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June 02, 2020, 12:54:41 am

Author Topic: VCE Biology Question Thread  (Read 1670426 times)  Share 

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darkz

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Re: VCE Biology Question Thread
« Reply #10605 on: August 27, 2018, 08:14:23 am »
0
Restriction endonucleases and restriction enzymes are the same thing, just different names.

Yeh. I was trying to make the point that not all endonucleases have restriction sites. Only restriction endonucleases do.
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galaxy21

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Re: VCE Biology Question Thread
« Reply #10606 on: August 27, 2018, 04:06:10 pm »
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Yeh. I was trying to make the point that not all endonucleases have restriction sites. Only restriction endonucleases do.

Haha right! Sorry!
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PopcornTime

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Re: VCE Biology Question Thread
« Reply #10607 on: August 29, 2018, 09:48:33 am »
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What does it mean by hominid, hominin and hominoid?

PhoenixxFire

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Re: VCE Biology Question Thread
« Reply #10608 on: August 29, 2018, 09:51:26 am »
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What does it mean by hominid, hominin and hominoid?
They're different classifications. Hominin is the most specific. All hominins are hominids and all hominids are hominoids.

Hominoids: Great apes, lesser apes.
Hominids: Great apes
Hominins: Modern humans and our extinct bipedal ancestors.
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I\'m Not A Robot

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Re: VCE Biology Question Thread
« Reply #10609 on: August 29, 2018, 11:00:29 pm »
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Hey, i had this question on my sac and i was unable to answer it.

It was: Describe how researchers can determine how long ago populations separated from each other.

I was thinking that the answer might be related to DNA hybridisation, but that only tells us how genetically different two species are.

sooo how would i answer that question?

Also, how does allopatric speciation occur in relation to neanderthals and modern humans?... if they can still interbreed with each other? Do we just say that that they are in that transitional state and are in the process of speciation?

Mod edit: merged double post
« Last Edit: August 29, 2018, 11:13:17 pm by K888 »

LifeisaConstantStruggle

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Re: VCE Biology Question Thread
« Reply #10610 on: August 30, 2018, 12:43:12 am »
+2
Hey, i had this question on my sac and i was unable to answer it.

It was: Describe how researchers can determine how long ago populations separated from each other.

I was thinking that the answer might be related to DNA hybridisation, but that only tells us how genetically different two species are.

sooo how would i answer that question?

Also, how does allopatric speciation occur in relation to neanderthals and modern humans?... if they can still interbreed with each other? Do we just say that that they are in that transitional state and are in the process of speciation?

Mod edit: merged double post

Yes it IS definitely related to DNA hybridisation (or other methods like amino-acid or mtDNA sequencing etcetc), which shows the magnitude of difference between two species. This magnitude can then be related to the molecular clock, in which scientists use differences in data to map a timeline so they can see when they've diverged.

Also you might wanna rehash in your understanding of allopatric speciation, which is one specific type of speciation that occurs due to the existence of a gene flow-restricting geographical barrier, there are definitely more ways in which organisms can diverge to form 2 distinct species (eg: mutations which alter the mating call so one group separates themselves from another).
In many cases neanderthals and modern humans do not experience allopatric speciation at all, and interbreeding between these two groups of organisms just show how blur the line between species can be, and how it is hard to define what a species actually is. This question is still up for debate between scientists on whether or not they should be considered different species, you might wanna look up this because it is interesting! A good book on this would be 'Sapiens: A Brief History of Humankind' by Yuval Noah Harari which covers a lot of ground on human evolution and relationships with other prehistoric hominins.
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Erutepa

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Re: VCE Biology Question Thread
« Reply #10611 on: August 30, 2018, 07:18:52 am »
+1
Hey, i had this question on my sac and i was unable to answer it.

It was: Describe how researchers can determine how long ago populations separated from each other.

I was thinking that the answer might be related to DNA hybridisation, but that only tells us how genetically different two species are.

sooo how would i answer that question?

Also, how does allopatric speciation occur in relation to neanderthals and modern humans?... if they can still interbreed with each other? Do we just say that that they are in that transitional state and are in the process of speciation?

Mod edit: merged double post

If the question was specifically asking for techniques that allow you to determine how long ago two species diverged, than it is probably wanting you to explain the idea of a 'molecular clock', particualrly that of using the stably mutation rate of a gene and looking at accumulated mutations unique to each speices today to determine how long ago they diverged. Ususally you would want to talk about this in terms of a highly conserved nuclear DNA gene, or using mDNA.
With human evolution, what I have learn't is that modern humans (homo sapeins) evolved from homo erectus in africa and then migrated through the rest of the world where they then encountered species like the neaderthals who arose from previsouly migrated homo erectus populations. With reguards to their clasification as a species, what seems to be the case is that the classical definition of a species as something reproductively isolated from other species (meaing can't mate to give fertile/viable offspring), is not always applicable. For most part of phylogenetic studies of now extinct ancestors (and other animals for that matter) from studying things like fossil evidence, general consensuses based around morphilogical differences are the basis for determining species (although assisted by genetics increasingly so).
Hope this helps!
« Last Edit: August 30, 2018, 08:12:20 pm by Erutepa »
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peachxmh

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Re: VCE Biology Question Thread
« Reply #10612 on: August 31, 2018, 05:40:26 pm »
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Hi guys, what exactly do we need to know about transgenic crops in this SD dot point?

- The distinction between genetically modified and transgenic organisms, their use in agriculture to increase crop productivity and to provide resistance to insect predation and/or disease, and the biological, social and ethical implications that are raised by their use

Do we need to know how they are made or any examples? Thanks :)
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Phoenix11

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Re: VCE Biology Question Thread
« Reply #10613 on: September 01, 2018, 11:56:18 am »
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Hi.
I was wondering if anyone knew the answers to these questions(taken from Nature of Biology Edition 5 textbook).

1.  What is the main excretory product found in human urine?

True or False
2. Amino acids in excess if needs cannot be stored by animals.
3. The concentration of urea in the blood is equal to its concentration in the urine.
4. Reabsorbtion of substances occurs by both passive diffusion and active transport.

Thanks.
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PhoenixxFire

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Re: VCE Biology Question Thread
« Reply #10614 on: September 01, 2018, 12:08:52 pm »
+3
Hi guys, what exactly do we need to know about transgenic crops in this SD dot point?

- The distinction between genetically modified and transgenic organisms, their use in agriculture to increase crop productivity and to provide resistance to insect predation and/or disease, and the biological, social and ethical implications that are raised by their use

Do we need to know how they are made or any examples? Thanks :)
For that dot point you don’t need to know how they’re made, but I think there’s a different one that refers to it? You do need to know a bit about how they’re made in order to distinguish between transgenic and gmo though.

You don’t need to know an example for the exam however you might have to for your SAC (I did).

You need to know:
-definitions and differences between transgenic and GMO’s
- their use in agriculture (making crops bigger, making insect that eat them die, making them resistant to insecticide/pesticides so that more can be sprayed on them)
-biological issues - things like wiping out natural plants
-social issues - e.g. farmers who can’t afford the modified plants going bankrupt
-ethical issues - e.g. ‘playing god’

Hi.
I was wondering if anyone knew the answers to these questions(taken from Nature of Biology Edition 5 textbook).

1.  What is the main excretory product found in human urine?

True or False
2. Amino acids in excess if needs cannot be stored by animals.
3. The concentration of urea in the blood is equal to its concentration in the urine.
4. Reabsorbtion of substances occurs by both passive diffusion and active transport.

Thanks.
Hey, it’s not very useful for us to just answer them for you. If you want to explain what you think the answer might be/what you think the question relates to then we’ll be able to help :)
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Phoenix11

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Re: VCE Biology Question Thread
« Reply #10615 on: September 01, 2018, 01:48:38 pm »
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I wrote down my answers but I am just not sure if they're correct. That's why I wanted to clarify.

1. water as it makes up 95% of the urine but I'm not sure what they mean by 'main'? Like the most important or the one that there is the most of as it could be urea.
2. Supposed to be 'of' needs. Well, the amino acids transported to the liver are split into the N-part (ammonia) and the carbon skeleton. Ammonia is excreted but the carbon skeleton is kept. So, the carbon skeleton is stored. So, technically, the amino acids are stored if a part of it is stored. So, i put true for this.
3. This one I checked. The concentration is higher in the urine than in the blood. False.
4. About this one, never mind. Reabsorbtion does occur by passive transport and diffusion.

So, I get question 3 and 4 but 1 and 2 I'm not sure of. I think it's because I don't understand the question.
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PopcornTime

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Re: VCE Biology Question Thread
« Reply #10616 on: September 01, 2018, 09:17:38 pm »
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2 things:

- in electron transport chain, I understand that hydrogen ions are transferred from NADH and FADH2 to create a hydrogen ion concentration gradient, but what is the purpose of this gradient?

- I am still confused about hominoid, hominin and primates and how it is relevant to questions. Any advice?

Owlbird83

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Re: VCE Biology Question Thread
« Reply #10617 on: September 01, 2018, 09:24:10 pm »
+1
- in electron transport chain, I understand that hydrogen ions are transferred from NADH and FADH2 to create a hydrogen ion concentration gradient, but what is the purpose of this gradient?


I think that it's so that the hydrogen ions have a high concentration so they want to move out, and move through the ATP synthase which creates energy to turn ADP,P into ATP.
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Scooby

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Re: VCE Biology Question Thread
« Reply #10618 on: September 02, 2018, 12:23:20 am »
+3
2 things:
- in electron transport chain, I understand that hydrogen ions are transferred from NADH and FADH2 to create a hydrogen ion concentration gradient, but what is the purpose of this gradient?

You want to create a H+ gradient (a "proton gradient") across the inner mitochondrial membrane where H+ is higher in the intermembrane space (the space between the inner and outer mitochondrial membranes) and lower in the matrix. You create that by pumping H+ into the intermembrane space from the matrix - this is an energy-dependent process (using energy of the electrons provided by NADH and FADH2).

Once you have a H+ gradient across the inner mitochondrial membrane, H+ will move down its gradient (from the intermembrane space back into the matrix) through ATP synthase. This movement of H+ through ATP synthase provides the energy ATP synthase uses to generate ATP from ADP and Pi.

This is beyond the scope of the course, though - just know your inputs and outputs, and site, and maybe just that ATP synthesis in this step requires a proton gradient created using electrons from NADH and FADH2 :)
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PhoenixxFire

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Re: VCE Biology Question Thread
« Reply #10619 on: September 02, 2018, 09:44:15 am »
+1
I wrote down my answers but I am just not sure if they're correct. That's why I wanted to clarify.

1. water as it makes up 95% of the urine but I'm not sure what they mean by 'main'? Like the most important or the one that there is the most of as it could be urea.
2. Supposed to be 'of' needs. Well, the amino acids transported to the liver are split into the N-part (ammonia) and the carbon skeleton. Ammonia is excreted but the carbon skeleton is kept. So, the carbon skeleton is stored. So, technically, the amino acids are stored if a part of it is stored. So, i put true for this.
1. Water is most of it but I think the question wants the waste product so urea.
2. This sort of depends on what the person who wrote the question meant by stored, unfortunately it's a textbook question and they sometimes have weird meanings. I agree with your interpretation of it though, that amino acids can be stored (this makes the answer false though as they statement says they cannot be stored).

- I am still confused about hominoid, hominin and primates and how it is relevant to questions. Any advice?
What specifically don't you understand about it? It's a broad topic haha. In terms of relevance to questions, you need to know about them because it's used to classify different species. You can then use this when talking about evolution. For example if you have 3 species, 2 of which can walk upright then you know that both of the bipedal species are hominins but that the third species is not.
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