Where signals are sent from the hair cells in the organ of Corti via the auditory nerve to the brain
- Auditory association area: Processes and interprets auditory information
- Speech:
- Wernicke's Area: Sensory speech
- Broca's Area: Motor speech
(https://i.imgur.com/r8KXYVE.png)
Hope this helps
your answers are always so good!
Post by: justwannawish on September 27, 2017, 11:22:15 am
Memorising is KEY. if you have your notes memorised, then when you respond to questions, the syllabus metalanguage with flow automactically, but you need to have written with that kind of language in the first place :)
Is there like a good guide for writing with the syllabus meta language? Like any example study notes?
Post by: Daniyahasan on September 27, 2017, 11:34:04 am
Is there like a good guide for writing with the syllabus meta language? Like any example study notes?
Atarnotes has a bunch of free notes you can download or if you want the BEST notes you can buy the Atarnotes biology notes for $25
trust me you need those notes in your life:)
(i should be paid for the amount of promotion i do for Atarnotes lolll, i literelly tell everyone)
Post by: Opengangs on September 27, 2017, 11:50:47 am
Content-heavy subjects, like biology, assesses you to understand the syllabus in full. Each dot point connects with another, so to minimise the work we are required to do, try to create a mind map listing out the dot points in each topic with links to another dot point. For instance, if antigenic particles trigger the immune response and we have antigens in our own organs, why doesn't our body trigger an immune response?
Understanding and asking questions is often the best way, then, to approach your studies. This will then lead you to being able to retain information clearer than just memory, because it's embedded into your knowledge now. Then we can begin to tackle questions that require specific language (jargon), particularly questions involving organ rejection.
In summary:
1) Do you know your content well enough?
2) Can you interpret the question correctly?
3) Are you able to sustain a logical response?
If you answer no to any one of these questions, you do not understand the content; you just memorise them.
Post by: justwannawish on September 27, 2017, 12:53:39 pm
Atarnotes has a bunch of free notes you can download or if you want the BEST notes you can buy the Atarnotes biology notes for $25
trust me you need those notes in your life:)
(i should be paid for the amount of promotion i do for Atarnotes lolll, i literelly tell everyone)
Yep, thank you. I've bought the practice papers but will look at getting the book 😀
Post by: Angeleca on September 27, 2017, 01:00:22 pm
Thanks!
Post by: Daniyahasan on September 27, 2017, 01:02:06 pm
Hey guys! So for anyone doing the communications elective, do we have to know how to modulate sound waves? :-[
Thanks!
yep! we did a prac on it remember
Post by: Nym1 on September 27, 2017, 01:54:43 pm
How would you answer this question or any other 6-8 mark question? I really like tables so I would probably break it down into a table and put a concluding statement at the end but my bio teacher says I should always write it as an essay whilst my physics teacher prefers tables!. Usually, if I write it as an essay I just repeat myself over and over again. Any help would be much appreciated!
Thanks!
Post by: arunasva on September 27, 2017, 02:00:55 pm
Hey guys! So for anyone doing the communications elective, do we have to know how to modulate sound waves? :-[
Thanks!
it isn't so hard its just the larynx get longer or shorter to change pitch and mouth and tongue produce different sounds. That's it ?
Post by: Annie657 on September 27, 2017, 02:14:20 pm
So I just have a quick question for action potentials in communication,
Do the sodium channels open as soon as stimulus is detected to begin depolarisation? Also, is it ok to say -50mv for the threshold p, not -55,v?
Post by: Daniyahasan on September 27, 2017, 02:17:38 pm
Hi,
So I just have a quick question for action potentials in communication,
Do the sodium channels open as soon as stimulus is detected to begin depolarisation? Also, is it ok to say -50mv for the threshold p, not -55,v?
i think you'll be safer saying -55v
Post by: pikachu975 on September 27, 2017, 02:43:14 pm
Hi,
So I just have a quick question for action potentials in communication,
Do the sodium channels open as soon as stimulus is detected to begin depolarisation? Also, is it ok to say -50mv for the threshold p, not -55,v?
Yep stimulus opens voltage-gated sodium ion channels which causes them to rush in. However, if the stimulus is too weak it doesn't open enough so it doesn't depolarise enough to reach an action potential.
Threshold is anywhere between -50 and -60 mV but best to use -55 mV.
Post by: Annie657 on September 27, 2017, 03:01:14 pm
Yep stimulus opens voltage-gated sodium ion channels which causes them to rush in. However, if the stimulus is too weak it doesn't open enough so it doesn't depolarise enough to reach an action potential.
Threshold is anywhere between -50 and -60 mV but best to use -55 mV.
Thankyou so much! Makes sense now :)
Post by: Becky234 on September 27, 2017, 03:36:09 pm
Does anyone understand what refraction of light has to do with myopia and hyperopia
Post by: pikachu975 on September 27, 2017, 03:39:41 pm
Hey, Guys
Does anyone understand what refraction of light has to do with myopia and hyperopia
Myopia is shortsightedness that can result from an eyeball being too long or the lens/cornea's refractive power isn't correct. Refraction relates because the parallel rays are refracted TOO MUCH so the light converges IN FRONT of the retina, meaning distant objects are blurred.
Hyperopia is longsightedness that can result from an eyeball being too short or the lens/cornea's refractive power isn't correct. Refraction relates because the diverging rays are refracted TOO LITTLE so the light converges AFTER the retina, meaning close objects are blurred.
Post by: Daniyahasan on September 27, 2017, 03:40:27 pm
Hey, Guysmyopia (short sightedness) – close objects can be seen clearly but distant objects (more than about 5 meters away) appear blurred and out of focus
Does anyone understand what refraction of light has to do with myopia and hyperopia
A common cause is the eyeball being too long
This makes the image position to not lie on the retina, but in front of it
Hyperopia (long sightedness) – distant objects can be see clearly, but close objects appear blurred and out of focus
A common cause is the lens using its flexibility
So that it is unable to become thick enough to clearly focus images of objects which are close
Another cause is the eyeball being too short
This makes the focus position to lie behind the retina
Post by: Potatohater on September 27, 2017, 04:59:53 pm
- Outline the role of rhodopsin in rods and cones
- describe rods as containing a form of rhodopsin that is sensitive to blue green light
Post by: Natasha.97 on September 27, 2017, 05:06:39 pm
Hi, the biology syllabus printed for us by our teacher has extra parts to the syllabus that I can't seem to find any notes on and a lot of people just seem to ignore, so I'm a bit confused by this. What I can't find is
- Outline the role of rhodopsin in rods and cones
- describe rods as containing a form of rhodopsin that is sensitive to blue green light
Hi!
- Cones don't contain rhodopsin; they contain iodopsin. They are the type of photoreceptor cells that are sensitive to colour
- Blue = 455 nm (Short wavelength)
- Green = 530nm (Medium wavelength)
- Red = 625 (Long wavelength)
- Wavelengths either side of these values can stimulate more than one Iodopsin type to create secondary colours (Magenta: Blue/Red, Cyan: Green/Blue, Yellow: Red, Green)
- The brain can perceive colours and shades depending on the number and combination of iodopsins stimulated
Hope this helps
Post by: Daniyahasan on September 27, 2017, 05:08:22 pm
Hi, the biology syllabus printed for us by our teacher has extra parts to the syllabus that I can't seem to find any notes on and a lot of people just seem to ignore, so I'm a bit confused by this. What I can't find isi just looked at the syllabus and i agree i dont really see those dotpoints (iv linked the syllabus below if you wanna look again)
- Outline the role of rhodopsin in rods and cones
- describe rods as containing a form of rhodopsin that is sensitive to blue green light
https://www.boardofstudies.nsw.edu.au/syllabus_hsc/pdf_doc/biology-st6-syl.pdf
BUT maybe your teacher just wants you guys to have extra understanding of the topic or it may be an old syllabus...
Post by: Daniyahasan on September 27, 2017, 05:10:01 pm
Hi!
- Cones don't contain rhodopsin; they contain iodopsin. They are the type of photoreceptor cells that are sensitive to colour
- Blue = 455 nm (Short wavelength)
- Green = 530nm (Medium wavelength)
- Red = 625 (Long wavelength)
- Wavelengths either side of these values can stimulate more than one Iodopsin type to create secondary colours (Magenta: Blue/Red, Cyan: Green/Blue, Yellow: Red, Green)
- The brain can perceive colours and shades depending on the number and combination of iodopsins stimulated
Hope this helps
why is their school giving them a dotpoint to study if it isnt even correct......?
Post by: Potatohater on September 27, 2017, 05:38:29 pm
why is their school giving them a dotpoint to study if it isnt even correct......?Maybe it's an old syllabus and hence why that part has been taken out (because it's supposedly incorrect), cause knowing my school it wouldn't have been on purpose, my teacher has been teaching for aggggeees (at this point he looks like Santa Claus) and probably gave us the old one by mistake
Post by: pikachu975 on September 27, 2017, 05:43:43 pm
Maybe it's an old syllabus and hence why that part has been taken out (because it's supposedly incorrect), cause knowing my school it wouldn't have been on purpose, my teacher has been teaching for aggggeees (at this point he looks like Santa Claus) and probably gave us the old one by mistake
The bottom part of your question is good to know. Rhodopsin is more sensitive to blue-green light which are at the lower end of the wavelength spectrum.
Post by: Daniyahasan on September 27, 2017, 05:50:38 pm
Maybe it's an old syllabus and hence why that part has been taken out (because it's supposedly incorrect), cause knowing my school it wouldn't have been on purpose, my teacher has been teaching for aggggeees (at this point he looks like Santa Claus) and probably gave us the old one by mistakeoh yeah probably! luckily you asked so thats cleared up for you know. My maths teacher is like that to HAHAHAHA, shes been teaching for 40 years damn
Post by: justwannawish on September 27, 2017, 07:02:11 pm
Post by: pikachu975 on September 27, 2017, 07:47:50 pm
Could anyone offer a summary of the different types of bio options? Our school usually does communication but our teacher is willing to change it seeing as it's the final year and he really likes the genetics option (which he said was like an extension of the things we did in year 10, like dihybrid). Which topics are more conceptual and which ones are more equation-y?
None of them are really equation-y because it's biology, but I'd DEFINITELY recommend communication. It's so interesting to learn, and you can relate it to real life which helps with on-the-go study such as when you see the colour red "my red cones are being stimulated" etc while you can't really relate genetics to everyday life. Also it's interesting to learn how you see and hear etc.
Post by: Diala on September 27, 2017, 07:58:07 pm
Post by: Opengangs on September 27, 2017, 07:58:33 pm
It's such an interesting topic, because of how you can apply this to the Blueprint of Life topic, which already allows you to further your understanding of the Blueprint of Life topic, so I highly recommend you being taught by your school.
Post by: Daniyahasan on September 27, 2017, 08:24:23 pm
Hi! I'm super confused about a Communication dotpoint because I'm receive 2 different answers. In the textbook it says that when detecting yellow light the blue and green cones are responding, however, websites and pictures depict red and green cones responding to interpret yellow. Which is correct?
i dont think its THAT important to know that, because we werent really taught that at school...but i may be wrong
Post by: inescelic on September 27, 2017, 08:51:15 pm
Hi!
- Light/Sight (Occipital Lobe)
- Visual cortex: Where signals are sent from the retina via the optic nerve to the brain
- Visual association area: Processes and interprets visual information)
- Sound (Temporal Lobe)
- Auditory area: Where signals are sent from the hair cells in the organ of Corti via the auditory nerve to the brain
- Auditory association area: Processes and interprets auditory information
- Speech:
- Wernicke's Area: Sensory speech
- Broca's Area: Motor speech
(https://i.imgur.com/r8KXYVE.png)
Hope this helps
Post by: inescelic on September 27, 2017, 09:15:21 pm
Q: "Gregor Mendel revealed the world of genetics to future biologists". Using your knowledge of the HSC Biology course, discuss the contribution of Mendel in relation to the development of our understanding of inheritance and modern genetics". (7 marks)
Mendel's investigations using pea plants have grown our understanding of genetics, contributing to future developments. In his experiment, Mendel first established pure breeding lines of tall and short pea plants. He then cross bred the tall and short and recorded the height of the plants. He had found that they were all tall. Again, he crossbred the offspring of the first generation and found that 75% of the offspring were tall, while 25% were short. From this, Mendel inferred that individual held two variants ( now called alleles) of a characteristic (now called a gene), and that each allele was provided by each parent.
In addition, he also established that certain alleles were dominant over others. This means that if at least one dominant allele was present in a genotype, it would be reflected in the phenotype. Recessive genes on the other hand, mean that both alleles need to be present in the genotype for it to be expressed in the phenotype. This dominance was demonstrated through the tall plants in Mendel's experiments, for both Tt and TT plants were tall, hence tall is dominant, while recessive alleles were shown through the short plants (tt), hence short is recessive.
Importantly, Mendel's work on alleles and dominance in inheritance has led to new developments. Firstly, Sutton and Boveri's work on sea urchins and grasshoppers elaborated upon Mendel's ideas, suggesting that chromosomes were the carriers of hereditary information, or as described by Mendel, "characteristics". Furthermore, more work into alleles has revealed different types of dominance. For example, Morgan's work on fruit flies, demonstrated "sex-linked" traits, where certain traits were more dominant depending on sex, such as if they only appeared on the X chromosome. Also, later work also revealed more complex forms of dominance such as co-dominance, in which both alleles are expressed in the phenotype.
More currently, Mendel's work has led to methods such as DNA hybridisation within a species. Individuals within species, who have desirable characteristics e.g. Labrador and Poodle, are bred so that offspring (Labradoodle) possess a favourable combination of characteristics from each parent. This stems from Mendel's findings, as he established that we receive an allele from each parent. Hence, this process relies upon the offspring inheriting the desirable traits from their parents.
Thus, Mendel's work has increased our understanding of inheritance, including alleles, genes and dominance, leading to many further developments.
Thank you! :)
Post by: Mathew587 on September 27, 2017, 09:28:29 pm
Hi, could someone please mark and give me feedback on this question?
Q: "Gregor Mendel revealed the world of genetics to future biologists". Using your knowledge of the HSC Biology course, discuss the contribution of Mendel in relation to the development of our understanding of inheritance and modern genetics". (7 marks)
Mendel's investigations using pea plants have grown our understanding of genetics, contributing to future developments. In his experiment, Mendel first established pure breeding lines of tall and short pea plants. He then cross bred the tall and short and recorded the height of the plants. He had found that they were all tall. Again, he crossbred the offspring of the first generation and found that 75% of the offspring were tall, while 25% were short. From this, Mendel inferred that individual held two variants ( now called alleles) of a characteristic (now called a gene), and that each allele was provided by each parent.
In addition, he also established that certain alleles were dominant over others. This means that if at least one dominant allele was present in a genotype, it would be reflected in the phenotype. Recessive genes on the other hand, mean that both alleles need to be present in the genotype for it to be expressed in the phenotype. This dominance was demonstrated through the tall plants in Mendel's experiments, for both Tt and TT plants were tall, hence tall is dominant, while recessive alleles were shown through the short plants (tt), hence short is recessive.
Importantly, Mendel's work on alleles and dominance in inheritance has led to new developments. Firstly, Sutton and Boveri's work on sea urchins and grasshoppers elaborated upon Mendel's ideas, suggesting that chromosomes were the carriers of hereditary information, or as described by Mendel, "characteristics". Furthermore, more work into alleles has revealed different types of dominance. For example, Morgan's work on fruit flies, demonstrated "sex-linked" traits, where certain traits were more dominant depending on sex, such as if they only appeared on the X chromosome. Also, later work also revealed more complex forms of dominance such as co-dominance, in which both alleles are expressed in the phenotype.
More currently, Mendel's work has led to methods such as DNA hybridisation within a species. Individuals within species, who have desirable characteristics e.g. Labrador and Poodle, are bred so that offspring (Labradoodle) possess a favourable combination of characteristics from each parent. This stems from Mendel's findings, as he established that we receive an allele from each parent. Hence, this process relies upon the offspring inheriting the desirable traits from their parents.
Thus, Mendel's work has increased our understanding of inheritance, including alleles, genes and dominance, leading to many further developments.
Thank you! :)
sounds pretty good but can't give a mark without a guideline :)
Post by: justwannawish on September 27, 2017, 09:40:25 pm
Genetics is such a good topic to learn, because a lot of what is assessed in Genetics has already been highlighted in Blueprint of Life. You learn about protein synthesis in more depth, you learn about the role of introns and exons in establishing fingerprinting and VNTR in DNA fingerprinting, and why they are important to establishing a unique fingerprint.
It's such an interesting topic, because of how you can apply this to the Blueprint of Life topic, which already allows you to further your understanding of the Blueprint of Life topic, so I highly recommend you being taught by your school.
None of them are really equation-y because it's biology, but I'd DEFINITELY recommend communication. It's so interesting to learn, and you can relate it to real life which helps with on-the-go study such as when you see the colour red "my red cones are being stimulated" etc while you can't really relate genetics to everyday life. Also it's interesting to learn how you see and hear etc.
Thank you for your advice. Both of them sound really interesting but I work better with things I can see and observe in front of me, so I might vote for communication haha. Our school has done it for a while so I feel like they'd teach it better too
Is communication a very content heavy topic? Is it likely to have a 8 mark question because they sound quite frightening to me? Any tips of how to tackle such questions
Post by: Opengangs on September 27, 2017, 09:53:25 pm
Thank you for your advice. Both of them sound really interesting but I work better with things I can see and observe in front of me, so I might vote for communication haha. Our school has done it for a while so I feel like they'd teach it better tooFrom memory, I believe that every option topic will have the extended response at the end.
Is communication a very content heavy topic? Is it likely to have a 8 mark question because they sound quite frightening to me? Any tips of how to tackle such questions
Post by: Daniyahasan on September 27, 2017, 09:56:01 pm
Thank you for your advice. Both of them sound really interesting but I work better with things I can see and observe in front of me, so I might vote for communication haha. Our school has done it for a while so I feel like they'd teach it better too
Is communication a very content heavy topic? Is it likely to have a 8 mark question because they sound quite frightening to me? Any tips of how to tackle such questions
Communications is VERY content heavy let me tell you. Theres SOO much memorising and i kind of hate it. I agree its interesting but its a bit much. If i had a choice i definatley wouldnt choose it tbh. Im not saying its a shit topic or anything, but it just ddnt work for me :/
and yeah the do have the 8 markers which are usually about cochlear implants and hearing aid which is okay
but i hate the brain and nurones part eeekkkkkkk
plus notes are quite hard to find too, but iv done my notes so maybe ill upload them later if anyone wants:)
Good luck!
Post by: Daniyahasan on September 27, 2017, 09:58:11 pm
From memory, I believe that every option topic will have the extended response at the end.
Thats right, all the options have some sort of extended response included:)
Post by: justwannawish on September 27, 2017, 10:47:13 pm
From memory, I believe that every option topic will have the extended response at the end.
Communications is VERY content heavy let me tell you. Theres SOO much memorising and i kind of hate it. I agree its interesting but its a bit much. If i had a choice i definatley wouldnt choose it tbh. Im not saying its a shit topic or anything, but it just ddnt work for me :/
and yeah the do have the 8 markers which are usually about cochlear implants and hearing aid which is okay
but i hate the brain and nurones part eeekkkkkkk
plus notes are quite hard to find too, but iv done my notes so maybe ill upload them later if anyone wants:)
Good luck!
Thank you! I'll see what the rest of the cohort chooses and we'll go from there I guess :)
Post by: pikachu975 on September 28, 2017, 01:27:41 am
Thank you for your advice. Both of them sound really interesting but I work better with things I can see and observe in front of me, so I might vote for communication haha. Our school has done it for a while so I feel like they'd teach it better too
Is communication a very content heavy topic? Is it likely to have a 8 mark question because they sound quite frightening to me? Any tips of how to tackle such questions
Communication might have a lot of content but it's easier to remember by a lot. Me and my friends randomly make communication jokes in the playground which helped us remember it. For example we see the green grass "ahh my green cones are being stimulated" or seeing a far object "my lens is thin" etc which essentially reduced the content to memorise by A LOT.
It's all up to the individual so just go with what you are interested in
Post by: bridie_2345 on September 28, 2017, 12:28:23 pm
are sterile/physiologically inert?
Post by: Daniyahasan on September 28, 2017, 05:41:09 pm
Hi there I was wondering if HBOCs (haemoglobin based oxygen carriers)
are sterile/physiologically inert?
isnt HBOC artifical blood? if it is then yes its sterile
but if it isnt then idk sorry
Post by: sidzeman on September 28, 2017, 08:18:03 pm
Q7 - why is the answer not thermoreceptors within the skin? Its them that detect changes from the norm temperature not the brain right?
Q15 I'm at a complete loss as how to do
Q23 - should the process not be DNA unzipping - how can we tell its DNA replication does DNA not also unzip during transcription
Post by: Opengangs on September 28, 2017, 09:34:40 pm
Questions from the 2015 biology HSCQ7: You're correct in that thermoreceptors detect changes within the skin, but these thermoreceptors merely send a signal to the brain. The brain enacts on these messages and sends them back to the arterioles and muscles. So, it is a trick question because really, two things happen at or near X.
Q7 - why is the answer not thermoreceptors within the skin? Its them that detect changes from the norm temperature not the brain right?
For the full picture, we'd get:
Core body temp falls below normal -> Thermoreceptors detect these changes in the skin -> Hypothalamus (brain) enacts to these changes -> Signal is sent to the muscles and arterioles -> Return to normal body temp.
So, that's why the brain is the most correct answer.
Questions from the 2015 biology HSCQ15: this is a pretty tough question, so don't feel bad!
Q15 I'm at a complete loss as how to do
If we read the question properly, we can see that: individual plants have either yellow, red or orange flowers.
Right off the bat, this implies either co-dominance or incomplete dominance as three phenotypes are involved.
We can then eliminate dominant/recessive relationships (B)
Next, the sentence tells us that two plants contain different flower colours. This allows us to eliminate (A).
We now have an even 50/50 split between (C) and (D). The question tells us that the breeding experiment was carried out like Mendel did.
If we recall how Mendel crossed his plants, the parent plants had to be pure bred or homozygous, meaning that (D) cannot be correct.
(C) will be the final answer (based on elimination).
Questions from the 2015 biology HSCQ23:
Q23 - should the process not be DNA unzipping - how can we tell its DNA replication does DNA not also unzip during transcription
I see what you mean -- transcription or DNA unzipping is the process by which the DNA strand is copied into the mRNA. To observe why it's not transcription, consider what the end result of transcription is and what the end result of DNA replication is from a top-down perspective of the model. If we ever get a model, we should always approach the model with a top-down focus (ie from the top and reading the model going down), because that's the intended direction of how they are made.
Transcription is simply the unwinding and unzipping of the DNA strands using the enzyme helicase. It splits the two strands into its leading and lagging strands, while elongation (which is a process under DNA replication) is simply the synthesis of the complementary base pair onto the leading strand or the "template" strand.
Both of these "processes" comes under the umbrella process we call: DNA replication, which is the preferred process to name. But really, transcription and elongation are procedures that finally accumulate to the process of DNA replication.
Post by: sidzeman on September 28, 2017, 10:29:52 pm
Q7: You're correct in that thermoreceptors detect changes within the skin, but these thermoreceptors merely send a signal to the brain. The brain enacts on these messages and sends them back to the arterioles and muscles. So, it is a trick question because really, two things happen at or near X.
For the full picture, we'd get:
Core body temp falls below normal -> Thermoreceptors detect these changes in the skin -> Hypothalamus (brain) enacts to these changes -> Signal is sent to the muscles and arterioles -> Return to normal body temp.
So, that's why the brain is the most correct answer.
Q15: this is a pretty tough question, so don't feel bad!
If we read the question properly, we can see that: individual plants have either yellow, red or orange flowers.
Right off the bat, this implies either co-dominance or incomplete dominance as three phenotypes are involved.
We can then eliminate dominant/recessive relationships (B)
Next, the sentence tells us that two plants contain different flower colours. This allows us to eliminate (A).
We now have an even 50/50 split between (C) and (D). The question tells us that the breeding experiment was carried out like Mendel did.
If we recall how Mendel crossed his plants, the parent plants had to be pure bred or homozygous, meaning that (D) cannot be correct.
(C) will be the final answer (based on elimination).
Q23:
I see what you mean -- transcription or DNA unzipping is the process by which the DNA strand is copied into the mRNA. To observe why it's not transcription, consider what the end result of transcription is and what the end result of DNA replication is from a top-down perspective of the model. If we ever get a model, we should always approach the model with a top-down focus (ie from the top and reading the model going down), because that's the intended direction of how they are made.
Transcription is simply the unwinding and unzipping of the DNA strands using the enzyme helicase. It splits the two strands into its leading and lagging strands, while elongation (which is a process under DNA replication) is simply the synthesis of the complementary base pair onto the leading strand or the "template" strand.
Both of these "processes" comes under the umbrella process we call: DNA replication, which is the preferred process to name. But really, transcription and elongation are procedures that finally accumulate to the process of DNA replication.
Those are some really indepth responses hahhaaha thank you so much for your help!!
Post by: Zizzle on September 29, 2017, 06:30:07 pm
I was wondering if anyone knew the distribution of the types of cones in the retina (red cones, green cones, blue cones). So like, what are the percentages of each.
Thanks!
Post by: Daniyahasan on September 29, 2017, 06:39:19 pm
Hi,
I was wondering if anyone knew the distribution of the types of cones in the retina (red cones, green cones, blue cones). So like, what are the percentages of each.
Thanks!
im pretty sure you dont need to know the percentage of them
Post by: Mounica on September 29, 2017, 06:43:33 pm
Post by: Daniyahasan on September 29, 2017, 06:45:56 pm
does anyway know an easy was to remember the function of veins/arteries/capillaries :)
i like it remember it like this
Arteries take blood Away from the heart -- Arteries -> away
veins bring blood back to the heart
capillaries join the artieris and veins and are one cell thick
Hope that helps:)
Post by: Mounica on September 29, 2017, 06:48:37 pm
i like it remember it like this
Arteries take blood Away from the heart -- Arteries -> away
veins bring blood back to the heart
capillaries join the artieris and veins and are one cell thick
Hope that helps:)
Yup! makes sense
btw do arteries have valves or veins?
and what is the function of valves
Post by: Daniyahasan on September 29, 2017, 06:50:30 pm
Yup! makes sense
btw do arteries have valves or veins?
and what is the function of valves
Veins have valves (you can remember it like V-veins,valves)
veins stop the blood from flowing in the other direction
Post by: pikachu975 on September 29, 2017, 08:38:21 pm
Q23:
I see what you mean -- transcription or DNA unzipping is the process by which the DNA strand is copied into the mRNA. To observe why it's not transcription, consider what the end result of transcription is and what the end result of DNA replication is from a top-down perspective of the model. If we ever get a model, we should always approach the model with a top-down focus (ie from the top and reading the model going down), because that's the intended direction of how they are made.
Transcription is simply the unwinding and unzipping of the DNA strands using the enzyme helicase. It splits the two strands into its leading and lagging strands, while elongation (which is a process under DNA replication) is simply the synthesis of the complementary base pair onto the leading strand or the "template" strand.
Both of these "processes" comes under the umbrella process we call: DNA replication, which is the preferred process to name. But really, transcription and elongation are procedures that finally accumulate to the process of DNA replication.
Transcription is copying DNA to mRNA not the unwinding of the DNA strand. Transcription is part of polypeptide synthesis not DNA replication.
i like it remember it like this
Arteries take blood Away from the heart -- Arteries -> away
veins bring blood back to the heart
capillaries join the artieris and veins and are one cell thick
Hope that helps:)
Just be aware that the pulmonary artery takes deoxygenated blood TO the heart, so not all arteries take it away.
Post by: Opengangs on September 29, 2017, 08:42:25 pm
Transcription is copying DNA to mRNA not the unwinding of the DNA strand. Transcription is part of polypeptide synthesis not DNA replication.Oh, my bad! Haha, you're correct; transcription doesn't occur in the replication of DNA.
Post by: av-angie-er on September 30, 2017, 11:11:32 am
Post by: blasonduo on September 30, 2017, 11:17:29 am
Hi! For a question that asks for you to describe the work of three named scientists who have contributed to our understanding of inheritance, would it be appropriate to address Sutton and Boveri together, as well as Mendel and Morgan? So sort of like a packaged deal; equating their work to that of one scientist since their ideas are pretty similar? Thanks :)
yes! That seems like a great idea! Putting them as one can really strengthen your argument. The great part of these questions is the freedom we get! However, you could argue that you are talking about 4 scientists, but I doubt marks would be lost on that technicality
Post by: av-angie-er on September 30, 2017, 04:06:07 pm
yes! That seems like a great idea! Putting them as one can really strengthen your argument. The great part of these questions is the freedom we get! However, you could argue that you are talking about 4 scientists, but I doubt marks would be lost on that technicalityOoh, good point! Thanks so much :D
Post by: Arvacado on September 30, 2017, 09:17:53 pm
Post by: Arvacado on September 30, 2017, 09:22:31 pm
Post by: Arvacado on September 30, 2017, 09:25:55 pm
1.How does the kidney function?
2.What is the interaction between T cells and B cells?
Post by: Potatohater on September 30, 2017, 10:21:42 pm
More questions ;D ;D ;D1. The kidney functions by filtering the blood in the glomerulis, with all the filtrate entering the bowman's capsule (blood cells stay in the blood) then various substances such as glucose are reabsorbed in the proximal tubule, and water and salts are reabsorbed in the loop of henle and distal tubules. In the collecting duct some water and salts may also be reabsorbed if ADH and aldosterone hormones have been released. So basically it filters blood and reabsorbs what is needed.
1.How does the kidney function?
2.What is the interaction between T cells and B cells?
2. Pretty sure when presented with an antigen helper T cells stimulate B cells to produce plasma B cells and memory B cells - but I'm a little rusty on this so you might wanna double check
Post by: rainbowsparkles15 on September 30, 2017, 10:28:56 pm
More questions ;D ;D ;D
1.How does the kidney function?
2.What is the interaction between T cells and B cells?
To answer your second question, when a phagocyte such as a macrophage presents an antigen on its MHCII marker, a specific T Helper cell will recognise it and bind. It will then release cytokines that stimulate the specific B cell with the same receptors to undergo clonal expansion and differentiate into B plasma cells and B memory cells
(I do VCE so sorry if some of this isn't relevant) Hope this helps, good luck!
Post by: Potatohater on September 30, 2017, 10:33:47 pm
To answer your second question, when a phagocyte such as a macrophage presents an antigen on its MHCII marker, a specific T Helper cell will recognise it and bind. It will then release cytokines that stimulate the specific B cell with the same receptors to undergo clonal expansion and differentiate into B plasma cells and B memory cellsDon't worry, it's all relevant, I think the only part we don't look at for HSC is clonal expansion, but the extra knowledge doesn't hurt
(I do VCE so sorry if some of this isn't relevant) Hope this helps, good luck!
Post by: sidzeman on October 01, 2017, 02:52:18 pm
1. The kidney functions by filtering the blood in the glomerulis, with all the filtrate entering the bowman's capsule (blood cells stay in the blood) then various substances such as glucose are reabsorbed in the proximal tubule, and water and salts are reabsorbed in the loop of henle and distal tubules. In the collecting duct some water and salts may also be reabsorbed if ADH and aldosterone hormones have been released. So basically it filters blood and reabsorbs what is needed.Just a few nitpicky things - ADH is released in the collecting yes - but aldosterone is released in the ascending loop of Henle, and concerns salt reabsorption specifically (although it also causes water reabsorption due to changing the osmotic pressure).
2. Pretty sure when presented with an antigen helper T cells stimulate B cells to produce plasma B cells and memory B cells - but I'm a little rusty on this so you might wanna double check
More specifically for the function of the kidney there are 2 main functions -
1) osmoregulation - e.g. reabsorbing water to ensure there are sufficient levels in the body
2) Excretion of nitrogenous wastes e.g. urea (this is what potatohater meant when he said it filters blood)
Post by: Arvacado on October 01, 2017, 09:53:32 pm
What is one of the limitations of Koch's postulates?
Post by: pikachu975 on October 01, 2017, 10:34:47 pm
Hiiii!
What is one of the limitations of Koch's postulates?
Doesn't work for non-infectious diseases because those are not caused by pathogens
OR
Requires a second host to be inoculated with the disease which could be dangerous to their health
Don't worry, it's all relevant, I think the only part we don't look at for HSC is clonal expansion, but the extra knowledge doesn't hurt
Clonal expansion is part of clonal selection theory, formed by Macfarlane Burnet - which can be tested in the HSC as it is one of the dot points in the left hand column of the syllabus.
More questions ;D ;D ;D
2.What is the interaction between T cells and B cells?
B cells can bind to a specific antigen and present it to a helper T cell via an MHC II molecule or a macrophage can lyse the pathogen through phagocytosis and present the antigen to the helper T cell. The helper T cell then releases interleukin-2 to stimulate B and T cells to rapidly divide and differentiate, also known as clonal selection theory. The helper T cell can also stimulate production of antibodies.
A further interaction can be seen as suppressor T cells can signal B cells to stop producing antibodies once the infection is gone.
Hiii! Another question ;D ;D Analyse the ways in which theories in biology are tested and validated, using the theory of evolution as an example.
I learnt this from physics but there has to be an observation, problem raised, new hypothesis, experiment, data analysis, and then if the results support the hypothesis it becomes a new theory or law, if not then they come up with a new hypothesis.
I guess for this you could look at that dot point talking about theories of evolution.
You've got Linnaeus who classified humans and apes together. Then Erasmus Darwin who said all life came from a single source. Then Lamarck who talked about use/disuse of body parts which was proved wrong which then led to a new hypothesis by Darwin and Wallace about natural selection and isolation. This was tested and validated through Darwin's 14 finches in the Galapagos and Cocos Islands where he noticed divergent evolution as all the new species had adapted to their respective niches.
Post by: left right gn on October 02, 2017, 07:50:42 pm
Post by: Potatohater on October 02, 2017, 09:41:21 pm
For line/curve of best fits, do we join the dots??No! Don't mean to come off as aggressive with that no, but whatever you do, do not join the dots for a line or curve of best fit
Only join the dots if it is an epidemiological graph, otherwise it is always either a curve or a line of best fit.
Post by: Mathew587 on October 02, 2017, 10:13:49 pm
For line/curve of best fits, do we join the dots??dont connect the dots
just chuck a line through what seems to be the majority of the dots and make it neat
a mark right there
Post by: sidzeman on October 02, 2017, 10:47:16 pm
Clonal expansion is part of clonal selection theory, formed by Macfarlane Burnet - which can be tested in the HSC as it is one of the dot points in the left hand column of the syllabus.Sorry what exactly is the clonal selection theory and clonal expansion? Don't think I've ever come across these terms before. My knowledge of Burnet is also kinda iffy - didn't he identify MCH I or II molecules as being present on cells that identified them as being part of ones own body, and so did not trigger the immune response?
Post by: Opengangs on October 02, 2017, 10:57:57 pm
Sorry what exactly is the clonal selection theory and clonal expansion? Don't think I've ever come across these terms before. My knowledge of Burnet is also kinda iffy - didn't he identify MCH I or II molecules as being present on cells that identified them as being part of ones own body, and so did not trigger the immune response?The clonal selection theory explains the process of immunological memory in the form of two lymphocytes. One of these lymphocyte act as the immediate combatant to the infection, while the other remains in the body in the form of memory cells. It is these memory cells that enable an individual to have immunity over these specific antigens. While Burnet was not the one who proposed this idea, he extended the pre-existing theories surrounding these experiments and publicised his findings, naming it 'the clonal selection theory'.
Post by: sidzeman on October 02, 2017, 11:20:29 pm
The clonal selection theory explains the process of immunological memory in the form of two lymphocytes. One of these lymphocyte act as the immediate combatant to the infection, while the other remains in the body in the form of memory cells. It is these memory cells that enable an individual to have immunity over these specific antigens. While Burnet was not the one who proposed this idea, he extended the pre-existing theories surrounding these experiments and publicised his findings, naming it 'the clonal selection theory'.Ahhhh I see thank you so much you may have just saved me some easy marks in the hsc!
Post by: Potatohater on October 03, 2017, 12:04:31 am
Ahhhh I see thank you so much you may have just saved me some easy marks in the hsc!Lol, I personally wouldn't have called that easy marks, I'm still confused, I feel like all that just went in one eye and out the other
Post by: Mounica on October 03, 2017, 08:56:21 am
Does anyone know what part of the Communication syllabus this question is referring to:
"Compare mechanisms in the human body for detection and perception of a range
of frequencies in visual and auditory communication"
Post by: Potatohater on October 03, 2017, 09:05:03 am
Hey Guys,It might be one of those tricky questions that ask you to refer to multiple dot points such as
Does anyone know what part of the Communication syllabus this question is referring to:
"Compare mechanisms in the human body for detection and perception of a range
of frequencies in visual and auditory communication"
- identify the limited range of wavelengths of the electro magnetic spectrum detected by humans etc.
- explain why sound is useful and versatile form of communication
- 2ndary sources to outline frequencies detected by humans
Basically this question wants you to have a good knowledge of lots of dot points and link them together
Post by: julia_warren13 on October 03, 2017, 10:40:00 am
Post by: Potatohater on October 03, 2017, 10:43:33 am
Even if the question does not specifically ask, is it possible to use a table when answering a 'compare' or 'contrast' question? (And still get the full marks!!) ThanksFor sure! I do it all the time internally and I'm certain this counts externally too - I reckon it's the best method
Post by: julia_warren13 on October 03, 2017, 10:45:58 am
For sure! I do it all the time internally and I'm certain this counts externally too - I reckon it's the best method
Okay thank you! I also used tables for my trial but just wasn't sure if external markers would accept it :)
Post by: inescelic on October 03, 2017, 01:26:11 pm
sounds pretty good but can't give a mark without a guideline :)
thanks :) unfortunately i don't have it as it came from my friend's trial :( but at least it sounds pretty good haha
Post by: inescelic on October 03, 2017, 01:32:31 pm
HSC 2009
Q26: Describe how processes such as enantiostasis and homeostasis are used to maintain metabolic functions when salt concentration varies in plants living in estuarine environments.
Sample answer:
Homeostasis involves maintaining a constant internal environment to maintain metabolic functions. This is difficult if there are large variations in salt concentration. In organisms that use enantiostasis, other physical or chemical conditions are varied to compensate for the variations in salt concentration so the metabolic functions are maintained.
Post by: Potatohater on October 03, 2017, 01:58:15 pm
Hi could someone please help with this question? I don't really understand how to distinguish homeostasis and enantiostasis, and in which cases one is used over the other. The sample answer didn't really help me either :(Homeostasis: maintainance of a constant internal environment
HSC 2009
Q26: Describe how processes such as enantiostasis and homeostasis are used to maintain metabolic functions when salt concentration varies in plants living in estuarine environments.
Sample answer:
Homeostasis involves maintaining a constant internal environment to maintain metabolic functions. This is difficult if there are large variations in salt concentration. In organisms that use enantiostasis, other physical or chemical conditions are varied to compensate for the variations in salt concentration so the metabolic functions are maintained.
Enantiostasis: maintainance of functionality in a changing environment
Enantiostasis is how organisms that live in saline conditions deal with the fluctuations in their environment. They can do this by being either:
Osmoconformers: able to maintain metabolic function with a changing internal environment - eg. A starfish matches it's body fluids to the external environment so it doesn't gain or lose too much water via osmosis
Osmoregulators: keep internal salt levels within a narrow range - eg. Mangroves have leaves where they store salt and drop off, and pnumetaphores which try and stop as much salt coming in as possible, this tries to minimise salt in the organism
So basically the sample answer is trying to say that in saline environments (such as estuaries where the salt levels are constantly fluctuating) it is incredibly hard to maintain homeostasis due to osmosis. Therefore these organisms change their behaviours and/or internal environment so they can continue to function.
If you still don't understand let me know and I'll attempt to clarify :)
Post by: inescelic on October 03, 2017, 02:22:46 pm
Both are from the 2009 HSC
Question 27 (8 marks)
Most offspring resemble their parents in a number of characteristics, but there are often some characteristics in the offspring that are unexpected.
Explain, using examples, how genetics and the environment can affect the phenotype of individuals.
Environment and genotype both affect the phenotype of individuals. Genotype refers to the combination of alleles one inherits from their parents for a certain characteristic. According to Mendel's law of segregation, alleles are separated in meiosis, forming gametes with half of the genetic information of a diploid cell. However, this number is restored in fertilisation, as for each characteristic or gene, a zygote will receive one allele form each parent. Whether the alleles are dominant or recessive determines the phenotype of the offspring. For example, in Mendel's experiment with pea plants, if offspring inherited one dominant allele for tall height and a recessive allele for short height, they would present a tall phenotype.
However, genotype does not always confirm the phenotype of an individual. Environment also has an impact on phenotype, and can change how the characteristic is presented. For example, if seedlings are placed in a covered box, their environment is changed as they do not have sunlight available. Although a seedling may have the genotype to be tall and green, the lack of sunlight limits photosynthesis, thus the plant is not able to grow tall and be green in appearance.
Therefore, though genes are inherited from parents to offspring, the presented phenotype can also change due to environmental factors.
Q28 Communication
e) Explain how an understanding of hearing mechanisms has been used to develop 7 technologies to overcome hearing difficulties.(7 marks)
Understanding hearing mechanisms has led us to develop technologies such as hearing aids and the cochlear implant.
Sound waves are first channeled into the ear by the pinna. Then, as sound hits the tympanic membrane, sound waves are converted to mechanical energy. Then, the ear ossicles serve to transmit and and amplify this energy to the cochlea through the oval window. The mechanical energy travels through the fluid in the cochlea, stimulating hair cells in the Organ of Corti, which release chemicals as they are stimulated and bent, ultimately releasing an electrochemical signal which is sent as a nerve impulse to the brain through the auditory nerve.
Our understanding of the outer and middle ear, including the role of the tympanic membrane and ear ossicles has led us to develop the hearing aid, which amplifies sound if these areas are broken or not working properly. The microphone firstly picks up sounds, which is then amplified and this amplified sound is then channeled into the ear by an earpiece. As a result, the person is able to hear sounds at a louder volume.
Also, our understanding of the cochlea and its role has lead to the development of the cochlear implant if someone has inner ear damage to the cochlea or hair cells. Hair cells, in the Organ of Corti are important as they stimulate an electrochemical signal, initiating a nerve impulse. If any part of the cochlea is not working, the cochlear implant is used to stimulate the auditory nerve so the brain can receive the message. It works by a sound processor firstly capturing sound through a microphone. Then, the sound processor converts the sound information into digital information. This digital information is sent over a transmitter antenna to the internal implant receiver through radio waves. The digital receiver then converts the digital sound information into electronic signals and sends them to an electrode array. The electrode array in the cochlea then delivers direct stimulation to the auditory nerve fibres, where a signal is sent to the brain to be interpreted.
Therefore, through our understanding of hearing mechanisms and their role, we have developed technologies to assist people with hearing failures.
Post by: inescelic on October 03, 2017, 02:34:14 pm
Homeostasis: maintainance of a constant internal environment
Enantiostasis: maintainance of functionality in a changing environment
Enantiostasis is how organisms that live in saline conditions deal with the fluctuations in their environment. They can do this by being either:
Osmoconformers: able to maintain metabolic function with a changing internal environment - eg. A starfish matches it's body fluids to the external environment so it doesn't gain or lose too much water via osmosis
Osmoregulators: keep internal salt levels within a narrow range - eg. Mangroves have leaves where they store salt and drop off, and pnumetaphores which try and stop as much salt coming in as possible, this tries to minimise salt in the organism
So basically the sample answer is trying to say that in saline environments (such as estuaries where the salt levels are constantly fluctuating) it is incredibly hard to maintain homeostasis due to osmosis. Therefore these organisms change their behaviours and/or internal environment so they can continue to function.
If you still don't understand let me know and I'll attempt to clarify :)
Thank you! It kind of makes sense :) So because it is too hard for organisms to maintain homeostasis in fluctuating environments they must change their metabolic functions? But what I don't understand is how these behaviours are not also considered processes to achieve homeostasis(e.g. how is it different to homeostatic salt regulation of aldosterone)? Also, how does osmosis interfere with homeostasis?
Post by: Potatohater on October 03, 2017, 03:01:41 pm
Thank you! It kind of makes sense :) So because it is too hard for organisms to maintain homeostasis in fluctuating environments they must change their metabolic functions? But what I don't understand is how these behaviours are not also considered processes to achieve homeostasis(e.g. how is it different to homeostatic salt regulation of aldosterone)? Also, how does osmosis interfere with homeostasis?In enantiostasis, the organisms don't change their metabolic functions, they change their internal environment. So in the case of the starfish the starfish will make its body more or less saline to match the external environment. This is different to homeostasis because in homeostasis the internal environment is kept constant, so in humans for example, the salt levels in our bodies stay more or less the same regardless of our environment.
These processes are not considered as achieving homeostasis because the internal environment does change, where as in homeostasis it does not. Throughout this process the metabolic functions remain the same but the internal environment does not.
What I meant abuout osmosis impacting homeostasis:
In terms of estuarine environments osmosis can cause water to enter or leave an aquatic organism if there were no processes to regulate this. As you know, fresh water fish produce heaps of dilute urine to maintain their water levels, as water moves into the fish because it is more concentrated than the external environment, and salt water fish produce small amounts of concentrated urine to prevent water going out because the external environment is more saline than the fish. However, organisms in estuaries, where the water is brackish and can fluctuate in salt levels, can't change their function to deal with the salinity, so they change the internal environment to match the situation so that they can continue to operate
Post by: Potatohater on October 03, 2017, 03:07:21 pm
Could someone please mark these?
Both are from the 2009 HSC
Is there a marking criteria? I do have acsess to a bunch of sample answers for these questions which I can mark against (and so far your answers are looking pretty good) but if there's a marking scheme that would make the assignment of a mark more accurate
Post by: pikachu975 on October 03, 2017, 04:21:59 pm
Sorry what exactly is the clonal selection theory and clonal expansion? Don't think I've ever come across these terms before. My knowledge of Burnet is also kinda iffy - didn't he identify MCH I or II molecules as being present on cells that identified them as being part of ones own body, and so did not trigger the immune response?
Clonal expansion is when B and T cells divide rapidly so that they can specialise after. The theory in detail explains how lymphocytes (B and T cells) interact in the immune response.
Hey Guys,
Does anyone know what part of the Communication syllabus this question is referring to:
"Compare mechanisms in the human body for detection and perception of a range
of frequencies in visual and auditory communication"
Basically talk about the process of sight and hearing as well as listing the ranges of each:
Sight: 700-400 nm
Sound: 2000-20000 Hz with most sensitivity at 2000-4000 Hz due to speech
Post by: pikachu975 on October 03, 2017, 04:26:46 pm
Homeostasis: maintainance of a constant internal environment
Enantiostasis: maintainance of functionality in a changing environment
Enantiostasis is how organisms that live in saline conditions deal with the fluctuations in their environment. They can do this by being either:
Osmoconformers: able to maintain metabolic function with a changing internal environment - eg. A starfish matches it's body fluids to the external environment so it doesn't gain or lose too much water via osmosis
Osmoregulators: keep internal salt levels within a narrow range - eg. Mangroves have leaves where they store salt and drop off, and pnumetaphores which try and stop as much salt coming in as possible, this tries to minimise salt in the organism
So basically the sample answer is trying to say that in saline environments (such as estuaries where the salt levels are constantly fluctuating) it is incredibly hard to maintain homeostasis due to osmosis. Therefore these organisms change their behaviours and/or internal environment so they can continue to function.
If you still don't understand let me know and I'll attempt to clarify :)
How is homeostasis used to maintain metabolic function though? As asked in the question. I was having trouble with this one as well
Post by: inescelic on October 03, 2017, 05:28:34 pm
How is homeostasis used to maintain metabolic function though? As asked in the question. I was having trouble with this one as well
From what I now understand, I think homeostasis is used to create a stable internal environment FOR metabolic function (think of how if pH or temp are out of optimum range, metabolism doesn't function effectively). Whereas when it is difficult for the organism to do this in a fluctuating environment, enantiostasis is used to maintain metabolic functions by which the organism changes with the environment. (Blue crabs change the pH of their blood in brackish water to increase the ability to bind with oxygen)
Post by: inescelic on October 03, 2017, 05:36:06 pm
In enantiostasis, the organisms don't change their metabolic functions, they change their internal environment. So in the case of the starfish the starfish will make its body more or less saline to match the external environment. This is different to homeostasis because in homeostasis the internal environment is kept constant, so in humans for example, the salt levels in our bodies stay more or less the same regardless of our environment.Ok so when it is difficult for the organism to maintain homeostasis in a fluctuating environment, enantiostasis is used to maintain metabolic functions by which the organism changes with the environment? So that is where osmoconformers come in as they vary along with the environment. But how do osmoregulators vary along with the environment since they are keeping salt in a narrow range?
These processes are not considered as achieving homeostasis because the internal environment does change, where as in homeostasis it does not. Throughout this process the metabolic functions remain the same but the internal environment does not.
What I meant abuout osmosis impacting homeostasis:
In terms of estuarine environments osmosis can cause water to enter or leave an aquatic organism if there were no processes to regulate this. As you know, fresh water fish produce heaps of dilute urine to maintain their water levels, as water moves into the fish because it is more concentrated than the external environment, and salt water fish produce small amounts of concentrated urine to prevent water going out because the external environment is more saline than the fish. However, organisms in estuaries, where the water is brackish and can fluctuate in salt levels, can't change their function to deal with the salinity, so they change the internal environment to match the situation so that they can continue to operate
Post by: inescelic on October 03, 2017, 05:39:36 pm
Is there a marking criteria? I do have acsess to a bunch of sample answers for these questions which I can mark against (and so far your answers are looking pretty good) but if there's a marking scheme that would make the assignment of a mark more accurate
Yep here you go :)
Post by: inescelic on October 03, 2017, 05:44:26 pm
I was a little unsure as to whether I took a valid approach to this question :( Also I'm not sure if competition for resources would be an acceptable point.
Much appreciated :)
Biology has allowed us to validate theories of evolution, supporting the significance of isolation and environmental pressures in the gradual change of species over time. Our increased use of biogeography and palaeontology practice has ultimately affirmed Darwin’s theory of evolution.
Darwin described evolution as the gradual change of species over many generations. Many species have evolved due to the separation of land forms as shown through biogeography. 85 million years ago, New Zealand separated from New Zealand. As New Zealand drifted east and subsided, its land was mostly under sea water. As individuals in a species on New Zealand may have become isolated, from other individuals of the same species on Australia, they have become subject to different environmental pressures on each island. This means that individuals on New Zealand who were more favourable to marine environments, as New Zealand was then mostly under water, such as those who had a streamline body or or fins were able to survive and reproduce. These traits were then passed to offspring, and over many generations, a new species was eventually formed. This is validated by palaeontology, as the source says “most fossils were marine at this time”.
Furthermore, the source also shows that new land was created by volcanoes 22 million years ago. This acted as an environmental pressure on species, and those individual with traits more favourable for a volcano environment also survived, passing these traits to their offspring. Over many generations, Darwin’s theory states new species would be formed, and is validated by palaeontology as “many unique species of birds appeared in the fossil record”, affirming the evolution of species. Thus, palaeontology techniques, such as using carbon dating have been very important in validating the evolution of New Zealand.
Also, 700 years ago, the island became completely devoid of mammals. Considering that there were many birds earlier, that “occupied niches that were usually occupied by mammals”, this suggests that the birds competed for resources with the mammals, ultimately being successful. Thus, this information supports how competition for resources can affect the path of evolution.
Therefore, biological practices such as biogeography and palaeontology have been important in validating ideas about the role of isolation, environmental pressures and competition for resources in evolution.
Question and marking criteria are attached :)
Post by: angelahchan on October 03, 2017, 08:39:04 pm
does anyone know what "hybridisation within a species" mean? At first I thought it was something to do with transgenic organisms, but is it more about cross breeding within a species (e.g. different dog breeds)
Post by: Natasha.97 on October 03, 2017, 08:50:58 pm
Hi,
does anyone know what "hybridisation within a species" mean? At first I thought it was something to do with transgenic organisms, but is it more about cross breeding within a species (e.g. different dog breeds)
Hi!
- Hybridisation is defined as the cross - breeding of two genetically non-identical individuals within the same species
Example (as you've mentioned): Labradoodle (Labrador/Poodle)
- Transgenic organisms have had genes from other organisms artificially inserted into them
Example: Salmon (bGH - Bovine Growth Hormone inserted, which results in larger + faster growing fish) and Potatoes (Lectin inserted: interferes with insect digestion to protect against insects, which helps to maintain and increase food production)
Hope this helps
Post by: Potatohater on October 04, 2017, 09:28:37 am
Ok so when it is difficult for the organism to maintain homeostasis in a fluctuating environment, enantiostasis is used to maintain metabolic functions by which the organism changes with the environment? So that is where osmoconformers come in as they vary along with the environment. But how do osmoregulators vary along with the environment since they are keeping salt in a narrow range?Ok from my understanding osmoregulators either have functions to keep salt in a narrow range or the avoid the changes eg. Some crabs bury themselves in the mud when the tides change to avoid salinity changes.
Post by: pikachu975 on October 04, 2017, 11:13:08 am
Hi,
does anyone know what "hybridisation within a species" mean? At first I thought it was something to do with transgenic organisms, but is it more about cross breeding within a species (e.g. different dog breeds)
Hybridisation is interbreeding organisms of the same species.
Labradoodle (Labrador x Poodle):
- Doesn't shed much (Poodle)
- Doesn't have much body odour (Poodle)
- Doesn't need to be washed much (Poodle)
- Easy to train as guide dogs (Labrador)
- Friendly (Labrador)
So they're mainly good for asthma sufferers, and can also be used in jobs as they're easy to train.
If it says INBREEDING like CSSA it means dogs of the same organism, e.g. labrador x labrador. Easily confused with INTERbreeding.
Post by: Arvacado on October 04, 2017, 12:41:24 pm
Post by: Potatohater on October 04, 2017, 03:40:32 pm
Hiii!! When they ask 'outline how different antibiotics work' do you talk about the drug antibiotic and the antibiotic activated by B-cells?Antibiotics kill bacteria
Antibodies are produced by B plasma cells
They are totally different things. So when they ask about antibiotics you talk about the drugs
When they ask about antibodies you talk about the 3rd line of defence
Post by: pikachu975 on October 04, 2017, 07:00:44 pm
Hiii!! When they ask 'outline how different antibiotics work' do you talk about the drug antibiotic and the antibiotic activated by B-cells?
I would speak about narrow and broad-range antibiotics and how narrow range only kill specific bacteria while broad-range kill numerous and are administered for a general bacterial illness.
I doubt this would be asked in HSC though.
Post by: Aaron12038488 on October 04, 2017, 07:18:26 pm
Post by: pikachu975 on October 04, 2017, 10:04:14 pm
just wondering in general for hsc science subjects if flashcards help in memorising and consolidating yr knowledge thx. Might try it out.
Different for everyone but yes it can be useful
Post by: Potatohater on October 05, 2017, 07:53:29 pm
Could someone please mark these?
Both are from the 2009 HSC
Question 27 (8 marks)
Most offspring resemble their parents in a number of characteristics, but there are often some characteristics in the offspring that are unexpected.
Explain, using examples, how genetics and the environment can affect the phenotype of individuals.
Q28 Communication
e) Explain how an understanding of hearing mechanisms has been used to develop 7 technologies to overcome hearing difficulties.(7 marks)
Ok so I'm just getting sound to marking your responses based off criteria and sample answers.
DISCLAIMER: I am by no means a marking expert since I am also doing th HSC this year, and when I mark myself I tend to mark myself a mark or two harsher than what I actually think because of this, and I guess that pushes me a little
Ok so for 27, I think I would give it a 7. All the info was there, I just felt like its coherence could be improved slightly, but this isn't a major deal, since as previously stated, I try and mark harsher just in case.
For 28 e, I'm giving that a 7 too since it followed a very logical procedure and demonstrated a thourough understanding of how these technologies work to overcome hearing difficulties.
Good job!
Can someone please mark this?
I was a little unsure as to whether I took a valid approach to this question :( Also I'm not sure if competition for resources would be an acceptable point.
Much appreciated :)
Question and marking criteria are attached :)
For this question I think I'll have to give you a 5. Unfortunatley the top band requires you to talk about theories where as you only discussed Darwins theory of gradual evolution. To access the 6/7 marks you would have to also talk about punctuated equilibrium. This is where the birds come in, since many fossils appeared all at once. I feel you could also make more explicit links between the biological evidence and the theories, but maybe that's just me. Other than that I think you have a sound understanding and explained in a clear manner.
Post by: inescelic on October 05, 2017, 10:16:17 pm
Ok so I'm just getting sound to marking your responses based off criteria and sample answers.
DISCLAIMER: I am by no means a marking expert since I am also doing th HSC this year, and when I mark myself I tend to mark myself a mark or two harsher than what I actually think because of this, and I guess that pushes me a little
Ok so for 27, I think I would give it a 7. All the info was there, I just felt like its coherence could be improved slightly, but this isn't a major deal, since as previously stated, I try and mark harsher just in case.
For 28 e, I'm giving that a 7 too since it followed a very logical procedure and demonstrated a thourough understanding of how these technologies work to overcome hearing difficulties.
Good job!
For this question I think I'll have to give you a 5. Unfortunatley the top band requires you to talk about theories where as you only discussed Darwins theory of gradual evolution. To access the 6/7 marks you would have to also talk about punctuated equilibrium. This is where the birds come in, since many fossils appeared all at once. I feel you could also make more explicit links between the biological evidence and the theories, but maybe that's just me. Other than that I think you have a sound understanding and explained in a clear manner.
No that's good, thank you! I definitely understand what you meant with the different theories of evolution, makes sense :) Also competition for resources and its role in evolution can be a bit confusing, but do you think what I have said about it in the above response makes sense?
Bio seriously stress me out because I feel like I never know if what I'm writing is going to match the marking criteria. Some questions in bio are open to many different interpretations and that makes it so stressful:( Any tips?
Post by: Thebarman on October 06, 2017, 12:48:54 pm
Do we need to know in detail the glottis?
Post by: sidzeman on October 06, 2017, 05:07:48 pm
For the punnete square cross, I've forgotten how to draw it up when you have dihybrid crosses
Post by: Opengangs on October 06, 2017, 06:55:04 pm
Hey could someone explain these 2 questions for me please?I'm on my phone so I can't give an extensive answer. For the time being, I'll just briefly explain the mc.
For the punnete square cross, I've forgotten how to draw it up when you have dihybrid crosses
Consider the sixth and the seventh couple on generation II. We notice that if it were recessive, then all of the offspring will not be affected; this suggests that the couple must be heterozygous dominant. This means the genetic inheritance being affected carries the recessive gene, which looks to be (C)
Post by: av-angie-er on October 06, 2017, 06:56:24 pm
Post by: maddiewainwright on October 06, 2017, 08:22:46 pm
Hi! For the genetics elective, can anyone explain the difference between endonuclease/exonuclease enzymes and DNA glycosylase in relation to the repair of damaged DNA? I was taught in class about glycosylase but found that a past HSC paper example response only mentioned endonuclease and exonuclease enzymes, which appear to have a similar function. Thanks :)
Hi av-angie-er,
Basically, endonuclease enzymes are able to cut double stranded DNA anywhere along the molecule, and exonucleases are only able to cleave DNA at the ends of the molecule. Both of types enzymes break the sugar phosphate backbone to cleave DNA strands.
DNA glycosylase does not cleave the sugar phosphate backbone, it only cuts out damaged nitrogenous base pairs, leaving a site for DNA repair.
These different enzymes would perform different functions in repair, depending on the extent of damage (i.e. whether a sequence + its sugar/phosphate backbone need to be removed).
Hope this helps!
Post by: sidzeman on October 06, 2017, 10:47:05 pm
I'm on my phone so I can't give an extensive answer. For the time being, I'll just briefly explain the mc.Ahhhh I see that makes sense thank you!
Consider the sixth and the seventh couple on generation II. We notice that if it were recessive, then all of the offspring will not be affected; this suggests that the couple must be heterozygous dominant. This means the genetic inheritance being affected carries the recessive gene, which looks to be (C)
Hi! For the genetics elective, can anyone explain the difference between endonuclease/exonuclease enzymes and DNA glycosylase in relation to the repair of damaged DNA? I was taught in class about glycosylase but found that a past HSC paper example response only mentioned endonuclease and exonuclease enzymes, which appear to have a similar function. Thanks :)Is this for the genetics: the code broken elective? I study it as well but I've never heard of these terms (endonuclease and etc) - what syllabus dotpoints is this under?
Post by: inescelic on October 06, 2017, 10:48:56 pm
Can someone please clarify how metabolism changes for homeostasis?
I have read that when temperature is low, metabolism increases as energy is being taken up to generate heat in the body.
Yet when animals experience cold, their metabolism instead drops as they hibernate?
A quick summary of metabolism and temperature change would be nice :)
Post by: pikachu975 on October 07, 2017, 02:49:36 am
Hi,
Can someone please clarify how metabolism changes for homeostasis?
I have read that when temperature is low, metabolism increases as energy is being taken up to generate heat in the body.
Yet when animals experience cold, their metabolism instead drops as they hibernate?
A quick summary of metabolism and temperature change would be nice :)
External temperature increasing causes lower metabolism in ENDOTHERMS as it generates heat so they don't want too much metabolism. It causes higher metabolism in ECTOTHERMS as they are more active when it's hot.
When external temperature decreases, endotherm metabolism increases as cellular respiration generates heat. For ectotherms it decreases as they conserve body heat until it is warm enough to search for food efficiently as searching for food to replenish energy while it is cold would be inefficient.
Note that internal temperature for humans barely varies due to homeostasis so enzymes are always efficient while for ectotherms their internal temperature changes.
Post by: av-angie-er on October 07, 2017, 12:37:44 pm
Hi av-angie-er,Ohh okay, thank you! Super helpful :)
Basically, endonuclease enzymes are able to cut double stranded DNA anywhere along the molecule, and exonucleases are only able to cleave DNA at the ends of the molecule. Both of types enzymes break the sugar phosphate backbone to cleave DNA strands.
DNA glycosylase does not cleave the sugar phosphate backbone, it only cuts out damaged nitrogenous base pairs, leaving a site for DNA repair.
These different enzymes would perform different functions in repair, depending on the extent of damage (i.e. whether a sequence + its sugar/phosphate backbone need to be removed).
Hope this helps!
Post by: inescelic on October 07, 2017, 01:48:55 pm
External temperature increasing causes lower metabolism in ENDOTHERMS as it generates heat so they don't want too much metabolism. It causes higher metabolism in ENDOTHERMS as they are more active when it's hot.Alright the second bit makes sense so thank you!
When external temperature decreases, endotherm metabolism increases as cellular respiration generates heat. For ectotherms it decreases as they conserve body heat until it is warm enough to search for food efficiently as searching for food to replenish energy while it is cold would be inefficient.
Note that internal temperature for humans barely varies due to homeostasis so enzymes are always efficient while for ectotherms their internal temperature changes.
But for the second bit:
You're saying temp increase causes higher metabolism in ENDOTHERMS as they are more active when it's hot. But hang on, don't they want to lower metabolism so they don't generate as much heat when its already hot? I thought animals like kangaroos reduced activity and metabolism in hot temperatures so they generated less heat?
Post by: pikachu975 on October 07, 2017, 04:48:43 pm
Alright the second bit makes sense so thank you!
But for the second bit:
You're saying temp increase causes higher metabolism in ENDOTHERMS as they are more active when it's hot. But hang on, don't they want to lower metabolism so they don't generate as much heat when its already hot? I thought animals like kangaroos reduced activity and metabolism in hot temperatures so they generated less heat?
My bad I meant ectotherms it was a typo
Post by: arunasva on October 07, 2017, 11:21:44 pm
Post by: pikachu975 on October 08, 2017, 01:31:40 am
I don't get the concept of threshold potential, can someone clear it out ? Thanks
It's the membrane potential value that must be fulfilled to start an action potential, i.e. -55 mV
Post by: Potatohater on October 08, 2017, 07:52:30 am
I don't get the concept of threshold potential, can someone clear it out ? ThanksNot all stimuli generate a response, if they did we'd probably go crazy! Therefore the membrane potential must reach the -55 threshold (from a resting potential of -70) to stimulate an electrochemical signal, and thus response. It's like a gun, all or nothing, either the trigger is pulled or it doesn't.
When the response is triggered the electrochemical signal is generated by making the normally negative inside, positive. This is done by opening sodium channels. The more sodium that's let in, the easier it is for more sodium to come in, and so the inside becomes positive and the out side negative. (Depolarisation)
Once the signal has been generated and sent along the neurone the negatively charged inside is restored by removing potassium ions. This causes the downward turn of the graph (repolarisation)
When graphing action potential there's also a little dip below the resting membrane potential (hyperpolerisation) which is just to create a break between signals so we aren't constantly buzzing with constant streams of infomation.
I'm hoping that cleared things up
Post by: Potatohater on October 08, 2017, 07:59:37 am
No that's good, thank you! I definitely understand what you meant with the different theories of evolution, makes sense :) Also competition for resources and its role in evolution can be a bit confusing, but do you think what I have said about it in the above response makes sense?I know right! This where I lose my marks, I know all the content but I'm not sure what to write to make the markers happy. As for tips, I try and deconstruct the question and try and work out how many components there are to it and match that up to the question. So if it says compare and contrast X and Y and its 4 marks I tend to assume I get a mark for 2 simularities and 2 differences. I havnt quite worked out the trick to the longer ones though. When I have the marking guidelines it all makes sense but in the exam I have no idea what they want. As for the competition for recourse section, it made sense to me that without competition from mammals birds are able to occupy environmental niches, but I think it could be explained a tad more clearly and concisely.
Bio seriously stress me out because I feel like I never know if what I'm writing is going to match the marking criteria. Some questions in bio are open to many different interpretations and that makes it so stressful:( Any tips?
Post by: Ciararonq on October 09, 2017, 10:30:10 am
Post by: Potatohater on October 09, 2017, 12:47:44 pm
Hi there! This might be a silly question but I was wondering if there are any strategies or tips in answering questions along the lines of "Evaluate the reliability/validity of this experiment? How would you go about answering these questions (eg. Q 28a 2016 paper) Thank you ! :)Ok so, evaluate according to BOSTES/NESA = make a judgment based on criteria; determine the value of
Reliability is "is the experiment consistent and trustworthy?"
Validity is "is the experiment testing what I want to test?"
So in these sorts of questions I would go about it by explaining the criteria against which you are evaluating the experiment (validity/reliability) then show what makes the experiment valid/ reliable, what makes the experiment invalid/ unreliable and then give a final judgment as to the degree of validity/reliability.
For this evaluation it's good to use words such as: nearly, slightly, moderately, relitivley, somewhat, very, greatly, extremley, substantially, little, average, huge etc. there are lots of words you can use but basically they all give an extent to which the experiment is valid/ reliable
Eg. Due to XYZ, this experiment is of substantial reliability/validity
Hope this helps :)
Post by: av-angie-er on October 09, 2017, 09:21:09 pm
Post by: taylorlucy on October 09, 2017, 10:13:35 pm
Hi! When a question refers to the 'management' of a disease, would this include both the prevention and treatment of it? For example, would vaccination be appropriate as a method of managing a disease even though it's administered as a measure of prevention before the disease is contracted and needs to be 'managed'? Probably a silly question, but thanks in advance! :)
Hi! I'm no expert so my answer may not be totally correct, but I'll help how I can. First of all, are you referring to a particular question? If so, is it specifically about non-infectious disease? I have found that 'management' itself has to do with how one copes with/responds to a non-infectious disease once they have it; similarly to 'treatment', as infectious diseases aren't really 'managed' - but rather controlled and eventually (hopefully) defeated by the immune system. To talk about this further we'll want to refer to two particular parts of the syllabus:
Identify data sources, gather, process and analyse information from secondary sources to describe one named infectious disease in terms of its: cause, transmission, host response, major symptoms, treatment, prevention and control.
Identify data sources, gather information from secondary sources to analyse and present information about the occurrence, symptoms, cause and treatment/management of a named non-infectious disease
So basically one of these requires an in depth study of an infectious disease and the other requires an in depth study of a non-infectious disease. The specifics that each dot point asks for, however, are slightly different. For infectious disease you do not need to know about 'management', which to me implies that one only 'manages' a non-infectious disease. I believe this would be the case especially in terms of incurable disorders, where the focus is on alleviating the symptoms and improving a person's quality of life, rather than preventing or controlling it as you would an infectious diseases.
The infectious disease I focused on was Cystic Fibrosis: an incurable genetic disorder. Some of the examples I have under 'treatment/management' are 'antibiotics to treat lung infections', 'enzyme replacement tablets to aid food digestion' and 'salt and vitamin supplements'.
Hope this helps!
Post by: arunasva on October 10, 2017, 05:08:29 am
Not all stimuli generate a response, if they did we'd probably go crazy! Therefore the membrane potential must reach the -55 threshold (from a resting potential of -70) to stimulate an electrochemical signal, and thus response. It's like a gun, all or nothing, either the trigger is pulled or it doesn't.THat's pretty dope, you're amazing, ty fam
When the response is triggered the electrochemical signal is generated by making the normally negative inside, positive. This is done by opening sodium channels. The more sodium that's let in, the easier it is for more sodium to come in, and so the inside becomes positive and the out side negative. (Depolarisation)
Once the signal has been generated and sent along the neurone the negatively charged inside is restored by removing potassium ions. This causes the downward turn of the graph (repolarisation)
When graphing action potential there's also a little dip below the resting membrane potential (hyperpolerisation) which is just to create a break between signals so we aren't constantly buzzing with constant streams of infomation.
I'm hoping that cleared things up
Post by: gillv2017 on October 10, 2017, 12:20:18 pm
Post by: angelahchan on October 10, 2017, 12:22:06 pm
(https://i.imgur.com/vL7OZle.png)
Post by: Sine on October 10, 2017, 12:27:57 pm
Hi, can someone please help explain why the answer for this question is C? thank youY chromosome is not in a pair of homologous chromosomes.
(https://i.imgur.com/vL7OZle.png)
Recombination occurs between homologous chromosomes.
Your Puzzle journey is almost complete. You're almost done!
193455 +1185874 = Your next destination
After all your thinking, sometimes overthinking may be your hindrance
Post by: Potatohater on October 10, 2017, 12:40:39 pm
Hi, can someone please help explain why the answer for this question is C? thank youNo crossing over occurs since a pair of homologous chromosomes entail one paternal and one maternal chromosome for each pair. Since females do not have a Y chromosome, there is no partner for the Y chromosome supplied by the male, and hence, crossing over cannot occur as this only happens with identical chromosomes (homologous pairs)
(https://i.imgur.com/vL7OZle.png)
Post by: av-angie-er on October 10, 2017, 01:44:58 pm
Hi! I'm no expert so my answer may not be totally correct, but I'll help how I can. First of all, are you referring to a particular question? If so, is it specifically about non-infectious disease? I have found that 'management' itself has to do with how one copes with/responds to a non-infectious disease once they have it; similarly to 'treatment', as infectious diseases aren't really 'managed' - but rather controlled and eventually (hopefully) defeated by the immune system. To talk about this further we'll want to refer to two particular parts of the syllabus:Hey! Thanks so much for your answer, it was really excellent and beyond helpful :) As for whether or not I was addressing a question that specifically asked for an answer about non-infectious disease, the question that caught my attention was:
Identify data sources, gather, process and analyse information from secondary sources to describe one named infectious disease in terms of its: cause, transmission, host response, major symptoms, treatment, prevention and control.
Identify data sources, gather information from secondary sources to analyse and present information about the occurrence, symptoms, cause and treatment/management of a named non-infectious disease
So basically one of these requires an in depth study of an infectious disease and the other requires an in depth study of a non-infectious disease. The specifics that each dot point asks for, however, are slightly different. For infectious disease you do not need to know about 'management', which to me implies that one only 'manages' a non-infectious disease. I believe this would be the case especially in terms of incurable disorders, where the focus is on alleviating the symptoms and improving a person's quality of life, rather than preventing or controlling it as you would an infectious diseases.
The infectious disease I focused on was Cystic Fibrosis: an incurable genetic disorder. Some of the examples I have under 'treatment/management' are 'antibiotics to treat lung infections', 'enzyme replacement tablets to aid food digestion' and 'salt and vitamin supplements'.
Hope this helps!
"Describe how TWO named methods have changed the way we manage disease and/or insect pests" (5 marks)
It doesn't specifically ask about the management of non-infectious disease, and its reference to insect pests kind of suggests that we can address infectious diseases caused by vectors. But I still totally see where you're coming from, so maybe I could address the management of non-infectious disease as one method (like the use of antibiotics for Cystic Fibrosis), and describe a method used to manage infectious disease like quarantine or immunisation programs as the other. I managed to find an exemplar answer for this question that focused on transgenic species and quarantine as methods of 'management', so I assume that these preventative measures are also considered to be valid ways of managing disease. But again, thank you so much for your help :D
Post by: av-angie-er on October 10, 2017, 08:53:58 pm
Post by: pikachu975 on October 11, 2017, 02:24:23 am
Post by: av-angie-er on October 11, 2017, 03:41:53 pm
Do antibodies work on intracellular pathogens and do cytotoxic t cells work on extracellular pathogens? ThanksIt's the other way around :) Plasma B cells secrete antibodies which mediate the humoral immune response, whereby the antibodies move through the blood and lymph fluid to attack extracellular microorganisms. Conversely, T cells control the cell-mediated response, which involves the activation of cytotoxic T cells, phagocytes and various cytosines that destroy intracellular pathogens. Hope this makes senses :D
Post by: pikachu975 on October 13, 2017, 08:34:48 pm
It's the other way around :) Plasma B cells secrete antibodies which mediate the humoral immune response, whereby the antibodies move through the blood and lymph fluid to attack extracellular microorganisms. Conversely, T cells control the cell-mediated response, which involves the activation of cytotoxic T cells, phagocytes and various cytosines that destroy intracellular pathogens. Hope this makes senses :D
Oh yeah I meant like can they work on the opposite type too e.g. can cytotoxic also kill extracellular and can antibodies help with intracellular?
Post by: arunasva on October 17, 2017, 01:43:36 am
Oh yeah I meant like can they work on the opposite type too e.g. can cytotoxic also kill extracellular and can antibodies help with intracellular?
While I do not precisely know the answer. But if Maurice Wilkins can get a Nobel Prize. Anything can happen. EVERYTHING IS POSSIBLE !
Post by: martinarena_ on October 17, 2017, 05:41:19 pm
I was just wondering, as someone just starting their HSC course, what books/textbooks would you recommend using as notes and studying for Biology?
Thank you :))
Post by: pikachu975 on October 17, 2017, 10:04:38 pm
Hi!
I was just wondering, as someone just starting their HSC course, what books/textbooks would you recommend using as notes and studying for Biology?
Thank you :))
Biology in Focus is good and I even know a few guys who solely study from that and it works. 20th in the state last year used bio in focus solely I think
Post by: sophiegmaher on October 18, 2017, 10:05:03 am
Post by: Potatohater on October 18, 2017, 04:43:32 pm
Does anyone know the difference between random segregation and independent assortment, and what phase of meiosis they each occur in? I've looked at heaps of definitions, videos and explanations and I still feel like they are just different explanations of the same process?I could he wrong bit pretty sure independent assortment is when they all line up along the middle in their pairs before the first split and random segregation is where the two copies of the chromosome split in the 2 split. I don't know what phases they are cause we were told we wouldnt need to know the phase names so i never tried leaning them
Post by: Tempestuous on October 18, 2017, 05:17:31 pm
Does anyone who is doing the option Genetics: The Code Broken? know how in depth our knowledge of "the way in which transposable genetic elements operate" needs to be? (This is for the dotpoint "Describe the way in which transposable genetic elements operate and discuss their impact on the genome") As in, do we need to know the entire processes of replicative and non-replicative transposition and reverse transcription?
Thanks, been confused on this for a while :)
Also, in regards to second-hand investigations, is bias, repute, currency of source relevant to reliability or validity?
Post by: angelahchan on October 18, 2017, 05:42:55 pm
Post by: liya1234 on October 18, 2017, 05:59:28 pm
Hi all - What are the top 10 diagrams we should know how to draw for the cores heading into the exam???
Personally I would say:
Maintaining a Balance:
- kidney
- transverse/longitudinal cross sections of xylem and phloem
- arteries, veins, capillaries
- blood cells prac diagrams
Blueprint of Life:
- DNA structure
- pedigree trees
- cloning methodology flowchart
plus bonus ones (ie idk if they are necessary but i find it very helpful to know them): meiosis, dna replication, polypeptide production process (transcription and translation)
The Search for Better Health
- Pasteur swan neck flask prac
- not necessarily draw but be able to identify the differences in diagrams of viruses, prions, bacteria, protozoan etc
Please feel free to add if i have missed anything!!
Post by: caitlinlddouglas on October 18, 2017, 06:51:44 pm
Thanks heaps :)
Post by: pikachu975 on October 18, 2017, 07:49:58 pm
Hey I was wondering if someone could give me a guide on how to graph? In never know whether to do column / dots with straight or curved lines/ where the dependent or independent variable goes!
Thanks heaps :)
Never do column graphs unless it asks
Always do crosses not dots to plot your points
Independent variable on the x axis
Usually you join up the dots if it looks linear but if not do freehand. Also if it says line of best fit do that.
Post by: caitlinlddouglas on October 18, 2017, 08:10:53 pm
Never do column graphs unless it asksThanks so much !
Always do crosses not dots to plot your points
Independent variable on the x axis
Usually you join up the dots if it looks linear but if not do freehand. Also if it says line of best fit do that.
Post by: taylorlucy on October 18, 2017, 10:01:17 pm
Hi!
I was just wondering, as someone just starting their HSC course, what books/textbooks would you recommend using as notes and studying for Biology?
Thank you :))
I personally haven't relied a textbook as such - I do have a copy of Heinemann Biology which I used occasionally as this is the book my school uses. It has some serious gaps in it though, as do most singular resources on their own. I've found that every resource has slightly different information, and some may be less specific in some areas that requires a higher level of content/understanding, whereas others may go overboard on a more simple section of the syllabus where you really don't need to waste your time knowing more than a sentence or two about it. There are SO many online resources for this subject, including stacks here on ATARnotes as well as a heap of others that come up with a simple google search. Aside from buying the ATARnotes biology summary book (10/10 would recommend for helping to revise content once you've learnt it) I didn't spend any money on this subject; I just compiled my notes from online resources! I would have multiple documents/tabs open at a time and go through dot point by dot point and compare each resource, and pull the better parts from each one into my own document of summaries. The content that you see is clearly in every single summary helps you understand what the really crucial parts of the syllabus are, as oppoised to the extra bits and pieces that sound good an exam but aren't actually necessary knowledge to get all the marks. Note that it's important not to assume these to be reputable sources as lots are written by students like you and I, not by paid professionals, so there's potential that whole sections might be missing or incorrect. But the bonus of student-written summaries is that they are written in a language we understand! This approach has really worked for me, I've made these summaries into a palm card for each dot point and used those to revise!
Hi, for the communication elective do we have to understand how depth perception works and how we see things three dimensionally? because I'm seeing questions on it in old papers (e.g. 2003), but I have no notes on it and idk where it corresponds to in our syllabus
Under communication syllabus statement #3: explain how the production of two different images of a view can result in depth perception
Hi all - What are the top 10 diagrams we should know how to draw for the cores heading into the exam???
Hi! to add to the other response you got (which I would say is pretty spot on for the most part) diagrams of meiosis and also polypeptide production (transcription/translation) are very important, there are specific syllabus points on being able to draw a model for both of these!
Post by: bridie_2345 on October 19, 2017, 09:32:54 am
Post by: vox nihili on October 19, 2017, 09:54:35 am
hi there what is the difference between random segregation and independent assortment during meiosis? thanks heaps!
There isn’t really a difference.
Random segregation basically just means that in each pair of chromosomes, which way they go is random.
Independent assortment is fairly similar. It basically means that wherever one chromosome goes doesn’t influence where any other chromosome goes. So if the paternal chromosome one ends up in one cell, that has no influence over where paternal chromosome two goes, for example.
Post by: Potatohater on October 19, 2017, 10:18:46 am
I just practiced a 5 marker for blueprint of life and spent almost a page answering it, we wont get that much space in the exam though so how do I make it more concise?
Post by: kdurante on October 19, 2017, 11:00:51 am
Post by: kdurante on October 19, 2017, 11:15:39 am
hi there what is the difference between random segregation and independent assortment during meiosis? thanks heaps!
Hey! To my understanding, Independent assortment occurs when homologous chromosomes align for the first division during metaphase, as homologous chromosomes will assort and split in a way that is independent of any others i.e all the mothers chromosomes aren't all on one side. Conversely, random segregation refers to the manner in which chromatids randomly 'segregate' into the newly formed gametes during the second division.
Post by: liya1234 on October 19, 2017, 12:26:07 pm
Can someone please help me with this question and also explain it... there are no marking guidelines for 2007 hsc bio so I don't know if I'm doing it right.
So for part a) I would talk about:
- independent assortment: the chromosomes have randomly lined up in the centre with their homologous pair
- crossing over: the inner chromatids of the AB and ab chromosomes have crossed over to form new allele combinations
For part b), the allele combinations would be 1. ABDE 2.AbDE 3.aBde 4. abde
To figure this out, I just imagine the four gametes that would be produced. In this case they have shown the two sets of chromosomes moving to opposite sides of the cell to form two cells for the next phase, so we know that in prophase II one cell has the AB/Ab and DE/DE chromosomes while the other cell has the aB/ab and de/de chromosomes.
- In that first cell (AB/Ab and DE/DE) the chromosomes will again line up randomly and go through the process to produce two more cells. Each of these two cells should have one allele of each of the genes so if you just imagine them separating into the chromatids you can see one cell will have an ABDE combination and the other will have an AbDE combination of alleles.
- repeat this with the other cell with prophase II (aB/ab and de/de) and the combinations produced would be aBde and abde
Thus, the four combinations produced would be ABDE, AbDE, abde, abde
Hope that was helpful and sorry if that explanation was kinda complicated lol! Please feel free to clarify anything
Post by: angelahchan on October 19, 2017, 01:25:59 pm
So for part a) I would talk about:
- independent assortment: the chromosomes have randomly lined up in the centre with their homologous pair
- crossing over: the inner chromatids of the AB and ab chromosomes have crossed over to form new allele combinations
For part b), the allele combinations would be 1. ABDE 2.AbDE 3.aBde 4. abde
To figure this out, I just imagine the four gametes that would be produced. In this case they have shown the two sets of chromosomes moving to opposite sides of the cell to form two cells for the next phase, so we know that in prophase II one cell has the AB/Ab and DE/DE chromosomes while the other cell has the aB/ab and de/de chromosomes.
- In that first cell (AB/Ab and DE/DE) the chromosomes will again line up randomly and go through the process to produce two more cells. Each of these two cells should have one allele of each of the genes so if you just imagine them separating into the chromatids you can see one cell will have an ABDE combination and the other will have an AbDE combination of alleles.
- repeat this with the other cell with prophase II (aB/ab and de/de) and the combinations produced would be aBde and abde
Thus, the four combinations produced would be ABDE, AbDE, abde, abde
Hope that was helpful and sorry if that explanation was kinda complicated lol! Please feel free to clarify anything
So for part a) I would talk about:Your method of doing part b makes heaps of sense, but I'm confused about the answers on the success one HSC Bio book
- independent assortment: the chromosomes have randomly lined up in the centre with their homologous pair
- crossing over: the inner chromatids of the AB and ab chromosomes have crossed over to form new allele combinations
For part b), the allele combinations would be 1. ABDE 2.AbDE 3.aBde 4. abde
To figure this out, I just imagine the four gametes that would be produced. In this case they have shown the two sets of chromosomes moving to opposite sides of the cell to form two cells for the next phase, so we know that in prophase II one cell has the AB/Ab and DE/DE chromosomes while the other cell has the aB/ab and de/de chromosomes.
- In that first cell (AB/Ab and DE/DE) the chromosomes will again line up randomly and go through the process to produce two more cells. Each of these two cells should have one allele of each of the genes so if you just imagine them separating into the chromatids you can see one cell will have an ABDE combination and the other will have an AbDE combination of alleles.
- repeat this with the other cell with prophase II (aB/ab and de/de) and the combinations produced would be aBde and abde
Thus, the four combinations produced would be ABDE, AbDE, abde, abde
Hope that was helpful and sorry if that explanation was kinda complicated lol! Please feel free to clarify anything
it says that for part b) answers are AE, BD, bD, ae, Bd, bd
I'm confused because why would alleles for non homologous chromosomes (idk what you call them) mix together?
Post by: kdurante on October 19, 2017, 01:51:37 pm
So for part a) I would talk about:
- independent assortment: the chromosomes have randomly lined up in the centre with their homologous pair
- crossing over: the inner chromatids of the AB and ab chromosomes have crossed over to form new allele combinations
For part b), the allele combinations would be 1. ABDE 2.AbDE 3.aBde 4. abde
To figure this out, I just imagine the four gametes that would be produced. In this case they have shown the two sets of chromosomes moving to opposite sides of the cell to form two cells for the next phase, so we know that in prophase II one cell has the AB/Ab and DE/DE chromosomes while the other cell has the aB/ab and de/de chromosomes.
- In that first cell (AB/Ab and DE/DE) the chromosomes will again line up randomly and go through the process to produce two more cells. Each of these two cells should have one allele of each of the genes so if you just imagine them separating into the chromatids you can see one cell will have an ABDE combination and the other will have an AbDE combination of alleles.
- repeat this with the other cell with prophase II (aB/ab and de/de) and the combinations produced would be aBde and abde
Thus, the four combinations produced would be ABDE, AbDE, abde, abde
Hope that was helpful and sorry if that explanation was kinda complicated lol! Please feel free to clarify anything
Thankyou so much for the help !!
Post by: liya1234 on October 19, 2017, 01:53:29 pm
Your method of doing part b makes heaps of sense, but I'm confused about the answers on the success one HSC Bio book
it says that for part b) answers are AE, BD, bD, ae, Bd, bd
I'm confused because why would alleles for non homologous chromosomes (idk what you call them) mix together?
Oh that's so weird I can't see how that would be the answer either?? Maybe I'm missing something but I think it may just be that the answer in the book is wrong bc my chem tutor has told me that the success one book for chemistry, though very helpful, is not always entirely accurate as it is written independently by teachers not nesa so i'm guessing it's the same with the bio one? I'm not sure, sorry - maybe someone else can shed some light onto this?
Post by: pikachu975 on October 19, 2017, 01:57:58 pm
Hey, how do I stop writing excessivley long answers for the core component of the exam?
I just practiced a 5 marker for blueprint of life and spent almost a page answering it, we wont get that much space in the exam though so how do I make it more concise?
Ask for an extra writing booklet
Post by: adelaidecruz on October 19, 2017, 08:04:08 pm
Post by: sidzeman on October 19, 2017, 09:07:20 pm
Membrane bound organelles means it cannot be a virus or prion, but I''m not sure where to go from there.
For q19, I thought opening stomota's would result in the plant become less cool, as its the site of water loss. Is it meant to be because it inititates the transpiration pull of water up the plant, thus cooling it maybe?
Post by: adelaidecruz on October 19, 2017, 09:30:22 pm
For q19, I thought opening stomota's would result in the plant become less cool, as its the site of water loss. Is it meant to be because it inititates the transpiration pull of water up the plant, thus cooling it maybe?
Opening of the plant's stomata would allow water inside of the plant to evaporate (evaporative cooling), reducing the internal temperature of the plant. And yes you're right, it also initiates transpiration pull as it creates tension at the top of the water column in the xylem. :) It's also worth it to note that the plant runs the risk of dehydration during this process.
Post by: caitlinlddouglas on October 19, 2017, 09:32:08 pm
Hey could someone help me out with these 2 questions from the 2012 HSCHey! For the first question bacteria are procariotic cells so by elimination it's a protozoan.
Membrane bound organelles means it cannot be a virus or prion, but I''m not sure where to go from there.
For q19, I thought opening stomota's would result in the plant become less cool, as its the site of water loss. Is it meant to be because it inititates the transpiration pull of water up the plant, thus cooling it maybe?
For the second one I think the plant opens its stomata to lose some water through transpiration as this process helps to remove heat energy, thus cooling the plant. When the temperature gets really hot I'm pretty sure some plants close their stomata so they don't lose too much water .
Post by: caitlinlddouglas on October 19, 2017, 09:33:49 pm
Hi everyone -- not sure if this has been asked before but does anyone know of a good example for a transgenic animal? Info on oncomouse seems a bit limited..I think there are a type of salmon by I can't remember the name! Do we need to know an animal?
Post by: Natasha.97 on October 19, 2017, 09:34:21 pm
Hi everyone -- not sure if this has been asked before but does anyone know of a good example for a transgenic animal? Info on oncomouse seems a bit limited..
Hi!
bGH (Bovine Growth Hormone) is inserted into salmon, which results in larger + faster growing fish :)
Post by: adelaidecruz on October 19, 2017, 09:35:12 pm
Hi!
bGH (Bovine Growth Hormone) is inserted into salmon, which results in larger + faster growing fish :)
Awesome, thanks! :D
Post by: sidzeman on October 19, 2017, 10:07:52 pm
Also, could someone help me with what I would discuss for this 8 marker (Genetics elective)
(d) Compare and contrast the effects of germ line mutation and transposable genetic 8 elements on whole organisms.
Post by: bridie_2345 on October 20, 2017, 09:29:11 am
1. Identify desired gene
2.Isolate genes using restriction enzymes that cuts out sections of DNA from both organisms (often bacteria) so sticky ends of DNA match, creating recombinant DNA when inserted into the genome of the second organism (the plasmid of the bacteria)
3. Make multiple copies of the gene
4. Insert gene into the organism/culture and infect a tissue with it.
Post by: ca052267 on October 20, 2017, 10:26:40 am
It's from 2015 HSC paper - q15
I thought the answer was A, but apparently it's C.
Someone please explain...
Post by: angelahchan on October 20, 2017, 10:41:10 am
Hey this is the method i have for how to produce a transgenic species and i just wanted to make sure it was correct or if it had too much/too little detail? Thanks!Yeah that's pretty much it in terms of detail. Just remember it's the enzyme ligase which helps the gene stick to the bacteria plasmid. Also make sure you know a few ways the gene is inserted into the genome (i.e. micro-injection of DNA, gene gun, and using a virus) but I see you have briefly mentioned it
1. Identify desired gene
2.Isolate genes using restriction enzymes that cuts out sections of DNA from both organisms (often bacteria) so sticky ends of DNA match, creating recombinant DNA when inserted into the genome of the second organism (the plasmid of the bacteria)
3. Make multiple copies of the gene
4. Insert gene into the organism/culture and infect a tissue with it.
can someone help me with this question?
It's from 2015 HSC paper - q15
I thought the answer was A, but apparently it's C.
Someone please explain...
The trick is the question writing "F2 generation" (idk how to put this in bold), meaning the flowers have been crossed twice. So RR x YY = RY, RY, RY, RY
And then the next cross is RY * RY = RR, RY, RY, YY which satisfies the ration of approx. 1:2:1 red:orange:yellow
Thus the answer is C (RR x YY)
Post by: ca052267 on October 20, 2017, 10:44:29 am
I was really confused, but it makes so much sense now...
Post by: bridie_2345 on October 20, 2017, 11:17:59 am
Post by: kemi on October 20, 2017, 11:42:46 am
hi there was just wondering what the difference was between cell differentiation and cell specialisation?
Hello :)
From what I understand, cell differentiation is the process by which cells become specialised. That is, stem cells differentiate to become muscle cells, skin cells, blood cells, etc and their specialisation is the function they carry out i.e. red blood cells carry oxygen. Though it is more complex, differentiation is like the 'structural' differences and 'specialisation' refers to the switching on of specific genes, so that the cell carries out specific functions. That's all I'd suggest you know for HSC :)
Post by: adelaidecruz on October 20, 2017, 12:23:44 pm
Post by: bridie_2345 on October 20, 2017, 01:55:46 pm
Hi! Does anyone know if we need to know anything about complement proteins and neutrophils in the 2nd line of defence (or just macrophages)? Thanks!Hey there as its so complex i think we just need to know about macrophages
Post by: Daniyahasan on October 20, 2017, 05:30:52 pm
Hey there as its so complex i think we just need to know about macrophages
It's just neutrophils basophils that kinda stuff not too much in detail
Post by: Daniyahasan on October 20, 2017, 05:33:04 pm
Hi everyone -- not sure if this has been asked before but does anyone know of a good example for a transgenic animal? Info on oncomouse seems a bit limited..Idk many animals but you could do strawberries with the antifreeze salmon gene or by cotton...
Post by: bridie_2345 on October 20, 2017, 06:40:15 pm
Hello :)
From what I understand, cell differentiation is the process by which cells become specialised. That is, stem cells differentiate to become muscle cells, skin cells, blood cells, etc and their specialisation is the function they carry out i.e. red blood cells carry oxygen. Though it is more complex, differentiation is like the 'structural' differences and 'specialisation' refers to the switching on of specific genes, so that the cell carries out specific functions. That's all I'd suggest you know for HSC :)
Ahh my god that's so much clearer, thanks so much! X
Post by: farheen_hameed1 on October 20, 2017, 08:08:19 pm
Post by: farheen_hameed1 on October 20, 2017, 08:10:52 pm
Post by: kemi on October 20, 2017, 08:29:19 pm
Hey guys, just wanted to ask if a flowchart counts as a diagram? Say the question was "Draw a diagram showing the path of soundwaves", could I just show it in a flowchart or would I have to draw a diagram of the ear?
Yes, a flowchart would be fine. But ensure you include enough detail, mentioning the specific part of the ear, indicating the beginning of the outer, middle and inner ear. Depending on the amount of marks you may have to mention energy transformations, but "path of sound" sounds like it requires a brief outline.
Post by: kemi on October 20, 2017, 08:36:09 pm
Hi! Does anyone know if we need to know anything about complement proteins and neutrophils in the 2nd line of defence (or just macrophages)? Thanks!
Complement sounds like s stretch and is more relevant in the 3rd line of defence, with the action of antibodies. Neutrophils are a type of phagocyte, like macrophages, except macrophages act for a longer period. Macrophages are also antigen presenting cells, whereas neutrophils are not. Neutrophils are the first cells that act in the inflammatory response, ingesting bacteria or fungi and breaking them down with enzymes, but in the later stages of infection, macrophages become dominant. Just know that neutrophils are first on site and act in the short-term to eliminate pathogens.
Post by: angelahchan on October 20, 2017, 09:17:03 pm
(https://i.imgur.com/oUNnxiD.png)
Post by: kemi on October 20, 2017, 09:24:52 pm
Hi, could someone please help explain why the answer is D? I just don't know how we're meant to use our prior knowledge to work it out - because aren't dissolved nutrients carried in the phloem? (I don't think the phloem would be on the outer layer of the bark, idk tho)
(https://i.imgur.com/oUNnxiD.png)
Remember the phloem is usually located on the outermost part of the vascular bundle, so I'm assuming as ringbarking continues it will eventually disrupt the flow of nutrients through the phloem. We know it must be the phloem because the roots have died, and nutrient sap in the phloem travels all over the plant whereas water in the xylem travels from the roots to the leaves.
Post by: mjorfian on October 20, 2017, 10:47:41 pm
Post by: angelahchan on October 20, 2017, 10:56:24 pm
anyone know how to do q 18 of the 2010 paper? It's just a simple calculation but I can't seem to get it!
The section of the virus given to us is approx 50 nm and since they're all some form of "13", the whole virus is probably 130 nm.
and since 1 micrometer = 1000 nm, we have to convert the nm into micrometers by dividing by 1000. therefore 130/1000= 0.13. So the answer is D.
Post by: J.B on October 21, 2017, 10:00:08 am
I was how recombinant DNA technology is used to make a gene probe? (2016 CSSA Trial - Code Broken)
Thanks
Post by: Natasha.97 on October 21, 2017, 11:32:09 am
anyone know how to do q 18 of the 2010 paper? It's just a simple calculation but I can't seem to get it!
Hi!
Hope this helps
Post by: liya1234 on October 21, 2017, 11:43:19 am
Post by: itssona on October 21, 2017, 12:59:21 pm
so we have citrus greening which occurs due to the psyllid insect but we also have another citrus disease where citrus fruits borers tunnel into the rind of citrus fruits? and is this the same as fruit flies? which one should i use?
(this is for the quarantine dotpoint)
Post by: kemi on October 21, 2017, 01:53:42 pm
heey im really lost,
so we have citrus greening which occurs due to the psyllid insect but we also have another citrus disease where citrus fruits borers tunnel into the rind of citrus fruits? and is this the same as fruit flies? which one should i use?
(this is for the quarantine dotpoint)
Just select one. Probably citrus greening is best.
Post by: kemi on October 21, 2017, 02:02:44 pm
Hi, just wondering if we need to know about plant grafting? Also what's the difference between that and root culturing? Thanks!
They are both forms of plant reproductive technologies
Cutting and grafting involves inserting the stem of one plant into rhe stem of another such that they grow as one plant. The new plant will have characteristics of both of these plants (see attached picture)
Root culture is when a sample of the root tip of a plant is cultured in a liquid in a laboratory. It will develop into a clone of the original (I believe it can be done with carrots)
No need for excessive detail; just know the impacts on biodiversity, which is usually that it is decreased as certain genes are propagated while others are depleted or removed.
Post by: caitlinlddouglas on October 21, 2017, 03:11:54 pm
1. An extremely high concentration of carbon dioxide is undesirable in active muscle tissue because it will:
Answer is: A) increase the pH.
----> wouldn't this cause the blood to be more alkaline, not acidic?
Also are we supposed to know the size of pathogens in relation to different cells as there was question 9 from the same paper that showed a redblood cell and a a larger cell with cell wall and membrane next to it and we were supposed to the know that the cell was a fungi?
Thanks heaps!
Post by: blasonduo on October 21, 2017, 03:28:56 pm
hey could someone please explain this answer for a multiple choice from 2015 hsc paper?
1. An extremely high concentration of carbon dioxide is undesirable in active muscle tissue because it will:
Answer is: A) increase the pH.
----> wouldn't this cause the blood to be more alkaline, not acidic?
Also are we supposed to know the size of pathogens in relation to different cells as there was question 9 from the same paper that showed a redblood cell and a a larger cell with cell wall and membrane next to it and we were supposed to the know that the cell was a fungi?
Thanks heaps!
Yes, this is true! I believe you just looked at a different answer because 6 is B! (cause enzymes to denature) :P
For the other one, I believe the size of the size of the pathogen was to throw people off because the dead giveaway is the cell wall, so relative size was not needed in this question, will they do something similar but with another pathogen? Who knows!
I'd say, just know the size's of the pathogens in ascending order (which is easy because the syllabus gives them in ascending order!) But it wouldn't hurt to know all their sizes!
Post by: angelahchan on October 21, 2017, 04:19:19 pm
https://www.boardofstudies.nsw.edu.au/hsc_exams/2015/exams/2015-hsc-biology.pdf
I don't really understand the diagram for Q7. And for Q18 I don't get why there's 2 independent variables - because if they're determining the optimum pH isn't the pH the only thing they're changing?
Post by: caitlinlddouglas on October 21, 2017, 04:28:08 pm
Hi, could someone please help me with Q7 and Q18 from the 2015 paper?Hey haha I just did that paper too. For question 7 it's just skipped a few steps and jumped straight to where the message would have been processed by the brain and a corrective response sent for.
https://www.boardofstudies.nsw.edu.au/hsc_exams/2015/exams/2015-hsc-biology.pdf
I don't really understand the diagram for Q7. And for Q18 I don't get why there's 2 independent variables - because if they're determining the optimum pH isn't the pH the only thing they're changing?
For the next one I just went off the face that an independent variable is something you change so you changes he ph for four different types of enzymes ( imagine maybe that you were doing four separate experiments ) meaning there were 4 IV
Post by: angelahchan on October 21, 2017, 04:35:40 pm
Hey haha I just did that paper too. For question 7 it's just skipped a few steps and jumped straight to where the message would have been processed by the brain and a corrective response sent for.for 18 the correct answer is B tho - 2 IV rather than 4
For the next one I just went off the face that an independent variable is something you change so you changes he ph for four different types of enzymes ( imagine maybe that you were doing four separate experiments ) meaning there were 4 IV
Post by: J.B on October 21, 2017, 05:03:12 pm
I was wondering how you would answer this question:
how is recombinant DNA technology used to make a gene probe? (2016 CSSA Trial - Code Broken)
Thanks
Post by: kemi on October 21, 2017, 05:07:16 pm
for 18 the correct answer is B tho - 2 IV rather than 4
So the aim was to find the optimum pH for four different enzymes.
An IV is something you can change, so in this case it is the pH and the type of enzyme = 2 IV
Post by: Potatohater on October 21, 2017, 07:48:05 pm
Relate specialised features of the eyes of TWO named animals to their environment (2 marks)
Post by: pikachu975 on October 21, 2017, 08:16:17 pm
Hey, I'm not sure how to answer this question as I'm a bit confused as to which dot point it refers to and which examples to use:
Relate specialised features of the eyes of TWO named animals to their environment (2 marks)
Humans have rods and cones in the retina which allow for colour perception and sight in general to navigate around, communicate, and for depth perception.
Flies have a compound eye with thousands of ommatidia which provide dots of shade and colour to indicate predators or prey with a change in colour/shade.
Post by: angelahchan on October 21, 2017, 08:34:42 pm
Post by: Potatohater on October 21, 2017, 09:57:14 pm
Humans have rods and cones in the retina which allow for colour perception and sight in general to navigate around, communicate, and for depth perception.
Flies have a compound eye with thousands of ommatidia which provide dots of shade and colour to indicate predators or prey with a change in colour/shade.
Ahh ok, I got it mixed up with a different dot point and wrote about honey bees and ratlle snakes but I see now
Post by: Potatohater on October 21, 2017, 09:58:45 pm
Hi, does anyone know how much info we have to know about Macfarlane Burnet? I've honestly learnt nothing about him in bio class, but I've come across the occasional question about him...I dont think we need to know much, just who he is and what scientiffic knowledge he contributed to. It rarely comes up though.
Post by: stephjones on October 21, 2017, 10:29:49 pm
Hi, does anyone know how much info we have to know about Macfarlane Burnet? I've honestly learnt nothing about him in bio class, but I've come across the occasional question about him...
So the fact that we have to know about him (but don't really cover him that much) is because he's mentioned in the overarching DP 5 in Search for Better Health:
MacFarlane Burnet’s work in the middle of the twentieth century contributed to a better understanding of the immune response and the effectiveness of immunisation programs
So he came up with this theory that an organism's immune system can distinguish between its own cells and foreign cells (which triggers the immune response) which basically allowed for the the development of more effective immunisation programs.
In 2012 for an 8 marker the HSC asked for his contribution into the understanding of the nature of the prevention of infectious diseases, and the sample answers BOSTES released just included this:
Specific studies and development of techniques to understand viruses also led MacFarlane Burnet to begin our understanding of the immune system. Burnet concluded that a human immune system contained unactivated B cells that could be activated and produce an immune response following their exposure to a microbe. This led to the development of the understanding of mechanisms underlying previous vaccination technologies and led to the exploration of further vaccination technologies such as sub unit vaccines.
which tbh is all I'm going to remember
Post by: itssona on October 22, 2017, 01:26:46 pm
Post by: pikachu975 on October 22, 2017, 03:36:15 pm
heey guys, in the dotpoint for analysing methods for purifying drinking water, do we need to give the disadvantages of methods of water purification??
Nah I don't think so, the questions always relate to "Describe two methods of cleaning water..."
Post by: DalvinT on October 22, 2017, 07:43:10 pm
How does Aldosterone help with water retention?
Wouldn't an increase in solvent concentration make it worse, especially when dehydrated?
Yet, when we are dehydrated, Aldosterone is still secreted...
Post by: angelahchan on October 22, 2017, 10:14:35 pm
Hey!
How does Aldosterone help with water retention?
Wouldn't an increase in solvent concentration make it worse, especially when dehydrated?
Yet, when we are dehydrated, Aldosterone is still secreted...
Aldosterone increases sodium reabsorption but decreases potassium reabsorption. Increased sodium (main solute of blood) = higher concentration of sodium in blood compared to water, meaning the concentration of water in blood decreases (relative to sodium, so this decrease in water conc. doesn't meant the actual water levels have decreased). So, more water from distal tubule and collecting duct is reabsorbed via osmosis as water moves from high concentration to low, compensating for the decrease in water concentration (thus increased water retention).
Post by: liya1234 on October 22, 2017, 10:29:09 pm
Aldosterone increases sodium reabsorption but decreases potassium reabsorption. Increased sodium (main solute of blood) = higher concentration of sodium in blood compared to water, meaning the concentration of water in blood decreases (relative to sodium, so this decrease in water conc. doesn't meant the actual water levels have decreased). So, more water from distal tubule and collecting duct is reabsorbed via osmosis as water moves from high concentration to low, compensating for the decrease in water concentration (thus increased water retention).
This makes a lot of sense but why isn't ADH just released instead because doesn't it increase reabsorption of water? These two always confuse me a lot idk
Post by: angelahchan on October 22, 2017, 11:04:56 pm
This makes a lot of sense but why isn't ADH just released instead because doesn't it increase reabsorption of water? These two always confuse me a lot idkYeah, ADH also increases reabsorption of water- but directly by making the distal and collecting tubule more permeable to water. I think ADH is used when there's already high sodium levels in blood but also low water levels, so use of aldosterone would make sodium levels too high. (I'm not entirely sure though, just my guess as to a reason why)
Post by: GabbyJesus on October 22, 2017, 11:09:07 pm
This makes a lot of sense but why isn't ADH just released instead because doesn't it increase reabsorption of water? These two always confuse me a lot idkI learnt it a different way, when sodium ions are reabsrobed as a result of aldosterone, water follows via omosis and therefore is also reabsorbed. This leads to increase in blood volume and blood pressure.
Post by: DalvinT on October 23, 2017, 02:44:27 pm
Aldosterone increases sodium reabsorption but decreases potassium reabsorption. Increased sodium (main solute of blood) = higher concentration of sodium in blood compared to water, meaning the concentration of water in blood decreases (relative to sodium, so this decrease in water conc. doesn't meant the actual water levels have decreased). So, more water from distal tubule and collecting duct is reabsorbed via osmosis as water moves from high concentration to low, compensating for the decrease in water concentration (thus increased water retention).
Ahhh! I see :) Thank you so muchhhh
Post by: sidzeman on October 23, 2017, 09:04:34 pm
Also, what are bigger fungi or macroparasites?
Post by: Mathew587 on October 23, 2017, 09:24:35 pm
Hey guys dotpoint from SFBH what are the distinguish features of every pathogen - e.g. prion's are the only pathogen with no genetic information at all.marcoparasites man...
Also, what are bigger fungi or macroparasites?
they refer to intestinal worms etc while fungi is smthn like thrush
Post by: angelahchan on October 23, 2017, 09:27:46 pm
https://www.boardofstudies.nsw.edu.au/hsc_exams/2014/pdf_doc/2014-hsc-biology.pdf
Post by: Opengangs on October 23, 2017, 09:30:49 pm
Hey guys dotpoint from SFBH what are the distinguish features of every pathogen - e.g. prion's are the only pathogen with no genetic information at all.Prions are non-cellular and they are proteins that can fold abnormally. They lack genetic material, such as DNA or RNA.
Also, what are bigger fungi or macroparasites?
Viruses are non-cellular and they are made of the genetic material of DNA or RNA, surrounded by an enveloped by a protein coat. The complete package (virus + protein coating) is called a virion. Viruses require a host cell to survive, and reproduce by injecting itself into the host cell. The host cell contains genetic material that then is used to make new viruses, splitting the host cell and exposing the virus.
Bacteria are prokaryotic (meaning they are single celled and do not contain a membrane bound organelle), and they reproduce through a process called binary fission. The bacterial cell splits into two halves, which then produces two new cells that have the capacity to grow to the size of the parent cell. A bacterium is living.
Fungi can be uni or multicellular, and they are eukaryotic organisms. They have a cell wall, composed mainly of chitin. Fungi reproduce by budding, spores, or fragmentation. They are living and motile.
Protozoan are single celled organisms. They are motile, and usually require a vector for transmission.
Macro parasites are the largest pathogens, they can be seen by the naked eye.
Post by: sidzeman on October 23, 2017, 09:52:16 pm
Prions are non-cellular and they are proteins that can fold abnormally. They lack genetic material, such as DNA or RNA.Thank you so much! Could someone also explain the lymph system in the 2nd line of defence for me please
Viruses are non-cellular and they are made of the genetic material of DNA or RNA, surrounded by an enveloped by a protein coat. The complete package (virus + protein coating) is called a virion. Viruses require a host cell to survive, and reproduce by injecting itself into the host cell. The host cell contains genetic material that then is used to make new viruses, splitting the host cell and exposing the virus.
Bacteria are prokaryotic (meaning they are single celled and do not contain a membrane bound organelle), and they reproduce through a process called binary fission. The bacterial cell splits into two halves, which then produces two new cells that have the capacity to grow to the size of the parent cell. A bacterium is living.
Fungi can be uni or multicellular, and they are eukaryotic organisms. They have a cell wall, composed mainly of chitin. Fungi reproduce by budding, spores, or fragmentation. They are living and motile.
Protozoan are single celled organisms. They are motile, and usually require a vector for transmission.
Macro parasites are the largest pathogens, they can be seen by the naked eye.
Also, do we have to know the different types of phagocytes e.g. neutrophils, macrophages
Post by: pikachu975 on October 23, 2017, 10:54:40 pm
Thank you so much! Could someone also explain the lymph system in the 2nd line of defence for me please
Also, do we have to know the different types of phagocytes e.g. neutrophils, macrophages
Lymph system has lymph nodes which store lymphocytes.
Lipids are also carried in chylomicrons in the lymph system.
Blood can leak into the lymph system and pass by lymph nodes and if antigens are detected by the lymphocytes then an immune response is started.
I think macrophages can bring debris from consuming a pathogen to the lymph nodes to initiate an immune response.
Also they're called LYMPHocytes because they're in the LYMPH system too!
Post by: archie33 on October 23, 2017, 11:07:50 pm
Thanks!
Post by: sophiegmaher on October 24, 2017, 08:15:51 am
Post by: sophiegmaher on October 24, 2017, 09:48:51 am
Post by: zalihall on October 24, 2017, 10:08:56 am
"Plant breeders have developed a new variety of terrestrial plant which has one structure
that appears to assist in water conservation in hot, dry environments.
Design a first-hand investigation the plant breeder could use to determine of this structure
assists in water conservation." (4 Marks)
Post by: liya1234 on October 24, 2017, 10:10:24 am
Post by: liya1234 on October 24, 2017, 10:23:24 am
Hi, could someone please help explain the answers for Q19 and 20 for the 2014 paper?
https://www.boardofstudies.nsw.edu.au/hsc_exams/2014/pdf_doc/2014-hsc-biology.pdf
Q19 would be A as this fits the information given the most i.e. the fish have different enzymes that do the same thing but have optimum efficiency at different temperature. this allows to fish to continue normal metabolic processes at a larger range of temperatures (as seen in the graph). however, as this only works when there is a gradual temp change (rather than sudden), we can conclude that it takes time for a different gene producing the enzyme that works in a higher temp to be switched on. thus, if there is a gradual temp change, the fish will be able to survive as different genes can be slowly switched on, but if there is a sudden temp change, the needed genes won't switch on fast enough to produce enough enzymes, decreasing metabolic efficiency
for Q20, I would say B just based on process of elimination. It's not A because substrates are not involved in any way in this case. It's not C as, in this case, the wide range of temperature over which the fish can survive is demonstrated. It's not D as these different enzymes show that metabolic efficiency can be maintained even with changing temperature. Thus, B fits best
Post by: adelaidecruz on October 24, 2017, 10:25:52 am
Does someone have a simple definition for recombinant DNA? i'm struggling to understand what exactly it encompasses, is it just DNA which has been genetically altered in some way? Thanks!Essentially, recombinant DNA is an artificially-made DNA strand formed by the combination of two or more gene sequences. :)
Post by: adelaidecruz on October 24, 2017, 10:26:56 am
Post by: adelaidecruz on October 24, 2017, 10:39:33 am
Could someone quickly give a rundown about all the action potential stuff? (Part of Option topic: Communications)
Thanks!
Hey!
So action potential is the change in electrical potential (or, more explicitly, change in the charge of the neurone's membrane) associated with the passage of an impulse along a neurone. This charge is maintained by a pump that keeps Na+ out and K+ in.
At resting potential, the cell membranes are polarised (unequal charges on either side of the membrane) -- its inside is (-ve) and its outside is (+ve).
At depolarisation, nerve cells are stimulated due to the transient reversal in the membrane potential. Na+ ions move in making the inside (+ve). Consequently, K+ ions move out, creating a wave of (-ve) charge outside the membrane. This electrical wave travels down the axon --> axon terminal.
When an electrical impulse reaches the axon terminals, neurotransmitters (chemical substances) are released which passes across the synapse and to the dendrites of the next cell, causing a new electrical impulse to start in subsequent neurones.
Now some stimuli do not reach said action potential if the stimulus is not 'intense' enough during the refraction period to reach the minimum threshold (minimum amount of voltage needed at which depolarisation becomes "unstoppable") that is required for an impulse to be produced, hence no signal is transferred at all.
Post by: Opengangs on October 24, 2017, 10:47:57 am
Quick question: do we need to know about 2 kinds of artificial blood? Or is 1 enough?Considering the difficulties of the exams this year, I think it's better to know about both kinds: perfluorocarbons, and haemoglobin-based oxygen carriers.
I would also recommend outlining the disadvantages and advantages for each.
Post by: phebsh on October 24, 2017, 10:49:02 am
Post by: angelahchan on October 24, 2017, 10:50:56 am
Also, what's the difference between photopsin and iodopsin? The text book says one and some youtube videos say the other, but I think they're pretty much the same as they're both describing the photosensitive pigment in cone cells?
i think you can use the two terms interchangeably, since I've tried to look for differences and most sources do the same. This definition of photopsin does talk about their differences: "The protein component of the pigment iodopsin in the cones of the retina of the eye." So I'm guessing photopsin is a component of iodopsin?
Post by: adelaidecruz on October 24, 2017, 10:53:32 am
Considering the difficulties of the exams this year, I think it's better to know about both kinds: perfluorocarbons, and haemoglobin-based oxygen carriers.
I would also recommend outlining the disadvantages and advantages for each.
Awesome, thank you!
Post by: adelaidecruz on October 24, 2017, 10:56:53 am
Hi there, anything in particular we are recommended to do today being the day before the bio exam?
Maybe read over your notes and work on your weak points? I personally saved all the multiple choice from 2016-2004 for a chill study sesh today lol
Post by: phebsh on October 24, 2017, 11:00:38 am
Maybe read over your notes and work on your weak points? I personally saved all the multiple choice from 2016-2004 for a chill study sesh today lol
Great idea, thanks!!
Post by: angelahchan on October 24, 2017, 11:05:45 am
Hey, I've been going through some past papers and i'm so stuck on what is actually required for this question (method? variables? equipment?), any ideas would be greatly appreciated!
"Plant breeders have developed a new variety of terrestrial plant which has one structure
that appears to assist in water conservation in hot, dry environments.
Design a first-hand investigation the plant breeder could use to determine of this structure
assists in water conservation." (4 Marks)
So the marking guidelines for this question are really brief:
Better responses outlined the features of good experimental design, including aspects such as
control of variables, repetition and data collection.
Here's an exemplar response from the success one hsc bio
1) Take a reasonable quantity of each of the new variety possessing the special feature and a similar species that does not possess the new feature
2) Plant the individual plant specimens in identical conditions (pot type and size, soil type and quantity)
3) Place half each type of the specimens in the same hot, dry environment and the other half in the same relatively hot, moist enivronment
4) Water specimens sparingly over the period (e.g. once per 2 week cycle) with an identical measured amount of water
5) Monitor each group over a period of time, measuring growth, new leaf production/loss of leaves, and recording results in a table of chart
So I'll try to break down the marks for you
1) Clear method, easy to follow through - i.e. the steps are in order from one another- when followed your method must clearly test out the aim
2) State what variables you would control and how you'd do it, as well as which one you would change
3) State how you would repeat the experiment for reliability - e.g. in the exemplar with the "reasonable quantity of each variety" of plants - you could state how many plants as well for specificity
4) State how you would record the data and what would you be recording, as well as how long you would be recording it for- e.g. the exemplar writes about measuring growth and recording it in a chart.
Post by: adelaidecruz on October 24, 2017, 11:09:45 am
- Not fast enough to maintain required solute concentration in the cell and to remove significant buildup of nitrogenous wastes
- Slows down once the difference in concentration gradient becomes smaller and stops once concentrations have hit equilibrium
- Diffusion: toxins can only be removed if there was a high concentration of it in the blood than in the urine itself.
- Osmosis: would only remove toxins if it is dissolved in water; if there is a high concentration of urine, water will continually be drawn out from the body to even out the concentration gradient.
Post by: phebsh on October 24, 2017, 11:15:36 am
Hi can anyone please help me with this dot point in MAB "inadequacy of diffusion and osmosis in waste removal". Here's an outline of my notes on it. Just wanna know if these are enough of if there are any errors. Thanks :)
- Not fast enough to maintain required solute concentration in the cell and to remove significant buildup of nitrogenous wastes
- Slows down once the difference in concentration gradient becomes smaller and stops once concentrations have hit equilibrium
- Diffusion: toxins can only be removed if there was a high concentration of it in the blood than in the urine itself.
- Osmosis: would only remove toxins if it is dissolved in water; if there is a high concentration of urine, water will continually be drawn out from the body to even out the concentration gradient.
Yeah I think the main idea is that they are slow and passive processes and it's inadequate for larger organisms because they build up toxins quickly and therefore need more efficient processes to remove waste
Post by: liya1234 on October 24, 2017, 11:31:04 am
Post by: Opengangs on October 24, 2017, 11:52:25 am
I've got so many last minute q's sorry! Would someone be able to help me with this dot point in the genetics option: "explain how the use of recombinant DNA technology can identify the position of a gene on a chromosome" - is it okay just to talk about the FSH method here? Also what would come under "identify the role of genes in embryonic development", I'm really lost with this one and can't really find anything online. Thank you so much!Yeahh, but you need to go in great detail about the process of "Fluorescent In Situ Hybridisation".
Talk about probes as a sequence of DNA that has been prepared through the process of recombinant DNA technology.
Talk about how the probe is annealed so that the DNA denatures.
Talk about the binding of the probe to the actual gene (by complementary base pairing).
Talk about how the probes are then placed under electrophoresis gel, where the probes can then be used to identify the locus of the gene along a chromosome.
Role of genes:
We have two main genes that compose of embryonic development:
The first one is called a structural gene, and these encode for polypeptides that code for the proteins and enzymes of the embryo.
The second one is called a regulatory gene, and these control the expression of the structural genes.
We also have a third gene, a homeotic gene that encodes for the patterns of development within the early stages of embryonic development.
Post by: biancakhalil0106 on October 24, 2017, 12:08:42 pm
Post by: angelahchan on October 24, 2017, 12:18:46 pm
For HSC bio exam do we draw in pencil or pen? because it says to only use black pen.Pen. If you're unsure, do it in pencil first then trace over with pen. this is because the papers are scanned (I think markers were given physical copies in the past), and pencil wouldn't be able to show well
Post by: sidzeman on October 24, 2017, 12:28:32 pm
1) The protein that is produced by that gene is used to determine the amino acid sequence this is used to synthesise a DNA sequence (probe) that would be complementary to the gene of interest
2) Using heat DNA strands are denatured – split into single strands (similar to DNA hybridisation)
3) Fluorescent probes – synthetic strands of DNA that are complementary to the gene wishing to be located, produced in step 1
4) Probes are added to the slide of the denatured DNA strands
5) As DNA and probe are both single stranded – they will bind together where the bases are complementary
6) The area at which they are joined will glow due to the fluorescence of the probe – therefore position of gene on chromosome is determined
Would this be a sufficient amount of detail? I'm not too sure about the last step
Post by: liya1234 on October 24, 2017, 12:40:22 pm
Yeahh, but you need to go in great detail about the process of "Fluorescent In Situ Hybridisation".
Talk about probes as a sequence of DNA that has been prepared through the process of recombinant DNA technology.
Talk about how the probe is annealed so that the DNA denatures.
Talk about the binding of the probe to the actual gene (by complementary base pairing).
Talk about how the probes are then placed under electrophoresis gel, where the probes can then be used to identify the locus of the gene along a chromosome.
Role of genes:
We have two main genes that compose of embryonic development:
The first one is called a structural gene, and these encode for polypeptides that code for the proteins and enzymes of the embryo.
The second one is called a regulatory gene, and these control the expression of the structural genes.
We also have a third gene, a homeotic gene that encodes for the patterns of development within the early stages of embryonic development.
Okay thank you so much!!! Just about the electrophoresis gel - why is that used here? I thought fluorescence microscopes were used to identify the position of the probe on the chromosome?
Post by: Opengangs on October 24, 2017, 12:47:43 pm
Okay thank you so much!!! Just about the electrophoresis gel - why is that used here? I thought fluorescence microscopes were used to identify the position of the probe on the chromosome?Ahah, my mistake. Gel electrophoresis is used in DNA fingerprinting.
You use the fluorescence microscopes to identify loci.
Post by: angelahchan on October 24, 2017, 12:55:58 pm
Post by: sidzeman on October 24, 2017, 01:16:35 pm
Post by: angelahchan on October 24, 2017, 01:29:07 pm
Stupid question but, in humans the diploid number is 46 therefore every cells has 23 pairs of homologous chromosomes. However in males the X and Y chromosomes are not homologous, so do we still say that they have 23 pairs?You can still say that males have 23 pairs. Just that 22 pairs (of autosomes) are homologous and 1 pair (of sex chromosomes) isn't. In general if you say something like "humans have 23 pairs of chromosomes" it'll be fine.
Post by: juliamillburn on October 24, 2017, 01:48:49 pm
I don't know how to squeeze 4-6 marks out of ethics
Post by: sidzeman on October 24, 2017, 02:04:00 pm
You can still say that males have 23 pairs. Just that 22 pairs (of autosomes) are homologous and 1 pair (of sex chromosomes) isn't. In general if you say something like "humans have 23 pairs of chromosomes" it'll be fine.Alright thanks for clarifying haha
For gene therapy in genetics could someone also explain the difference between ex vivo and invo gene therapy. Also, for producing linkage maps, the dihybrid cross must be between 2 homozygous recessive and double heterozygous correct?
Post by: bimberfairy on October 24, 2017, 02:48:07 pm
Alright thanks for clarifying haha
For gene therapy in genetics could someone also explain the difference between ex vivo and invo gene therapy. Also, for producing linkage maps, the dihybrid cross must be between 2 homozygous recessive and double heterozygous correct?
Hi! I'm not too sure about your second question, but I can definitely answer your question on ex vivo and in vivo gene therapy.
In vivo gene therapy is the DIRECT delivery of genes into cells in the body, and are usually carried out by viral or non-viral vectors like injections, biolistic gene guns etc.
On the other hand, ex vivo gene therapy is INDIRECT. The genes you want to administer aren't directly "inserted" into the body. Instead, the defective cells of the patient are often taken out, grown in a culture, and within that culture, the genes are added. This whole "bundle" (in simpler terms) is then grown and transplanted back into the patient.
Hopefully that cleared things up!
Post by: archie33 on October 24, 2017, 03:11:46 pm
I'm just a bit confused about Sutton & Boveri's contributions, like what did they establish at the end of the day?
I can't seem to figure out what they did, and if they both found out the same thing about chromosomes.
Post by: sophiegmaher on October 24, 2017, 03:21:31 pm
Hey,
I'm just a bit confused about Sutton & Boveri's contributions, like what did they establish at the end of the day?
I can't seem to figure out what they did, and if they both found out the same thing about chromosomes.
They together determined that Chromosome Theory of Inheritance: that patterns of inheritance in mammals matched those established by Mendel and his pea plants. So, they found that the law of random segregation, the law of independent assortment, and the law of simple dominance applied in mammals by testing sea urchin eggs, in relation to Boveri, and grasshopper testes, in Sutton's case. It is important to note that each of them were observing the process of meiosis in each of these two different organisms, hence the fact that these same laws applied to them enhances the reliability of the theory. This theory also includes that chromosomes are found in the nucleus, where previously it was thought to be found in the cytoplasm AND the nucleus, and that fertilisation allows new pairs of chromosomes to form as those that randomly segregate/independently assort come together.
And to answer the latter part of your question, they found out slightly different things that all contributed to the one theory explained above!
There are heaps of youtube videos on them if you need further clarification.
Hope that makes sense :)
Post by: sophiegmaher on October 24, 2017, 03:40:49 pm
Yeah I think the main idea is that they are slow and passive processes and it's inadequate for larger organisms because they build up toxins quickly and therefore need more efficient processes to remove waste
And also diffusion and osmosis can only move along the concentration gradient, whereas some nutrients need to be moved against it: hence the need for active transport. This is seen through uric acid, where it needs to move against the concentration gradient from blood into the urine in the kidney at the proximal convoluted tubule. Also, if osmosis was only used, too much water would be lost in urine as the high concentration of wastes would create a concentration gradient that would lead to water being drawn in by osmosis, leading to an inability to conserve water in organisms that may inhabit arid areas, such as the spinifex hopping mouse.
Post by: c.conol on October 24, 2017, 03:41:17 pm
Post by: sophiegmaher on October 24, 2017, 03:48:25 pm
Hello! Would they ever ask us to design an epidemiological study?
There was an 8 marker asked in a HSC paper, I can't remember when but it was a fairly older paper I think. It gave a scenario and you had to discuss how an epidemiological study could be used to find the cause of the infections disease. So I guess the general answer to your question is: yes they can, unfortunately :/
Post by: c.conol on October 24, 2017, 03:55:53 pm
There was an 8 marker asked in a HSC paper, I can't remember when but it was a fairly older paper I think. It gave a scenario and you had to discuss how an epidemiological study could be used to find the cause of the infections disease. So I guess the general answer to your question is: yes they can, unfortunately :/
How would I go about answering this question? I'm stumped.
Post by: angelahchan on October 24, 2017, 04:09:53 pm
There was an 8 marker asked in a HSC paper, I can't remember when but it was a fairly older paper I think. It gave a scenario and you had to discuss how an epidemiological study could be used to find the cause of the infections disease. So I guess the general answer to your question is: yes they can, unfortunately :/it was in the 2004 paper
Post by: sophiegmaher on October 24, 2017, 04:10:59 pm
How would I go about answering this question? I'm stumped.
I'm no expert, but I would break the question down in correspondence to the 4 marks that are allocated to it. In general, I would focus on the main features that you know are a part of an epidemiological study and just link it to the scenario given by the question:
1. Create a large population sample of individuals with diverse backgrounds, including living in different areas, differences in age and gender, occupation, lifestyle, etc
2. Gather data on the eating habits of those affected and those not affected, paying particularly attention to if fish is the main food source or meat, due to the recent chemical factor that had started up nearby.
3. Gather data on the location the individuals affected and not affected live: i.e if they live near the far side of the bay where the chemical factory is situated
4. Compare the data gathered on the affected and control groups and interpret for trends: i.e: similarities, differences. You could also potentially make a prediction as to what the cause of the symptoms may be, which, judging from the information provided, you could hypothesise that it is the chemical run-off from the chemical factory into the water that the fish, which is the main food source for town, live. Thus, individuals who eat a diet mainly of fish have contracted the disease.
What HSC paper is it from?
Post by: c.conol on October 24, 2017, 04:21:26 pm
I'm no expert, but I would break the question down in correspondence to the 4 marks that are allocated to it. In general, I would focus on the main features that you know are a part of an epidemiological study and just link it to the scenario given by the question:
1. Create a large population sample of individuals with diverse backgrounds, including living in different areas, differences in age and gender, occupation, lifestyle, etc
2. Gather data on the eating habits of those affected and those not affected, paying particularly attention to if fish is the main food source or meat, due to the recent chemical factor that had started up nearby.
3. Gather data on the location the individuals affected and not affected live: i.e if they live near the far side of the bay where the chemical factory is situated
4. Compare the data gathered on the affected and control groups and interpret for trends: i.e: similarities, differences. You could also potentially make a prediction as to what the cause of the symptoms may be, which, judging from the information provided, you could hypothesise that it is the chemical run-off from the chemical factory into the water that the fish, which is the main food source for town, live. Thus, individuals who eat a diet mainly of fish have contracted the disease.
What HSC paper is it from?
This is from a trial paper I found online
Post by: sophiegmaher on October 24, 2017, 04:23:37 pm
This is from a trial paper I found online
Does my answer make sense, like how would you have answered it/how did the sample answers go about it?
Post by: archie33 on October 24, 2017, 04:48:18 pm
They together determined that Chromosome Theory of Inheritance: that patterns of inheritance in mammals matched those established by Mendel and his pea plants. So, they found that the law of random segregation, the law of independent assortment, and the law of simple dominance applied in mammals by testing sea urchin eggs, in relation to Boveri, and grasshopper testes, in Sutton's case. It is important to note that each of them were observing the process of meiosis in each of these two different organisms, hence the fact that these same laws applied to them enhances the reliability of the theory. This theory also includes that chromosomes are found in the nucleus, where previously it was thought to be found in the cytoplasm AND the nucleus, and that fertilisation allows new pairs of chromosomes to form as those that randomly segregate/independently assort come together.
And to answer the latter part of your question, they found out slightly different things that all contributed to the one theory explained above!
There are heaps of youtube videos on them if you need further clarification.
Hope that makes sense :)
@sophiegmaher Thank you so much! Makes sense now. :)
Post by: vanessalouiseee on October 24, 2017, 05:07:20 pm
Post by: pvee123 on October 24, 2017, 05:26:31 pm
Post by: caitlinlddouglas on October 24, 2017, 05:30:22 pm
Thanks!!
Post by: sidzeman on October 24, 2017, 05:30:57 pm
Can anyone explain the functions of DNA helicase and DNA polymerase??DNA Helicase is responsible for the "unzipping" of DNA during RNA replication - this creates the exposed strand where new, complementary nucleotide bases are then added - DNA Polymerase is what catalyses the addition of these new bases. Both are enzymes
Post by: sidzeman on October 24, 2017, 05:42:30 pm
Post by: ellybubble on October 24, 2017, 05:48:12 pm
hey guys would someone mind describing the lung cancer dot point for epidemiology? Do we have to know the names of specific studies?
Thanks!!
I think just know a brief outline of the epidemiological study by Hill and Doll from the 50's in the UK
so like the case study: by collecting data on the occurrence of the disease to identify the impacts of age, race, geographic specificity
e.g. lung cancer incidence was higher in UK than Japan and try to form a hypothesis for the etiology of the disease (E.g. could be due to increased smoking since WW2 or from increased construction of roads etc)
then they did a case control by determining the frequency of the determinant (smoking) in diseased and non diseased individuals
e.g. they asked 650 lung cancer sufferers and only 2 didn't smoke --> so there is a correlation b/w smoking and lung cancer
but this sample size was too small so they did a cohort study following 40,000 doctors for like 40 years or something where they one group is exposed to the determinant whereas the other isn't (analytical study)
and then Doll found the odds ratio b/w smoking and lung cancer to be like 9.01 and anything above 1 suggests there is a causal relationship
hope this is right lol
not sure if u needa know that much detail
Post by: left right gn on October 24, 2017, 05:49:46 pm
Post by: ellybubble on October 24, 2017, 05:51:18 pm
What exactly do we have to know about the structures of xylem and phloem?
Maybe the differences and similarities in structure and purpose and the associated theories of movement of substances?
like xylem is dead tissue and supported by lignin and passively transports water and mineral ions upwards only (unidirectionally) via the cohesion- adhesion- transpiration theory or whatever
and phloem is alive, has sieve plates and companion cells, sugars, bidirectionally, active transport... bleh
and xylem is larger than phloem i think (which is weird considering phloem transports sugar?)
Post by: ellybubble on October 24, 2017, 05:52:26 pm
Can i use down syndrome as an example of an inherited disease?
yeah i think so, since it is a genetic disease?
Post by: Mathew587 on October 24, 2017, 05:57:35 pm
Can i use down syndrome as an example of an inherited disease?No down syndrome isn't generally inherited as it's a mutation of the 21 chromosome and cos most peeps with down syndrome don't reproduce.
Post by: angelahchan on October 24, 2017, 06:03:27 pm
Can anyone explain the functions of DNA helicase and DNA polymerase??I know there's a genetics elective or something, so bear in mind this is just info from blueprint. DNA helicase is an enzyme that catalyses the unwinding of the double helix. DNA polymerase breaks the bonds between the bases of nucleotides, and it also checks to see whether the new bonds (during DNA replication) match (e.g. A with T, G with C)
Hey guys, just a quick question, does the fluid inside the cochlea pass through the Reissner and Basiler membrane into each canal, or does it just provoke other fluids located in different canals to transfer mechanical energy?The latter- the fluid (perilymph and endolymph depending on which chambers) in the different chambers don't actually mix because of the membranes separating them. instead, like you said, they push on each other from pressure from round window, transferring mechanical energy
Post by: ellybubble on October 24, 2017, 06:03:31 pm
No down syndrome isn't generally inherited as it's a mutation of the 21 chromosome and cos most peeps with down syndrome don't reproduce.
Translocation Down syndrome is sometimes hereditary apparently but i think in most cases it is not inherited (ur right). i think i would use another example like cystic fibrosis?
Post by: itssona on October 24, 2017, 06:24:11 pm
Hii wondering what type of adaptation sunbaking is? e.g. central netted dragon sunbake during the morning to absorb heat which activates their daily body functions.
also during day their skin becomes lighter? what type of adaptation is this too?
Post by: liya1234 on October 24, 2017, 06:33:04 pm
Pen. If you're unsure, do it in pencil first then trace over with pen. this is because the papers are scanned (I think markers were given physical copies in the past), and pencil wouldn't be able to show well
I thought this as well but I was just going through the 2016 paper and it says on the front page to draw diagrams in pencil so I think it should be okay to leave graphs in pencil
Post by: caitlinlddouglas on October 24, 2017, 06:42:17 pm
I think just know a brief outline of the epidemiological study by Hill and Doll from the 50's in the UKhey thanks! I've just got limited stuff on the Hammond and Horn study in the US - I think they surveyed 1 million people but did a follow up of 180 000 men for mortality to determine the link so hopefully that's enough, imight briefly mention the hill and doll study too.
so like the case study: by collecting data on the occurrence of the disease to identify the impacts of age, race, geographic specificity
e.g. lung cancer incidence was higher in UK than Japan and try to form a hypothesis for the etiology of the disease (E.g. could be due to increased smoking since WW2 or from increased construction of roads etc)
then they did a case control by determining the frequency of the determinant (smoking) in diseased and non diseased individuals
e.g. they asked 650 lung cancer sufferers and only 2 didn't smoke --> so there is a correlation b/w smoking and lung cancer
but this sample size was too small so they did a cohort study following 40,000 doctors for like 40 years or something where they one group is exposed to the determinant whereas the other isn't (analytical study)
and then Doll found the odds ratio b/w smoking and lung cancer to be like 9.01 and anything above 1 suggests there is a causal relationship
hope this is right lol
not sure if u needa know that much detail
Post by: Opengangs on October 24, 2017, 07:39:21 pm
I'll be here to answer any last minute requests for each of the three core + genetics
Post by: tsauceonchips on October 24, 2017, 07:44:14 pm
Post by: 66295 on October 24, 2017, 07:53:18 pm
Hey there, just wondering do we need to know the mechanisms that allow interaction between B and T lymphocytes?? If so, what are they? :DD
You do. There are three major Mechanisms:
1) MHC molecules: MHC molecules are the glycoprotein molecules on the surface of the cells from the body that allow them to identify them as belonging to the body. These Molecules also are able to identify the foreign cells found in the body.
2) Clonal selection: In short it pretty much talking about immunological memory (Immune system gaining a memory from previous exposures) and how the body will produce two different specific types of lymphocytes - one will remain in body to create a memory b or t cell and the other will fight off the pathogen/foreign cells.
3) Cytokines: these are a group of signalling compounds used for communication between cells.
Hope this helps it was based on my knowledge and off top of my head :)
Good luck
Post by: 66295 on October 24, 2017, 08:00:17 pm
Hii wondering what type of adaptation sunbaking is? e.g. central netted dragon sunbake during the morning to absorb heat which activates their daily body functions.
also during day their skin becomes lighter? what type of adaptation is this too?
Behavioural adaptation for the sun baking and physiological for the changing skin shade
Post by: Daniyahasan on October 24, 2017, 08:01:21 pm
a) outline the processes used to prodice a NAMED transgenic species. (3 marks)
b) Describe the environmental issues that arise from the species you describes in part a). (3 marks)
i was gonna do strawberries will the antifreeze gene from salmon but then that wouldnt make sense in part 2 cos it doesnt really arise any environmental issues
Post by: ellybubble on October 24, 2017, 08:03:53 pm
Thanks!
Post by: 66295 on October 24, 2017, 08:07:33 pm
help!!
a) outline the processes used to prodice a NAMED transgenic species. (3 marks)
b) Describe the environmental issues that arise from the species you describes in part a). (3 marks)
i was gonna do strawberries will the antifreeze gene from salmon but then that wouldnt make sense in part 2 cos it doesnt really arise any environmental issues
Im not going to address question fully but enough to get marks
BT cotton is an example of a transgenic organism.
Process used:
1.Normal cotton seedlings are cut into small pieces and placed into a solid growth medium, where they grow into calluses. The callus cells are then transferred into a liquid medium where they are given hormones so they can grow into cotton plant embryos.
2.The BT gene is extracted from a bacterium Bacillus thuringiensis, using restriction enzymes
3.The BT gene must then be transferred to the embryos using a vector bacteria. The embryos are dipped in a solution (containing the vector and the extracted BT genes, and the vector bacteria inject the BT genes into the cotton cells
4.Once the gene is inserted, the embryos are grown in tissue culture, then placed in a solid medium and germinated into small plants. These plants are now a transgenic species.
Post by: ellybubble on October 24, 2017, 08:08:29 pm
help!!
a) outline the processes used to prodice a NAMED transgenic species. (3 marks)
b) Describe the environmental issues that arise from the species you describes in part a). (3 marks)
i was gonna do strawberries will the antifreeze gene from salmon but then that wouldnt make sense in part 2 cos it doesnt really arise any environmental issues
a) maybe the production of BT cotton, using recombinant DNA technology to amplify the gene from BT bacteria, then using agrobacterium as a vector in putting it in the embryo of cotton. (then u can go through the recombinant DNA stuff like plasmid, restriction enzyme etc...)
b) one environmental impact is the creation of monocultures of BT cotton, which would become dominant as opposed to normal cotton due to natural pest resistant properties. and since they would be genetically similar, a selective pressure can easily wipe away the whole population.
hope this is right :) sorry if its not
Post by: sidzeman on October 24, 2017, 08:24:32 pm
Post by: ellybubble on October 24, 2017, 08:30:33 pm
Where in the kidney does active transport and passive transport take place? I know the obvious such as glomerulus --> bowmans capsule passive, proximal is active. However when sodium and water is reabsorbed by Aldosterone and ADH, is that also active transport or passive? Also, just to double check Aldosterone is released in the ascending loop of henle and ADH in the collecting tube correct?I think passive is like all the water reabsorption (osmosis), and filtration due to the high pressure of blood flow at the bowman's cap/glomuerulus, but when glucose and amino acids are reabsorbed at the proximal tubule, that is active transport as it moves against the concentration gradient . I think salt is also reabsorbed via active transport.
Post by: angelahchan on October 24, 2017, 08:54:59 pm
Hey guys, sorry if this is a stupid Q, but how does bio-geography support the theory of evolution? I'm a bit hazy when I explain it in an answer.Nah it isn't a stupid q.
Thanks!
According to theory of evolution, new species can arise when a group of organisms from the original population is isolated for a long time. Organisms should be more similar to species that lived close by. You can link this to all flightless birds having a common ancestor from Gondwana. And as a result of the separation of Gondwana and subsequent isolation of groups of the population, there are different species of flightless birds. For example emus in australia, ostriches in south africa, kiwis in new zealand etc.
Post by: bimberfairy on October 24, 2017, 08:55:30 pm
Where in the kidney does active transport and passive transport take place? I know the obvious such as glomerulus --> bowmans capsule passive, proximal is active. However when sodium and water is reabsorbed by Aldosterone and ADH, is that also active transport or passive? Also, just to double check Aldosterone is released in the ascending loop of henle and ADH in the collecting tube correct?
Pretty sure anywhere that salt is absorbed, that's active transport (goes against concentration gradient), while absorption of water is passive transport. Aldosterone increases the absorption of salt, which is active transport since it goes against the concentration gradient. But as a result of this, water follows due to osmosis (passive transport). As for ADH, it just increases the absorption of water, so passive transport only.
From what I have in my notes, ADH is released in the collecting duct, while aldosterone is released in the distal convoluted tubule? You should wait for someone else's reply too for a second opinion though haha
Post by: angelahchan on October 24, 2017, 08:59:06 pm
Pretty sure anywhere that salt is absorbed, that's active transport (goes against concentration gradient), while absorption of water is passive transport. Aldosterone increases the absorption of salt, which is active transport since it goes against the concentration gradient. But as a result of this, water follows due to osmosis (passive transport). As for ADH, it just increases the absorption of water, so passive transport only.
From what I have in my notes, ADH is released in the collecting duct, while aldosterone is released in the distal convoluted tubule? You should wait for someone else's reply too for a second opinion though haha
Both aldosterone and ADH act on the distal and collecting tubule. Also adding to this there's also secretion- urea diffuses in at the proximal tubule, whereas hydrogen ions moves into the distal tubule via active transport
Post by: sidzeman on October 24, 2017, 09:07:51 pm
Both aldosterone and ADH act on the distal and collecting tubule. Also adding to this there's also secretion- urea diffuses in at the proximal tubule, whereas hydrogen ions moves into the distal tubule via active transportReally i thought urea was present in blood and entered the bowmans capsule through the glomerulus? Secretion was only for drugs and poisons in my notes
Post by: angelahchan on October 24, 2017, 09:19:33 pm
Really i thought urea was present in blood and entered the bowmans capsule through the glomerulus? Secretion was only for drugs and poisons in my notes
Yeah, secretion involves drugs and poisons but there's more than that. Urea is filtered in bowman's capsule, but not 100% so some secretion is involved . Here's a brief diagram in my notes, it doesn't cover everything tho
(https://i.imgur.com/HQy0wrJ.png)
Post by: stephjones on October 24, 2017, 09:24:56 pm
Post by: angelahchan on October 24, 2017, 09:27:01 pm
hey guys, how much information to people have for the dot point on the social and political impacts/influences of developing theories of inheritance? the only thing i really have is the whole "they threatened creationist views" but ??Here are my notes, I hope you don't mind that I lazily copied and pasted them. but you definitely don't need to know that much detail, I think the dot point hasn't even been assessed before (not sure tho)
Social and political influences on the development of the theory of evolution
- Many ideas were put forward during the 1700-1800s, a time of political and social unrest, with the French revolution and industrial revolution
- People became more interested in science and explaining the structure of matter and how it behaved
- Erasmus Darwin came up with his vague idea of evolution during the late 1700s
- Lamarck was doing research at the height of the French Revolution and outlined some main components of his theory
- His ideas challenged the belief that species were created independently of each other and didn't change
- This challenged religious and social beliefs, opening the doors for new ideas
- The social and religious beliefs of times in the past also delayed Darwin publishing is ideas on evolution for 12 years
- In the 1860s the theory was widely accepted
- In the early 1900s in the US shifted from traditional beliefs to more modern beliefs.
Post by: angelahchan on October 24, 2017, 09:53:38 pm
my notes says the range for humans is 380-750nm, but wikipedia says it's 390-700nm
Post by: archie33 on October 24, 2017, 10:13:22 pm
Hi, does anyone know the range in the electromagnetic spectrum that humans, snakes, and bees can see?Hey,
my notes says the range for humans is 380-750nm, but wikipedia says it's 390-700nm
Humans: 380-750 nm
Bees: 300-700 nm
Snakes: 480-850 nm
This is what I have, I've checked around and these seem like the common answer. Wikipedia is a bit hard to trust. :)
Post by: hannahhhh on October 24, 2017, 10:27:36 pm
Post by: archie33 on October 24, 2017, 10:27:46 pm
Do we need to know anything in-depth about MacFarlane Burnet's work? Thanks :)
Post by: sidzeman on October 24, 2017, 10:29:08 pm
Yeah, secretion involves drugs and poisons but there's more than that. Urea is filtered in bowman's capsule, but not 100% so some secretion is involved . Here's a brief diagram in my notes, it doesn't cover everything thoThank you so much! Could someone also help me out with this question please
(https://i.imgur.com/HQy0wrJ.png)
Post by: hannahhhh on October 24, 2017, 10:37:18 pm
Thank you so much! Could someone also help me out with this question please
It would be B because they give you the tRNA so you have to go backwards twice to find the mRNA and then the original DNA:)
Post by: sidzeman on October 24, 2017, 10:38:11 pm
It would be B because they give you the tRNA so you have to go backwards twice to find the mRNA and then the original DNA:)ahhhh that makes sense i misread the question and thought they meant mRNA woops!
I know this has been asked a million times but, what is the difference between hybridisation and selective breeding?
Post by: hannahhhh on October 24, 2017, 10:52:19 pm
ahhhh that makes sense i misread the question and thought they meant mRNA woops!
I know this has been asked a million times but, what is the difference between hybridisation and selective breeding?
In my notes i have something that says 'selective breeding techniques are reproductive technologies that may be used to achieve hybridisation'
and
Hybridisation is a process in which two genetically different strains of an organism are crossed to produce
offspring with more desirable characteristics than the parents
So I think artificial insemination and artificial pollination are the selective breeding techniques used to achieve hybridisation ? Not 100% sure but I think so
Post by: mbdtHSC on October 24, 2017, 11:18:35 pm
Hi I know this is rather late, but I’m really struggling to wrap my mind around interaction between T and B lymphocytes, cell mediated immunity and antibody mediated immunity - I don’t understand it extensively and I don’t really know how much I need to know of it anyway! I would forever appreciate any help at all!!!
This is basically what I've remembered:
Think of the immune response as centered around helper T-cells (the starting point)
Helper T-cells have surface receptor proteins that are specific to an antigen, meaning they are able to detect a specific antigen
The way this detection can occur is by the helper T-cell recognising the antigen as it is displayed on MHCII molecules
MHCII molecules are glycoprotein molecules and are found on macrophages and B-cells, so either of these can hold the antigen on the surface of the MHCII molecule.
A macrophage can ingest an antigen and the fragments of the antigen are displayed on the MHCII molecule (can't think of a good analogy but maybe some jelly with the antigen fragments as sprinkles on top of jelly). So once the helper T-cell has the antigen brought by a B-cell or macrophage, its specific surface receptor protein will recognise the antigen and process it.
Then, the helper T-cell releases these 'signalling' chemicals called cytokines. The specific cytokine 'interleukin-2' basically stimulates B-cells to differentiate into PLASMA B-cells and MEMORY B-cells. T-cells also differentiate into CYTOTOXIC, MEMORY and SUPPRESSOR T-cells.
Plasma B-cells are important for the immune response as they can secrete antibodies, which specifically can inactivate or destroy the matching antigen.
Another mechanism comes into play for cytotoxic T-cells, which are MHCI molecules. These essentially mark infected body cells as targets for cytotoxic T-cells, which are ALSO specific to the antigen. The cytotoxic T-cells will move to find the infected cells, attach to them and release a chemical called 'perforin' which perforates the cell and causes it to lyse, which kills the infected cell.
Apart from this method of forming differentiated T and B cells, they can also be activated directly by antigens. Probably some stuff I missed, but if you know that in general you should be fine!
Post by: hannahhhh on October 24, 2017, 11:33:34 pm
This is basically what I've remembered:
Think of the immune response as centered around helper T-cells (the starting point)
Helper T-cells have surface receptor proteins that are specific to an antigen, meaning they are able to detect a specific antigen
The way this detection can occur is by the helper T-cell recognising the antigen as it is displayed on MHCII molecules
MHCII molecules are glycoprotein molecules and are found on macrophages and B-cells, so either of these can hold the antigen on the surface of the MHCII molecule.
A macrophage can ingest an antigen and the fragments of the antigen are displayed on the MHCII molecule (can't think of a good analogy but maybe some jelly with the antigen fragments as sprinkles on top of jelly). So once the helper T-cell has the antigen brought by a B-cell or macrophage, its specific surface receptor protein will recognise the antigen and process it.
Then, the helper T-cell releases these 'signalling' chemicals called cytokines. The specific cytokine 'interleukin-2' basically stimulates B-cells to differentiate into PLASMA B-cells and MEMORY B-cells. T-cells also differentiate into CYTOTOXIC, MEMORY and SUPPRESSOR T-cells.
Plasma B-cells are important for the immune response as they can secrete antibodies, which specifically can inactivate or destroy the matching antigen.
Another mechanism comes into play for cytotoxic T-cells, which are MHCI molecules. These essentially mark infected body cells as targets for cytotoxic T-cells, which are ALSO specific to the antigen. The cytotoxic T-cells will move to find the infected cells, attach to them and release a chemical called 'perforin' which perforates the cell and causes it to lyse, which kills the infected cell.
Apart from this method of forming differentiated T and B cells, they can also be activated directly by antigens. Probably some stuff I missed, but if you know that in general you should be fine!
Thank you so so so much!! This makes 1000x more sense than anything else I’ve read!:))) :) :)
Post by: sidzeman on October 24, 2017, 11:39:15 pm
Post by: Mathew587 on October 24, 2017, 11:59:09 pm
Translocation Down syndrome is sometimes hereditary apparently but i think in most cases it is not inherited (ur right). i think i would use another example like cystic fibrosis?
nah soz just found out that down syndrome is a genetic disease lol...
Post by: 66295 on October 25, 2017, 02:20:17 pm
Post by: Natasha.97 on October 25, 2017, 02:22:18 pm
Thoughts on paper???
Hi!
We have a thread for this here :)
Post by: tina1395 on November 19, 2017, 09:41:32 am
for the dotpoint "Process and analyse information from secondary sources to describe the effect of one name and described genetic mutation on human health", can i use SCID or colour-blindness ?
Post by: Potatohater on November 19, 2017, 03:01:08 pm
hi guys,
for the dotpoint "Process and analyse information from secondary sources to describe the effect of one name and described genetic mutation on human health", can i use SCID or colour-blindness ?
For sure! Just make sure you explain why these defects affect health as according to the definition we use in bio.
Post by: theyam on December 03, 2017, 02:47:55 pm
Does anyone or has anyone, had the problem with your teacher going through numerous slides for theory for just a single dot point? And then turns out for exams, you only needed literally one slide worth of theory? How do I distinguish between what I need or don't need?
Thank you~~
From theyam
Post by: Opengangs on December 04, 2017, 11:49:21 am
Hi guys~Hello, theyam.
Does anyone or has anyone, had the problem with your teacher going through numerous slides for theory for just a single dot point? And then turns out for exams, you only needed literally one slide worth of theory? How do I distinguish between what I need or don't need?
Thank you~~
From theyam
It's not so much the intense number of slides that's the problem, it's simply the way your teacher teaches you the concept. This is because everything in biology is linked nicely. And I mean very nicely. I suggest approaching your studies by linking concepts together, because that's the only way you'll ever remember these ideas without the burden of seeing so much content. What I tend to do with my notes is to adjust each new concept and squeeze it somewhere else so that there are less areas to remember.
Let me give you an example of what I mean. Enzyme activity plays an essential role in not only Maintaining a Balance, but Blueprint of Life and Search for Better Health. In MAB, you are introduced with the idea of enzyme activity and its significance to metabolism. We also note the denaturation process (conditions need to be optimal for enzymes to work efficiently), but this idea comes into play with the removal of carbon dioxide in the blood. If carbon dioxide is present in the blood, the blood becomes more acidic, lowering the pH of the blood, which in turn denatures the enzymes. See how they are linked very nicely? This is why biology isn't a hard subject, you just need to find the right mechanism to remember concepts easier and what better way than to link them up?
Perhaps, try this method and I can guarantee that you begin to find the content much easier to absorb, allowing you to memorise information that may not even be relevant in the exam.
Post by: cnimm2000 on December 29, 2017, 10:19:41 pm
I was doing a dot point in maintaining a balance:
T.3.5 Distinguish between active and passive transport and relate these to processes occurring in the mammalian kidney
Im struggling to relate active and passive to the processes occurring in the mammalian kidney
it would be great if you guys could help
Post by: Potatohater on December 29, 2017, 10:25:49 pm
Hey Guys,
I was doing a dot point in maintaining a balance:
T.3.5 Distinguish between active and passive transport and relate these to processes occurring in the mammalian kidney
Im struggling to relate active and passive to the processes occurring in the mammalian kidney
it would be great if you guys could help
Ok might be a little rusty but basically active transport occurs in the proximal distal tubule to reabsorb glucose and such. Passive transport occurs everywhere else to reabsorb water via osmosis - it's a bit of brief explanation but hopefully it's enough to get you on the right track
Post by: inescelic on December 29, 2017, 11:26:05 pm
Hey Guys,
I was doing a dot point in maintaining a balance:
T.3.5 Distinguish between active and passive transport and relate these to processes occurring in the mammalian kidney
Im struggling to relate active and passive to the processes occurring in the mammalian kidney
it would be great if you guys could help
Hi,
So passive transport means that NO ENERGY is required, and that substances will move from a high concentration to low concentration. In relation to the kidney, water and salts move by passive transport from the kidney tubules to the capillaries. HOWEVER, some water and salts are transported by active transport, depending on the body's needs. So, if the body needs more water, active transport will occur to ensure that more water is returned to the capillaries.
Active transport however does require energy. As aforementioned, some water and salt are transported by active transport. However, ALL glucose and amino acids are returned to the capillaries by active transport. Both of these transports occur during the reabsorption phase.
For the HSC, you are not required to know exactly where these processes occur (i.e. distal tube, proximal tube etc.), however I am not sure whether your school will include this in your assessments, so I think it would be good for you to ask your teacher whether you need to correspond the form of transport to the location on the tubules.
Hope this helps :)
Post by: cnimm2000 on December 31, 2017, 03:41:45 pm
I needed help answering this question about this dot point:
T.3.8 Define enantiostasis as the maintenance of metabolic and physiological functions in response to variations in the environment and discuss its importance to estuarine organisms in maintaining appropriate salt concentrations.
I have answered this dot point but however I don't think i have answered the 'discuss its importance to estuarine organisms.....'
It would be great, if you guys could help :)
Post by: Natasha.97 on December 31, 2017, 06:15:11 pm
Hey guys,
I needed help answering this question about this dot point:
T.3.8 Define enantiostasis as the maintenance of metabolic and physiological functions in response to variations in the environment and discuss its importance to estuarine organisms in maintaining appropriate salt concentrations.
I have answered this dot point but however I don't think i have answered the 'discuss its importance to estuarine organisms.....'
It would be great, if you guys could help :)
Hi!
Estuarine organisms experience wide variations in salt concentrations over a short period of time due to tidal movements:
- Tide in: Freshwater environment, water osmoses into cells
- Tide out: Saltwater environment, water osmotes out of cells
The main reason that enantiostasis is so important links back to the overarching theme of the module: Enzymes and their function. If an enzyme within an organism is not in its optimum condition, it won't be as efficient as it would have been.
Hope this helps :)
Post by: cnimm2000 on January 03, 2018, 07:11:17 pm
For the dotpoint:
T.4.2 Outline, using a simple model, the process by which DNA controls the production of polypeptides
what would be a good simple model to use to model protein synthesis?
Post by: inescelic on January 03, 2018, 08:26:59 pm
Hi,
For the dotpoint:
T.4.2 Outline, using a simple model, the process by which DNA controls the production of polypeptides
what would be a good simple model to use to model protein synthesis?
Hi cnnim2000,
The way you complete this dot point depends on what kind of activity your teacher instructed to do in class. In many schools, and in mine, we drew up a labelled diagram of the protein synthesis process within a cell. To keep it simple, we used different coloured textas to distinguish between different parts of the cell i.e. mRNA, DNA, nucleus, ribosome, tRNA. A good reference point would be the image I have attached below and I also have attached my own drawn model I used for my study notes (don't worry about the faint pencil writing, that was only a guide for me explaining what transcription and translation entailed) :)
Hope this makes sense, and feel free to ask more questions :)
Post by: cnimm2000 on January 03, 2018, 09:54:38 pm
I wasn't too sure if the dot point wanted me to draw a model as you said or link this process to an analogy.
Post by: inescelic on January 03, 2018, 11:18:41 pm
Thanks, that helped alot.
I wasn't too sure if the dot point wanted me to draw a model as you said or link this process to an analogy.
Good to hear :)
Your model would most definitely be a drawing as this biological concept is way too unique to compare it with anything else to be an analogy.
Also, keep in mind that this dot point will usually be testing biological skills e.g. reliability, validity, advantages and disadvantages of models. Thus, you should note that you researched and found the diagrams from which you based model from reputable sources (e.g. from a scientific institution) and that you compared a variety of sources for reliability.
Post by: cnimm2000 on January 05, 2018, 05:21:38 pm
Could i get an explanation on why sex-linked genes don't produce simple mendelian ratios
Post by: Potatohater on January 05, 2018, 07:40:12 pm
Hey guysSo sex linked inheritance depends on the sex of the offspring. Since the X chromosome is longer than the Y chromosome, characteristics carried on the X chromosome may not be masked by the Y. Let's say the allele in question is recessive, if it were inherited by a girl she would need this allele on both chromosomes for it to be expressed in the phenotype. If the offspring were a boy, he would only need one copy of the allele, on his only X chromosome, for it to show. Therefore the inheritance of sex linked traits does not follow simple Mendelian ratios. I hope that made sense, if not just let me know and I'll attempt to explain in another way.
Could i get an explanation on why sex-linked genes don't produce simple mendelian ratios
*AN suggestion: we should have some sort of drawing feature thing so that I could draw pedigrees and punnet squares to explain genetics Q's *
Post by: AngelWings on January 05, 2018, 07:55:12 pm
Hey guysFor organisms under the XY sex determination system (e.g. humans or Drosophila melanogaster [fruit/ vinegar fly]), females have two X chromosomes (XX), whereas males only have one and fill the other with a Y chromosome (XY) when they inherit sex chromosomes. This means that the presence of the Y chromosome makes an organism male under this system. Each of these sex chromosomes has alleles - these are known as sex-linked alleles (sometimes referred to as X-linked alleles). This is usually denoted as a superscript letter beside a capital X or Y as appropriate, such as XwXw for a white eyed female, where 'w' is the white eye allele. Why it doesn't produce normal Mendellian ratios is because the progeny's sex will impact how much of the genetic info will be shown (but this isn't the end of the story, more on that below).
Could i get an explanation on why sex-linked genes don't produce simple mendelian ratios
What do I mean by this? For sex-linked traits with the XY system, male progeny are hemizygous (This basically means it only shows up one copy from its parents.); they'll display whatever trait their mother gave them (they need an X chromosome to live) and automatically receive the Y chromosome their father had (because where else can they get a Y chromosome to become male?). The Y chromosome is often considered 'too small to have visible effect' ("gene-poor") and thus, Dad's genes don't show up in the male progeny's phenotype.
Mendellian ratios would show that both sexes of the progeny will be the same (female + males show Mum + Dad's info). Under sex-linked ratios, females will show both Mum + Dad's info (since they have 2 X chromosomes and inherit these equally from the parents), but males will only show Mum's (hemizygous). This difference causes the observed ratio differences.
The best example I can give you is on this link right here, which includes the research of Thomas Hunt Morgan on Drosophila melanogaster (the experiment that essentially discovered the existence of sex-linked alleles).
Some more helpful links: Sex-linked inheritance
See halfway down the page under "Inheritance of Sex Linked Traits"
NOTE: I got beaten by Potatohater, but I thought the links might be useful, so I'm posting anyway. Also, I know I explained it in a convoluted manner, but I hope it made sense. Since genetics is my major, I tend to have a more technical background.
Post by: cnimm2000 on January 07, 2018, 07:33:47 pm
So sex linked inheritance depends on the sex of the offspring. Since the X chromosome is longer than the Y chromosome, characteristics carried on the X chromosome may not be masked by the Y. Let's say the allele in question is recessive, if it were inherited by a girl she would need this allele on both chromosomes for it to be expressed in the phenotype. If the offspring were a boy, he would only need one copy of the allele, on his only X chromosome, for it to show. Therefore the inheritance of sex linked traits does not follow simple Mendelian ratios. I hope that made sense, if not just let me know and I'll attempt to explain in another way.
*AN suggestion: we should have some sort of drawing feature thing so that I could draw pedigrees and punnet squares to explain genetics Q's *
For organisms under the XY sex determination system (e.g. humans or Drosophila melanogaster [fruit/ vinegar fly]), females have two X chromosomes (XX), whereas males only have one and fill the other with a Y chromosome (XY) when they inherit sex chromosomes. This means that the presence of the Y chromosome makes an organism male under this system. Each of these sex chromosomes has alleles - these are known as sex-linked alleles (sometimes referred to as X-linked alleles). This is usually denoted as a superscript letter beside a capital X or Y as appropriate, such as XwXw for a white eyed female, where 'w' is the white eye allele. Why it doesn't produce normal Mendellian ratios is because the progeny's sex will impact how much of the genetic info will be shown (but this isn't the end of the story, more on that below).
What do I mean by this? For sex-linked traits with the XY system, male progeny are hemizygous (This basically means it only shows up one copy from its progeny.); they'll display whatever trait their mother gave them (they need an X chromosome to live) and automatically receive the Y chromosome their father had (because where else can they get a Y chromosome to become male?). The Y chromosome is often considered 'too small to have visible effect' ("gene-poor") and thus, Dad's genes don't show up in the male progeny's phenotype.
Mendellian ratios would show that both sexes of the progeny will be the same (female + males show Mum + Dad's info). Under sex-linked ratios, females will show both Mum + Dad's info (since they have 2 X chromosomes and inherit these equally from the parents), but males will only show Mum's (hemizygous). This difference causes the observed ratio differences.
The best example I can give you is on this link right here, which includes the research of Thomas Hunt Morgan on Drosophila melanogaster (the experiment that essentially discovered the existence of sex-linked alleles).
Some more helpful links: Sex-linked inheritance
See halfway down the page under "Inheritance of Sex Linked Traits"
NOTE: I got beaten by Potatohater, but I thought the links might be useful, so I'm posting anyway. Also, I know I explained it in a convoluted manner, but I hope it made sense. Since genetics is my major, I tend to have a more technical background.
Thanks guys for the great explanation
Post by: kaustubh.patel on January 22, 2018, 03:36:08 am
Post by: Opengangs on January 22, 2018, 05:36:50 am
So homeostasis is the process whereby am organism maintains their internal environment from a relatively stable environment. There may be sudden changes in the environment from time to time but it is generally stable.
On the other hand, some organisms live in an environment where it is constantly changing. Mangroves that live in estuaries have to constantly cope with the changes in salt levels as they live in an environment where the tide meets the stream.
At high tide, there are increased salt levels while at low tide there are decreased levels of salt. Thus, homeostasis will not be efficient. This is where enantiostasis comes into play.
Enantiostasis is the process whereby they keep a relatively stable physiological and metabolic function against the constant changes within the external environment. They do this by either conforming to the external environment (osmoconformers), that is their temperature is proportionate to the external environment or they maintain their own temperature regardless of external stimuli (osmoregulators).
Post by: mickinimaj on January 23, 2018, 09:57:02 pm
If so, what would be the explanation
Post by: Natasha.97 on January 23, 2018, 10:01:37 pm
Would the change in kangaroo teeth (from (ancient to modern) count as mac or mic evolution
If so, what would be the explanation
Hi!
I'd probably say that it is classified as microevolution, as no new species are formed as a result of the change in kangaroo teeth :)
Post by: cnimm2000 on January 23, 2018, 10:16:35 pm
Would the change in kangaroo teeth (from (ancient to modern) count as mac or mic evolutionJust to add onto what Jess1113 said:
If so, what would be the explanation
Here is a summary of the criteria, to help you differentiate if it is a result of macro-evolution or micro-evolution:
Macro-evolution:
Takes place over millions of years and results in the arising of new species (even larger groups such as families and orders)
Micro-evolution
Takes place over shorter periods of times and results in changes within the population, but doesn’t reproduce new species.
Post by: mickinimaj on January 25, 2018, 06:18:38 pm
Post by: markkhodair on January 25, 2018, 06:37:25 pm
Post by: Potatohater on January 25, 2018, 07:58:52 pm
Hey! This is probably a dumb question, but in our exams, are we ever allowed to talk in 1st/2nd person? Would "our body requires and wants to maintain a balance of water and salt, therefore, it passively reabsorbs and secretes water until we reach that balance." suffice? Or would that be illegible and we have to write "the human body requires and wants to maintain a balance of water and salt, therefore, it passively reabsorbs and secretes water until it reaches that balance."? I'm sorry if this is a dumb question I probably most likely know that we can't write in 1st/2nd person but I've gone blank. Thank you!!Sure you can write in 1st/2nd person so long as you are getting the point across clearly and concisely, so that 1st example is totally acceptable
Post by: Natasha.97 on January 25, 2018, 10:26:21 pm
what would be the reason for why maintaining body temeprature in mammals count as feedback system?
Hi!
One of the key focuses of this topic (MaB) is organisms and their enzymes. Enzymes function best at certain temperatures/pH/concentrations etc. Mammals have feedback mechanisms in place so that if the body temperature is below optimum, a series of actions will take place resulting in the return to the optimum temperature and vice-versa. An example is included below:
- Stimulus: Hot room
- Skin receptors detect change in temperature, and an impulse is transmitted along sensory neurone to the brain
- The brain transmits a response along the motor neurone to the effector (sweat gland)
- Sweating and vasodilation occurs to return the body back to normal temperature
Hope this helps :)
Post by: markkhodair on February 03, 2018, 09:46:01 pm
Post by: Natasha.97 on February 03, 2018, 10:15:36 pm
Hey! What are some examples of halophytes who use salt avoidance mechanisms rather than salt tolerance? Thank you!
Hi!
Red mangroves are adapted for salt exclusion, where root membranes in roots form a barrier against the passage of salt into xylem tissue.
Hope this helps :)
Post by: markkhodair on February 04, 2018, 12:25:09 pm
Hi!
Red mangroves are adapted for salt exclusion, where root membranes in roots form a barrier against the passage of salt into xylem tissue.
Hope this helps :)
It does! Thank you so much x
Post by: itssona on February 19, 2018, 04:55:40 pm
what does this mean? why would self fertilising plants fertilise other ones.. what
Post by: PhoenixxFire on February 19, 2018, 05:03:10 pm
as for Mendel, "Plants that were self-fertilised were isolated from others (no accidental pollination using paper bag)."So I don’t do hsc haha but this just means that the plants are normally able to either self-fertilise OR be fertilised by other plants. In this test he only wanted them to be self-fertilised so he had to stop accidental pollination.
what does this mean? why would self fertilising plants fertilise other ones.. what
ie. In the experiment they were self pollinated, but in the wild they didn’t have to be
Post by: itssona on February 19, 2018, 05:09:40 pm
So I don’t do hsc haha but this just means that the plants are normally able to either self-fertilise OR be fertilised by other plants. In this test he only wanted them to be self-fertilised so he had to stop accidental pollination.ohh makes sense!! thank you :)
ie. In the experiment they were self pollinated, but in the wild they didn’t have to be
Post by: Yagami Light on February 21, 2018, 10:53:16 pm
Post by: Potatohater on February 21, 2018, 11:29:48 pm
Can someone explain to me indepth speciation isolation? ThanksSo I guess you mean divergent evolution via isolation well basically it happens like this:
1. The species becomes isolated by some sort of natural factor
2. The two seperate populations cannot breed with each other
3. The two populations become genetically isolated due to inability to cross breed due to the physical isolation
4. Eventually many generations pass on the most favourable traits for the distinct habitats the populations have inhabited
5. Two different species have now evolved from a common ansestor due to thir physical and genetic isolation
Post by: beeangkah on February 28, 2018, 05:10:01 pm
I know the basics like the circle = female, square = male etc.
But I find trouble, for instance, in determining if a characteristic is dominant/recessive, or if a certain offspring is heterozygous/homozygous for a certain trait.
Also, are they that important to know well?
Thanks!
Post by: Sine on February 28, 2018, 05:21:29 pm
Does anyone have any tips for solving pedigree questions?The best way I found to tackle pedigree question is to rather than looking for a certain inheritance pattern I would try to prove all the patterns wrong.
I know the basics like the circle = female, square = male etc.
But I find trouble, for instance, in determining if a characteristic is dominant/recessive, or if a certain offspring is heterozygous/homozygous for a certain trait.
Thanks!
You can also use other tricks such as; trait is not seen in one generation but precedes and succeeds (i.e. skipping a generation) the trait is recessive.
or even if the trait only targets a specific gender is being impacted (usually male).
You can also try to write out the allelic pairs in order to make it a little clearer on which alleles have been passed down an inherited, if an allele is unknown I would write out a blank space e.g. A_ . Writing out punnet squares can help with determining the chances of an offspring have a trait/being a carrier.
Post by: markkhodair on March 01, 2018, 09:25:01 pm
Could someone please explain the following dot point to me: describe outcomes of monohybrid crosses involving simple dominance using Mendel’s experiment. I can't wrap my head around it and looking at so many resources there's so much info and I just don't know what to do!! Could you also define Mendel's first law of dominance and segregation as simply as possible please?
Thank you.
Post by: jasn9776 on March 02, 2018, 10:58:02 pm
Explanation(IK not trying to freak you out, its actually really simple once you get it. just trying to practice my expression, teaching is the best learning after all :D looks like an essay dont read it all unless you still can't get it ):
An Allele as you should recall is an alternative form of a gene. Organisms get one allele for each trait from each parent. This means they have two alleles, which may or may not be identical, for the same trait.
The two alleles that an organism has for a trait(for example height) has can be represented with letters. For example TT means two tall alleles(It is homozygous for tall). Tt means one allele is for tall and the other allele is for short(It is heterozygous for tall). tt means the organism has two short alleles and it will be short(homozygous for short). The letters can vary depending on what is dominant e.g. SS if short was the dominant trait. Or Rr or Zz or whatever letter you want depending on what trait you are talking about.
A punnett square (which give the same result as a monohybrid cross) is when you write the two genotypes(that is tt or TT for example) on the sides of the box. Write down what you get when you cross the two letters together. These are the possible combinations for the offspring. (each box has a 25% chance of occurring) (see attached, really hard to explain with words.)
When you cross one purebreed tall TT and one purebreed tt(which Mendel did), you should get Tt, Tt, Tt, Tt (100% chance of Tt which means heterozygous for tall). This means the F1 generation only has the phenotype for Tall(the dominant trait.) (See attached for an example or watch the video)
When Mendel crosses Tt with another Tt plant, he got this:
TT, Tt, Tt and tt.(see attached) Remember Tt means it is heterzygous for tall which means it will be tall since tall is dominant. tt means it will be short. So there are 3 three Tall plants for every 1 short plant offspring (on average). hence the ratio 3:1. This means the F2 generation has a ratio of 3:1. This ratio represents dominant:recessive phenotypes.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Mendel's law of dominance is:
The two different alleles for the trait have to have one that one is dominant over the other. (only the dominant actually matters and the recessive is ignored in terms of expressing the trait(that is only the dominant allele affects the phenotype. Phenotype means the physical characteristic of the plant-not its genetics)). If there are two recessive alleles, for example, two short alleles, the plant would express the short gene. that is it will be short.
For example, suppose there is only one gene that controls whether a plant is tall or short. Assume that tall is dominant. If the plant has one tall allele then it will be tall. It does not matter if the other allele is the short allele or if it is another tall allele in terms of the phenotype. There needs to be two short alleles for the plant to be short as the trait for shortness is recessive.
The law of segregation is:
Basically, Each trait(for example height) has only has one pair of alleles(Factors) that controls it(for example: either a short allele or a tall allele).
Factors of the same characteristic occur in pairs in an individual.
These pairs separate at gamete formation. see attached.
Law of independent assortment:
Going back to my previous example, The plant can only have two alleles(both can be either tall or short) that influences that trait. There are no other alleles that influence the trait. For example, just imagine there are alleles for the colour of the leaves (either green or yellow). This does not affect how tall the plant is. This is because all genes have a different locus(location) on the chromosome.
You can inherit one trait without inheriting another. You can have a tall plant with a yellow leaves . The plant could also have green leaves.In fact, no other alleles affect how tall the plant is.
I would try to revise some monohybrid crosses to help you understand this better. It is much easier to learn with videos or pictures.
Everything I said is just Mendelian laws and it may not always apply for example a plant could blend the characteristics. e.g. Another species of plant with a tall allele and a short allele can be a medium height plant.
Post by: beeangkah on March 05, 2018, 04:01:36 pm
I need help with this question - it asks, referring to the diagram:
What is the most likely mode of inheritance?
I got autosomal recessive, is it correct?
Thankss
Post by: jasn9776 on March 05, 2018, 04:19:11 pm
IDK oh well procrastinating in class :)
Edit:
well google says autosomal recessive
The MC1R recessive variant gene that gives people red hair generally results in skin that is unable to tan. ... This type of inheritance is described as an autosomal recessive mode of inheritance
Edit 2: Okay i really need to revise that isn't a child!!! that is the spouse!
Post by: theyam on March 18, 2018, 02:34:57 pm
Could someone help me with this dot point: process information to construct a flow chart that shows that changes in DNA sequences can result in changes in cell activity
I tried searching it up but I didn't really understand it..
Thank you
Post by: Potatohater on March 18, 2018, 03:46:48 pm
Hi
Could someone help me with this dot point: process information to construct a flow chart that shows that changes in DNA sequences can result in changes in cell activity
I tried searching it up but I didn't really understand it..
Thank you
Hi,
So basically a mutation in DNA can change cell function in this way
Mutation -> mRNA codons are altered due to changed DNA -> tRNA codons altered due to changed mRNA -> potentially different amino acids in the chain -> different polypeptide -> different protein -> different cell function
I do hope that makes sense :)
Post by: Razeen25 on March 18, 2018, 07:50:50 pm
For the dot point "Compare responses of named ectothermic and endothermic organisms...", do we need to know the scientific name of each organism, or is 'Red Kangaroo' enough?
Also for "Develop a model of a feedback mechanism" is a flowchart of how the stimulus-response pathway assists temperature control in the body enough? I don't know if I'm studying less than I should be lol
Thank you!!
Post by: Potatohater on March 18, 2018, 08:27:28 pm
Hii,1. Red kangaroo is enough, but just kangaroo is not. So yes, use your red kangaroos and, for ectotherms, red bellied black snakes, blue tounge lizards etc.
For the dot point "Compare responses of named ectothermic and endothermic organisms...", do we need to know the scientific name of each organism, or is 'Red Kangaroo' enough?
Also for "Develop a model of a feedback mechanism" is a flowchart of how the stimulus-response pathway assists temperature control in the body enough? I don't know if I'm studying less than I should be lol
Thank you!!
You have to be speciffic but not scientiffic
2. Yes that's perfect, a flow chart that explains how different tempratures trigger the stimulus-response pathway and what happens as a result, eg. Sweating, shivering etc. is exactly what they mean
Post by: theyam on March 19, 2018, 05:17:14 am
Hi,
So basically a mutation in DNA can change cell function in this way
Mutation -> mRNA codons are altered due to changed DNA -> tRNA codons altered due to changed mRNA -> potentially different amino acids in the chain -> different polypeptide -> different protein -> different cell function
I do hope that makes sense :)
Hello,
Man every time I tried searching it up, I'd see the below flow charts and I was just like ._. So thank you so much for that explanation it really helped me!
Thank you
from theyam :)
Post by: Potatohater on March 19, 2018, 08:31:50 am
Hello,Ahhh yes, so that diagram makes sense to me but I agree, it's not the best at explaining the concept when people havnt learnt it before. I'm glad I helped :)
Man every time I tried searching it up, I'd see the below flow charts and I was just like ._. So thank you so much for that explanation it really helped me!
Thank you
from theyam :)
Post by: Razeen25 on March 19, 2018, 04:59:26 pm
1. Red kangaroo is enough, but just kangaroo is not. So yes, use your red kangaroos and, for ectotherms, red bellied black snakes, blue tounge lizards etc.
You have to be speciffic but not scientiffic
2. Yes that's perfect, a flow chart that explains how different tempratures trigger the stimulus-response pathway and what happens as a result, eg. Sweating, shivering etc. is exactly what they mean
Thank you so so much! :D
Post by: beeangkah on March 24, 2018, 03:21:47 pm
I think that at least B is definitely out as males can't be carriers, but how do I go on from there?
Post by: PhoenixxFire on March 24, 2018, 03:28:22 pm
Helllo could someone explain the reasoning to get the answer to this?Hey,
I think that at least B is definitely out as males can't be carriers, but how do I go on from there?
So first you need to identify the mode of transmission. It must be X linked because individual 1 is not affected (he would be if it was Y linked). It also must be recessive because Individual 2 is not affected. So now you know that it is a X linked recessive trait.
This means that individual 1 cannot be a carrier (as you have already identified). Therefore individual 2 must be a carrier (otherwise their children could not have the condition).
Males cannot be carries of X linked recessive disorders as they only have 1 X chromosome so therefore Individual 3 must be normal. (Individual 3's partner would be the carrier who gave their son the condition).
Therefore the answer is C.
Post by: beeangkah on March 27, 2018, 07:37:25 pm
Thanks
Post by: jasn9776 on March 27, 2018, 09:19:53 pm
What is important to note is that the two different sides of the second cell(in the diagram) will split into two different cells.
This means that the ABAb chromosome will end up with the EDED chromosome in a separate cell after the cell divides into two.
After this they will split again and the end result is a daughter cell with two single chromatids(without the centromere connecting another one).
Remember each big chromosome e.g. AB or Ab must have a small chromosome e.g. ED or ED in each daughter cell since they are different chromosomes and the daughter cell needs a copy of each.
So really the AB can go with ED or ED but they are the same so
combo 1: ABED
combo 2:AbED
combo 3:aBed
combo 4:abed
Hope that helps. See the attachment for what the end result should look like. :) though it doesn't show crossing over
Post by: BrittyG on March 27, 2018, 11:08:01 pm
I'm having trouble with 9.4 Search for better health FQ3 where it asks to describe a named infectious disease in terms of cause, transmission etc. My class has chosen to do Malaria and I'm struggling to understand how the transmission of Malaria takes place. I was wondering if someone could lay it out in steps of what happens in the malaria transmission cycle (pretend you're explaining to a five-year-old)
Thanks in advance :)
Post by: Potatohater on March 28, 2018, 07:19:26 am
Hi all,
I'm having trouble with 9.4 Search for better health FQ3 where it asks to describe a named infectious disease in terms of cause, transmission etc. My class has chosen to do Malaria and I'm struggling to understand how the transmission of Malaria takes place. I was wondering if someone could lay it out in steps of what happens in the malaria transmission cycle (pretend you're explaining to a five-year-old)
Thanks in advance :)
Ok so mosquitoes suck people's blood
Malaria is in persons blood
Mosquito carries malaria inside it
Mosquito sucks another person's blood
They inject a little bit of saliva as they suck the blood
Malaria goes into the new person's blood
Malaria then attacks red blood cells and reproduces in the liver
Malaria continues to attack blood cells and make person sick.
Another mosquito can then come and transfer malaria from sick person to a healthy person in the same way and the cycle continues
Post by: BrittyG on March 28, 2018, 11:55:50 am
Ok so mosquitoes suck people's blood
Thank you so much, clears everything up :)
Post by: Mate2425 on April 01, 2018, 09:25:39 am
Thanks :)
Post by: Potatohater on April 01, 2018, 10:03:31 am
Hi i just wondering if they are any alternatives to the HSC Biology 2017 Q27a answer. The answer seems too simple.Ayy that was my year! Remind me, what was the question again?
Thanks :)
Post by: blasonduo on April 01, 2018, 11:04:33 am
Hi i just wondering if they are any alternatives to the HSC Biology 2017 Q27a answer. The answer seems too simple.
Thanks :)
Hey! I agree, when those answers came out, my class was baffled at how simplistic their answer was, clearly that wasn't worth the 2 marks... right?
My answer looked like something like the attached, and I feel like that was plenty for the 2 marks.
Post by: Potatohater on April 01, 2018, 11:08:11 am
Post by: jasn9776 on April 01, 2018, 11:13:18 am
Hi i just wondering if they are any alternatives to the HSC Biology 2017 Q27a answer. The answer seems too simple.I would say just remember it is lignified (thus the wall on the marking criteria looks bigger) and that phloem is actually a lot smaller than xylem. It isn't obvious but xylem is actually bigger than phloem.
Thanks :)
(http://ib.bioninja.com.au/_Media/root1_med.jpeg)
Question 27
In better responses, students were able to:
draw a scientific diagram of transverse sections of both xylem tissue and phloem tissue
demonstrate a distinguishing feature of xylem tissue and phloem tissue
so basically 1 mark for diagram. and 1 mark for 1 distinguishing feature. easy!.
Post by: Mate2425 on April 01, 2018, 08:25:49 pm
I would say just remember it is lignified (thus the wall on the marking criteria looks bigger) and that phloem is actually a lot smaller than xylem. It isn't obvious but xylem is actually bigger than phloem.Thanks Mate :)
(http://ib.bioninja.com.au/_Media/root1_med.jpeg)
Question 27
In better responses, students were able to:
draw a scientific diagram of transverse sections of both xylem tissue and phloem tissue
demonstrate a distinguishing feature of xylem tissue and phloem tissue
so basically 1 mark for diagram. and 1 mark for 1 distinguishing feature. easy!.
Post by: Mate2425 on April 01, 2018, 08:26:33 pm
Ahhh yes I remeber that one now - yeah I agree the marking criteria was really simple. For mine I showed that the phloem had companion cells and sieve plates where as the xylem has thick lignin wallsCheers ;D
Post by: edumax on April 03, 2018, 03:11:15 pm
Post by: PhoenixxFire on April 03, 2018, 03:18:07 pm
You'll have
ABG
abg
Post by: Razeen25 on April 03, 2018, 07:53:18 pm
Please help
Post by: itssona on April 04, 2018, 10:01:15 am
hi how is the answer D? Thanks :)
Post by: TheBigC on April 04, 2018, 10:29:09 am
http://www.boardofstudies.nsw.edu.au/hsc_exams/hsc2011exams/pdf_doc/2011-hsc-exam-biology.pdf
hi how is the answer D? Thanks :)
I am a VCE kid, but I am sure I can aid you with this.
My assumption is that you are perplexed over Q17 (the other questions with an answer 'D' look fairly straight-forward - correct me if I am wrong).
Now, we already know that the parents express the same phenotype, which implies that they have the have the same alleles for the gene concerned, immediately eliminating A and B.
Through examination of the offspring produced, we can clearly observe that three phenotypes result, which eliminates C, as only two possible phenotypes are displayed (BB = dominant phenotype, Bb = dominant phenotype, bb = recessive phenotype).
Thus, the answer is D (AA = Phenotype A, AB = codominant phenotype and BB = Phenotype B).
Post by: itssona on April 04, 2018, 10:48:14 am
I am a VCE kid, but I am sure I can aid you with this.OMG THANK YOU1!
My assumption is that you are perplexed over Q17 (the other questions with an answer 'D' look fairly straight-forward - correct me if I am wrong).
Now, we already know that the parents express the same phenotype, which implies that they have the have the same alleles for the gene concerned, immediately eliminating A and B.
Through examination of the offspring produced, we can clearly observe that three phenotypes result, which eliminates C, as only two possible phenotypes are displayed (BB = dominant phenotype, Bb = dominant phenotype, bb = recessive phenotype).
Thus, the answer is D (AA = Phenotype A, AB = codominant phenotype and BB = Phenotype B).
(also LOL thanks for understanding the question I was stuck on XD ur a lifesaver)
Post by: Razeen25 on April 04, 2018, 07:32:53 pm
Today in my The Search For Better Health exam there was a multiple choice question showing a picture of Pasteur's experiment being modelled, and there were 2 answers (the other 2 were silly answers) I'm confused about.
The diagram showed two flasks containing broth (one broken, one unbroken) being boiled and the question was 'How is this experiment valid' or something and the two answers were:
c) The use of a control
d) The heat used to boil the broth
I chose C but I don't know if I should have chosen D smh since IDEK if there was a control rip
Post by: PhoenixxFire on April 04, 2018, 09:42:24 pm
(I don’t know anything about that particular experiment and I did vce though)
Post by: Ironiic on April 04, 2018, 10:02:42 pm
Hii!
Today in my The Search For Better Health exam there was a multiple choice question showing a picture of Pasteur's experiment being modelled, and there were 2 answers (the other 2 were silly answers) I'm confused about.
The diagram showed two flasks containing broth (one broken, one unbroken) being boiled and the question was 'How is this experiment valid' or something and the two answers were:
c) The use of a control
d) The heat used to boil the broth
I chose C but I don't know if I should have chosen D smh since IDEK if there was a control rip
Hey, like Phoenixx said, validity is when the independent variable (the variable changed) is the only changing variable in the experiment and all other factors are controlled, hence the experiment is measuring what it's supposed to.
From what I can get from the answers, d sounds to me like a controlled variable itself but I'm not too sure; it depends on what the experiment is investigating specifically.
Post by: PhoenixxFire on April 04, 2018, 10:27:29 pm
Hey, like Phoenixx said, validity is when the independent variable (the variable changed) is the only changing variable in the experiment and all other factors are controlled, hence the experiment is measuring what it's supposed to.I would still say that C is the correct answer. Controlling variables is more a part of reliability not validity. An experiment can be valid but not reliable.
From what I can get from the answers, d sounds to me like a controlled variable itself but I'm not too sure; it depends on what the experiment is investigating specifically.
For example if your hypothesis is ‘chickens who eat more will lay larger eggs’ but your IV is the amount of water you give them, your experiment is not valid.
To be valid your experiment just needs to be capable of testing the hypothesis. So if you use the above hypothesis but your IV is the amount of food you feed them then it is a valid experiment.
However if you then give them different amounts of water it is not a reliable experiment as the results will change each time it is repeated (because there is not a set amount of water). It is still a valid experiment though because it is still testing the effect of food on egg size.
A control also implies that all other conditions are the same.
Post by: Ironiic on April 05, 2018, 01:27:36 am
I would still say that C is the correct answer. Controlling variables is more a part of reliability not validity. An experiment can be valid but not reliable.
For example if your hypothesis is ‘chickens who eat more will lay larger eggs’ but your IV is the amount of water you give them, your experiment is not valid.
To be valid your experiment just needs to be capable of testing the hypothesis. So if you use the above hypothesis but your IV is the amount of food you feed them then it is a valid experiment.
However if you then give them different amounts of water it is not a reliable experiment as the results will change each time it is repeated (because there is not a set amount of water). It is still a valid experiment though because it is still testing the effect of food on egg size.
A control also implies that all other conditions are the same.
Oh okay, that’s interesting. I guess your explanation makes a lot more sense; my understanding of reliability was also that when the experiment was repeated several times by a different experimenter, the same results would occur. Although I understood that validity was that the IV was the only ‘IV’ and there weren’t other factors that affected the outcome of the experiment.
Eg, if we take the experiment where beetroot slices were placed in different concentrations of pH, testing for colour of pigment leakage after a set period of time, I would say if there were varying sizes of beetroot slices in each concentration of pH, this would no longer be a controlled variable and essentially be another ‘IV’, hence the experiment would be no longer valid because the experiment is no longer testing the aim, and other variables are being investigated (if that makes sense).
I think you are definitely correct in this case, but maybe my wording was wrong, feel free to correct me.
That being said, I also agree that the answer would be C, thanks for your explanation!
Post by: Razeen25 on April 05, 2018, 01:49:00 am
Post by: PhoenixxFire on April 05, 2018, 10:28:59 am
my understanding of reliability was also that when the experiment was repeated several times by a different experimenter, the same results would occur.Reliability means that you or another person could repeat the experiment and get the same results. The only thing that could change the results of the experiment are if you make a mistake, your method is not clear enough for someone else to follow or (most commonly) if there are variables that aren't controlled - hence why controlling variables is part of reliability.
Post by: ateenytinybear on April 07, 2018, 06:27:32 pm
Which of the following statements best describes the process of hybridisation frequently used in agriculture?
A The transfer of a gene from one species to another.
B The crossing of two genetically different strains of a species.
C The production of genetically identical offspring by cloning.
D The artificial selection and breeding of suitable offspring within a species.
I kinda see how all of these could be the answer so idkkkk :(
thankyou for any help :)
Post by: KT Nyunt on April 08, 2018, 11:11:41 am
can anybody help with this past hsc question?
Which of the following statements best describes the process of hybridisation frequently used in agriculture?
A The transfer of a gene from one species to another.
B The crossing of two genetically different strains of a species.
C The production of genetically identical offspring by cloning.
D The artificial selection and breeding of suitable offspring within a species.
I kinda see how all of these could be the answer so idkkkk :(
thankyou for any help :)
Hybridisation is crossing two organisms of different species or two organisms of different strains of a species, producing a hybrid which has hybrid vigour. Thus, I believe the answer should be (B). (A) is definitely transgenic species. (C) is cloning. Whereas, (D) is just artificial selection or artificial insemination/pollination. So by the process of elimination the answer is (B). A,C and D are processes under the reproductive technologies topic. Although they all (including hybridisation) aim to produce offspring that has favourable characteristics, the process in which they do so is different.
Hope this helps!
Post by: Mate2425 on April 08, 2018, 04:19:21 pm
https://www.boardofstudies.nsw.edu.au/hsc_exams/2015/exams/2015-hsc-biology.pdf
Post by: jasn9776 on April 08, 2018, 04:25:27 pm
Hi could i please get help with understanding why the answer to the 2015 MCQ15 is C. Thank you, please find attached below a link to the paper: :D :D
https://www.boardofstudies.nsw.edu.au/hsc_exams/2015/exams/2015-hsc-biology.pdf
Probably incomplete dominance so Ry is orange. I think they removed it from the syllabus anyways but to work it out just cross RR and YY to get RY then cross two RY to get RR, RY, RY, YY. These are just probablities and the experiment could be close enough to these ratios.
Post by: TheBigC on April 08, 2018, 04:33:15 pm
Hi could i please get help with understanding why the answer to the 2015 MCQ15 is C. Thank you, please find attached below a link to the paper: :D :D
https://www.boardofstudies.nsw.edu.au/hsc_exams/2015/exams/2015-hsc-biology.pdf
Awesome question! I am VCEer, however, hopefully I can be of some help here.
This question is tricky because it requires very careful reading. Notice how it specifically intimates that 'the F2 results were...': it is referring to generation 2, not 1. Thus, the answer is C, as the ORIGINAL parents had genotypes RR and YY, thus producing offspring: RY, RY, RY, RY. These offspring then mated (RY x RY) to yield: RR, RY, RY, YY. Hence, we can see that the ratio of RR (red) : YY (yellow) is roughly equivalent (6:5) and the amount of RY (orange - incomplete dominance) should be approx double, which it is (11).
Post by: Mate2425 on April 08, 2018, 04:46:25 pm
Probably incomplete dominance so Ry is orange. I think they removed it from the syllabus anyways but to work it out just cross RR and YY to get RY then cross two RY to get RR, RY, RY, YY. These are just probablities and the experiment could be close enough to these ratios.Thanks for your help :D
Post by: Mate2425 on April 08, 2018, 04:47:29 pm
Awesome question! I am VCEer, however, hopefully I can be of some help here.Thanks this helped a lot :D
This question is tricky because it requires very careful reading. Notice how it specifically intimates that 'the F2 results were...': it is referring to generation 2, not 1. Thus, the answer is C, as the ORIGINAL parents had genotypes RR and YY, thus producing offspring: RY, RY, RY, RY. These offspring then mated (RY x RY) to yield: RR, RY, RY, YY. Hence, we can see that the ratio of RR (red) : YY (yellow) is roughly equivalent (6:5) and the amount of RY (orange - incomplete dominance) should be approx double, which it is (11).
Post by: Razeen25 on April 11, 2018, 06:44:45 pm
In the 2 mark question 'Identify how the concentration of TWO substances will change as fluid moves through the proximal convoluted tubule', would it be correct to say that "As fluid passes through the proximal tubule, the fluid concentration of water will DECREASE as it passively is reabsorbed into blood by osmosis, and that the fluid concentration of amino acids will also DECREASE as it is re-absorbed into the blood through active transport"?
Thank you!
Post by: Potatohater on April 11, 2018, 08:48:25 pm
Hii!Yeah that's pretty much it, there are other substances but the question only asks for 2 so that's fine
In the 2 mark question 'Identify how the concentration of TWO substances will change as fluid moves through the proximal convoluted tubule', would it be correct to say that "As fluid passes through the proximal tubule, the fluid concentration of water will DECREASE as it passively is reabsorbed into blood by osmosis, and that the fluid concentration of amino acids will also DECREASE as it is re-absorbed into the blood through active transport"?
Thank you!
Post by: Razeen25 on April 11, 2018, 09:00:54 pm
Yeah that's pretty much it, there are other substances but the question only asks for 2 so that's fine
Thank you soo much!! :)
Post by: Kate Science on April 16, 2018, 01:59:02 pm
Hii!
Today in my The Search For Better Health exam there was a multiple choice question showing a picture of Pasteur's experiment being modelled, and there were 2 answers (the other 2 were silly answers) I'm confused about.
The diagram showed two flasks containing broth (one broken, one unbroken) being boiled and the question was 'How is this experiment valid' or something and the two answers were:
c) The use of a control
d) The heat used to boil the broth
I chose C but I don't know if I should have chosen D smh since IDEK if there was a control rip
(C) is the correct answer but it's important to understand the full scope of what you are dealing with. Validity, in first hand investigations, is determined by how well you control all the variables that could possibly impact on the experiment. For example if you wanted to test the effect of 'variable Y' on 'variable Z', then A, B, C, .... X must be controlled. If any factor of A, B, C, ... X is NOT kept constant, then you are now NOT testing the effect of Y on Z - you'll actually be measuring the effect of Y and B on Z etc - not your aim, not valid.
The next thing is about the idea of a 'control' and a 'test' version - in this case the intact and broken glass. This is to with VALIDITY - not reliability. Here's why:
Our test is investigating the effect of 'Variable X - air exposure' on 'Variable Y - microbial growth in broth'. Our CONTROL is testing 'Variable Y - microbial growth in broth' WITHOUT changing 'Variable X - air exposure' so that we can compare the two later on. This is validity - testing your aim - being able to compare an unchanged with something you've changed (i.e. broken neck of flask).
Be careful not to say this has to do with reliability which, in the context of first hand investigations, is purely to do with the consistency and replicability of your results - not the nature or method of your experiment (which fall under validity always).
Post by: Razeen25 on April 18, 2018, 02:31:57 pm
(C) is the correct answer but it's important to understand the full scope of what you are dealing with. Validity, in first hand investigations, is determined by how well you control all the variables that could possibly impact on the experiment. For example if you wanted to test the effect of 'variable Y' on 'variable Z', then A, B, C, .... X must be controlled. If any factor of A, B, C, ... X is NOT kept constant, then you are now NOT testing the effect of Y on Z - you'll actually be measuring the effect of Y and B on Z etc - not your aim, not valid.
The next thing is about the idea of a 'control' and a 'test' version - in this case the intact and broken glass. This is to with VALIDITY - not reliability. Here's why:
Our test is investigating the effect of 'Variable X - air exposure' on 'Variable Y - microbial growth in broth'. Our CONTROL is testing 'Variable Y - microbial growth in broth' WITHOUT changing 'Variable X - air exposure' so that we can compare the two later on. This is validity - testing your aim - being able to compare an unchanged with something you've changed (i.e. broken neck of flask).
Be careful not to say this has to do with reliability which, in the context of first hand investigations, is purely to do with the consistency and replicability of your results - not the nature or method of your experiment (which fall under validity always).
Thank you so much for this, it helped me understand this a lot!
Post by: cnimm2000 on April 19, 2018, 06:53:17 am
I was working on the genetics: code unbroken topic. For dihybrid crosses, does the question state if its linked or unlinked or do we need to figure it out. If so how would i figure out if its linked or unlinked?
Thanks in advance :)
Post by: gumscape on May 14, 2018, 11:17:07 am
thanks!!
Post by: preliminary17hsc18 on May 14, 2018, 04:15:31 pm
Hallo! Does anyone know the host response to influenza? I can't find it in my text book and all these scholarly articles on google aren't making much sense either...
thanks!!
Helloo! I found this really good video about the immune response to influenza, it's quite easy to understand. Hope it helps!
https://www.youtube.com/watch?v=z6TWFHf0g1s
Post by: Stringy on May 14, 2018, 11:43:11 pm
While i was looking at some practice biology questions, i found one worth 4 marks that asks;
"Modern methods of disease control place more emphasis on prevention than on treatment"
DISCUSS this statement using atleast one named disease in your answer.
Just wondering how I would approach the question? Should i provide + / - for both prevention & treatment and relate it to a named disease, or is there a better way to respond.
Cheers.
Post by: KT Nyunt on May 15, 2018, 08:42:36 pm
Hello ! :)
While i was looking at some practice biology questions, i found one worth 4 marks that asks;
"Modern methods of disease control place more emphasis on prevention than on treatment"
DISCUSS this statement using atleast one named disease in your answer.
Just wondering how I would approach the question? Should i provide + / - for both prevention & treatment and relate it to a named disease, or is there a better way to respond.
Cheers.
Hello :)
Yes you're correct. As this is a DISCUSS question, they're looking for you to provide points for and against. But make sure you're explicitly linking your response to the statement they provide, relating it to a named disease (ie. Malaria is a goodie)
Post by: martinarena_ on May 15, 2018, 08:52:08 pm
Hello ! :)
While i was looking at some practice biology questions, i found one worth 4 marks that asks;
"Modern methods of disease control place more emphasis on prevention than on treatment"
DISCUSS this statement using atleast one named disease in your answer.
Just wondering how I would approach the question? Should i provide + / - for both prevention & treatment and relate it to a named disease, or is there a better way to respond.
Cheers.
Hey there!
I'd probably go with what you've suggested, as 'discuss' refers to providing both sides of the argument, luckily, a judgement is not needed in a question like this. So, yes, you'll need to provide both advantages and disadvantages of modern methods of disease control with a named example. You'll probably have to write 2 advantages and 2 disadvantages to equate for the four marks, with an example OR maybe 2 advantages and 1 disadvantage (or the other way around) in addition to the named example. (to be safe, I'd probably chuck in 2 examples - one for an advantage and the other for the disadvantage)
Hope that helps ;D
Post by: Stringy on May 16, 2018, 11:26:11 pm
Malaria is often approached using both methods of prevention and treatment, but like any other disease there are pros and cons to methods related to disease control and relying on one more than the other can often be counter productive.
Prevention:
• Insecticide treated nets have been proven to prevent malaria transmission quite effectivley, with an approximate 20% decrease in disese cases in children under 5, and a 50% decrease in malaria related episodes. Unfortunatley since the introduction of ITNs mosquitos are slowly developing immunity, rendering certain insecticides useless, also giving rise to difficulties of producing insecticides that are effective.
Treatment:
• Antimalarial drugs like chloroquine are very effective at treating malarial infections, chloroquine specifically prevents malaria parasites growing in RBCs. This limits the spread & severity if the disease inside the host.
• Just like certain preventitive measures (ITNs), developed immunity is a problem. Overtime the overuse of chloroquine and other drugs has given rise to drug resistant parasites, this had lead to increased prices for newer treatments and the serious danger of malarial parasites that are unable to be treated effectivley.
Any tips to maybe improve this response or is it fine how it is?
Post by: KT Nyunt on May 17, 2018, 06:24:18 pm
Cheers for the reply, this was my response in the end;
Malaria is often approached using both methods of prevention and treatment, but like any other disease there are pros and cons to methods related to disease control and relying on one more than the other can often be counter productive.
Prevention:
• Insecticide treated nets have been proven to prevent malaria transmission quite effectivley, with an approximate 20% decrease in disese cases in children under 5, and a 50% decrease in malaria related episodes. Unfortunatley since the introduction of ITNs mosquitos are slowly developing immunity, rendering certain insecticides useless, also giving rise to difficulties of producing insecticides that are effective.
Treatment:
• Antimalarial drugs like chloroquine are very effective at treating malarial infections, chloroquine specifically prevents malaria parasites growing in RBCs. This limits the spread & severity if the disease inside the host.
• Just like certain preventitive measures (ITNs), developed immunity is a problem. Overtime the overuse of chloroquine and other drugs has given rise to drug resistant parasites, this had lead to increased prices for newer treatments and the serious danger of malarial parasites that are unable to be treated effectivley.
Any tips to maybe improve this response or is it fine how it is?
Yes, that's more than enough I reckon! The only thing I'd change is perhaps the length... exam time is precious so you wouldn't want to spend a lot of time writing that much on a 4 marker. (You might run out of writing space with your current length) You'd only need to cut a few words here and there, just to make it more succinct. But this isn't crucial, especially if you have small handwriting/write quickly. The importing thing is, you've attacked the question well and have addressed what you've needed to. :)
Post by: Stringy on May 17, 2018, 11:32:04 pm
Yes, that's more than enough I reckon! The only thing I'd change is perhaps the length... exam time is precious so you wouldn't want to spend a lot of time writing that much on a 4 marker. (You might run out of writing space with your current length) You'd only need to cut a few words here and there, just to make it more succinct. But this isn't crucial, especially if you have small handwriting/write quickly. The importing thing is, you've attacked the question well and have addressed what you've needed to. :)
thanks mate, appreciate the help!
Post by: martinarena_ on June 04, 2018, 07:51:27 pm
I was just wondering if anyone could think of an impact that the diphtheria vaccine has had on the environment?
So far, I can only think of social impacts :P
Thank you in advance ;)
Post by: Kate Science on June 18, 2018, 01:42:02 pm
Hi there!
I was just wondering if anyone could think of an impact that the diphtheria vaccine has had on the environment?
So far, I can only think of social impacts :P
Thank you in advance ;)
Hey there, check out my reply in the image below ;D
Post by: Kate Science on June 18, 2018, 02:14:01 pm
Hey guys,
I was working on the genetics: code unbroken topic. For dihybrid crosses, does the question state if its linked or unlinked or do we need to figure it out. If so how would i figure out if its linked or unlinked?
Thanks in advance :)
Hi cnimm2000,
For Genetics: The Code Broken you will need to be able to determine if it is linked or unlinked for some questions.
The simple trick around this is to check out your dihybrid ratios. Let's say we cross TtPp x TtPp
- if the phenotypic ratio is 9:3:3:1, then they are not linked
--- the gametes are far enough to be crossed over TP x Tp x tP x tp
- if the phenotypic ratio is 3:1, then they are linked
--- the gametes are too close and are not split by recombination hence we'll only get e.g. TP x tp cross results
Hope that helps. Cheers!
Post by: Mate2425 on June 19, 2018, 04:09:37 pm
Could i please have some help in finding resources in regards to this question for an assignment - Outline the response by the host - Influenza.
Does the response mean *Immune response and the various factions of it.
Thank yooouuu!!
Post by: KT Nyunt on June 19, 2018, 10:17:09 pm
Hi guys,
Could i please have some help in finding resources in regards to this question for an assignment - Outline the response by the host - Influenza.
Does the response mean *Immune response and the various factions of it.
Thank yooouuu!!
Yes, the host response involves the immune system where a fever is induced and antibodies are produced etc. It is how the host reacts to the invading pathogen to fight against it.
This is not to be confused with symptoms ... which are like what you can observe on a patient, indicating that they have a certain disease.
Hope this helps :)
Post by: itssona on June 20, 2018, 09:27:48 pm
do I just write U instead of T so its AUGGAA or do I reverse the DNA strand?
Post by: Kate Science on June 20, 2018, 09:54:25 pm
hey how do I find the complementary mRNA strand for TACCTTGTACCC
do I just write U instead of T so its AUGGAA or do I reverse the DNA strand?
Hi there 🐸
So complementary means you need to work out what its opposite strand would be. And yep, you're also right that you need to replace the new what-would-be-T's with Uracil because it's now mRNA.
The mRNA complement of TACCTTGTACCC would be:
AUGGAACAUGGG.
Happy to offer more help on transcription, translation, etc if you need clarification on anything else!
Post by: KT Nyunt on June 20, 2018, 10:33:36 pm
The mRNA complement of TACCTTGTACCC would be:
CUGGAACAUGGG.
Careful - That first base should be adenine (A).
The complement mRNA strand should be: AUGGAACAUGGG ;D
Post by: cnimm2000 on June 21, 2018, 07:45:24 am
I still dont seem to understand the benefits and the limitations of using quantitative and qualitative analysis. It would be great if someone can help.
thanks in advance :).
Post by: Kate Science on June 22, 2018, 11:01:48 am
Hey guys,
I still dont seem to understand the benefits and the limitations of using quantitative and qualitative analysis. It would be great if someone can help.
thanks in advance :).
Hiya!
First off you've got to ask yourself, what do qualitative and quantitative mean?
Simply put, qualitative means what is there and quantitative means how much of it is there.
So from that we can suss out some quick pros and cons.
Qualitative observations can be done quickly and are easy to interpret (e.g. you can immediately see a precipitate form in a solubility test and thus conclude what's there, or e.g. you can see what colour flame a compound makes and thus easily say what metal is present (that's examples from HSC Chem Monitoring and Management)). The cons here though are that you cannot measure the amount of anything present - you can not get statistical, numerical results and your results could potentially be unreliable due the variable subjectivity of observation.
Quantitative research involves actually measuring the value of something. You can get a large sample size of data values that will give you a reliable statistical average but inaccuracies are more likely - is it 16.3 mm, 16.2 mm, or 16.42 mm long? (rather than the simpler qualitative option: is it longer than a 15cm ruler? yes or no.)
Both qualitative and quantitative research are valid approaches to experimental aims. Just remember:
Qualitative: yes or no?
Quantitative: how much?
Post by: Razeen25 on June 22, 2018, 01:52:28 pm
I didn't finish :((. There goes my good ranking from half-yearly.
Also the whole assessment was set up so bad, like my teacher realised DURING the assessment she forgot to print out charts for amino acids from mRNA codons and ugh so many other things were a complete mess smhh.
Depressed though, since it was worth 25% :/.
I guess what annoys me is that it's not my lack of understanding the content, but rather my not being able to cut and glue the pieces of paper in time. Like you'd think a HSC assessment would have a more efficient way of modelling a process than a kindergarten-style cut and paste activity, but anyways.
Post by: BrittyG on June 23, 2018, 09:53:59 pm
Had my biology first hand practical on modelling polypeptide synthesis BUT I'M MAD. We had to make TWO models (one normal, one mutation)
I didn't finish :((. There goes my good ranking from half-yearly.
I guess what annoys me is that it's not my lack of understanding the content, but rather my not being able to cut and glue the pieces of paper in time. Like you'd think a HSC assessment would have a more efficient way of modelling a process than a kindergarten-style cut and paste activity, but anyways.
Wow, your practical assessment was so weird !! I had my prac a couple of weeks ago and we had to complete 3 practicals (Making a celery slide to identify Xylem and Phloem, estimate diameter of mammalian blood and recording effect of catalase in potato in hydrogen peroxide) and then answer questions on the other practicals in 9.2 and 9.4 (microbial growth, pH of carbon dioxide, microbes in decay). All up it was worth 80 marks and 25% as well.
The difference between our practical exams is massive. And the fact that yours was cut and paste is just really odd in my opinion, I agree, kindergarten stuff. As for thinking you've failed and your ranking going down, don't be disheartened. You still have your trials coming up (in which you most definitely won't have to cut and paste), work hard on your notes, do past HSC's, COME TO AN LECTURES (<< Hopefully that linked to the lectures page it's my first time trying to link something) and work towards smashing your trial exam. It weighs the most (I think). Put this task behind you and keep working hard, you got this!!
P.S. your teacher seems a bit howz it goin ;D
Post by: OverUnderachiever on June 23, 2018, 10:16:29 pm
if anyone could help, I'd be really grateful
Post by: Kate Science on June 24, 2018, 12:19:31 am
what's the difference between management, prevention, control and treatment of disease? they seem to all have different meanings?
if anyone could help, I'd be really grateful
Here are some literature definitions and references if you’d like to do some extra reading:
Disease management is a system of coordinated heath care interventions and communications for defined patient populations with conditions where self-care efforts can be implemented. Disease management empowers individuals, working with other health care providers to manage their disease and prevent complications. (http://www.who.int/kobe_centre/ageing/ahp_vol5_glossary.pdf) *use this reference to look at different types/components of defining prevention too*
Disease control is a reduction in the incidence, prevalence, morbidity or mortality of an infectious disease to a locally acceptable level; elimination as reduction to zero of the incidence of disease or infection in a defined geographical area; and eradication as permanent reduction to zero of the worldwide incidence of infection. (http://www.who.int/bulletin/volumes/84/2/editorial10206html/en/)
Disease prevention is a procedure through which individuals, particularly those with risk factors for a disease, are treated in order to prevent a disease from occurring. Treatment normally begins either before signs and symptoms of the disease occur, or shortly thereafter. Treatment can include patient education, lifestyle modification, and drugs. (https://www.nature.com/subjects/disease-prevention) *don’t be confused by this use of treatment, it’s merely within the context of this definition, see below for the definition of disease treatment*
Disease treatment can simply be defined as a process designed to achieve a desired health status for a patient or client. (http://www.who.int/kobe_centre/ageing/ahp_vol5_glossary.pdf)
Okay now let’s make those more simple and succinct for the context of the HSC
Disease management: system implemented by health care bodies that focusses on what the individual can do themselves.
Disease control: Deal with a present disease aiming to bring it down to ‘zero’ or ‘normal’ levels
Disease prevention: how to stop the incidence of disease (avoid getting it in the first place) by using eduction, protection (vaccination, immunisation, physical barriers…), quarantine, ‘preventative treatment’, etc….
Disease treatment: How to fix the disease if you’ve got it? May be therapeutic treatment (drugs etc.), education and lifestyle changes (for non-communicable diseases like obesity), or any other method of bringing the patient back to health (NOTE: a treatment improves patient’s quality of life but does not necessarily cure the disease e.g. antiretroviral therapy for HIV doesn’t cure HIV but allows patients to lead relatively normal lives provided they stay on their medication).
(am I right in thinking you’re looking at the tuberculosis dot point? I hope this is useful for that otherwise throw me a quick reply and I can help you out on that one specifically)
Cheers!
Post by: kauac on June 27, 2018, 08:11:49 pm
For well-known substances like DNA and RNA, are we allowed to write their shorthand names in the exam?
Or do we actually have to write 'deoxyribose nucleic acid' etc?
Post by: Opengangs on June 27, 2018, 08:12:57 pm
Hi...You can just write DNA and RNA; the syllabus even shortens it as well. :)
For well-known substances like DNA and RNA, are we allowed to write their shorthand names in the exam?
Or do we actually have to write 'deoxyribose nucleic acid' etc?
Post by: kauac on June 27, 2018, 08:21:37 pm
You can just write DNA and RNA; the syllabus even shortens it as well. :)
Sweet, that's a relief! Imagine how annoying the longer response questions would take if we had to write them out every single time! ;D
Thanks. :)
Post by: moq418 on June 28, 2018, 08:24:41 pm
Post by: KT Nyunt on June 29, 2018, 07:20:37 pm
How do you study for the hsc biology trials that are comming up soon?
I would suggest mainly consolidating your understanding of the 3 core topics so far (and maybe the option if you've done it). You could do this through:
Note making
During these holidays, if you haven't already it'd be a good idea to finalise your notes for all the topics: Maintaining a Balance, Blueprint of Life and A Search for Better Health. If you've already done this... then you could try condensing your notes or begin applying your knowledge...
Answering HSC Questions
A quick google search for "HSC Biology past papers" will get you pretty much all the material you need. You can find some from the NESA website here. Pay close attention to the marking guidelines and criteria as this will help you understand what exactly markers are looking for.
Practice extended response questions
A good place to try to maximise marks is in the extended response section. For this, you could try typing out responses, open book, and sending them to your teacher for feedback. Giving these a lot of thought and time will give you a good idea now, will help you form cohesive extended responses on the actual day. Also, these responses are supposed to test how well you can link and apply your knowledge, so by giving this a lot of time and effort, you're training yourself to think critically and will help you form these links between syllabus dot points.
Teaching
I've said this in many ATAR notes forums because it is honestly the most effective thing, I find, in my study routine. It REALLY helps to make content stick in an efficient and more engaging way. I would normally teach my parents or schoolmates, we'd get out a piece of paper or a whiteboard and I'd attempt to teach the content just as a classroom teacher would, drawing diagrams, writing key words etc. This also helps me measure how well I understand a topic as well as my ability to explain it. I would use my notes as prompters - if I rely on my notes heavily, I may need to revise this again later... or if I don't need it all all, and my explanations are clear (and correct), then I can move on to the next point. If you haven't tried adding this to your routine, I highly recommend you do. You'll surprise yourself on how much you actually understand, just by verbalising it.
I hope this was helpful! Good luck in your preparation for trials ;D
Post by: itssona on July 08, 2018, 02:54:20 am
Post by: Mate2425 on July 09, 2018, 08:14:21 am
Thank you. :D
Post by: AngelWings on July 09, 2018, 02:57:34 pm
can anyone please explain how the dihybrid pea experiment is shown on punnet squares? :/ thank youI won't provide the answer, as you will not learn anything, but I'll explain that a dihybrid pea is heterozygous for two traits.
In the classic case performed by Mendel, the parents (P) are homozygous for the two traits (one is double homozygous dominant, the other is double homozygous recessive). Generally, the F2 are what is shown as the final answer.
Post by: mhuss on July 15, 2018, 01:38:05 am
thank youu
Post by: jasn9776 on July 15, 2018, 10:33:58 pm
lymphocyte produced and matured in the bone marrow (thus B cell)
humoral response: antibody producers. They respond to antigens, which are foreign markers or molecules.
.antibodies are like things that stick on the surface of antigens(foreign particles) and form a antigen-antibody complex which helps disable it and allow phagocytes to engulf it.
T cells
lymphocyte that comes from bone marrow but matures in thymus gland (thus T cell)
cell-mediated response: They respond to i guess to infected cells which can present to cytotoxic t-cells. SO basically the difference is T-cells respond to cells which are infected and present fragments of the invader to t-cells and B-cells respond to antigens which are like foreign substances.
T cells kill cells. Unlike B-cells, they specifically attack other cells by inserting chemicals into them and killing the cell whereas B-cells just produce antibodies and attack the foreign fragments/substances from afar.
I'm not really that sure either but i'm pretty sure T-cells are intracellular and kill the invader that is inside the cell whilst B-cells are extracellular and kill what is not inside a cell.
Post by: mhuss on July 15, 2018, 11:53:18 pm
B-cell
lymphocyte produced and matured in the bone marrow (thus B cell)
humoral response: antibody producers. They respond to antigens, which are foreign markers or molecules.
.antibodies are like things that stick on the surface of antigens(foreign particles) and form a antigen-antibody complex which helps disable it and allow phagocytes to engulf it.
T cells
lymphocyte that comes from bone marrow but matures in thymus gland (thus T cell)
cell-mediated response: They respond to i guess to infected cells which can present to cytotoxic t-cells. SO basically the difference is T-cells respond to cells which are infected and present fragments of the invader to t-cells and B-cells respond to antigens which are like foreign substances.
T cells kill cells. Unlike B-cells, they specifically attack other cells by inserting chemicals into them and killing the cell whereas B-cells just produce antibodies and attack the foreign fragments/substances from afar.
I'm not really that sure either but i'm pretty sure T-cells are intracellular and kill the invader that is inside the cell whilst B-cells are extracellular and kill what is not inside a cell.
makes a little more sense. thank you
xx
Post by: cnimm2000 on July 17, 2018, 09:59:29 pm
Im a bit confused, for the interaction between T and B cells, do we just need to know the antibody mediated immunity?
Post by: KT Nyunt on July 18, 2018, 09:57:41 am
Hey guys
Im a bit confused, for the interaction between T and B cells, do we just need to know the antibody mediated immunity?
Hello,
No, you'll definitely need to understand cell-mediated immunity as well. Here's a run down of everything B cells and T cells...
Interaction between B and T lymphocytes
- Macrophages ingest antigens and display antigenic fragments on their MHCII molecules
- Helper T cells recognise these fragments and secrete cytokines to activate B tells and T cells, making them begin cloning and differentiating for further assistance.
Clonal selection theory
- Many B cells and T cells exist in the lymph nodes. Each B cell and T cell has unique receptors.
- When a foreign particle invades the body, lymph fluid carries them (or their antigenic fragments) to the lymph node is recognised by the specific receptors of one of the B cells. This B cell is ‘selected’ and produces clones of itself with the same receptors
- Antigen presenting cells with antigenic fragments travel to the lymph node. Its antigenic fragments are recognised by specific receptors of one of the T cells. This T cell is ‘selected and produces clones of itself with the same receptors
I've attached a table outlining all the types of B cells and T cells and their roles and an image I found online which sums up the whole process pretty nicely
Hope this helps :)
Post by: Razeen25 on July 22, 2018, 11:49:04 pm
For the dot point 'Discuss evidence for the mutagenic nature of radiation', since the directive term is a "Discuss", what points against evidence for the mutagenic nature of radiation would we use? Or do we not need to have points for and against?
Thank you!!
Post by: Ace2018 on July 23, 2018, 05:37:34 pm
Hii,
For the dot point 'Discuss evidence for the mutagenic nature of radiation', since the directive term is a "Discuss", what points against evidence for the mutagenic nature of radiation would we use? Or do we not need to have points for and against?
Thank you!!
The NESA website () directs students to "Identify issues and provide points for and/or against" for discuss. Therefore, it is not necessary to talk about issues against. Besides, with this dot point you simply have to find various evidence of the ways that the exposure to radiation has the potential to cause mutation. For example, victims of the Hiroshima and Nagasaki nuclear bomb show birth defect in offsprings.
Hope that helps!
Post by: Razeen25 on July 23, 2018, 05:40:17 pm
The NESA website () directs students to "Identify issues and provide points for and/or against" for discuss. Therefore, it is not necessary to talk about issues against. Besides, with this dot point you simply have to find various evidence of the ways that the exposure to radiation has the potential to cause mutation. For example, victims of the Hiroshima and Nagasaki nuclear bomb show birth defect in offsprings.
Hope that helps!
Thank you so much! I knew evidence for but wasn’t sure if we needed against. This clears it up! :)
Post by: Razeen25 on July 28, 2018, 08:33:06 pm
I'm confused over a 5 mark past trial question,
"Use the Darwin/Wallace theory of 'natural selection' to explain the increasing numbers of antibiotic-resistant bacteria AND how this knowledge can be used to reverse this resistance trend."
I understand the first half of the question, as it is just linking the way in which the theory of evolution is responsible for antibiotic resistance, but I don't understand how that knowledge can be used to reverse resistance. I thought antibiotic-resistance could be SLOWED through the use of narrow-spectrum antibiotics, finishing the course, etc, but reversed?
Any help would be appreciated!
Post by: beeangkah on July 28, 2018, 09:39:00 pm
I'm struggling with the meiosis diagram-type questions where it asks to find the possible genotypes.
For instance these HSC questions
2002 Q22
2007 Q22d
After looking at sample answers, I can work backwards and see how it was answered, but I don't understand why it was done that way.
Could someone please explain the thought process on how to answer the above questions?
Thanks ;D
Post by: KT Nyunt on July 29, 2018, 03:28:52 pm
Hii,
I'm confused over a 5 mark past trial question,
"Use the Darwin/Wallace theory of 'natural selection' to explain the increasing numbers of antibiotic-resistant bacteria AND how this knowledge can be used to reverse this resistance trend."
I understand the first half of the question, as it is just linking the way in which the theory of evolution is responsible for antibiotic resistance, but I don't understand how that knowledge can be used to reverse resistance. I thought antibiotic-resistance could be SLOWED through the use of narrow-spectrum antibiotics, finishing the course, etc, but reversed?
Any help would be appreciated!
Yeah that's confusing. I think in the exam I would've just talked about how knowledge of antibiotic resistance leads to solutions that would slow this process (like the ones you've pointed out). I think this technically is what they're asking for - slowing down the fast moving trend I guess reverses the resistance trend... (if that makes any sense to you)
It's not like strains of bacteria can de-evolve and become non-resistant. Maybe our B cells and T cells can evolve and become better at attacking bacterial infections??? I think this is just simply over complicating the question. It probably just wants you to talk about taking the full course and not overusing antibiotics on populations.
Hope this helps :)
Post by: KT Nyunt on July 29, 2018, 04:04:19 pm
Hi,
I'm struggling with the meiosis diagram-type questions where it asks to find the possible genotypes.
For instance these HSC questions
2002 Q22
2007 Q22d
After looking at sample answers, I can work backwards and see how it was answered, but I don't understand why it was done that way.
Could someone please explain the thought process on how to answer the above questions?
Thanks ;D
So for the 2002 paper with question 22, they've asked to construct a table listing possible genotypes that could be produced after meiosis with random segregation has occurred and the expected frequency of each genotype.
The cell features 3 pairs of homologous chromosomes. In meiosis this will divide into haploid cells like in the diagram if attached (see attachment). Note that a haploid cell has 1 chromatid of from each of the 3 homologous chromosomes pairs. So to find all the possible genotypes, we basically have to find all the possible combinations where one chromatid can be E or E, another can be B or b and the last one can be G or g
The possible combinations we can get are:
EBG
EBg
EbG
Ebg
As there are 4 of them and they all have an equal chance of being the genotype, they all have an expected frequency of 25%
For the 2007 paper, question 22d, make sure you:
1) show the difference between genes and alleles by defining them both
2) make reference to the diagram as well
A sample answer could be:
Spoiler
Genes are sections of DNA that code for the production of a specific polypeptide (e.g the section of DNA that codes for B or b). Whereas, alleles are variations of genes (e.g. B and b are variations of a gene)
Hope this helps :)
Post by: beeangkah on July 30, 2018, 08:54:20 am
So for the 2002 paper with question 22, they've asked to construct a table listing possible genotypes that could be produced after meiosis with random segregation has occurred and the expected frequency of each genotype.
The cell features 3 pairs of homologous chromosomes. In meiosis this will divide into haploid cells like in the diagram if attached (see attachment). Note that a haploid cell has 1 chromatid of from each of the 3 homologous chromosomes pairs. So to find all the possible genotypes, we basically have to find all the possible combinations where one chromatid can be E or E, another can be B or b and the last one can be G or g
The possible combinations we can get are:
EBG
EBg
EbG
Ebg
As there are 4 of them and they all have an equal chance of being the genotype, they all have an expected frequency of 25%
For the 2007 paper, question 22d, make sure you:
1) show the difference between genes and alleles by defining them both
2) make reference to the diagram as well
A sample answer could be:SpoilerGenes are sections of DNA that code for the production of a specific polypeptide (e.g the section of DNA that codes for B or b). Whereas, alleles are variations of genes (e.g. B and b are variations of a gene)
Hope this helps :)
Thanks for your answer! For the 2007 one I was meant to write b) though, sorry.
Post by: KT Nyunt on August 05, 2018, 10:13:26 am
Thanks for your answer! For the 2007 one I was meant to write b) though, sorry.
Sorry it took me a while to get back to you!
So for b)... I took a screenshot of the cell in the question. We see the the homologous chromosomes are separated and drawn to opposite sites of the cell by the spindles (as indicated by the dotted lines). So then after the first meiotic division, one cell will have the two chromosomes on the left of the picture and the other cell will have the two chromosomes on the right.
Then, we know in the process of meiosis, there's a second meiotic division, where we end up with 4 daughter cells. So for one cell, we separate it into 2 gametes.
The gametes that can come from cell with the chromosomes on the left are:
Spoiler
A B E D
A b E D
A b E D
Spoiler
a B e d
a b e d
a b e d
Remember each gamete must have one of each gene (ie. the gene that codes for A or a, the gene that codes for B or b etc.)
Hope this helps :)
Post by: amelia20181 on August 05, 2018, 07:04:06 pm
Post by: BrittyG on August 05, 2018, 07:19:24 pm
is it possible to learn the whole syllabus in 2 weeks and get a good mark and how??
Naomi's Syllabus notes + any other bio notes from the notes downloads section, highlight, sticky notes and annotate them to actively learn then complete past paper questions.
That is my best advice for you, my friend.
Post by: amelia20181 on August 05, 2018, 07:23:20 pm
a) transmission of sound waves
b) amplification of sound waves
c) Reception of sound waves
Post by: BrittyG on August 05, 2018, 07:36:14 pm
what are the parts of the ear involved in
a) transmission of sound waves
b) amplification of sound waves
c) Reception of sound waves
Haven't quite got up to this part of the syllabus yet but hopefully, this can help
(this can be found in communications notes in the downloads section)
Post by: amelia20181 on August 07, 2018, 10:31:47 am
Post by: Opengangs on August 07, 2018, 02:40:52 pm
do helper T cels help killer T cells identify the antibodyHey, amelia20181.
The primary role of helper T cells is to activate B cells to secrete antibodies. But they also play a huge role in activating cytotoxic T cells and macrophages to attack targeted cells. It's important to note that helper T cells don't actually kill the cells; that's what cytotoxic T cells are for (:
Post by: Scooby on August 08, 2018, 01:09:30 pm
do helper T cels help killer T cells identify the antibody
Cytotoxic (killer) T cells recognise and bind MHC-bound peptide, not antibody
Post by: amelia20181 on August 08, 2018, 10:27:48 pm
Post by: martinarena_ on August 08, 2018, 10:34:15 pm
what does a renal dialysis machine actually do?
Hey there,
Check out the info from these links on renal dialysis, found they were really helpful and explained it really well :)
https://www.sjog.org.au/our-services/medical-and-surgical/renal-dialysis
https://www.youtube.com/watch?v=i0fgukbjnQw
Post by: siimraan on August 10, 2018, 05:39:53 pm
analyse information from secondary sources to outline the evidence that led to Beadle and Tatum’s ‘one gene – one protein’ hypothesis and to explain why this was altered to the ‘one gene – one polypeptide’ hypothesis
Post by: Razeen25 on August 10, 2018, 09:16:31 pm
Can someone please explain this dot point,
analyse information from secondary sources to outline the evidence that led to Beadle and Tatum’s ‘one gene – one protein’ hypothesis and to explain why this was altered to the ‘one gene – one polypeptide’ hypothesis
For this dot point, its good to know that in the early 20th century, biologists were unsure about the chemical nature of hereditary material - whether it was proteins or DNA.
George Beadle and Edward Tatum hypothesised that one GENE produced one enzyme (pretty much that DNA/genes were indeed hereditary material).
To prove their hypothesis, they conducted an experiment using a bread mould called Neurospora crassa.
- They grew the Neurospora crassa mould on a minimal medium (sugars, salts and vitamins) in test tubes.
- The spores of the mould were then exposed to x-ray radiation which INDUCED mutations (changed sequence of DNA).
- They then found that some mutant strains of the mould could not produce an amino acid essential for its survival, and could not grow.
So from this; they hypothesised that the x-ray mutated the gene that coded for the particular enzyme which was responsible for producing the amino acid (that was no longer produced). Hence, showing that ONE GENE was responsible for the production of ONE ENZYME.
Their hypothesis was altered to 'one gene - one polypeptide' because it was found that genes code for some proteins that dont become enzymes, and proteins are made up of one or more polypeptides.
So now we know that ONE GENE codes for ONE ENZYME.
I hope I just made sense then lol smh
Post by: amelia20181 on August 11, 2018, 08:25:53 pm
for b can you say
ensure the temperature is kept constant throughout the experiment
Post by: BrittyG on August 15, 2018, 06:15:49 pm
for b can you say
ensure the temperature is kept constant throughout the experiment
If you have a look at the temperature column in all experiments it remains constant at 37şC, and the question asks to identify changes in the experiment to make it more valid. For b) you could say that having the students complete the experiment for the same amount if time would make it more valid :)
Post by: amelia20181 on August 15, 2018, 06:57:26 pm
around how much should you write for a 7 marker
if you just write pelvis and not renal pelvis when labelling a diagram of a kidney would you get a mark
if the ratio of urine concentration to plasma is 4:1 would the organism be more suited to a desert environment
Post by: KT Nyunt on August 16, 2018, 01:46:59 pm
if there is a decrease in blood pressure would you need aldosterone to increase salt reabsorption or antidiuretic hormone
Aldosterone - this would increase salt concentration of blood, consequently water follows due to osmosis, increasing blood volume/pressure
around how much should you write for a 7 marker
I would say for a 7-8 mark question, you're aiming to write around two pages, depending on your handwriting and how succinctly you can communicate your ideas. But generally, aim for 2 pages at least.
if you just write pelvis and not renal pelvis when labelling a diagram of a kidney would you get a mark
I think it's definitely more accurate to say renal pelvis. But maybe if you pointed at the right spot the teacher will be kind enough to give you a mark.
if the ratio of urine concentration to plasma is 4:1 would the organism be more suited to a desert environment
So the urine concentration is much higher than plasma. That means the organism is excreting a lot of wastes and solutes but not a lot of water, as water is being reabsorbed in the plasma, giving it a low concentration. Hence, yes, the organisms is more suited to a desert environment as it is conserving water.
Hope this helps! :)
Post by: kauac on August 16, 2018, 04:49:32 pm
• LT: explain how one of the following strategies has controlled and/or prevented disease:
- public health programs
- pesticides
- genetic engineering to produce disease-resistant plants and animals
Can we still be asked about any of the 3 in an exam question??
Post by: amelia20181 on August 16, 2018, 05:47:38 pm
can you say that a lizard lies in the shade so that its body temperature is cooler than the air
would respiratory tract infections or diarrhoeal diseases be caused by untreated drinking water
can you say that something is negative feedback because it returns to the stable state
when you are evaluating a statement should you first say the statement is correct
Post by: KT Nyunt on August 16, 2018, 07:06:39 pm
For the syllabus dotpoint:
• LT: explain how one of the following strategies has controlled and/or prevented disease:
- public health programs
- pesticides
- genetic engineering to produce disease-resistant plants and animals
Can we still be asked about any of the 3 in an exam question??
Yes I think so. I would have an idea of how each generally help control the spread and occurrence of disease and know an example for each.
I just had my trials and it included a question a stimulus with a public health program. So I would suggest not just learning one (even though that's what the syllabus says)
- note: it may just be something my school does but it's safer to just learn an example for each. You most likely already know an example for all of them through points in the search for better health or other core topics
Post by: KT Nyunt on August 17, 2018, 08:15:40 pm
would an organism with a 14:1 ratio be more suited to a desert environment than the organism with 4:1
what's the ratio? Solute/water concentration in urine vs blood?
Remember, to be more suited for a desert environment, it needs to conserve water by excreting very small amounts of highly concentrated urine (as it removed wastes but not a lot water as it is reabsorbed at the nephron, hence blood would have a higher amount of water) - use this to answer your question
can you say that a lizard lies in the shade so that its body temperature is cooler than the air
I think it's more accurate to say that since the lizard is an ectotherm, meaning that it cannot control internal body temperatures as it fluctuates with ambient temperature, in hot temperatures, it stays in the sheltered areas to avoid the hot sun.
would respiratory tract infections or diarrhoeal diseases be caused by untreated drinking water
Diarrhoeal illnesses - for example cholera, typhoid, and dysentery.
can you say that something is negative feedback because it returns to the stable state
Yeah, I'd also add that it's negative feedback because it counteracts changes from the stable state
when you are evaluating a statement should you first say the statement is correct
Yes, I think it's good to start by immediately answering the question and then breaking it down why you believe a statement is correct/incorrect/correct to some degree.
If it feels too robotic to say "The statement [insert statement here] is correct because" I would normally paraphrase the statement and then say "to a great extent/to some extent etc."
:D
Post by: amelia20181 on August 18, 2018, 05:16:37 pm
would you get a mark if you say humans can see in the visible spectrum but get the range wrong
how would you write an epidemiological study
Post by: amelia20181 on August 18, 2018, 09:16:29 pm
Post by: KT Nyunt on August 19, 2018, 10:55:05 am
would you get a mark if you say bees can see in infrared
No, because I believe that it's incorrect unfortunately. Bees can see ultraviolet, which allows them to see special patterns on flowers, allowing it to spot foot easily. If you need an animal that can see infrared, the snake is a good example. It has pits between each eye and nostril and can detect infrared. As heat is a form of infrared, this allows the snake to detect body heat emitted from their prey, allowing them to detect pray easily.
would you get a mark if you say humans can see in the visible spectrum but get the range wrong
mmm idk, maybe if it was out of 2 you'd get 1 mark?
how would you write an epidemiological study
A good epidemiological study (the study of diseases - which helps to explain the cause and effect relationship between a risk factor and a disease) always has these 5 features:
1) collects data from a wide range of people - age, sex, occupation, geographical location, ethnicities etc. - improves validity as it considers anything that might skew results
2) collects data from a large number of people (a couple hundred thousands) - this improves reliability
3) Shows the effect of an increased dosage of a risk factor (a proportional relationship should be seen - ie. people who smoke 40 packs a day had an higher number of cases of lung cancer than those who smoke 10 packs a day)
4) Has a control group - ie. people who don't smoke at all - improves validity
5) The study is conducted over a long period of time (as for cases like lung cancer, the number of years between the occurrence of lung cancer and the onset of smoking for an individual is ~40 years)
Thanks KT Nyunt!
No problem! ;D
Post by: BrittyG on August 19, 2018, 10:34:18 pm
Post by: amelia20181 on August 21, 2018, 05:11:50 pm
and how would you draw a diagram to show punctuated evolution
Post by: BrittyG on August 22, 2018, 12:32:11 pm
→ For example; sharks and dolphins. They both live in the open ocean (similar environment), similarities are flippers, strong swimmers and tails. Dolphins are mammals and Sharks are fish. The common ancestor is ichthyosaur (reptile).
Divergent evolution: when groups of a single species are geographically separated into isolated populations in different environments, and develop different adaptations as a result.
→ For example; Darwin found 14 different species of finches on the Galapagos and Coco islands. They all had grey/black feathers, similar calls, nests, eggs and courtship displays (indicating a common ancestor. But their habitats, diets, body sizes and beaks were all different (indicating divergence).
Punctuated Equilibrium is the theory by Eldrige and Gould which states that there are periods in which little or no evolution is taking place, followed by extreme amounts of change in a short space of time, usually as a product of high environmental pressures.
→ For Example; The apparent ‘sudden’ appearance of new species of dinosaurs in the Judith river area - there had been environmental pressures that caused a small group to move away and evolve quickly, then move back.
So the difference between these two would be the fact that Convergent involves species living in the same environment developing similar traits whereas Divergent involves the adaptation of a species due to its movement from an environment in order to survive.
Not too sure about that diagram though.
Post by: Mate2425 on September 03, 2018, 11:41:27 pm
Thanks, Mate2425.
Post by: amelia20181 on September 04, 2018, 08:53:13 pm
Post by: BrittyG on September 04, 2018, 11:33:33 pm
Hi everyone, i have been stirring on this syllabus dot point in the Biology option of Communication - Define the term threshold and explain why not all stimuli generate an action potential. ...... I am unsure what the last part of the question means "explain why not all stimuli generate an action potential". Any helps as soon as possible would be of great appreciation.
Thanks, Mate2425.
- Threshold refers to the minimum voltage required to generate an action potential in a neurone.
- The action potential is an ‘all-or-none’ response either the level of stimulation is below the threshold > nothing happens or it reaches threshold and > action potential is generated.
- THRESHOLD FOR ACTION POTENTIAL IS -55mV.
- Small stimulus still depolarises membrane but not enough to reach threshold > action potential. IF STIMULUS IS NOT INTENSE ENOUGH > DOESN’T REACH THRESHOLD > NO ACTION POTENTIAL!!
E.g. A weak stimulus like dim light might only produce 5 action potentials per second in the photoreceptor cells of the eye, whereas a strong stimulus like a flash of bright light might produce 150 action potentials, however for an action potential to occur both stimuli must reach the required threshold.
Post by: Mate2425 on September 04, 2018, 11:49:27 pm
A neurone and a neuron are the same thing but why is there different spelling
Hi, Amelia20181
Like you said they are the same thing, and the reason for the different spelling stems from the phrase neurone = restricted to non-technical concepts ... whereas in stark contrast neuron is reserved for the standard scientific spelling.
Hope this helps :)
Mate2425.
Post by: amelia20181 on September 08, 2018, 06:00:16 pm
Post by: kauac on September 08, 2018, 06:09:26 pm
Can you say Down syndrome is caused by a mutation
Hi,
Down syndrome is caused by the inheritance of an extra chromosome, as a result of incomplete separation during meiosis.
So to say that it is a 'mutation' could be a bit of a stretch, because the word can have connotations that the condition can be acquired at any given time, rather then being present at birth. And we know that it is definitely a condition inherited by genetics.
Hope this clarifies things. :)
Post by: Razeen25 on September 10, 2018, 01:54:30 am
I know not many schools do the Genetics option but unfortunately my school does, and my biology teacher has been away and I'm LOST. I'm not sure if anybody here has done it but if so, could somebody please help me understand the dotpoint 'outline the procedure to produce recombinant DNA'. From what I initially understood, this was a simple process just like in Blueprint of Life as recombinant DNA refers to combining DNA from two different species, eg the process of transgenesis which I understand. But for this specific dot point, all the information in textbooks is about separating DNA, inserting it into a plasmid and then cloning it in a bacterium and I'm confused. Where does the other species' DNA come from? Or is the plasmid the other species? Genetics is really hard :(
Post by: PhoenixxFire on September 10, 2018, 07:31:49 am
Hii,Obviously I don’t do HSC, so I’m not exactly sure what you need to know but we do a bit about plasmids in VCE.
I know not many schools do the Genetics option but unfortunately my school does, and my biology teacher has been away and I'm LOST. I'm not sure if anybody here has done it but if so, could somebody please help me understand the dotpoint 'outline the procedure to produce recombinant DNA'. From what I initially understood, this was a simple process just like in Blueprint of Life as recombinant DNA refers to combining DNA from two different species, eg the process of transgenesis which I understand. But for this specific dot point, all the information in textbooks is about separating DNA, inserting it into a plasmid and then cloning it in a bacterium and I'm confused. Where does the other species' DNA come from? Or is the plasmid the other species? Genetics is really hard :(
So the foreign DNA is normally something that is useful to humans - for example the insulin gene.
Both it and the plasmid (from bacteria) are cut with the same restriction enzyme, leaving them with conplimentary sticky ends. They are then mixed together and some of the foreign genes will bind to the plasmid (some of the plasmids will also just rejoin without the new gene). These recombinant plasmids are then put into bacteria (plasmids are naturally exchanged between similar bacteria).
The bacteria that have the recombinant plasmid then reproduce and you end up with lots of bacteria producing insulin (or whatever the gene is for) which can then be extracted and used.
Post by: amelia20181 on September 10, 2018, 01:15:15 pm
Post by: beeangkah on September 10, 2018, 05:14:25 pm
Could someone please explain why the answer is B lol
Post by: Razeen25 on September 10, 2018, 05:28:47 pm
Obviously I don’t do HSC, so I’m not exactly sure what you need to know but we do a bit about plasmids in VCE.
So the foreign DNA is normally something that is useful to humans - for example the insulin gene.
Both it and the plasmid (from bacteria) are cut with the same restriction enzyme, leaving them with conplimentary sticky ends. They are then mixed together and some of the foreign genes will bind to the plasmid (some of the plasmids will also just rejoin without the new gene). These recombinant plasmids are then put into bacteria (plasmids are naturally exchanged between similar bacteria).
The bacteria that have the recombinant plasmid then reproduce and you end up with lots of bacteria producing insulin (or whatever the gene is for) which can then be extracted and used.
Thank you this helped!
Post by: Bri MT on September 10, 2018, 05:32:44 pm
From 2015 HSC
Could someone please explain why the answer is B lol
D would suggest that strict hygiene practices shouldn't be followed for newborns, which rules it out as an answer
C isn't really relevant, so that is ruled out too
A suggests that personal hygiene is completely unnecessary for older babies - but this is untrue
We know that newborns' immune systems aren't yet mature, and that this makes them more susceptible to pathogens (hence why its an important advantage that antibodies from the mother diffuse across via the placenta before birth)
Hope this helps :)
Post by: 13kanel on September 13, 2018, 02:47:26 pm
I was wondering if someone can explain T cells and B cells to me i am completely lost on them
;D
Post by: KT Nyunt on September 13, 2018, 09:21:34 pm
Heyyyyy guys
I was wondering if someone can explain T cells and B cells to me i am completely lost on them
;D
Here are some screenshots from my notes :) this gives an overview on pre much everything you need to know about B cells and T cells. Hope this helps! If you need any further clarification on anything let me know.
Post by: KT Nyunt on September 13, 2018, 09:44:19 pm
can someone please explain this
Do you have the answers? I would probably say the answer is D.
- As substrate is being used and turned into products, the concentration of substrate will decrease (hence why it should be D)
- Enzymes can't decrease in concentration because enzymes are catalysts, hence they remain unchanged and unaffected after the reaction (so it's not C)
- The concentration of the product is technically increasing each time, it is just the rate at which the product is formed is decreasing because there's less and less substrate available (so it's not B)
- If D is not right it might be A tbh. The reason being as substrate concentration decreases, so would the rate of enzyme activity (so it's technically also right) but we have to pick the most correct answer. Since substrate concentration has a more direct correlation to the amount of product (the more product produced, the more substrate consumed), D is more correct as it explains the graph the best
Hope this helps :)
Post by: amelia20181 on September 14, 2018, 07:56:07 pm
can you explain why the answer for this question is b
Post by: Owlbird83 on September 14, 2018, 08:44:05 pm
Thanks!
can you explain why the answer for this question is b
Because there are two things you are changing in the experiment:
-the type of enzyme
-the pH
Post by: amelia20181 on October 01, 2018, 03:23:18 pm
Post by: ilovemycat on October 02, 2018, 08:15:04 am
explain why some stimuli would not generate an action potential in a neurone?
thanks so much
Post by: kauac on October 02, 2018, 10:34:44 am
hey, this is a question form 2015 hsc biology communciation section. just wondering , can someone help me out with it? im kind of confused even tho i know its supposed to be a "general/easy" question :'( :'(
explain why some stimuli would not generate an action potential in a neurone?
thanks so much
Hi...
The stimuli must exceed the threshold potential in order to generate the action potential in a neurone. Any level of stimulation below the threshold will not induce anything. :)
Are prions cells and can they reproduce outside a host cell
Prions are abnormal proteins, so they are a chemical, not a cell. Therefore, they cannot reproduce as such, but rather, can cause healthy proteins in cells to assume the abnormal shape, so that they cannot function effectively. This is how they cause disease. :)
Post by: kauac on October 02, 2018, 10:38:11 am
What is the difference between independent assortment and random segregation? I always get confused between these two...
Post by: PhoenixxFire on October 02, 2018, 12:59:49 pm
Hi...Random segregation means that homologous chromosomes are randomly placed into the daughter cells. Independent assortment means that which of a homologous chromosome is placed into a daughter cell has no effect on which copy of a different chromosome is placed into the same daughter cell.
What is the difference between independent assortment and random segregation? I always get confused between these two...
That's why when genes are independent it means that they're on different chromosomes. So if gene A and gene B are on different chromosomes (lets say gene A is on 13 and gene B is on 20) then getting allele A (located on the first homologous copy of chromosome 13) of gene A does not affect whether you will get allele A (chromosome 20, copy 1) or allele B (chromosome 20, copy 2) of gene B.
When genes are linked they're on the same chromosome - so they don't assort independently and are generally inherited together (barring things like crossing over separating them).
Post by: martinarena_ on October 02, 2018, 04:38:11 pm
Just had a quick question regarding the Biotechnology Syllabus - for the following dot points do we only choose one of the suggested or was it providing an example for EACH of the ones they've listed? (bit of a stupid question, but the wording of the dot point just hit me hard haha)
• describe one example from the following applications of aquaculture:
ー production of a pharmaceutical from algae
ー farming of a marine animal
• describe one example from the following applications of animal or plant biotechnology:
ー production of monoclonal antibodies
ー recombinant vaccines to combat virulent animal diseases
• describe one example from the following applications of biotechnology in medicine:
ー tissue engineering using skin transplantation as an example
ー gene delivery by nasal sprays
ー production of a synthetic hormone, such as insulin
Thank you in advance :) !
Post by: Ace2018 on October 02, 2018, 06:43:29 pm
Post by: martinarena_ on October 02, 2018, 07:22:58 pm
HEY GUYS! TO ANYONE DOING MALARIA AS AN INFECTIOUS DISEASE, WHAT IS THE HOST RESPONSE? I'VE DUG THROUGH THE INTERNET HIGH AND LOW BUT KEEP ENDING UP IN COMPLEX REPORTS AND ARTICLES THAT ARE REALLY IN DEPTH AND WAY BEYOND THE BIO SYLLABUS. ANY HELP WOULD BE APPRECIATED! :) :)
Hi there!
Basically, when the plasmodium is inside the human liver (where it produces asexually) it is isolated from the host's immune response. However, when the merozoites (daughter parasites) are released from the liver and enter the red blood cells, this is when the host begins to produce antibodies against it - but get this, the surface antigens of the plasmodium actually changes periodically! This allows it to avoid the host's immune response - therefore the changing surface antigens are not recognised by the antibodies already produced by the host.
Hope this is helpful :)
Post by: charlottemchenry on October 02, 2018, 07:32:32 pm
In regards to 'evaluate' and 'assess' questions for Biology are we allowed to be half half...
Like for English and Legal, often I'll say "somewhat effectiveness" or "mostly effective" however when I've read aloud bio answers in class despite me giving both positive and negative things whenever I say "somewhat" my teacher says we have to choose one or the other.
I just wanted to check if this is actually the case or in the HSC can we be on the fence?
Thank you :)
Post by: kauac on October 02, 2018, 08:15:54 pm
Hey,
In regards to 'evaluate' and 'assess' questions for Biology are we allowed to be half half...
Like for English and Legal, often I'll say "somewhat effectiveness" or "mostly effective" however when I've read aloud bio answers in class despite me giving both positive and negative things whenever I say "somewhat" my teacher says we have to choose one or the other.
I just wanted to check if this is actually the case or in the HSC can we be on the fence?
Thank you :)
Hi...
Let's take a look at the NESA definitions for each:
Evaluate: Make a judgement based on criteria; determine the value of.
Assess: Make a judgement of value, quality, outcomes, results or size.
So it is very clear that you need to make a judgement, and you techniquely have, by saying it is 'somewhat effective'. However, this choice of words can sometimes come across as too much like a discuss question, and you cannot really show a clear judgement and still sit at 50/50. Thus, it is always best to pick one side. You can still show in minor ways how they are / aren't effective (this shows you have thought about your response), but really emphasise which side you are taking - especially at the start and end of your answer.
Hope this helps. :)
Post by: charlottemchenry on October 02, 2018, 10:13:02 pm
Hi...
Let's take a look at the NESA definitions for each:
Evaluate: Make a judgement based on criteria; determine the value of.
Assess: Make a judgement of value, quality, outcomes, results or size.
So it is very clear that you need to make a judgement, and you techniquely have, by saying it is 'somewhat effective'. However, this choice of words can sometimes come across as too much like a discuss question, and you cannot really show a clear judgement and still sit at 50/50. Thus, it is always best to pick one side. You can still show in minor ways how they are / aren't effective (this shows you have thought about your response), but really emphasise which side you are taking - especially at the start and end of your answer.
Hope this helps. :)
Thanks so much that makes sense :)
Post by: edumax on October 05, 2018, 11:43:13 am
It's too overwhelming to know where to start :-[
Post by: Owlbird83 on October 05, 2018, 01:55:53 pm
HOW THE HECK DO YOU STUDY EFFECTIVELY FOR BIO???
It's too overwhelming to know where to start :-[
I did A4 sheets for each topic and did a mind map of key points, using my textbook and notes and the study design. I think it sort of helps to organise the big jumble of information.
Also, do practice exams and then you can identify areas where you need to focus more on.
Hope this helps ;D
Post by: Razeen25 on October 06, 2018, 01:20:54 am
Hi there!
Just had a quick question regarding the Biotechnology Syllabus - for the following dot points do we only choose one of the suggested or was it providing an example for EACH of the ones they've listed? (bit of a stupid question, but the wording of the dot point just hit me hard haha)
• describe one example from the following applications of aquaculture:
ー production of a pharmaceutical from algae
ー farming of a marine animal
• describe one example from the following applications of animal or plant biotechnology:
ー production of monoclonal antibodies
ー recombinant vaccines to combat virulent animal diseases
• describe one example from the following applications of biotechnology in medicine:
ー tissue engineering using skin transplantation as an example
ー gene delivery by nasal sprays
ー production of a synthetic hormone, such as insulin
Thank you in advance :) !
I don't do biotech, but maybe look through all the past papers for biology up till 2001, and see if they've ever specified one of those and generally ask for an example
Post by: amelia20181 on October 06, 2018, 09:29:42 pm
A) releasing ADH to increase reabsorption of water
B) releasing ADH to increase uptake of salts
C) releasing aldosterone to increase reabsorption of water
D) releasing aldosterone to increase uptake of salts
Why is the answer for this question A and not d
Post by: amelia20181 on October 06, 2018, 09:35:21 pm
Post by: terassy on October 06, 2018, 10:43:56 pm
When blood pressure drops, the body responds by:
A) releasing ADH to increase reabsorption of water
B) releasing ADH to increase uptake of salts
C) releasing aldosterone to increase reabsorption of water
D) releasing aldosterone to increase uptake of salts
Why is the answer for this question A and not d
Can't be B or C. So either A or D, since it's talking about blood pressure the answer should be D.
Post by: Mate2425 on October 08, 2018, 03:54:30 pm
https://educationstandards.nsw.edu.au/wps/wcm/connect/fc23024b-f91e-468c-90b5-8d522b8d2dbf/2017-hsc-biology.pdf?MOD=AJPERES&CACHEID=ROOTWORKSPACE-fc23024b-f91e-468c-90b5-8d522b8d2dbf-m0Qr1Ki
Many thanks ;)
Post by: Razeen25 on October 09, 2018, 07:14:45 pm
My understanding is this:
1. A restriction enzyme is used to cut a section of DNA
2. The fragments are placed on gel where electrical impulses cause fragments to separate by size (gel electrophoresis).
3. The fragments are then stained by fluorescent dye which glows, and cut again.
4. A radioactive probe (single stranded sequence of DNA that is complementary to the gene) is are tagged with radioactive marker, and attached to complementary gene and inserted into human chromosome.
5. When a light is shone, the probe glows showing the location of the gene.
That’s what I recall from reading notes, however I don’t understand how the process (if that’s even correct) is recombinant DNA technology or why original DNA is cut up TWICE and probe isn’t just added in initially ugh smh.
Any help would be greatly appreciated :((.
Post by: kauac on October 10, 2018, 07:42:55 am
When blood pressure drops, the body responds by:
A) releasing ADH to increase reabsorption of water
B) releasing ADH to increase uptake of salts
C) releasing aldosterone to increase reabsorption of water
D) releasing aldosterone to increase uptake of salts
Why is the answer for this question A and not d
Potentially because more water = higher blood volume, and higher blood volume increases blood pressure more rapidly? In homeostasis, the body works efficiently to counteract changes, whilst I think the effect of increased salts would more gradually increase blood pressure. :)
Hey guys was wondering if someone could please give me a thorough explanation to HSC 2017 MCQ9. and MC.Q20.
https://educationstandards.nsw.edu.au/wps/wcm/connect/fc23024b-f91e-468c-90b5-8d522b8d2dbf/2017-hsc-biology.pdf?MOD=AJPERES&CACHEID=ROOTWORKSPACE-fc23024b-f91e-468c-90b5-8d522b8d2dbf-m0Qr1Ki
Many thanks ;)
Hi...
Q9: Definitely seems a bit like a trick question! Test tube Y is the experiment because it is the only one containing both amylase and starch. Test tube W is the control because they wanted to check whether starch naturally reacted with itself. The 1ml of water ensures there is the same ratio of molecules as in Test tube Y. Thus, the Y & W option is A, so this is the answer. :)
Q20: Straightaway we know it cannot be C, because enzymes are not used in the reaction. It can't be B, because the reaction is still producing the product, so product concentration cannot be decreasing. A seems logical, but it is stretched to get this conclusion from the graph. Therefore, the answer must be D. :)
Post by: jasn9776 on October 10, 2018, 07:54:10 pm
2008 Q15: i need help with this punnett square. I understand how to narrow it down to C and D since the male gets the X-chromosome from the mother but i don't know why D is wrong.
Post by: Sine on October 10, 2018, 08:16:00 pm
http://www.k6.boardofstudies.nsw.edu.au/wps/wcm/connect/88b8b597-9f96-46d5-a389-0a86145f97bb/biology-hsc-exam-2008.pdf?MOD=AJPERES&CACHEID=ROOTWORKSPACE-88b8b597-9f96-46d5-a389-0a86145f97bb-lGcvlf6D is wrong because there is nothing called a male "carrier" they are either affected on unaffected for sex linked diseases .
2008 Q15: i need help with this punnett square. I understand how to narrow it down to C and D since the male gets the X-chromosome from the mother but i don't know why D is wrong.
Post by: siimraan on October 15, 2018, 11:45:12 pm
Post by: blasonduo on October 16, 2018, 09:09:18 pm
Can someone please explain what Sutton and Boveri did?
Hey!
Walter Sutton : Studied meiosis in grasshoppers, noted similarities between chromosomal behaviour and laws of segregation/independent assortment
- Segregation: During meiosis, each gamete cell receives one chromosome of each pair
- Independent Assortment: Chromosomes arrange themselves independently along the middle of the cell just before it divides
This meant that genes would segregate independently if they were on different homologous chromosomes and suggested that all characteristics followed Mendel’s law of independent assortment. Through this, he concluded that several Mendelian factors are present in 1 chromosome, could be inherited as a unit and that chromosomes were carriers of hereditary information.
Theodore Boveri: Experimented with sea urchins, provided evidence for the halving of chromosome numbers during the process of meiosis and that a definite set of chromosomes is required to produce normal development.
- Zygote chromosomes: 50% egg, 50% sperm
He showed that if the nucleus of only one parent was present, the larvae resembled that parent, but with some abnormalities. When a healthy egg and sperm fused, the resulting offspring showed characteristics of both parents.
Both of their works led to the Chromosomal theory of inheritance which means chromosomes carry genetic information (DNA).
I hope this helps! :)) If you need any of this explained more, let us know!
Post by: jasmineghanem on October 21, 2018, 04:02:27 pm
in regards to SFBH, for the gene expression & maintenance of health and repair of body tissue dotpoint, is there an easier/simpler example other than the BRCA1 gene & PTEN gene example?
thanks in advance!!
Post by: kauac on October 21, 2018, 05:21:23 pm
hey guys
in regards to SFBH, for the gene expression & maintenance of health and repair of body tissue dotpoint, is there an easier/simpler example other than the BRCA1 gene & PTEN gene example?
thanks in advance!!
Hi...
Not sure what example you are referring to, but for this dotpoint, I generally talk about the ramifications of the mutations of different genes involved with the cell cycle. Some examples:
- Mutation of p53 gene --> cell cycle does not pause to repair DNA --> --> can lead to tumours (50% of cancer cases involve a mutation of p53).
- Mutation of DNA repair genes --> DNA damage accumulates --> production of incomplete proteins --> impaired functioning of cells.
- Mutation of tumour supressor genes or proto-oncogenes --> uncontrolled cell division --> tumour.
I have seen examples talking about the gene for cystic fibrosis (CFTR), but I think the above ones are easier to use. Hope this helps! :)
Post by: jasmineghanem on October 21, 2018, 06:22:25 pm
Hi...
Not sure what example you are referring to, but for this dotpoint, I generally talk about the ramifications of the mutations of different genes involved with the cell cycle. Some examples:
- Mutation of p53 gene --> cell cycle does not pause to repair DNA --> --> can lead to tumours (50% of cancer cases involve a mutation of p53).
- Mutation of DNA repair genes --> DNA damage accumulates --> production of incomplete proteins --> impaired functioning of cells.
- Mutation of tumour supressor genes or proto-oncogenes --> uncontrolled cell division --> tumour.
I have seen examples talking about the gene for cystic fibrosis (CFTR), but I think the above ones are easier to use. Hope this helps! :)
thank you so much! they're heaps easier :)
Post by: MrBarbour on October 22, 2018, 08:53:25 am
I thought it was like a targeting system that enables white blood cells to see which cells to kill
Do antibodies kill the pathogen?
Post by: vox nihili on October 22, 2018, 09:34:30 am
Could someone explain the role of Antibodies?
I thought it was like a targeting system that enables white blood cells to see which cells to kill
Do antibodies kill the pathogen?
This link provides a pretty straightforward answer to this :) http://bfy.tw/KTQD
Post by: Mate2425 on October 22, 2018, 10:31:07 am
Post by: MrBarbour on October 22, 2018, 12:19:35 pm
Hey, so what do we do if we need more writing space/paper for the short response Q and not option Q?You ask one of the exam supervisors for another spare booklet to re-write or for more writing space for that particular question. They give you a booklet, write your student number, centre number and the question you are answering in that box which states which question you are answering.
Post by: moq418 on October 22, 2018, 01:15:13 pm
ALSO ANY TRENDS FOR BIOLOGY QUESTIONS PLEASE TELL ME
THANKS IN ADVANCE!
Post by: jswimj on October 22, 2018, 01:54:33 pm
Is anyone familiar with questions in HSC bio that always pop up in different years?
If so, could you please let me know, because i've been looking but i cant find them :(
Thanks in advanced!!
Post by: Razeen25 on October 22, 2018, 01:59:23 pm
What if you write below the lines of 6 lines for example and there so space can’t you just write on the black space provided ??
I REALLY need to know this. I always overwrite my biology answers over the lines, and the thought of having to ask for a new writing booklet for every single question feels like it'll be the biggest waste of time. My legal supervisors today said you cant write in the blank space :((
Post by: charlottemchenry on October 22, 2018, 03:52:30 pm
What if you write below the lines of 6 lines for example and there so space can’t you just write on the black space provided ??
OMG I was wondering the exact same thing!
Post by: jasn9776 on October 22, 2018, 06:45:08 pm
OMG I was wondering the exact same thing!yes you are allowed to use the blank space. I know this isn't for all subjects but yes, I have confirmation from the HSC4ME UTS live chat biology marker that you can.
Post by: kauac on October 22, 2018, 07:35:11 pm
increases or decreases genetic diversity?
(I asked my teacher this, she didn't know the answer. :o)
Post by: vox nihili on October 22, 2018, 07:44:51 pm
Producing transgenic species:
increases or decreases genetic diversity?
(I asked my teacher this, she didn't know the answer. :o)
Decreases. Let me know your thoughts on why you think this is :)
Post by: kauac on October 22, 2018, 07:52:02 pm
Decreases. Let me know your thoughts on why you think this is :)
Well, I originally thought that it would create new combination of genes (hence the increase)...
But when producing transgenic species, they make heaps of copies of the same gene to insert - which makes one allele more common than the others. I'm not sure if this is the correct reasoning for why genetic diversity decreases, or just something else I have observed?
Post by: charlottemchenry on October 22, 2018, 08:20:48 pm
Well, I originally thought that it would create new combination of genes (hence the increase)...
But when producing transgenic species, they make heaps of copies of the same gene to insert - which makes one allele more common than the others. I'm not sure if this is the correct reasoning for why genetic diversity decreases, or just something else I have observed?
Hey, So I too was so confused about this. I think this is right based on questions I've seen and it sorta makes sense with like the biological principles we learn.
From what I've gathered initially it increases genetic diversity as new genes are being introduced. However over time these favourable characteristics will survive and hence eventually decrease genetic diversity.
I saw like a 5 marker on this saying short and long term effects I think and also a mc with a table and it was like short term long term and had transgenic and something else like say cloning and you had to pick the correct row. Sorry I don't remember where the question was from.
Hope this helps.
Post by: vox nihili on October 22, 2018, 08:51:39 pm
Well, I originally thought that it would create new combination of genes (hence the increase)...
But when producing transgenic species, they make heaps of copies of the same gene to insert - which makes one allele more common than the others. I'm not sure if this is the correct reasoning for why genetic diversity decreases, or just something else I have observed?
Hey, So I too was so confused about this. I think this is right based on questions I've seen and it sorta makes sense with like the biological principles we learn.
From what I've gathered initially it increases genetic diversity as new genes are being introduced. However over time these favourable characteristics will survive and hence eventually decrease genetic diversity.
I saw like a 5 marker on this saying short and long term effects I think and also a mc with a table and it was like short term long term and had transgenic and something else like say cloning and you had to pick the correct row. Sorry I don't remember where the question was from.
Hope this helps.
Good on you both for thinking through this question. By and large I think you've got the right idea.
My reason for saying decrease was the practicalities of transgenic organisms. We tend to use transgenic organisms to replace organic organisms. For instance, we foritifed rice with vitamin A making genes and then planted this rice instead of native rices. The effect of this is to decrease the diversity in rice crops, even though we've technically added a gene to the gene pool. This is one of the most pressing concerns with the use of GMOs, which despite what some groups might say, are safe but do decrease diversity and therefore potentially increase the risk of catastrophic famines if a change in the environment prevails to kill that crop (less diversity means less capacity to deal with the change).
Post by: charlottemchenry on October 22, 2018, 08:56:05 pm
Good on you both for thinking through this question. By and large I think you've got the right idea.
My reason for saying decrease was the practicalities of transgenic organisms. We tend to use transgenic organisms to replace organic organisms. For instance, we foritifed rice with vitamin A making genes and then planted this rice instead of native rices. The effect of this is to decrease the diversity in rice crops, even though we've technically added a gene to the gene pool. This is one of the most pressing concerns with the use of GMOs, which despite what some groups might say, are safe but do decrease diversity and therefore potentially increase the risk of catastrophic famines if a change in the environment prevails to kill that crop (less diversity means less capacity to deal with the change).
Yeah I 100% agree, just based on HSC questions I've seen I've noticed a few do say short term increase which is tricky as you pointed out the aim is to decrease the diversity. I think it's cause they want you to use your knowledge of natural selection and evolution.
Thank you!
Post by: vox nihili on October 22, 2018, 08:58:38 pm
Yeah I 100% agree, just based on HSC questions I've seen I've noticed a few do say short term increase which is tricky as you pointed out the aim is to decrease the diversity. I think it's cause they want you to use your knowledge of natural selection and evolution.
Thank you!
Whether or not there is an increase depends on how the transgenic organism is used. Remember, if you take 1000 rice plants from a single transgenic organism, the variation in that population is 0. So if that crop then replaces another, it has to decrease diversity (because the new crop has none). If anything diversity increases over time as the transgenic organism evolves.
Post by: 3.14159265359 on October 22, 2018, 10:19:35 pm
thank you!!
Post by: charlottemchenry on October 22, 2018, 10:48:22 pm
. and for the multiple choice I'm really confused because my punnet square showed that only 1 child(25%) should get the disease but there is already one child. so how can the answer be b?
thank you!!
So by doing the punnet square with Rr and Rr you got RR, Rr, Rr and rr. Hence 25% chance that a child will be affected. Having one child doesn't decrease the chance that the next will also have it. So there's still a 25% chance.
Post by: jasn9776 on October 22, 2018, 11:34:34 pm
hey can someone please tell me how to approach the long response question and what I should include.?looking at it i'm as stumped as you. but looking at the sample answer:
thank you!!
https://educationstandards.nsw.edu.au/wps/wcm/connect/e3d9318d-2d4c-4084-8164-4b9198813e07/biology-hsc-sa-2011.pdf?MOD=AJPERES&CACHEID=ROOTWORKSPACE-e3d9318d-2d4c-4084-8164-4b9198813e07-lyVfTRI
it seems that you need to look at the advances that led to the development of the fungus i.e. bacterium understanding as a pathogen. DNA mutation using radiation and understanding of antibiotics. Then it actually goes on to describe the benefits of the technology like fewer deatsh due to infection, etc.
Post by: olliclark4 on October 23, 2018, 11:25:50 am
Post by: kauac on October 23, 2018, 11:46:18 am
hey can someone please tell me how to approach the long response question and what I should include. and for the multiple choice I'm really confused because my punnet square showed that only 1 child(25%) should get the disease but there is already one child. so how can the answer be b?
thank you!!
Just to add on from what jasn9776 has already said,
You could also talk about:
- Enzyme specificity to their substrate (lock and key model)
- One gene-one polypeptide and Beadle/Tatum's neurospora findings.
It is actually a very broad question, and gives you scope to choose the areas of biological understanding you feel most confident with, to expand on. :)
Post by: 3.14159265359 on October 23, 2018, 11:25:26 pm
I NEED URGENT HELP
DIFFERENCE BETWEEN CELL DIFFERENTIATION AND CELL SPECIALISATION
I READ THROUGH SO MANY NOTES AND EACH IS DIFFERENT TO THE PREVIOUS ONE
THANK YOUU
Post by: Razeen25 on October 24, 2018, 12:15:04 am
hELLOO
I NEED URGENT HELP
DIFFERENCE BETWEEN CELL DIFFERENTIATION AND CELL SPECIALISATION
I READ THROUGH SO MANY NOTES AND EACH IS DIFFERENT TO THE PREVIOUS ONE
THANK YOUU
Cell differentiation is the PROCESS in which an unspecialised cell becomes specialised to perform a particular function/role.
Cell specialisation is the RESULT/ROLE of cell differentiation (the cell is specialised following the process of differentiation).
But they're so similar tbh i dont think they'd even ask for a difference (i hope)
Post by: 3.14159265359 on October 24, 2018, 12:42:53 am
But they're so similar tbh i dont think they'd even ask for a difference (i hope)
THANK YOUU AND I HOPE NOTT
GOODLUCK IN 9 HOURS XX
Post by: SaskiaN on November 03, 2018, 10:46:02 pm
Post by: InnererSchweinehund on November 05, 2018, 08:07:55 pm
Could someone please explain the difference between protein synthesis and polypeptide synthesis??
Thanks!!
Post by: jasn9776 on November 08, 2018, 02:52:52 pm
Hi,Proteins are made of one or more polypeptides. So polypeptide synthesis is the process of joining amino acids together via peptide bonds. Then these polypeptides may join or fold to form proteins. For example, Enzymes are globular proteins and can be made of many polypeptides folded together.
Could someone please explain the difference between protein synthesis and polypeptide synthesis??
Thanks!!
So basically, they refer to the same process but I would suggest using the term polypeptide synthesis(and this is also what the syllabus specifies) since not all proteins are made up of only one polypeptide.
Post by: Erutepa on November 08, 2018, 03:20:57 pm
Does direct contact include blood transfusion? Say Malaria, if a blood transfusion containing the malaria parasite, that would be direct contact? cause blood is a bodily fluid. Am I right?As far as my quick research goes, direct contact is specifically person-to-person, while indirect contact can include transmission by vectors (like mosquitos). Therefore, blood transfusions would be considered via. indirect contact.
Post by: jamonwindeyer on November 11, 2018, 03:26:39 pm
Keen to see this thread be just as much of a collaborative resource for the new course as it was for the old :)
Post by: mirakhiralla on January 12, 2019, 05:32:41 pm
Post by: Karlamineeeee on January 13, 2019, 05:02:37 pm
The first dot point of the syllabus mentions an 'including but not limited to'... what does this refer to? The organism or type of reproduction. And what is an example for an additional?
● explain the mechanisms of reproduction that ensure the continuity of a species, by analysing sexual and asexual methods of reproduction in a variety of organisms, including but not limited to:
– animals: advantages of external and internal fertilisation
– plants: asexual and sexual reproduction
– fungi: budding, spores
– bacteria: binary fission (ACSBL075)
– protists: binary fission, budding
thanks
Hi! I hope I'm replying to this correctly (this is my first time using this forum and site). I believe that this dot point refers to the type of reproduction. We definitely have to study the types of reproduction as listed, but there are additional methods of reproduction. For example, with protists there is also the method of multiple fission, and with bacteria, they have other methods of reproduction to ensure genetic variation (these are transformation, transduction and conjugation). Basically, the syllabus says that we will study those listed, but not only those. This is just what I believe, based on what I've learnt at my school (we haven't done any other organisms' method of reproduction!).
Hope this helps!!
Post by: Karlamineeeee on January 13, 2019, 05:09:10 pm
Can someone please attach the new HSC bio syllabus because I cannot find it, thank you.
I was able to find it here: https://educationstandards.nsw.edu.au/wps/wcm/connect/657d2611-c201-49ce-a18e-ef0f786a5de0/biology-stage-6-syllabus-2017.pdf?MOD=AJPERES&CVID=
I know the syllabus says it's from 2017, but from what I've seen, it's very similar (if not the same) to what I've already been learning in my Prelim course and my one term of HSC from last year.
I found the syllabus PDF from https://educationstandards.nsw.edu.au/wps/portal/nesa/11-12/stage-6-learning-areas/stage-6-science/biology-2017. There's also a Word version of this available. Unfortunately, I can't attach the syllabus because it's a little too large. Please access one of the links and download the PDF/Word version of the syllabus if you want a copy!
Hope this helps!
Post by: Eshhkayyy at Biolowgeey on January 19, 2019, 06:15:46 pm
EB
Post by: kauac on January 19, 2019, 06:22:40 pm
Hello guy so i got holiday homework and this is one of the questions, do you reckon you can give me a hand with this protien syntheis question it is worth 6 marks. I would greatly appreciate your kindness and willingness to help me like me to learn and become better people. Much love
EB
Hi, it appears that you haven't written the question yet. Did you try to attach a photo? :)
Post by: mirakhiralla on January 19, 2019, 07:36:23 pm
I was able to find it here: https://educationstandards.nsw.edu.au/wps/wcm/connect/657d2611-c201-49ce-a18e-ef0f786a5de0/biology-stage-6-syllabus-2017.pdf?MOD=AJPERES&CVID=
I know the syllabus says it's from 2017, but from what I've seen, it's very similar (if not the same) to what I've already been learning in my Prelim course and my one term of HSC from last year.
I found the syllabus PDF from https://educationstandards.nsw.edu.au/wps/portal/nesa/11-12/stage-6-learning-areas/stage-6-science/biology-2017. There's also a Word version of this available. Unfortunately, I can't attach the syllabus because it's a little too large. Please access one of the links and download the PDF/Word version of the syllabus if you want a copy!
Hope this helps!
Thank you so much :)
Post by: Eshhkayyy at Biolowgeey on January 20, 2019, 02:38:59 pm
Hi, it appears that you haven't written the question yet. Did you try to attach a photo? :)
Hey, sorry i totally forgot about actually sending the question, so dumb of me lol. All the stress is finally catching up to me :)
"For the amino acid sequence that you have been given (Met-Cys-Lys-Asp-STOP) predict what could happen if a single point mutation occurred within the corresponding DNA sequence. Name the type of mutation that could occur and explain how it would affect the mRNA sequence, tRNA, corresponding amino acid and polypeptide chain (6 marks)."
Thank you very much for assisting me through this stressful times. I don't know what i will do without you guys. :)
ED
Post by: annabeljxde on February 07, 2019, 11:38:25 pm
My biology teacher has been getting us to learn a lot about the history of Mendel's experiments with his garden peas and the steps he took to obtain his results (F1- monohybrid cross produced offspring that took on the characteristics/phenotype of only one parent, F2 produced offspring in ratio 3:1 etc.) In terms of the new syllabus, how significant do you think the context of Mendel's experiments are to the syllabus content because I feel as though I am wasting time learning content that potentially may not be tested in the HSC exam for the new curriculum.
Do you guys have any opinions?
Thank you and have a good night :)) ;D
Post by: KT Nyunt on February 11, 2019, 12:01:22 am
Is this the same for other sciences like chemistry?
Post by: KT Nyunt on February 11, 2019, 12:15:08 am
Hello everyone :)
My biology teacher has been getting us to learn a lot about the history of Mendel's experiments with his garden peas and the steps he took to obtain his results (F1- monohybrid cross produced offspring that took on the characteristics/phenotype of only one parent, F2 produced offspring in ratio 3:1 etc.) In terms of the new syllabus, how significant do you think the context of Mendel's experiments are to the syllabus content because I feel as though I am wasting time learning content that potentially may not be tested in the HSC exam for the new curriculum.
Do you guys have any opinions?
Thank you and have a good night :)) ;D
I think it's always safe to listen to your teacher seeing that they're marking you on your internal exams thus determining 50% of your HSC mark. Also understanding Mendel's work does help us understand the principles of dominant and recessive genes and how alleles are passed on to offspring which are the foundations of Module 5: Heredity. So in my opinion, it's worth learning it. But I'm also aware that the new syllabus is removing a lot of historical aspects. So understand his experiment and why he got particular results, but learning why his work wasn't immediately recognised as significant (which was in the old syllabus) may not be as critical in the new syllabus. Keep in mind, even if his name is not in the syllabus anymore, a question can still be asked about him in the HSC as his work is very relevant to the heredity module.
Hope this helps :)
Post by: InnererSchweinehund on February 18, 2019, 05:24:07 pm
I am just about to start writing up my biology depth study based on genetic diseases and technologies.
I was wondering if anyone has any advice/tips on how to write the best depth study eg. what to include where, how to start and end it, how to use diagrams and references within the essay, important things to include...??
Thanks!!
Post by: annabeljxde on February 19, 2019, 09:38:41 pm
I think it's always safe to listen to your teacher seeing that they're marking you on your internal exams thus determining 50% of your HSC mark. Also understanding Mendel's work does help us understand the principles of dominant and recessive genes and how alleles are passed on to offspring which are the foundations of Module 5: Heredity. So in my opinion, it's worth learning it. But I'm also aware that the new syllabus is removing a lot of historical aspects. So understand his experiment and why he got particular results, but learning why his work wasn't immediately recognised as significant (which was in the old syllabus) may not be as critical in the new syllabus. Keep in mind, even if his name is not in the syllabus anymore, a question can still be asked about him in the HSC as his work is very relevant to the heredity module.
Hope this helps :)
Thank you so much!
Post by: annabeljxde on February 19, 2019, 09:41:35 pm
Can anyone help me out with this question:
So I have to discuss the advantages and issues with cross-breeding humans.
So far I have:
- Advantages: may reduce the chance of inheriting a congenital disorder, hybrid vigour (healthier offspring)
- Issues: (i'm having trouble with this)
Any help or advice is greatly appreciated! Thank you~
Post by: Coolmate on March 09, 2019, 09:32:25 pm
I'm in year 11 doing the Preliminary Course and was just wondering what the best resources or advice there is out there/ suggestions. Anything is much appreciated!
Kind Regards,
Coolmate :D
Post by: Kombmail on April 23, 2019, 02:46:04 pm
I needed to update notes on module 5 cuz i have basically one ( technically) and i really need ur help!
anyone willing to share module 5 notes please:)
Post by: RichardEadie on April 24, 2019, 09:02:28 pm
I was wondering if someone can tell me where I can find the powerpoints from these lectures.
If someone can direct me then that would be awesome ;D
Post by: Owlbird83 on April 24, 2019, 09:24:20 pm
I attended the biology lecture at uts today.
I was wondering if someone can tell me where I can find the powerpoints from these lectures.
If someone can direct me then that would be awesome ;D
Spoiler
(https://i.imgur.com/T9AAh4N.jpg)
Edit: Maybe not. I just tried and I couldn't find the recent ones, maybe they're not up yet?
Post by: PhoenixxFire on April 24, 2019, 09:36:43 pm
I attended the biology lecture at uts today.They'll be in the notes section as owlbird said, but they're generally not uploaded until the end of the lecture series. Assuming it's the same as for vic, you'll probably also get an email with the link and the link will be posted on ANs social media.
I was wondering if someone can tell me where I can find the powerpoints from these lectures.
If someone can direct me then that would be awesome ;D
Post by: KC181 on April 28, 2019, 10:01:48 pm
Hi guys,
This is a bit of a general question but I am currently finishing off my bio depth study, and am approx. 500 words over the word count...
Does anyone have advice on things I could do to cut it down (I have already removed almost all of the adjectives)? I'm a bit concerned that cutting down will mean losing content...
Thanks!!
Hi there! I know you posted this a while ago but just for future reference. My advice to decrease word count is using SST’s, in my school SST’s are Subject Specific Terminology. These are like fancy words used throughout a subject (e.g. for biology = polypeptide synthesis, RNA, meiosis, crossing over, Human Genome Bank etc).
My advice is to find and use words that sound scientific and sophisticated in bio, a lot of times these words encompass the entire concept/idea which will help to lower the word count.
E.G.
‘GM crops can possibly lead to humans only cultivating a single crop in a certain area’
Compare this to:
‘GM crops can possibly lead to monocultures’
In this case the SST I used was ‘monocultures’. Even though in the second sentence I’ve removed 10 words the idea I’m arguing is still the same, it’s just that I’ve used a fancier word that encompasses that entire idea of cultivating a single crop. Besides lessening the word count, SST’s also makes your responses sound more concise and sophisticated.
So I would say, go back over your response and think, is there any place where I’m explaining a concept or idea (especially since explaining can take up a couple of words). And then, is there a possible word I have or can find that conveys that exact same idea?
Hope this helps for the future!
Post by: Pearlmilktea on April 29, 2019, 06:47:12 pm
Hi, I graduated last year but I've had a look at the new Biology syllabus and I'm a little confused: are there option topics anymore (like communication or genetics in the old syllabus) or does everyone have to do the same 4 modules?
Is this the same for other sciences like chemistry?
Sorry super late reply but no, there are no option topics for Bio anymore - everyone does the same four modules just schools can choose what order to study them in. As for Chemistry I don't know but I wouldn't be surprised if it was the same deal.
Post by: jen10 on April 30, 2019, 05:33:34 pm
Can anyone provide some tips on writing an introduction and discussion for a depth study - what to include etc?
Thanks!
Post by: Pearlmilktea on May 01, 2019, 10:03:35 pm
Hello!
Can anyone provide some tips on writing an introduction and discussion for a depth study - what to include etc?
Thanks!
Hey !! Here's what I'd include:
Introduction :
Depending on your topic of study this could be a variety of things. My year 11 and year 12 depth studies were super different but it could include things such as:
- Info about your independent variable (e.g. UV light)
- Applications of your depth study in real world contexts (e.g. food preservation)
- Other studies on your topic area/ scientific journals on it/ previous experiments
- Info on your controlled variables e.g. type of bacteria being tested on
- What you intend to do in your experiment
- Processes + explanations for them
- Basically any info you want them to have going into the experiment - any assumed knowledge e.g. this organism is a bacteria which means that...
Discussion is a bit more clear cut. You should comment on:
- Reliability
- Validity
- Accuracy
- Explaining results
- Problems/ challenges while conducting your experiment
- Future directions/ future hypothesis
Hope this helps!
-Gracie
Post by: InnererSchweinehund on May 12, 2019, 08:02:07 pm
Hi,
I'm in year 11 doing the Preliminary Course and was just wondering what the best resources or advice there is out there/ suggestions. Anything is much appreciated!
Kind Regards,
Coolmate :D
Hi Coolmate!
This response is quite a while after you first posted your question, but I hope it can still help you.
Firstly, get on top of your notes + key concepts ASAP!! Biology is quite content heavy so if you can grasp the concepts and practice them from the very start until the very end, you will find it very useful. Make sure you ask your teacher to go over any concepts you don't understand, and pay attention to any feedback they give you on assignments/exams.
I found the ATAR Notes biology course notes super helpful, and if you can, try and attend some ATAR Notes biology lectures because they recap the previous topics, and prepare you for what's coming up - this definitely gives you an advantage over all your peers who haven't attended!! You should also look at the previous lecture slides and use them to your advantage when making study notes!!
Finally, find out what study techniques work for you. It's better to do this while you are in year 11, so you can set yourself up well for year 12.
Best of luck and have fun!!
:)
Post by: InnererSchweinehund on May 17, 2019, 09:52:28 pm
I was wondering if someone could explain what the control is in Pasteur's experiment??
Is it the flask with the straight neck or the sterilized broth??
At the moment I have this as my response and not sure if it is correct:
Is a control used in this experiment? If so, identify it and explain why it was used.
The control in this experiment is the broth. A constant amount of broth is used, and boiled for the same amount of time. Since the aim of this experiment is to test whether nutrient broth could spontaneously generate microbial life, the broth was boiled to sterilize, so it it contained no living microbes. By having a sterile broth in both flasks it was impossible for germs to spontaneously generate, hence, it could be determined that organisms carried in the air were able to enter the straight neck flask and contaminate broth and cause it to decay.
Thanks in advance!!
Post by: InnererSchweinehund on May 18, 2019, 08:11:49 am
At the moment I have this as my response and not sure if it is correct:
Is a control used in this experiment? If so, identify it and explain why it was used.
The control in this experiment is the broth. A constant amount of broth is used, and boiled for the same amount of time. Since the aim of this experiment is to test whether nutrient broth could spontaneously generate microbial life, the broth was boiled to sterilize, so it it contained no living microbes. By having a sterile broth in both flasks it was impossible for germs to spontaneously generate, hence, it could be determined that organisms carried in the air were able to enter the straight neck flask and contaminate broth and cause it to decay.
Or is this better / more accurate?
The control in Pasteur’s experiment is the straight necked flask, which allowed particles from the air to fall into the flask and contaminate it. Pasteur believed that organisms that contaminated the broth and caused it to decay must be carried in the air and not be spontaneously generated. Therefore, by having a straight necked flask, he was able to observe the different between the two flasks - one that was exposed to microbes, and one that wasn’t. If the theory of spontaneous generation was correct, the broth in both flasks would be cloudy and decaying, even if they weren’t directly exposed to the air (like the Swan necked flask).
Post by: stella_atarnotes on May 19, 2019, 02:14:07 pm
Hi :)!
I was wondering if someone could explain what the control is in Pasteur's experiment??
Is it the flask with the straight neck or the sterilized broth??
At the moment I have this as my response and not sure if it is correct:
Is a control used in this experiment? If so, identify it and explain why it was used.
The control in this experiment is the broth. A constant amount of broth is used, and boiled for the same amount of time. Since the aim of this experiment is to test whether nutrient broth could spontaneously generate microbial life, the broth was boiled to sterilize, so it it contained no living microbes. By having a sterile broth in both flasks it was impossible for germs to spontaneously generate, hence, it could be determined that organisms carried in the air were able to enter the straight neck flask and contaminate broth and cause it to decay.
Thanks in advance!!
Hi! You're correct in the aim- that Pasteur was trying to test the theory of spontaneous generation where living organisms arose from a non-living source. However, you might be a little confused between control and controlled variable. The controlled variable is something you keep constant throughout your experiment to ensure that and results you obtained are in fact due to you changing the independent variable. In this case, a constant amount of broth was used for both flasks and they were both boiled to eliminate any pre-existing microorganisms. Pasteur then used identical swan-necked flasks (another controlled variable) and snapped the neck off one flask so that it became a straight neck. The straight neck flask allowed for organisms from the air to enter the broth and thus micro-organisms grew in the broth. It would be more accurate for you to identify the positive and negative controls in this experiment; the positive control is the flask which you expect growth and the negative control is the flask where you wouldn't expect growth. So your negative control would be the swan necked flask and your positive control would be the straight neck flask.
Hope that helps!
Post by: InnererSchweinehund on May 19, 2019, 04:28:06 pm
Hope that helps!
Thank you so much!!
Post by: Kombmail on June 10, 2019, 05:29:50 pm
Q. 4. Apply your understanding of evolution by natural selection to explain how plants and animals have developed such complex and successful defences against pathogens.
Post by: InnererSchweinehund on June 12, 2019, 01:28:44 pm
Q. 4. Apply your understanding of evolution by natural selection to explain how plants and animals have developed such complex and successful defences against pathogens.
Hi!
Basically what this question is asking you is: How have plants and animals have evolved over time (due to natural selection) to be able to successfully defend themselves against pathogens?
The most basic answer to this question would be that due to natural selection, plants and animals that didn't have certain adaptations against pathogens would have died. This allowed plants and animals with the adaptations to reproduce and produce offspring with the adaptation.
An example of this is the behavioural adaptation of mammals and birds grooming themselves to remove parasites (ticks, fleas, lice).
This prevents a parasitic relationship that can be potentially harmful to the animal.
Another behavioural and structural adaptation of animals in fly infested areas are large ears (eg. elephants). Whilst this adaptation allows them to
release heat easier, as the blood vessels in the ears are closer to the surface, it also provides them with an effective mechanism to swat away flies,
hence preventing flies landing on and biting them. They can also hold branches with their trunks to swat flies.
An example of a plant adaptation is the production of essential oils, which act as toxins against bacteria and fungus.
A structural plant adaptation are thick, waxy cuticles, or thorns or spines to prevent against predators.
Plants and animals that were unable to do this, wouldn't have been able to survive.
Here are two good articles with further, more in depth explanations:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3189355/
https://courses.lumenlearning.com/boundless-biology/chapter/plant-defense-mechanisms/
As it is an explain question, it is probably good form to make a judgement to say how successful each of these adaptations are.
(If it was an evaluate question you must include a judgement!!)
Hope this provides you with a few ideas to get you started!!
:D
Post by: e2503 on July 03, 2019, 12:04:07 pm
Im stuck with this dodgy question here (Question 4b and d) and am in urgent need of help.
If anyone could send help it would be very much appreciated. Thank you in advance. ;D ;D ;D
For 4a i got 3.2 x 10^-11g and 4c i got 28.8pi (90.47787cm^3)
Post by: sofe2003 on July 03, 2019, 03:35:41 pm
Post by: sofichu on July 09, 2019, 12:34:39 am
thanks!!
Post by: Kombmail on July 09, 2019, 10:56:32 am
Hi :)!
I was wondering if someone could explain what the control is in Pasteur's experiment??
Is it the flask with the straight neck or the sterilized broth??
At the moment I have this as my response and not sure if it is correct:
Is a control used in this experiment? If so, identify it and explain why it was used.
The control in this experiment is the broth. A constant amount of broth is used, and boiled for the same amount of time. Since the aim of this experiment is to test whether nutrient broth could spontaneously generate microbial life, the broth was boiled to sterilize, so it it contained no living microbes. By having a sterile broth in both flasks it was impossible for germs to spontaneously generate, hence, it could be determined that organisms carried in the air were able to enter the straight neck flask and contaminate broth and cause it to decay.
Thanks in advance!!
Both broths were under the same experimental conditions however flask one had a straight neck tube. The straight neck tube was conducted to make sure the contaminants aren’t forming from the external environment.
Post by: Coolmate on July 10, 2019, 07:08:53 pm
I am in Year 11 and am going to do my Biology prelim exams soon. I was wondering whether anyone has any good tips and what the most important things I should study that I can use for the exam, to achieve a high mark?
Also, does anyone have any past prelim papers for biology?... (The new syllabus is making it hard to find them).
Thanks in advance,
Coolmate ;)
Post by: ushna on July 14, 2019, 09:25:45 pm
Post by: Kombmail on July 17, 2019, 07:57:08 pm
Hey. For pedigrees, how do we know if a trait is dominate or recessive or whether it is X-linked dominant or X-linked recessive?If it’s dominant, it would be represented by a capital letter, if recessive a lower case. I’m not too sure about the other two.
Post by: caffinatedloz on July 18, 2019, 07:28:50 pm
Hey. For pedigrees, how do we know if a trait is dominate or recessive or whether it is X-linked dominant or X-linked recessive?
On a pedigree, there are clues you can look for when identifying if a trait is X-linked or autosomal and dominant or recessive. It is mainly a common sense thing but you can ask yourself questions to work through it.
X-Linked or Autosomal
Does this trait occur equally in men and women?
(If carriers are shown, are there carriers of both sexes?)
If the trait occurs equally in both genders, then it is most likely autosomal.
Dominant or Recessive
Does every affected child have an affected parent? (Then it is most likely dominant.)
Does the trait disappear from a family line and reappear (skip a generation)? (Then it is recessive.)
Are there carriers? (Recessive.)
In Summary:
X-Linked Dominant: Occurs more often in women, no carriers, cannot skip generations, every child has affected parents.
X-Linked Recessive: Occurs more in men, female carriers (but no male carriers), can skip generations.
Autosomal Dominant: Equal in both genders, no carriers, cannot skip generations, every child has affected parents.
Autosomal Recessive: Equal in both genders, carriers (but these may not be shown directly), can skip generations.
If it’s dominant, it would be represented by a capital letter, if recessive a lower case. I’m not too sure about the other two.
This is true if they give you the genotype.
eg. Dominant allele (B) and recessive allele (b). Then genotypes could be (BB, Bb or bb)
If it is X-linked, the alleles and genotypes would look like this: XR or Xr. Then genotypes could be ( XR XR, XRXr or XrXr in females. In males they could be XRY or XrY.
Note: Remember men would only get one copy of the X chromosome.
Post by: Coolmate on July 25, 2019, 07:08:28 pm
Hi Coolmate!
This response is quite a while after you first posted your question, but I hope it can still help you.
Firstly, get on top of your notes + key concepts ASAP!! Biology is quite content heavy so if you can grasp the concepts and practice them from the very start until the very end, you will find it very useful. Make sure you ask your teacher to go over any concepts you don't understand, and pay attention to any feedback they give you on assignments/exams.
I found the ATAR Notes biology course notes super helpful, and if you can, try and attend some ATAR Notes biology lectures because they recap the previous topics, and prepare you for what's coming up - this definitely gives you an advantage over all your peers who haven't attended!! You should also look at the previous lecture slides and use them to your advantage when making study notes!!
Finally, find out what study techniques work for you. It's better to do this while you are in year 11, so you can set yourself up well for year 12.
Best of luck and have fun!!
:)
Hi InnererSchweinehund thanks so much for your response this will definetly help me in my biology studies! 😀👍
Post by: dani01 on August 06, 2019, 06:32:45 pm
also does anyone have any good mnemonics for remembering the pathogens that order?
thanks!
Post by: InnererSchweinehund on August 06, 2019, 07:18:44 pm
Would someone be able to say in order from smallest to largest the size of different pathogens
also does anyone have any good mnemonics for remembering the pathogens that order?
thanks!
Hi,
Unfortunately I don't have any memorable mnemonics but in order from smallest to largest the pathogens are:
Prion
Virus
Bacteria
Protozoa
Fungi
Macroparasite
Hope this helps!
;D
Post by: dani01 on August 07, 2019, 09:04:19 am
Hi,
Unfortunately I don't have any memorable mnemonics but in order from smallest to largest the pathogens are:
Prion
Virus
Bacteria
Protozoa
Fungi
Macroparasite
Hope this helps!
;D
That's ok and thanks for your help
Post by: thereal_laura on August 14, 2019, 08:55:33 pm
just asking bc trials tomorrow, wack
Post by: viraankumar on August 24, 2019, 05:08:06 pm
Post by: Kombmail on September 23, 2019, 11:07:59 pm
The most likely explanation for this is that the alleles for fur colour demonstrate?
A)sex- linkage
B)co-dominance
C)incomplete dominance
D) sex linkage and co - dominance
Guys for this question the answer is D but can someone explain why? I tried doing a punnett square with the female being heterozygous and the male homozygous recessive but it didnt seem to work...
Post by: caffinatedloz on September 25, 2019, 09:45:36 pm
Q. In domestic cats, when exploring crosses involving two fur colours (black and orange) the following observation is always made: A cross between an orange female and black male produces orange males and tortoiseshell shell female offspring. (Tortoiseshell is a mix of orange and black fur)
The most likely explanation for this is that the alleles for fur colour demonstrate?
A)sex- linkage
B)co-dominance
C)incomplete dominance
D) sex linkage and co - dominance
Guys for this question the answer is D but can someone explain why? I tried doing a punnett square with the female being heterozygous and the male homozygous recessive but it didnt seem to work...
Hey Kombmail!
I think that for this question, before you break out the Punnett Square, you can determine that this trait is certainly codominant, as a blending of the two alleles is shown (the tortoiseshell cats). This is different to incomplete dominance, which is where both alleles are shown (eg. a black and orange patchy/spotted cat). This leaves us with options B and D.
Now we need to ask, is it sex linked? When we are told that a trait is different in all females and all males (coming from the same parents), this is pretty clear evidence that it must be sex linked. However, we can also see that in a Punnet Square. We will start by assuming it is sexd linked and attempting to disprove it. The mother's genotype (if sex linked): XOXO. And the father: XBY.
Crossing these would produce males who inherit an XO from the mother and a Y from the father, and females with XO from the mother and XB from the father, which leads to the blended phenotype.
This means the answer must be D. Does that make sense?
Post by: Kombmail on September 27, 2019, 10:15:35 am
HSC BIOLOGY Q&A THREADTo go straight to posts for the new syllabus, click here.
What is this thread for?
If you have general questions about the HSC Biology course or how to improve in certain areas, this is the place to ask! 👌
Hey dude! do you know how many treatments you should know for your chosen non- infectious disease in module 8?
Who can/will answer questions?
Everyone is welcome to contribute; even if you're unsure of yourself, providing different perspectives is incredibly valuable.
Please don't be dissuaded by the fact that you haven't finished Year 12, or didn't score as highly as others, or your advice contradicts something else you've seen on this thread, or whatever; none of this disqualifies you from helping others. And if you're worried you do have some sort of misconception, put it out there and someone else can clarify and modify your understanding!
There'll be a whole bunch of other high-scoring students with their own wealths of wisdom to share with you. So you may even get multiple answers from different people offering their insights - very cool.
To ask a question or make a post, you will first need an ATAR Notes account. You probably already have one, but if you don't, it takes about four seconds to sign up - and completely free!OTHER BIOLOGY RESOURCESCLICK ME!* Free Biology notes
* HSC Biology Question Thread
* How to Get a Band 6 in HSC Biology
* HSC Biology - How to Get a Band 6
* HSC BIO GUIDE: BLUEPRINT OF LIFE
* HSC BIO GUIDE: THE SEARCH FOR BETTER HEALTH
* Long Responses in HSC Biology
* HSC Biology: How to Ace the 8 Marker Questions
* How to Go About Studying for Any ScienceOriginal post.Hello Bio Students, Whilst I may not be one of the ATARNotes legends, I noticed that there wasn't one of these threads in our section of the forums so I thought I'd start one up.
Basically this is a place where any of the Biology Students or Lecturers to come and place any questions that they need help with, or answered questions that you want marked or feedback on, or even just questions on the general concepts in Biology that you may need help with.
For me, I've done the core modules for Biology and I've gotten through a little bit of the Communications Option so feel free to ask me any questions regarding that. I'm currently first in my Biology class so I feel as though I can help some other people out, but feel free to prove me wrong and help others out with any questions. Looking forward to seeing these questions too
Let's get this thread rolling
Skidous
Post by: Mia-lexa on October 03, 2019, 09:29:19 am
Thanks!
Post by: Karlamineeeee on October 03, 2019, 07:12:29 pm
Thank you!!
Post by: InnererSchweinehund on October 04, 2019, 07:42:00 pm
Hey, would anyone be able to explain to me metaphase I/anaphase I in meiosis - or more specifically just how homologous chromosomes work. I know that when they line up, it's the paternal and maternal copy of the same chromosome lining up, but I don't understand how this fits in with the whole scheme of things because fertilisation happens after this point, right? So how does one cell that is preparing for fertilisation already have the genetic material from both parents?
Thanks!
Hi! This is a really good question!
Homologous chromosomes, as you correctly said, are one copy of each chromosome from the mother, and one copy of each chromosome from the father. They are similar in length but may have different alleles.
In females, meiosis occurs before birth, and in males in continually occurs after puberty. In both these cases, the male and the female already have the genetic material from their parents.
To make it a bit simpler, let's call the parents generation 1, and the child generation 2
Generation 1 are adults therefore they have all their genetic material
Generation 2 is created as a result of reproduction by generation 1. This means generation 2 has all their genetic material from their parents.
As generation 2 develops, their cells undergo meiosis giving them (generation 2) the capacity to create generation 3 once their bodies have matured to be able to do so as they now have their own gametes that can be fertilised.
It's quite a difficult concept to understand, but when you said, "how does one cell that is preparing for fertilisation already have the genetic material from both parents?" this cell 'preparing for fertilisation' is already inside a living organism created by reproduction, therefore they already have the genetic information from their parent.
Let me know if this still doesn't make sense!!
:)
Post by: InnererSchweinehund on October 04, 2019, 07:46:25 pm
Hi! I just had a question about the ATAR Notes Biology Topic Tests. For the Reproduction Test 1 Q7, could I make a table on sexual and asexual reproduction rather than internal/external fertilisation?
Thank you!!
Hi Karlamineeeee,
If you could attach a picture of the specific question I would be more than happy to help you out!!!
In general (without seeing the question), if the question asks about internal/external fertilisation it is asking specifically about sexual reproduction, therefore it may not be appropriate to compare asexual and sexual reproduction (and it could potentially cost you some marks).
If, however, the question is just asking you to compare different types of reproduction, it is definitely appropriate to use a table!!
:D
Post by: Mia-lexa on October 04, 2019, 07:56:59 pm
Hi! This is a really good question!
Homologous chromosomes, as you correctly said, are one copy of each chromosome from the mother, and one copy of each chromosome from the father. They are similar in length but may have different alleles.
In females, meiosis occurs before birth, and in males in continually occurs after puberty. In both these cases, the male and the female already have the genetic material from their parents.
To make it a bit simpler, let's call the parents generation 1, and the child generation 2
Generation 1 are adults therefore they have all their genetic material
Generation 2 is created as a result of reproduction by generation 1. This means generation 2 has all their genetic material from their parents.
As generation 2 develops, their cells undergo meiosis giving them (generation 2) the capacity to create generation 3 once their bodies have matured to be able to do so as they now have their own gametes that can be fertilised.
It's quite a difficult concept to understand, but when you said, "how does one cell that is preparing for fertilisation already have the genetic material from both parents?" this cell 'preparing for fertilisation' is already inside a living organism created by reproduction, therefore they already have the genetic information from their parent.
Let me know if this still doesn't make sense!!
:)
Ahhh thank you so much!! Makes a lot more sense now! :)
Post by: dani01 on October 08, 2019, 09:57:34 pm
Post by: InnererSchweinehund on October 14, 2019, 08:03:54 pm
Hi does anyone have any info on a viral plant response all I am able to find is fungal! Would really appreciate some help. I can find the name and the pathogen but not the actual response if that makes sense :P :P
Hi there!
This is some information on viral pathogens and the response of an Australian plant from easyhsc.com.au
Hope this helps!
Turnip Mosaic Virus
Causative pathogen:
Turnip Mosaic Virus (TuMV), a potyvirus belonging to the family Potyviridae.
Host Range:
Almost all Brassica species and other plants including:
B. oleracea
B. campestris
B. juncea
B. pekinensis
Latuca sativa
Nasturtium officinale
Raphanus sativus
Symptoms:
Chlorotic spots on inoculated leaves
Mottling followed by systemic vein clearing
Mosaic and/or necrosis
Leaf distortion
Stunting
Management:
Exclusion or avoidance – quarantine, growing crops in regions where the virus seldom occurs or during periods when the virus or its vector are at a low activity level and using virus-free seedling transplants.
Reduction in virus spreading sources – controlling weeds and other virus hosts and insect vectors, destroying old crops promptly, separating new crops from maturing crops, and avoiding overlapping crops, particularly year-round cropping.
Protection of the host plant – planting virus-resistant varieties, using barrier crops to reduce insect vector activity in the crop, using insecticides to protect plants, and using highly reflective mulches and oil sprays to deter insects.
Post by: dani01 on October 16, 2019, 09:43:09 am
Hi there!
This is some information on viral pathogens and the response of an Australian plant from easyhsc.com.au
Hope this helps!
Turnip Mosaic Virus
Causative pathogen:
Turnip Mosaic Virus (TuMV), a potyvirus belonging to the family Potyviridae.
Host Range:
Almost all Brassica species and other plants including:
B. oleracea
B. campestris
B. juncea
B. pekinensis
Latuca sativa
Nasturtium officinale
Raphanus sativus
Symptoms:
Chlorotic spots on inoculated leaves
Mottling followed by systemic vein clearing
Mosaic and/or necrosis
Leaf distortion
Stunting
Management:
Exclusion or avoidance – quarantine, growing crops in regions where the virus seldom occurs or during periods when the virus or its vector are at a low activity level and using virus-free seedling transplants.
Reduction in virus spreading sources – controlling weeds and other virus hosts and insect vectors, destroying old crops promptly, separating new crops from maturing crops, and avoiding overlapping crops, particularly year-round cropping.
Protection of the host plant – planting virus-resistant varieties, using barrier crops to reduce insect vector activity in the crop, using insecticides to protect plants, and using highly reflective mulches and oil sprays to deter insects.
Hey thanks for that! yeah i did see that website except I'm pretty sure we need the host response. so instead of quarantine and stuff what does the actual plant do to kill the antigen? But thankyou again for the info- it is hard to find
Post by: worldno1 on October 16, 2019, 09:55:26 am
Hey thanks for that! yeah i did see that website except I'm pretty sure we need the host response. so instead of quarantine and stuff what does the actual plant do to kill the antigen? But thankyou again for the info- it is hard to find
Cmiiw but in the syllabus, you only need to know an Australian plant response to either a fungus or virus (that's what my teacher said). Since you already have one for fungus, should be all good. :)
Post by: annabeljxde on October 26, 2019, 11:12:33 pm
This is a question from Excel Success One and the answers say that for the condition to be sex-linked, the unrelated females in the second generation must be carriers. I used this reason in my justification, so I'm a bit confused. Sex-linked inheritance can occur even in non-blood-related individuals, right? Or must the inheritance of the 'disorder' be strictly between blood-related individuals?
Post by: InnererSchweinehund on October 27, 2019, 08:31:06 am
I need someone to explain to me why this pedigree chart is autosomal recessive and not sex-linked.
This is a question from Excel Success One and the answers say that for the condition to be sex-linked, the unrelated females in the second generation must be carriers. I used this reason in my justification, so I'm a bit confused. Sex-linked inheritance can occur even in non-blood-related individuals, right? Or must the inheritance of the 'disorder' be strictly between blood-related individuals?
Hi there!
By looking at the pedigree, we immediately know that if the condition were to be sex-linked, it would have to be recessive, as the mother in the very first generation is a carrier, but is not affected herself.
By filling out the pedigree (attached), you can see that the condition can be both sex-linked recessive and autosomal recessive.
Based on the answer from Success One (which I have put below), I think they are arguing that it would be unlikely that "two of the unrelated mothers in the second generation must have independently both been carriers (as well as the daughter from the initial parents)", therefore it's more likely to be autosomal recessive.
If I had received this question in the exam and had filled out the pedigree and seen that it's possible for it to be sex-linked recessive, I definitely would've answered that, on the basis that sex-linked inheritance can occur in non-blood-related individuals. Unless the question states that the disorder is super rare and something crazy like "less than 0.000000006% of the population has it, as long as you can prove that it is sex-linked (by filling out the pedigree and giving clear evidence to how it can be sex-linked) I think you'll be fine.
Answer from success one:
The pedigree diagram indicates that only males are affected by the condition; however, as the female has to pass on the affected X chromosome to the son, two of the unrelated mothers in the second generation must have independently both been carriers (as well as the daughter from the initial parents) for this to be sex-linked inheritance. This would suggest the condition is autosomal recessive. Both of the initial parents could have been carriers, resulting in half of their offspring with the condition (ie. homozygous recessive) and their unaffected daughter and son could have been carriers (ie. heterozygous), as well as their partners.
Post by: Hawraa on October 27, 2019, 11:28:58 am
Considering the following question
("increased scientific understanding of processes of reproduction has allowed for rapid growth of the agricultural industry over the past few decades." Evaluate this statement with reference to at least specific scientific techniques.)
When we are asked to evaluate, isn't like give positives and negatives and a judgement? Because the way I structured my answer is :
Tech 1+definition+ advantages (2)
Tech 2+definition+ advantages (2)
Common disadvantage of the 2 techs
Judgement.
However, the answer only talks about the advantages without any disadvantages. So can someone please explain why? And which way is better? Thanks
Post by: InnererSchweinehund on October 27, 2019, 12:10:46 pm
Hi everyone,
Considering the following question
("increased scientific understanding of processes of reproduction has allowed for rapid growth of the agricultural industry over the past few decades." Evaluate this statement with reference to at least specific scientific techniques.)
When we are asked to evaluate, isn't like give positives and negatives and a judgement? Because the way I structured my answer is :
Tech 1+definition+ advantages (2)
Tech 2+definition+ advantages (2)
Common disadvantage of the 2 techs
Judgement.
However, the answer only talks about the advantages without any disadvantages. So can someone please explain why? And which way is better? Thanks
Hi Hawraa!
The way you answered the question is definitely correct. If the question asks you to evaluate, you should definitely make a judgement, but to be able to make a judgement you need to give reasons for and against!
The only reason I could think of, for why they didn't provide disadvantages, would possibly be because of the mark allocation??
To be safe in the HSC, definitely provide reasons for an against and specifically state the reasons for your judgement/decision.
Good luck tomorrow!!
;D
Post by: Hawraa on October 27, 2019, 12:13:35 pm
Hi Hawraa!
The way you answered the question is definitely correct. If the question asks you to evaluate, you should definitely make a judgement, but to be able to make a judgement you need to give reasons for and against!
The only reason I could think of, for why they didn't provide disadvantages, would possibly be because of the mark allocation??
To be safe in the HSC, definitely provide reasons for an against and specifically state the reasons for your judgement/decision.
Good luck tomorrow!!
;D
Thanks a lot 🌷
Post by: dani01 on October 27, 2019, 02:14:18 pm
Cmiiw but in the syllabus, you only need to know an Australian plant response to either a fungus or virus (that's what my teacher said). Since you already have one for fungus, should be all good. :)
nup! the syllabus says doesn't say "or" its says for example so I think they could ask either either. your teacher may have confused it with the fact that the point says "conduct practical and/or secondary-sourced investigation."
I think they are more likely to ask about fungus since there is not much about host response for viral. but yeah doesn't say "or" so thought i would let you know :))
Post by: dani01 on October 27, 2019, 05:04:05 pm
Post by: Hawraa on October 27, 2019, 05:19:58 pm
Can someone please help me with this question.
How could a change in a polypeptide effect cell activity?
Is it correct to say that since polypeptides are folded and modified to produce proteins, a change in polypeptide would result in a dysfunctional protein. This would impact cell activity such as for example if the affected polypeptide encoded for a protein functioning as an enzyme to regulate cellular processes such as DNA replication, it could prevent the process from occurring thus preventing it from copying and passing the genetic material to daughter cells, or if the polypeptide is encoding for a protein functioning as an antibody it would affect the immune system ability to recognise foreign particles and impair its ability to initiate an immune response.
Which one is a better example? (by the way, the question worths 2 marks.) thanks.
Post by: Hawraa on October 27, 2019, 05:26:55 pm
hey! just wanted to know is dolly a transgenic organism? if the question asks for transgenic organism can i talk about somatic cell nuclear transfer? thanks
Hi there,
Dolly was a clone produced by whole organism cloning, which occurs through somatic cell nuclear transfer.
With transgenic organisms or transgenesis, it does not include somatic cell nuclear transfer. It is the introduction of DNA from different organism into another organism to exhibit a particular trait and pass it to offsprings. Such as pest resistent crops. Hope this answers your question.
Post by: InnererSchweinehund on October 27, 2019, 06:23:14 pm
Hi,
Can someone please help me with this question.
How could a change in a polypeptide effect cell activity?
Is it correct to say that since polypeptides are folded and modified to produce proteins, a change in polypeptide would result in a dysfunctional protein. This would impact cell activity such as for example if the affected polypeptide encoded for a protein functioning as an enzyme to regulate cellular processes such as DNA replication, it could prevent the process from occurring thus preventing it from copying and passing the genetic material to daughter cells, or if the polypeptide is encoding for a protein functioning as an antibody it would affect the immune system ability to recognise foreign particles and impair its ability to initiate an immune response.
Which one is a better example? (by the way, the question worths 2 marks.) thanks.
Hi!
I think the best answer is to say that a change in a polypeptide chain (such as alterations to the amino acid sequence) could affect/alter/damage the protein produced, hence impacting its functional ability. You could then use your example, "This would impact cell activity, as if the polypeptide is encoding for a protein functioning as an antibody" it would affect the ability of the antibody to bind to and neutralise a specific antigen, hence compromising the immune response.
As this question is only worth two marks, I think it's enough just to give a basic definition / overview of what would happen if a change occurred, and one solid example.
Hope this helps!
:)
Post by: Hawraa on October 27, 2019, 06:31:21 pm
Hi!
I think the best answer is to say that a change in a polypeptide chain (such as alterations to the amino acid sequence) could affect/alter/damage the protein produced, hence impacting its functional ability. You could then use your example, "This would impact cell activity, as if the polypeptide is encoding for a protein functioning as an antibody" it would affect the ability of the antibody to bind to and neutralise a specific antigen, hence compromising the immune response.immune system ability to recognise foreign particles and impair its ability to initiate an immune response.
As this question is only worth two marks, I think it's enough just to give a basic definition / overview of what would happen if a change occurred, and one solid example.
Hope this helps!
:)
Awesome, thanks.
Post by: dani01 on October 27, 2019, 08:42:42 pm
Hi there,
Dolly was a clone produced by whole organism cloning, which occurs through somatic cell nuclear transfer.
With transgenic organisms or transgenesis, it does not include somatic cell nuclear transfer. It is the introduction of DNA from different organism into another organism to exhibit a particular trait and pass it to offsprings. Such as pest resistent crops. Hope this answers your question.
thank you so very much. best of luck for tomorrow :)
Post by: Annasimon on June 03, 2020, 02:18:33 pm
Post by: Annasimon on June 03, 2020, 02:49:33 pm
Post by: Einstein_Reborn_97 on June 03, 2020, 05:09:49 pm
Why are white blood cells bigger and fewer in number compared to red blood cellsHey Annasimon,
Um...well, I think this has to do with their respective functions. Red blood cells facilitate gaseous transport around the body; they carry oxygen from the lungs to all body tissues and carbon dioxide away from the tissues back to the lungs. White blood cells are mainly responsible for defending the body against infection. I'd say red blood cells are more frequently needed over the entire life span of a human than white blood cells. Oxygen, from the red blood cells, is used to produce energy which the body needs.
As for why white blood cells are bigger than red blood cells, I think it has to do with the nature of their roles. Red blood cells have to be really small to squeeze through the capillaries (which are tiny). White blood cells, however, contain several substances that they release at the site of infections and they also perform phagocytosis and have to produce antibodies.
Hope that answers your questions ;)
Post by: Einstein_Reborn_97 on June 03, 2020, 06:26:35 pm
Why does a small cube have a higher surface area to volume ratioThis video should help...
If you need anything to be clarified, ask away ;)
Post by: Annasimon on June 03, 2020, 06:54:08 pm
And would the definition of homologous chromosomes be chromosomes that have the exact same genes but different versions of the gene-alleles
Thanks!!
Post by: Annasimon on June 03, 2020, 06:54:46 pm
Post by: Annasimon on June 03, 2020, 07:00:52 pm
Also what stage do they occur
Post by: Einstein_Reborn_97 on June 03, 2020, 07:09:22 pm
I can’t see the video . It says playback error...Try this: https://youtu.be/uu9eHX6Tu8Q
Post by: Einstein_Reborn_97 on June 03, 2020, 08:58:35 pm
Ok . Also why does the Y chromosome not undergo crossing overHomologous chromosomes are a pair of chromosomes with the same genes, one originating from the mother and the other from the father in sexual reproduction (And yes, they have different of the same genes).
And would the definition of homologous chromosomes be chromosomes that have the exact same genes but different versions of the gene-alleles
Thanks!!
Crossing over can only occur between homologous chromosomes. The X and Y chromosomes are not homologous and so crossing over doesn't occur. However, the X and Y chromosomes have homologous sequences (sections that contain the same genes), called pseudoautosomal regions, and crossing over is restricted to these regions. I doubt we'll need to know this for the HSC, it's not included in any HSC resource I'm aware of.
Hope that helps ;)
Post by: Annasimon on June 03, 2020, 11:14:23 pm
How would you draw a diagram to show DNA replication
Post by: Coolmate on June 04, 2020, 01:07:14 pm
Independent assortment and crossing over both occur in meiosis and not mitosis right?
Also what stage do they occur
Hey Annasimon!
Yes, you are correct --> Independent assortment and crossing over only occur in meiosis
🧬Independent Assortment occurs during Metaphase 1
🧬Crossing Over occurs during Prophase 1
I hope this helps!
Coolmate 8)
Post by: Coolmate on June 04, 2020, 01:42:23 pm
Is random segregation the same thing as independent assortment??
How would you draw a diagram to show DNA replication
Random segregation is not the same thing as independent assortment. This is because:
🔹Random Segregation = Occurs during gamete formation and alleles that are responsible for the same trait are separated from each other
🔹Independent Assortment = Alleles for different traits are lined up and are independently separated from each other when gametes form
Here is a YouTube video for further explanation:
https://www.youtube.com/watch?v=9yTgUvLORkA
To draw a diagram to show DNA Replication, I have attached an image that goes through the various steps of DNA Replication succinctly for an exam question response. (accessed from Google Images)
I hope this helps!
Coolmate 8)
Post by: Annasimon on June 04, 2020, 02:21:54 pm
Post by: Annasimon on June 04, 2020, 02:26:25 pm
During protein synthesis the nucleic acids DNA and rna act in which of the following orders?
A messenger rna, transfer rna, dna
B DNA , transfer rna, messenger rna
C DNA, messenger RNA, transfer rna
D transfer rna, messenger rna, dna
Would the answer be c??
Thanks!
Post by: Annasimon on June 04, 2020, 02:32:30 pm
All of the following plant transport processes are directly driven by osmosis , except one .which one does not directly involve osmosis?
A guard cells losing turgor pressure
B oxygen diffusion into leaves
C transpiration
D translocation
Post by: Coolmate on June 04, 2020, 03:43:07 pm
For this question:
During protein synthesis the nucleic acids DNA and rna act in which of the following orders?
A messenger rna, transfer rna, dna
B DNA , transfer rna, messenger rna
C DNA, messenger RNA, transfer rna
D transfer rna, messenger rna, dna
Would the answer be c??
Thanks!
Hey!
The answer would be C.
(DNA --> mRNA --> tRNA)
This is because DNA is untwisted by the enzyme, Helicase, then the order of bases of the DNA are transcribed onto messenger RNA (mRNA). This mRNA, travels out of the nucleic pores into the cytoplasm, by which it binds to a ribosome, then transfer RNA (tRNA), carrying a correct respective amino acid begins to create a polypeptide chain.
Thus, the answer is C, the other answers are out of the correct order.
Hope this helps,
Coolmate 8)
Post by: Coolmate on June 04, 2020, 04:36:04 pm
Also for this question I think the answer is b am I correct?
All of the following plant transport processes are directly driven by osmosis , except one .which one does not directly involve osmosis?
A guard cells losing turgor pressure
B oxygen diffusion into leaves
C transpiration
D translocation
Yes, the correct answer to this multiple-choice question is B.
This is because:
💧Osmosis = Is a type of water diffusion from molecules of a higher concentration of water to a lower concentration of water, through a selectively permeable membrane.
📌But, option "B" involves the word, 'Diffusion' 💨, which is the movement of molecules other than water from areas of high concentration to areas of low concentration
Hope this helps,
Coolmate 8)
Post by: Chocolatepistachio on June 04, 2020, 05:37:16 pm
Some living cells were maintained in a culture medium under aerobic conditions. They were supplied with glucose labelled with radioactive carbon-14? Which of the following is likely to be true
A carbon14 atoms would be found in NADH
B carbon 14 atoms would be found in atp
C carbon 14 atoms would be found in carbon dioxide produced by the cells
D Carbon 14 atoms would be found in pyruvate
Thanks
Post by: Annasimon on June 04, 2020, 06:10:36 pm
Which of the following best describes a gene?
A a single DNA molecule wound around proteins
B one leg of a pair of blue denim pants
C an allele that exists in 2 or more forms
D. A sequence of DNA nucleotides that encode a protein
Thanks!
Post by: Annasimon on June 04, 2020, 06:12:04 pm
Post by: Coolmate on June 04, 2020, 10:10:34 pm
Isn’t translocation the movement of sugars though not the movement of water?
Yes, that's true I just modified the above answer. Translocation is the movement of sugars and other food substances from the leaves to rest of the plant via the Phloem, not the movement of water.
Post by: Coolmate on June 04, 2020, 10:30:48 pm
Would the answer for this question be d??
Which of the following best describes a gene?
A a single DNA molecule wound around proteins
B one leg of a pair of blue denim pants
C an allele that exists in 2 or more forms
D. A sequence of DNA nucleotides that encode a protein
Thanks!
I would say the answer to this question is "D".
Because:
Genes are made up of sequences of DNA nucleotides and these genes encode for proteins which control cell function. Thus, I would say "D" is the answer as it sounds most correct.
Hope this helps,
Coolmate 8)
Post by: Annasimon on June 04, 2020, 11:25:49 pm
How would you explain the relationship between the circulatory and respiratory systems?
They both work together to maintain homeostasis ..?
Post by: Chocolatepistachio on June 05, 2020, 04:10:24 pm
which organisms undergo mitosis without cytokinesis following and why would cells which undergo mitosis and not cytokinesis have 1 cell and 2 nuclei?
Thanks
Post by: kauac on June 05, 2020, 08:33:39 pm
Sorry for all the questions...
How would you explain the relationship between the circulatory and respiratory systems?
They both work together to maintain homeostasis ..?
Hi, I think that's a great way of explaining it!
You can talk specifically about the homeostasis mechanisms they are involved. e.g. balance of O2 and CO2.
You could even say that they are codependent on each other - because the circulatory system provides O2 rich blood to the lungs and respiratory muscles, and the lungs provide an oyxgen supply for the heart muscle to stay healthy. :)
Post by: Chocolatepistachio on June 05, 2020, 08:54:45 pm
Hello for this multiple choice question is the answer c?
Some living cells were maintained in a culture medium under aerobic conditions. They were supplied with glucose labelled with radioactive carbon-14? Which of the following is likely to be true
A carbon14 atoms would be found in NADH
B carbon 14 atoms would be found in atp
C carbon 14 atoms would be found in carbon dioxide produced by the cells
D Carbon 14 atoms would be found in pyruvate
Thanks
Pls can someone help me with this question
Post by: kauac on June 05, 2020, 09:14:41 pm
Pls can someone help me with this question
Hi!
This is a tricky question! I'm not entirely sure why the answer is c, but maybe it's something to do with CO2 being the only option that is a by-product of aerobic respiration - whereas the others are helpful metabolites!
Hopefully someone else may have a better idea of why it's C. :)
Post by: Einstein_Reborn_97 on June 05, 2020, 09:36:13 pm
Hello for this multiple choice question is the answer c?Yeah I'm pretty sure it's C. The question states "aerobic conditions" so that implies that aerobic cellular respiration was being observed. In cellular respiration, the reactants are glucose (which was supplied with radioactive carbon-14) and oxygen, whilst the products are carbon dioxide and water. The logical aim of this experiment would be to trace the movement of the glucose molecules and the logical conclusion would be that the carbon-14 isotope ends up in the carbon dioxide product. Therefore, the answer should be C.
Some living cells were maintained in a culture medium under aerobic conditions. They were supplied with glucose labelled with radioactive carbon-14? Which of the following is likely to be true
A carbon14 atoms would be found in NADH
B carbon 14 atoms would be found in atp
C carbon 14 atoms would be found in carbon dioxide produced by the cells
D Carbon 14 atoms would be found in pyruvate
Thanks
Post by: Chocolatepistachio on June 05, 2020, 10:31:23 pm
Also for this question
From which of the following is the waste product urea formed
A sugars
B fats
C protein
D Glycerol
Is the answer c??
Post by: Einstein_Reborn_97 on June 05, 2020, 11:01:48 pm
Ok thanks!Yes. The liver breaks down excess amino acids (which make up protein) to make ammonia, then converts this into urea.
Also for this question
From which of the following is the waste product urea formed
A sugars
B fats
C protein
D Glycerol
Is the answer c??
Post by: Chocolatepistachio on June 05, 2020, 11:27:00 pm
Atp synthase produces atp.....
A during the electron transport chain in the krebs cycle of cellular respiration
B only during glycolysis in cellular respiration
C in cellular respiration and the light dependent reactions of photosynthesis
D directly from the photolysis of water
Would it be a??
Thank you for your help!
Post by: Einstein_Reborn_97 on June 06, 2020, 12:10:22 am
For this question:Yes, the answer is a.
Atp synthase produces atp.....
A during the electron transport chain in the krebs cycle of cellular respiration
B only during glycolysis in cellular respiration
C in cellular respiration and the light dependent reactions of photosynthesis
D directly from the photolysis of water
Would it be a??
Thank you for your help!
Post by: Annasimon on June 06, 2020, 01:11:43 am
Would this be an example of divergent evolution?
Post by: Annasimon on June 06, 2020, 01:14:53 am
Which is the correct
Post by: Coolmate on June 06, 2020, 09:34:52 am
Two birds with the same ancestor have evolved different beak shapes suited to eating different types of food eg insects and fruit.
Would this be an example of divergent evolution?
Yes, this is an example of divergent evolution.
Humoral immunity or humoural immunity?
Which is the correct
I'm not quite sure about the correct spelling for this word (maybe Humoral Immunity?)
Hope this helps!
Coolmate 8)
Post by: Einstein_Reborn_97 on June 06, 2020, 11:03:09 am
Humoral immunity or humoural immunity?Humoral immunity.
Which is the correct
Post by: Chocolatepistachio on June 06, 2020, 11:58:15 am
Two proteins actin and myosin are responsible for the contraction of muscles. Cellular extracts of these proteins will contract in a Petri dish in the presence of certain mineral ions. However this only occurs if a certain molecule is also present. This is
A adp
B Glucose
C nad
D atp
Would it be atp?
Can someone explain
Post by: JeffBecker on November 11, 2020, 08:20:53 pm
I got this question on edzion
Question 3. [6 marks]
Evaluate whether sexual or asexual reproduction is more favorable for the continuation of a species.
Anyone got any idea how to do it?
Post by: Owlbird83 on November 11, 2020, 08:58:31 pm
For this question:Yeah, ATP. ATP is what provides energy for muscles to contract. It's the best way of providing energy to cellular processes, by breaking the bond to a phosphate and releasing energy contained in the bond.
Two proteins actin and myosin are responsible for the contraction of muscles. Cellular extracts of these proteins will contract in a Petri dish in the presence of certain mineral ions. However this only occurs if a certain molecule is also present. This is
A adp 'unloaded' energy molecule, the bond to the 3rd phosphate has been broken and released energy already.
B Glucose The glucose needs to undergo cellular respiration in order for the energy to be converted to a form thats useful to the cell (ATP)
C nad An 'unloaded' carrier of H ions and electrons, not useful to help cell move
D atp
Would it be atp?
Can someone explain
Hi,
I got this question on edzion
Question 3. [6 marks]
Evaluate whether sexual or asexual reproduction is more favorable for the continuation of a species.
Anyone got any idea how to do it?
Some ideas for you to think about
Which method of reproduction produces more variation?
Why is increased variation in a population beneficial?
some hints
-sexual reproduction -> mutation, independent assortment, crossing over, fertilisation create variation
-asexual reproduction -> mutation only source of variation
-variation is important for natural selection to occur
-in event of environmental change, it's more likely that in a population with more variation there will be one or some individuals with beneficial traits that allow it to survive --> overtime the population can adapt as a whole through natural selection
-organisms that produce asexually will be more similar and therefore may be wiped out because none can deal with a sudden environmental change
-asexual reproduction -> mutation only source of variation
-variation is important for natural selection to occur
-in event of environmental change, it's more likely that in a population with more variation there will be one or some individuals with beneficial traits that allow it to survive --> overtime the population can adapt as a whole through natural selection
-organisms that produce asexually will be more similar and therefore may be wiped out because none can deal with a sudden environmental change
Post by: Bri MT on November 11, 2020, 09:08:58 pm
Yeah, ATP. ATP is what provides energy for muscles to contract. It's the best way of providing energy to cellular processes, by breaking the bond to a phosphate and releasing energy contained in the bond.
Some ideas for you to think about
Which method of reproduction produces more variation?
Why is increased variation in a population beneficial?some hints-sexual reproduction -> mutation, independent assortment, crossing over, fertilisation create variation
-asexual reproduction -> mutation only source of variation
-variation is important for natural selection to occur
-in event of environmental change, it's more likely that in a population with more variation there will be one or some individuals with beneficial traits that allow it to survive --> overtime the population can adapt as a whole through natural selection
-organisms that produce asexually will be more similar and therefore may be wiped out because none can deal with a sudden environmental change
Adding to this to give a couple of advantages of asexual reproduction
Spoiler
much faster population growth (given each mother has same amount of daughter) & no need to find a partner before reproduction (which can take energy and resources, open self to predation risk, disease etc.).
As Owlbird has said, the huge advantage of sexual reproduction which sees it evolve again and again is increased diversity
As Owlbird has said, the huge advantage of sexual reproduction which sees it evolve again and again is increased diversity
I haven't looked into HSC assessment much but hopefully this information helps you form a syllabus-suitable response :)
Post by: Coolmate on November 20, 2020, 04:00:28 pm
Can someone please explain to me how polypeptide synthesis and DNA replication are related to each other?
Also if anyone has any assignments that they've completed on polypeptide synthesis, I would definitely appreciate it if you could upload it or send it to my email.
Thanks! :)
Hey neha.singh4! :D
Polypeptide Synthesis and DNA Replication are related to each other. DNA Replication is the process of producing two identical DNA units from an original DNA unit, whereas Polypeptide Synthesis is the process of creating polypeptide chains, ultimately folding to form a functional protein. Firstly, DNA Replication must occur so there is a DNA unit available to be transcribed by mRNA and translated by tRNA (both processes in Polypeptide Synthesis).
Secondly, when a protein is required to be produced, the process of Polypeptide Synthesis is initiated where it uses a DNA molecule's template strand (From DNA Replication) to match opposing bases (EG. A - T or C - G), which after the processes of mRNA and tRNA, produces a protein. (Polypeptide Synthesis)
Hence, if DNA Replication did not occur, then Polypeptide Synthesis would not be able to occur as a result of no genetic material/ codons, meaning the mRNA cannot match complementary bases, leaving tRNA with nothing to translate. This means a protein cannot be produced, affecting the functions of certain parts of the body (EG. Hair Growth). But because (usually, unless a mutation is evident) DNA Replication occurs, this means so too can Polypeptide Synthesis, thus a relationship (one cannot occur without the other)
(https://scontent-syd2-1.xx.fbcdn.net/v/t1.15752-0/p280x280/124072163_730450621201967_5464457814452749498_n.png?_nc_cat=100&ccb=2&_nc_sid=ae9488&_nc_ohc=fTY9Ji64wg8AX8BHKku&_nc_ht=scontent-syd2-1.xx&oh=aa82104144d27366312dbfa480c9d157&oe=5FDAEF38)
---> This image illustrates the process of DNA Replication
(https://scontent-syd2-1.xx.fbcdn.net/v/t1.15752-0/p280x280/49948896_292947558233983_8719007627784224768_n.png?_nc_cat=108&ccb=2&_nc_sid=ae9488&_nc_ohc=hS8qdvU7jrcAX-NK5Zd&_nc_ht=scontent-syd2-1.xx&oh=52970b523d5ca10247fa3bb2024dc3fe&oe=5FDDCDFD)
---> In this image you can see how Polypeptide Synthesis relies on the DNA unit to create functional proteins
About the assignment question, sorry I don't have one that I completed on Polypeptide Synthesis. Could you ask your teacher to see samples of assignments from last year?
I hope this helps!
Coolmate 8)
Post by: Maroon and Gold Never Fold on February 06, 2021, 05:14:30 pm
Post by: Coolmate on February 06, 2021, 05:22:01 pm
What is PCR in simple terms and is it used in both DNA profiling and sequencing.
Hey! :D
Polymerase Chain Reaction (PCR)'s aim is to rapidly create many copies (can be thousands) of a DNA unit (kind of like a printer, but for DNA). From this amplification, the DNA can be used by scientists as it is easier to study, test and observe. It is advantageous as it is cheap yet effective.
PCR is used in DNA Profiling to increase the amount of DNA present to study in the next stage of Profiling, Gel Electrophoresis (comparing bands).
PCR is used in DNA Sequencing also.
I hope this helps!
Coolmate 8)
Post by: Maroon and Gold Never Fold on February 06, 2021, 05:27:26 pm
Hey! :D
Polymerase Chain Reaction (PCR)'s aim is to rapidly create many copies (can be thousands) of a DNA unit (kind of like a printer, but for DNA). From this amplification, the DNA can be used by scientists as it is easier to study, test and observe. It is advantageous as it is cheap yet effective.
PCR is used in DNA Profiling to increase the amount of DNA present to study in the next stage of Profiling, Gel Electrophoresis (comparing bands).
PCR is used in DNA Sequencing also.
I hope this helps!
Coolmate 8)
helps a lot
Post by: neha.singh4 on March 10, 2021, 10:19:51 pm
Evaluate the use of whole organism cloning in agriculture. Include considerations of the social, ethical and environmental implications of its use.
Post by: Coolmate on March 12, 2021, 10:51:07 pm
How would you go about tackling this question?
Evaluate the use of whole organism cloning in agriculture. Include considerations of the social, ethical and environmental implications of its use.
Hey neha.singh4! :D
This is a question that not only tests a wide range of content, but also connections between content in the syllabus. In addition, these questions are a great way to revise, as they teach you question structure, succintness and a wide variety of content.
If I were answering this question, I would go about it like this:
1. Split the question up into parts:
Evaluate (Make a judgement based on criteria: NESA Glossary of Key Terms) the use of whole organism cloning (This is the overarching main topic required to be discussed) in agriculture (Not medical or industrial but agricultural; This is asking about the effects on agriculture only). Include considerations of the social, ethical and environmental implications of its use (We must include these 3 vital considerations in the response).
2. See if you can use the question to your advantage:
This question specifies 3 vital implications we must talk about, so I would consider structuring your response like this:
Introduction
Firstly, make a stance/ opinion on the question in the first setence to demonstrate to the marker that you understood the question by providing a direct response. Next, define Biotechnology and slightly reveal what you will talk about in the following paragraphs.
1st Paragraph
Firstly, define what "Social" means, then get into the social implications of using Whole Organism Cloning and provide at least 2 examples to illustrate an understanding. Some social implications include, we are currently facing a major global issue of "Overpopulation" and cloning will only exacerbate this issue, another one is what about the telomeres (caps on chromosomes) of the cloned organism? Will they be shorter, indicating a higher death rate among cloned organisms?
2nd Paragraph
Firstly, define what "Ethics" are, then get into the ethical implications of using Whole Organism Cloning and like the first paragraph, provide at least 2 examples to showcase a broad length and depth of knowledge. Some ethical implications include, is it ethically viable to clone an organism? Does this contradict Bioethical considerations?
3rd Paragraph
Firstly, define what "Environment" means in this scenario, then get into the ethical implications of using Whole Organism Cloning. Then, using at least 2 examples, link your ideas. Some environmental implications include, taking in consideration our Biosphere, will the cloning of organisms 'upset' the Biosphere on Earth (EG. some populations may become extinct due to a higher amount of a predative species, interfering with the food chain)
❗REMEMBER - Continually evaluate within your paragraphs so you don't "waffle on" and indicate to your marker that you are answering the given question.
A classic example is Dolly the Sheep, who was cloned in 1996 and was only successfully cloned after 277 attempts (very expensive!)
I hope this helps and if you have any questions, please ask! ;)
Coolmate 8)
Post by: neha.singh4 on May 11, 2021, 09:39:50 am
What would be the first, second and third lines of defence against plasmodium?
Post by: Maroon and Gold Never Fold on July 14, 2021, 08:47:07 am
Post by: Billuminati on July 14, 2021, 10:56:40 am
How many homeostatic processes do we need to know? The syllabus says glucose and temperature which I have already done, however my school is doing homeostasis for water balance where we go in depth into kidney function along with a kidney dissection. Is this really needed for HSC and am I better of not bothering about this as I have already done temperature and glucose in my own time?
I had a look at your study design for bio from NESA, they said “including but not limited to glucose and temperature” so including osmoregulation is technically allowed. In Victoria where I completed the VCE, VCAA (our version of your NESA) expects you to know only 3 mechanisms, glucose, temperature and osomoregulation.
Post by: anonymous_bean on July 18, 2021, 06:43:30 pm
Post by: Billuminati on July 18, 2021, 07:10:29 pm
Hi, I'm having difficulty solving this question. Could you help?
Use a ruler, it seems that 5 stoma fit into the FOV, so the FOV size is 250 um or 0.25 mm
For the 2nd question, you'll find using a ruler that the image has been enlarged 2.5 times. You originally had 20*10= 200x magnification, so you'll need something that gives you a grand total of 500x magnification. 20x ocular and 25x objective fits this description
Post by: dylan.turner on May 09, 2022, 11:38:49 pm