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March 28, 2024, 07:36:46 pm

Author Topic: VCE Biology Question Thread  (Read 3570299 times)  Share 

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PhoenixxFire

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Re: VCE Biology Question Thread
« Reply #10710 on: September 30, 2018, 12:06:35 pm »
+1
What should we know about aneuploid, polyploidy and tetraploidy for the exam?
Pretty sure you just need to know what they are. So know that aneuploidy and polyploidy are types of mutations. Know that monosomy and trisomy are types of aneuploidy. Triploidy and tetraploidy are types of polyploidy etc. you should also know how to write that (so 2n+1, 2n-1, 3n, 4n)
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juntyhee

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Re: VCE Biology Question Thread
« Reply #10711 on: September 30, 2018, 06:14:06 pm »
0
Few questions:
1. What's the difference between protein-based and peptide-based hormones?
2. What does the "recycling of cell debris" stage of apoptosis comprise of?
3. What is the final stage of apoptosis? Signal for macrophages? Cell fragments into apoptotic bodies?
4. Does light energy excite electrons in the ETC of light dependent stage, or is it only used for photolysis?
5. What are "prominent heelbones" and how do they provide a selection advantage?
6. What's the difference between clonal selection and expansion?
7. For inflammation, doesn't vasodilation DECREASE blood pressure? So why is there an increased blood flow?

Thanks so much!

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Re: VCE Biology Question Thread
« Reply #10712 on: September 30, 2018, 11:27:24 pm »
0
7. For inflammation, doesn't vasodilation DECREASE blood pressure? So why is there an increased blood flow?
Vasodilation means that blood vessles dilate, mean get bigger or wider, allowing more blood to flow through, thus increasing blood pressure. I think you have vasodilation confused with vasoconstriction here. Vasodilation decreases blood pressure, by making the width of the veins go thinner.

Hope this helps.  :)
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vox nihili

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Re: VCE Biology Question Thread
« Reply #10713 on: October 01, 2018, 04:33:28 pm »
+2
Vasodilation means that blood vessles dilate, mean get bigger or wider, allowing more blood to flow through, thus increasing blood pressure. I think you have vasodilation confused with vasoconstriction here. Vasodilation decreases blood pressure, by making the width of the veins go thinner.

Hope this helps.  :)

Vasodilation DECREASES blood pressure. Simple analogy is to think of a balloon. If you squeeze a balloon (constrict it) pressure rises. If you stop squeezing it, allowing it to dilate, pressure falls.
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juntyhee

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Re: VCE Biology Question Thread
« Reply #10714 on: October 01, 2018, 04:53:51 pm »
0
Vasodilation DECREASES blood pressure. Simple analogy is to think of a balloon. If you squeeze a balloon (constrict it) pressure rises. If you stop squeezing it, allowing it to dilate, pressure falls.

But how does that assist in delivery of white blood cells? Don't they reach infection site slower since blood pressure is decreased ...?
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peter.g15

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Re: VCE Biology Question Thread
« Reply #10715 on: October 01, 2018, 05:32:43 pm »
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But how does that assist in delivery of white blood cells? Don't they reach infection site slower since blood pressure is decreased ...?

It helps delivery by making the capillaries more 'spaced out' to let bigger items through. So, dilation increases the size and therefore allows bigger objects (i.e. white blood cells) to pass through it and into the site of infection. The speed at which it occurs shouldn't really change and it wouldn't make a noticeable difference.
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darkz

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Re: VCE Biology Question Thread
« Reply #10716 on: October 01, 2018, 06:14:33 pm »
0
2015, Q7C
In the rat pituitary gland, GC stimulates the production of the growth hormone protein, However, in the rat liver, GC stimulates the production of the enzyme tryptophan oxygenase. Given that the genetic sequence is identical in all somatic rat cells, explain how the production of distinct proteins in different cell types could occur.

The answer is: Factors expressed by regulator genes could lead to the production of the different proteins

Could someone please explain what the factors expressed by regulator genes actually are? And would exon juggling/ alternative splicing be considered a valid answer?

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galaxy21

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Re: VCE Biology Question Thread
« Reply #10717 on: October 01, 2018, 06:40:53 pm »
0
Hi, can anybody explain what this question means?


A protein-based fibre could be constructed from repeated monomers of:

A. C5H13N4COOH
B. CH3(CH2)nCOOH
C. CX(H2O)Y
D. C6H5COOC1

The correct answer is A.
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darkz

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Re: VCE Biology Question Thread
« Reply #10718 on: October 01, 2018, 06:44:16 pm »
+4
Hi, can anybody explain what this question means?


A protein-based fibre could be constructed from repeated monomers of:

A. C5H13N4COOH
B. CH3(CH2)nCOOH
C. CX(H2O)Y
D. C6H5COOC1

The correct answer is A.

Proteins are made out of an amino group (NH2), carboxyl group (COOH), and then the R, variable group. Therefore it cannot be B, C or D as they all lack nitrogen. Therefore the answer must be A
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PopcornTime

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Re: VCE Biology Question Thread
« Reply #10719 on: October 01, 2018, 09:51:49 pm »
0
can we say RNA polymerase breaks the dna strand open?

darkz

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Re: VCE Biology Question Thread
« Reply #10720 on: October 01, 2018, 09:56:32 pm »
+1
can we say RNA polymerase breaks the dna strand open?

It would probably be better to say that transcription factors unwind the DNA, but I doubt you'd need to incorporate this into your answer. For example, if a question asks for you to describe transcription, you can simply say that the double stranded DNA is unwound, allowing for RNA polymerase to ....etc
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peter.g15

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Re: VCE Biology Question Thread
« Reply #10721 on: October 01, 2018, 10:58:30 pm »
+3
2015, Q7C
In the rat pituitary gland, GC stimulates the production of the growth hormone protein, However, in the rat liver, GC stimulates the production of the enzyme tryptophan oxygenase. Given that the genetic sequence is identical in all somatic rat cells, explain how the production of distinct proteins in different cell types could occur.

The answer is: Factors expressed by regulator genes could lead to the production of the different proteins

Could someone please explain what the factors expressed by regulator genes actually are? And would exon juggling/ alternative splicing be considered a valid answer?



I feel like the mean something similar to transcriptional factors. I emailed my teacher about this question too and she said that the old study design didn't have an emphasis on the stuff we do now. So, i think exon juggling could be considered a valid answer IMO. I think if it's reasonably justified and correct in terms of your knowledge, you should get the marks. The examiners reports don't list out all the potential solutions :)
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PopcornTime

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Re: VCE Biology Question Thread
« Reply #10722 on: October 02, 2018, 08:18:17 am »
0
Is enzyme optimal temperature an example of natural selection?

- so only organisms with correct enzyme optimal temperature survived, reproduced, passed on favourable alleles to offspring

Am I overthinking this or would this be correct?

PhoenixxFire

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Re: VCE Biology Question Thread
« Reply #10723 on: October 02, 2018, 12:41:09 pm »
+7
Few questions:
1. What's the difference between protein-based and peptide-based hormones?
2. What does the "recycling of cell debris" stage of apoptosis comprise of?
3. What is the final stage of apoptosis? Signal for macrophages? Cell fragments into apoptotic bodies?
4. Does light energy excite electrons in the ETC of light dependent stage, or is it only used for photolysis?
5. What are "prominent heelbones" and how do they provide a selection advantage?
6. What's the difference between clonal selection and expansion?
7. For inflammation, doesn't vasodilation DECREASE blood pressure? So why is there an increased blood flow?

Thanks so much!
1. Protein based hormones have longer amino acid chains than peptide-based hormones. You don't need to distinguish between them for VCE though, you just need to know that some hormones are amino-acid based (amine, peptide, protein) and some are steroid based.

2. Not really sure on this. I think it just means that after blebs have been phagocytosed the individual components are reused in the body. Not sure whether they would be broken down into base components or entire organelles reused or what though.

3.
According to VCAA 2016
Quote from: Q3.c.
As a wound heals, cells that are no longer needed for the healing process are removed by apoptosis.
Apoptosis is stimulated by external cell signalling from cells such as cytotoxic T cells (Tc).
    Outline the main stages in cell apoptosis once stimulated by the Tc cells.

Quote from: suggested solutions
Possible answers included:
• enzymes; for example, caspases are activated within the cell
• digestion of cell contents
• cell shrinkage
• cell blebbing
• cell breaks up
• cell signals macrophages.
Phagocytosis of cell debris was not accepted.
So I'd take this to mean that VCAA believes 'signal for macrophages' is the last step.

4. Haven't got a clue. Definitely not something you need to know for VCE though.

5. Prominent heelbones refers to your heel sticking out. Like if you point your toes you have a bump where your heel is. The selection advantage is that they make bipedalism more efficient and does a better job of supporting the increased weight associated with bipedalism & evolution.

6. Clonal selection is when a B or T cell is activated. Clonal expansion is when it multiplies producing lots and lots of identical daughter cells.

7. Vasodilation does decrease blood pressure but there'll be more blood in the area at any one time because the capillaries are bigger (also it makes it more permeable, which allows white blood cells to cross the membrane as peter.g15 said)



Is enzyme optimal temperature an example of natural selection?

- so only organisms with correct enzyme optimal temperature survived, reproduced, passed on favourable alleles to offspring

Am I overthinking this or would this be correct?
Purely speculation, but given the importance of enzymes I'd imagine that a mutation that resulted in an enzyme functioning less efficiently would probably result in the death of that individual. So in a way yes it would be natural selection. Probably not something you'll ever have to talk about for VCE though haha
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$noopDodd

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Re: VCE Biology Question Thread
« Reply #10724 on: October 02, 2018, 03:43:06 pm »
0
2015, Q7C
In the rat pituitary gland, GC stimulates the production of the growth hormone protein, However, in the rat liver, GC stimulates the production of the enzyme tryptophan oxygenase. Given that the genetic sequence is identical in all somatic rat cells, explain how the production of distinct proteins in different cell types could occur.

The answer is: Factors expressed by regulator genes could lead to the production of the different proteins

Could someone please explain what the factors expressed by regulator genes actually are? And would exon juggling/ alternative splicing be considered a valid answer?

I feel like the mean something similar to transcriptional factors. I emailed my teacher about this question too and she said that the old study design didn't have an emphasis on the stuff we do now. So, i think exon juggling could be considered a valid answer IMO. I think if it's reasonably justified and correct in terms of your knowledge, you should get the marks. The examiners reports don't list out all the potential solutions :)

Would the following be a valid answer for this question?
-Different receptors/second messengers in the two cells leading to different signal transduction pathways
-therefore different genes are activated, producing two distinct proteins
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