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March 29, 2024, 04:22:35 pm

Author Topic: VCE Biology Question Thread  (Read 3571301 times)  Share 

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TheAspiringDoc

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Re: VCE Biology Question Thread
« Reply #9930 on: March 11, 2018, 12:10:05 pm »
+2

vox nihili

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Re: VCE Biology Question Thread
« Reply #9931 on: March 11, 2018, 12:40:11 pm »
+1


An unnecessary distinction in VCE Biology :)

EDIT: but obviously relevant to Chem
« Last Edit: March 11, 2018, 12:42:19 pm by vox nihili »
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TheAspiringDoc

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Re: VCE Biology Question Thread
« Reply #9932 on: March 11, 2018, 12:55:26 pm »
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An unnecessary distinction in VCE Biology :)

EDIT: but obviously relevant to Chem
Maybe for the exam, but our SACs were marked very pedantically

vox nihili

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Re: VCE Biology Question Thread
« Reply #9933 on: March 11, 2018, 02:28:55 pm »
+1
Maybe for the exam, but our SACs were marked very pedantically

Hmm a reasonable point. Would be disappointing to lose a mark for that. In biological terms, the words should be used interchangeably to be perfectly honest. Even at Uni you wouldn't cop that.
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missile

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Re: VCE Biology Question Thread
« Reply #9934 on: March 11, 2018, 03:03:07 pm »
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Hi everyone
I just have a question regarding photosynthesis, and the most effective light colour: after clear light, is it red or blue, or does it depend entirely on the pigments present in the plant's cells?
At school they showed us graphs that showed chlorophyll a and b absorbing mostly violet/blue light (I'm aware there are other pigments), but then there's this question from the 2010 E1, Q17:
http://www.vcaa.vic.edu.au/Documents/exams/biology/2010biol1-w.pdf
http://www.vcaa.vic.edu.au/Documents/exams/biology/biology1_assessrep_10.pdf
The answer is given as red light. Is this due to the plant being aquatic (going back to Engelmann's spirogyra experiment)?
Thanks in advance

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vox nihili

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Re: VCE Biology Question Thread
« Reply #9935 on: March 11, 2018, 03:18:49 pm »
+1
Hi everyone
I just have a question regarding photosynthesis, and the most effective light colour: after clear light, is it red or blue, or does it depend entirely on the pigments present in the plant's cells?
At school they showed us graphs that showed chlorophyll a and b absorbing mostly violet/blue light (I'm aware there are other pigments), but then there's this question from the 2010 E1, Q17:
http://www.vcaa.vic.edu.au/Documents/exams/biology/2010biol1-w.pdf
http://www.vcaa.vic.edu.au/Documents/exams/biology/biology1_assessrep_10.pdf
The answer is given as red light. Is this due to the plant being aquatic (going back to Engelmann's spirogyra experiment)?
Thanks in advance



I'm not sure you'd be expected to remember which colour light is the most absorbed in photosynthesis anymore. VCAA seem to be moving away from this kind of question. You're more likely to get some data and be asked to interpret it.

You're actually quite right though, it does depend on the type of pigment in the plant. I suspect that the in-depth explanation of this is well beyond VCE (I don't know personally, as my focus has been on human Biology—blissfully ignorant about plants!).
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missile

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Re: VCE Biology Question Thread
« Reply #9936 on: March 11, 2018, 03:57:20 pm »
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Thanks for the reply

puts my mind at ease a bit
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KHE0024

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Re: VCE Biology Question Thread
« Reply #9937 on: March 11, 2018, 09:48:06 pm »
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 Hello guys,

I will have a SAC next Tuesday and Thursday about enzymes. It will be 1 lesson prac. and the other is write up. Does anyone know what is required of us. Will there be any unexpected questions and stuff.
Our teacher also said we will need to know about the hydrogen peroxide to water and oxygen reaction, and I am a little bit vague about it.
Thank you.

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Re: VCE Biology Question Thread
« Reply #9938 on: March 11, 2018, 10:06:05 pm »
+1
Hey,
Is your write up going to be a prac report or questions based on the prac result? If it’s the latter you can read about what types of questions you might see here.

If it’s a prac report it could either be entirely up to you or answering structured questions (your teacher should have told you which). If it’s entirely up to you, you just need to follow the normal introduction/method/results/discussion/conclusion format.

If it’s questions it will likely be things like
-what is your IV/DV
-what is your aim
-what generalisations can be made from your results
-are your results reliable/valid/accurate? Why/why not?
Basically just the same stuff you would include in a prac report but more structured.


Hydrogen peroxide (H2O2) is broken down into water and oxygen by an enzyme called catalase. I would say that you should know the formula (2H2O2—>2H2O + O2), It has to start with 2 hydrogen peroxide or you only get half an oxygen molecule. You should also be aware of limiting factors (substrate & enzyme concentration, temperature, etc) and what a graph showing that information would look like.
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Mr West

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Re: VCE Biology Question Thread
« Reply #9939 on: March 12, 2018, 03:38:08 pm »
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hey guys,

ive just got a couple of things I need help with regarding nucleic acids and proteins

1) do spliceosomes 'splice' out introns or 'splice' together exons?

2) why are premRNA strands usually said to be longer than their subsequent mRNA strand, even though during the post transciptional modificates polyadenylatoin occurs, adding over 200 adenines? even with the loss of introns, wouldnt it still be longer?

3) in edrolo douchy says that during nucleotide polymerisation, 2 phosphates break off of the deoxy nucleoside tri phosphate molecule, and an oxygen breaks off from the hydroxyl group of an existing nucleotide which then joins with the 2 phosphates. I cant recall him mentioning the release of a water molecule, which I though would happen due to it being a condensation reactions. So can someone please explain to me what happens during nucleotide polymerisation

4) why is proteomics important.

thanks in advance :)


EDIT: Added Q4
« Last Edit: March 12, 2018, 04:18:53 pm by Mr West »

PhoenixxFire

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Re: VCE Biology Question Thread
« Reply #9940 on: March 12, 2018, 04:21:59 pm »
+2
1. You do not need to know about spliceosomes in detail. I never learnt about them so I don’t know which they do. When describing it you need to say that the introns are removed and that the exons are joined/spliced together. ‘Splice’ means joining things together so I wouldn’t say the introns are spliced out.

2. pre-mRNA is still longer, introns can total thousands of base pairs in length.

3. This is a bit controversial. Some people think that a water molecule is produced, some say that phosphate is broken off. Douchy says that it is phosphate, but that most teachers say that it is water because that is what they were taught. Just ask your teacher and use whichever they tell you. (Also tell your teacher that douchy says it is phosphate so that other students aren’t marked wrong for it.)

4. Proteomics is the study of proteins. This can tell us many things but the one you will learn about is in relation to mutations. If you have a different version of a protein then you must have different amino acids making it up and therefore a different allele. Therefore we can study proteins to determine relatedness/disease/etc - all the things we can study DNA for but it is easier.
« Last Edit: March 12, 2018, 04:25:30 pm by PhoenixxFire »
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FabAsianZung

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Re: VCE Biology Question Thread
« Reply #9941 on: March 12, 2018, 04:23:15 pm »
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Just need help clarifying a few things. Can anyone explain how the limiting factors(main ones that we're expected to know about) affect photosynthesis and cellular synthesis.
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Calebark

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Re: VCE Biology Question Thread
« Reply #9942 on: March 12, 2018, 04:35:44 pm »
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Just need help clarifying a few things. Can anyone explain how the limiting factors(main ones that we're expected to know about) affect photosynthesis and cellular synthesis.

What are your thoughts on it? It's easier for us to help you if you try your hand first :) I'll give one example and explain my process, then you can try applying it to other ones. We can help from there

1: Pick a limiting factor -- I've chosen to use CO2 concentration in photosynthesis
2: What does this factor do? -- CO2 provides carbon to make C6H12O6
3: What would decreasing this do? -- If there was less CO2 available, then there would be less carbon available. If there is less carbon available, not as much glucose can form. This decreases the rate of production.
4. What would increasing this do? -- If there was more CO2 available, there would be more carbon available for glucose to form. Provided the other necessary ingredients are there, this would increase the rate of glucose production until it begins to plateau. Do you know why this plateaus?

You can apply this to anything. As long as you know what each factor does, you can work out how it is limiting. Please note that the limiting factor is whatever there is least of. It doesn't matter if you have all the CO2 in the world if you don't have any light, or vice versa. Hope this made sense/was helpful :)

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FabAsianZung

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Re: VCE Biology Question Thread
« Reply #9943 on: March 12, 2018, 10:23:35 pm »
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You can apply this to anything. As long as you know what each factor does, you can work out how it is limiting. Please note that the limiting factor is whatever there is least of. It doesn't matter if you have all the CO2 in the world if you don't have any light, or vice versa. Hope this made sense/was helpful :)


So, from what you've said, a limiting factor is something that makes the rate of photosynthesis plateau? If that's the case, if all factors are constant for photosynthesis, would you say that there are no limiting factors?


P.S thank you for replying!! This was really helpful, since I've found a way to approach this barrier of mine—limiting factors   ;D
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PhoenixxFire

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Re: VCE Biology Question Thread
« Reply #9944 on: March 12, 2018, 10:42:19 pm »
+1
So, from what you've said, a limiting factor is something that makes the rate of photosynthesis plateau? If that's the case, if all factors are constant for photosynthesis, would you say that there are no limiting factors?
Yep that is what a limiting factor is :) It’s something that makes any rate of reaction plateau, not just photosynthesis though.

There is always a limiting factor - the only case where there wouldn’t be were if everything were infinite which isn’t actually possible. If all factors are equal then they are all equally limiting factors.
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