Welcome, Guest. Please login or register.

July 16, 2019, 10:14:51 am

Author Topic: VCE Biology Question Thread  (Read 1259250 times)  Share 

0 Members and 8 Guests are viewing this topic.

DBA-144

  • MOTM: APR 19
  • Trendsetter
  • **
  • Posts: 192
  • Respect: +31
Re: VCE Biology Question Thread
« Reply #11655 on: May 05, 2019, 01:48:01 pm »
+3
Hello guys!
So I have a SAC 5 coming up and you have to design your own experiment relating to unit 3 stuff.
My experiment was testing the effect of amylase on different types of fruits i.e watermelon, banana, apple, lemon and dates.
My hypothesis was that dates will have the highest rate of reaction.
I did my experiment and I got really unexpected results (my POV anyway) and it was that white furry fungi was growing on the apple and banana. So my experiment backfired.
I'm not sure if I can relate this to biology unit 3 concepts so does anyone know how I can relate?
 I was also wondering whether anyone had any other original experiments relating to enzymes that would be good to carry out and would give quantitative data?
I am really struggling now and feel utterly hopeless. Any help at all would be appreciated.
Thanks.


Hey,
So for your experiment, it seems like you had an error due to contamination since fungi began to grow. Can you please explain what your method was in order to help others help you a little bit more? How did you measure 'rate of reaction'? And how did you add the amylase into the fruits? Did you cut up the pieces of fruit, or just leave them whole? If you did cut them up, I suspect that the fungi would have attached onto the infected fruits and would have obtained nutrients/energy from them, hence that is why you saw such a huge (guessing here) amount of fungi on the fruits (they had a pretty favourable environment).

From here, you could potentially find out why you got this error. Generally speaking, contamination is said to be a random error, but this is because we assume that experimenters are competent and very experienced (not attacking you here, this is what we assume in general, such errors occur a lot in real science, I believe).

You could then say that the fungi grew on x and y fruits but not a or b because (x and y have higher energy contents and hence are more favourable conditions for fungi to grow on). THis is what sometimes happens; we look for a specific result, only to find out that the results say that x is not related to y, but z is related to y. From here, we tailor our methodology to find out more about the results obtained. From my knowledge, this actually occurs more often than you might think. I would give an example, but don't want to ramble even more haha. If you don't want to do what I describe below, you might be able to use the bit about how fungi grow in favourable conditions, in sunlight, with lots of energy and oxygen for them to undergo aerobic respiration. This makes it really easy to link to AOS 1.

Your second option is to repeat the experiment, or to do another experiment, if time allows. There are heaps of easy experiments you can find online by googling, for example.

Like I said, giving details about the method would help a bit more I guess.

Sorry for rambling so much. Hope this helps and good luck with your sac.

Evolio

  • Trendsetter
  • **
  • Posts: 172
  • Respect: +50
Re: VCE Biology Question Thread
« Reply #11656 on: May 05, 2019, 02:23:08 pm »
0
Thank you so much for responding DBA-144!
Yeah, I was researching and I think the fungi grew because of the wet conditions since they thrive well and grow really fast in moist conditions.
The fruits were in pieces. I had two pieces of each fruit in each of the 5 petri dishes, cut roughly in rectangular pieces and I dropped amylase solution onto the fruit pieces until their entire surface was covered. Then I covered the petri dishes up and observed over a bit more than 1 week. It was a 5% amylase solution. The amylase was supposed to act on the starch on the fruits.
But the overarching problem is that I don't think I can get quantitative data from this experiment.
My teacher said to repeat it with controls where I have one fruit piece in amylase solution and another fruit piece not exposed to amylase solution. But I don't think I can get quantitative data, that's the real problem since it's a part of our rubric.


2019: Biology, Methods
2020: Literature, Psychology, Specialist Mathematics, Chemistry

DBA-144

  • MOTM: APR 19
  • Trendsetter
  • **
  • Posts: 192
  • Respect: +31
Re: VCE Biology Question Thread
« Reply #11657 on: May 05, 2019, 02:31:54 pm »
+4
Thank you so much for responding DBA-144!
Yeah, I was researching and I think the fungi grew because of the wet conditions since they thrive well and grow really fast in moist conditions.
The fruits were in pieces. I had two pieces of each fruit in each of the 5 petri dishes, cut roughly in rectangular pieces and I dropped amylase solution onto the fruit pieces until their entire surface was covered. Then I covered the petri dishes up and observed over a bit more than 1 week. It was a 5% amylase solution. The amylase was supposed to act on the starch on the fruits.
But the overarching problem is that I don't think I can get quantitative data from this experiment.
My teacher said to repeat it with controls where I have one fruit piece in amylase solution and another fruit piece not exposed to amylase solution. But I don't think I can get quantitative data, that's the real problem since it's a part of our rubric.

What are you measuring? HOw do you know that amylase acted more on fruit a than fruit b? This is how you get quantitative data. THere are a few errors in your method.
These include but are not limited to:
-THe fact that you have not measured how much amylase was added to each solution
-THe conditions in which you will be holding the fruit pieces, i.e if they are in closed petri dishes, you must ensure that the petri dishes have been washed/sterilised to remove the growth of fungi for example.
-The pieces of fruit in each dish must be the same and the size of each fruit needs to be in the same measurements.
-You needed to ensure that the fruit were ripe i.e if they were too ripe/not ripe enough then there would have been fewer/more carbohydrates for the amylase to act on. This is hard to control but needs to be considered.
What is your IV and DV? 
Seems like it is rate of reaction and fruit used but how are you measuring rate of reaction? You don't have any way to measure that, you won't get any quantitative data.

Hope this helps.

Donut

  • Adventurer
  • *
  • Posts: 16
  • Respect: 0
Re: VCE Biology Question Thread
« Reply #11658 on: May 08, 2019, 06:43:44 pm »
0
Could anyone help with this question with an explanation?

Question 17
A typical animal hormone has different actions on different tissues because
A.   the various target cells have different genes.
B.   hormones are directed to specific targets by the circulatory system.
C.   the receptors on different target cells are linked to different cell mechanisms.
D.   each different response is connected to a different receptor for the same hormone.

Owlbird83

  • Trendsetter
  • **
  • Posts: 183
  • Respect: +158
Re: VCE Biology Question Thread
« Reply #11659 on: May 08, 2019, 09:11:53 pm »
+3
Could anyone help with this question with an explanation?

Question 17
A typical animal hormone has different actions on different tissues because
A.   the various target cells have different genes.
B.   hormones are directed to specific targets by the circulatory system.
C.   the receptors on different target cells are linked to different cell mechanisms.
D.   each different response is connected to a different receptor for the same hormone.

It would be C
A-All cells contain the same DNA so same genes
B-The hormones aren't directed to specific target cells, they travel through the blood, and will bind to only cells with a specific complementary receptor (the target cell).
C-Yes, the hormone binds to the receptors on different cells and the process that will happen inside the cell can be different depending on the cell and have a different response.
D- the receptors on cells for that particular hormone should be the same because it must have a complementary shape so that it can bind.

Hope this helps!
2018: Biology
2019: Chemistry, Physics, Math Methods, English, Japanese

sarah15

  • Fresh Poster
  • *
  • Posts: 3
  • Respect: 0
Re: VCE Biology Question Thread
« Reply #11660 on: May 09, 2019, 07:38:19 pm »
0
Hi I have a few questions.
If a question asks to define signal transduction, is it asking to define the pathway (reception, transduction, response) or the stage (second messengers, enzyme cascade)?
Why does insulin have different responses in muscle, liver and adipose tissue?
Is the difference between the duration of hydrophobic and hydrophilic signalling that hydrophobic signalling is longer lasting because it relies on the hormone receptor complex to relay the message to the nucleus, while the duration of hydrophilic signalling is short lived because of the enzyme cascade which means that more signals reach the nucleus.
Thank you.

w0lfqu33n89

  • Trendsetter
  • **
  • Posts: 119
  • I overthink everything...wait, do I? Yeah I do
  • Respect: +44
Re: VCE Biology Question Thread
« Reply #11661 on: May 09, 2019, 09:11:24 pm »
0
HIIIIIIIII! doing a year 11 sac on Homeostasis! studying my butt off but just incase I am missing anything what are key bits I need to know and remember? TIA

Ans0007

  • Fresh Poster
  • *
  • Posts: 1
  • Respect: 0
Re: VCE Biology Question Thread
« Reply #11662 on: May 09, 2019, 09:33:44 pm »
+1
are all hydrophilic substances polar? and hydrophobic substances nonpolar?? ???

DBA-144

  • MOTM: APR 19
  • Trendsetter
  • **
  • Posts: 192
  • Respect: +31
Re: VCE Biology Question Thread
« Reply #11663 on: May 09, 2019, 09:44:28 pm »
+3
Hi I have a few questions.
If a question asks to define signal transduction, is it asking to define the pathway (reception, transduction, response) or the stage (second messengers, enzyme cascade)?
Why does insulin have different responses in muscle, liver and adipose tissue?
Is the difference between the duration of hydrophobic and hydrophilic signalling that hydrophobic signalling is longer lasting because it relies on the hormone receptor complex to relay the message to the nucleus, while the duration of hydrophilic signalling is short lived because of the enzyme cascade which means that more signals reach the nucleus.
Thank you.

Pretty sure that it would just refer to the stage, i.e the stuff that happens after reception that lead to the response.

Insulin has different responses in different tissues due to the different signal transduction mechanisms that exist in each of the different types of tissue. eg. muscle cells might have X second messenger which activates a, b and c second messengers (or enzymes) and this leads to a signal cascade that finally elicits the reponse (glucose uptake from the bloodstream). However, the lvier cells may have a different second messenger that activates x,y and z second messenger/enzymes, and hence this elicits a different response to the muscle cells as there are different molecules involved. Same idea for the adipose tissue. 

Not sure about the last one. imo you are probably right, but I think that it also could have something to do with how the responses are different (sort of). What I am referring to here is the fact that the hormone receptor complex acts as a transcription factor, causing a change in gene expression and regulation, whereas the signal cascade just goes and activates an enzyme OR it will go into the nucleus and then initiate the synthesis of an effector protein which initiates the response. But yeah the main time difference would have to do with the signal transduction pathway, I think.

 
are all hydrophilic substances polar? and hydrophobic substances nonpolar?? ???

Yes.

Rom_Dog

  • Adventurer
  • *
  • Posts: 15
  • You gotta' just straight up eat the lettuce
  • Respect: +8
Re: VCE Biology Question Thread
« Reply #11664 on: May 11, 2019, 10:26:03 am »
+3
HIIIIIIIII! doing a year 11 sac on Homeostasis! studying my butt off but just incase I am missing anything what are key bits I need to know and remember? TIA

Hey! It's likely that your teachers will base your SAC on the points in the study design, the ones below relate to homeostasis.

- How regulation of factors is needed to maintain a relatively constant internal environment, explained by the stimulus-response model and the use of homeostatic mechanisms including feedback loops
- Factors regulated by homeostatic mechanisms in humans, including temperature, blood glucose and water balance
- Malfunctions in homeostatic mechanisms that result in diseases, including Type 1 diabetes and hyperthyroidism in humans.

A key parts of homeostasis to note is that too much or too little can be dangerous! The body has a many sophisticated biochemical and physiological mechanisms to keep variable such as temperature, ion concentrations and the pH of different areas of the body in a narrow range. It's also good to note examples for the two types of feedback loops, blood clotting is a good example of a positive feedback loop and thermoregulation is a good example of a negative feedback loop. If you've gone over it in class, you should definitely revise hyperthyroidism and type 1 diabetes too!

I hope this helps!!  :D

2019 - 2021: Biomed @ Monash!

Chocolatemilkshake

  • Adventurer
  • *
  • Posts: 23
  • Respect: +1
Re: VCE Biology Question Thread
« Reply #11665 on: May 13, 2019, 08:20:17 pm »
0
Hi all,

Douchy on the Edrolo course says that Pheromones can be recognised and received by cells of different species/organisms. However, Atarnotes course notes and my teacher's slides have said that pheromones are only recognised and received by the same species.

If anyone could clear this up that would be great  :D

Thanks for all you help as always!
2019 - Biology

Erutepa

  • MOTM: FEB 19
  • Forum Obsessive
  • ***
  • Posts: 361
  • cold
  • Respect: +375
Re: VCE Biology Question Thread
« Reply #11666 on: May 13, 2019, 08:28:33 pm »
+1
 Pheromones are only received by members of the same species

In fact as per the [thrilling book] "Pheromones and Animal Behaviour", Pheromones are "substances secreted to the outside of an individual and received by a second individual of the same species in which they release a specific reaction, for example, a definite behaviour or developmental process"
Qualifications
 > Have counted to 102 (with a dapper koala)
 > Can draw really good spiders
 > 2 Poet points
 > 6.5 insanipi points

Chocolatemilkshake

  • Adventurer
  • *
  • Posts: 23
  • Respect: +1
Re: VCE Biology Question Thread
« Reply #11667 on: May 13, 2019, 08:51:33 pm »
0
Pheromones are only received by members of the same species

In fact as per the [thrilling book] "Pheromones and Animal Behaviour", Pheromones are "substances secreted to the outside of an individual and received by a second individual of the same species in which they release a specific reaction, for example, a definite behaviour or developmental process"

Thanks!!!!!!
2019 - Biology

eesimon

  • Fresh Poster
  • *
  • Posts: 1
  • Respect: 0
Re: VCE Biology Question Thread
« Reply #11668 on: May 14, 2019, 06:50:02 pm »
0
Hi!
For my depth study, I am investigating DNA profiling and I am trying to nail down some of the basics. However, I am confused about the following questions:
Are introns located in genes or between genes?
If introns are cut out of the new mRNA strand during splicing and broken down into nucleotides to be used again, how are they used in DNA profiling?

Thanks!

Erutepa

  • MOTM: FEB 19
  • Forum Obsessive
  • ***
  • Posts: 361
  • cold
  • Respect: +375
Re: VCE Biology Question Thread
« Reply #11669 on: May 14, 2019, 07:00:47 pm »
+5
Hi!
For my depth study, I am investigating DNA profiling and I am trying to nail down some of the basics. However, I am confused about the following questions:
Are introns located in genes or between genes?
If introns are cut out of the new mRNA strand during splicing and broken down into nucleotides to be used again, how are they used in DNA profiling?

Thanks!
Introns are segments within a gene that are spliced out during Pre mRNA splicing/modification.
Since they are only spliced from the Pre mRNA molecule, they still exist within the chromosomal DNA and thus could still be targeted for sequencing in DNA profiling.
Qualifications
 > Have counted to 102 (with a dapper koala)
 > Can draw really good spiders
 > 2 Poet points
 > 6.5 insanipi points