2015 Biology Exam PDF and Suggested Solutions

[plants]

i actually cant believe this, i lost 10 marks minimum this just stings..

Same bro we're in the same boat :/

[jamesbw]

How do you get an account tho?

Its free to sign up! all you need is an email address

[vox nihili]

For 7c, your solution states "Pituitary gland has different GC receptor to liver cells thus a different GCR-complex is
formed."

But i'm pretty sure that the receptors are the same. It's just that they have different signal transduction pathways within a cell that leads to different cellular responses.

It can be either way. For instance, adrenaline binds a wealth of different receptors, each with different signalling pathways. They'd award marks for either one.

[patphez]

Yeah lost at least 10 as well :/

[vox nihili]

I've had a look through the short answer questions, here are some thoughts that I'd add to the following:

1b
VCAA will award marks for a number of different answers here. Puncture a hole in the membrane would probably not get marks, as stated on the answers.
My guess is that VCAA were learning towards a more "gets in the way" kind of thing, interferes with normal cell processes because the aggregates accumulate. The reality is a lot more complex (aggregated amyloid beta, for instance, generates free radicals that wreak havoc etc.)

3a
Granum/grana would also get a mark

4a
Don't agree with the mark break up of this.

1 mark for Ebola antigen/attenuated Ebola or the like stimulates B-cell response

1 mark that after the antigen/virus is cleared memory B-cells are left

1 mark that upon reinfection with Ebola memory B-cell population expands quickly

1 mark plasma B-cells produce antibodies to remove the Ebola virus

If you got the essence of vaccine makes memory B-cell population and upon reinfection this population props up and kills it off you would probably get the marks. If they really need to discriminate they'll shift a mark to "memory B-cells are long-lived" because they did specifically ask about long-term immunity

5a
Answer is correct. Just wanted to note that this is a really disappointing question, I daresay most would not have been taught this. The valves allow for unidirectional flow of lymph.

5c
You must mention secretion to get full marks for this. It's not enough to just say that the rough ER allows for protein to be produced. It's new on the course (since 2013), but you have to know that the RER is involved in secretion.

So one mark for large amounts of protein produced, another for that that protein is secreted. They may even expect you to acknowledge that the protein produced is an antibody

6bi
Maybe synapsis too

6c
Mention the genes. Some gametes will lose T, others gain T, U and V also implicated. Not going to elaborate on all of it, but best to mention the letters since they're given. This is a clear application question. You need to respond to the material you're given and prove that you understand it specifically.

7c
Different GC receptors and different secondary messengers are both acceptable. Not sure which is actually right in this case though.


Even though I've picked on some things, these are brilliant answers. If yours are anywhere near these, you've done exceptionally well.

[adnauseam]

for 8a.ii, couldnt there be two possible nucleotide substitutions.
AAT -> ATT or
AAT -> ACT
i wrote both could happen im scared
i need closure
...

[julijulib]

Am I the only one that the 'download file' button is not showing up for the short answer solutions?   

[heids]

Am I the only one that the 'download file' button is not showing up for the short answer solutions?   

It should say 'Link to share this file with anyone' - copy and paste that link into a new tab, and you should get your download there

[julijulib]

It should say 'Link to share this file with anyone' - copy and paste that link into a new tab, and you should get your download there

Wow that was so dumb, thanks so much!! 

[Yacoubb]

5a
Answer is correct. Just wanted to note that this is a really disappointing question, I daresay most would not have been taught this. The valves allow for unidirectional flow of lymph.

This. It took me around 2 minutes to recognise that the shitty diagram was pointing to valves - I can almost guarantee a fair few students wouldn't have known this.

[CarterGray12]

Hmmmm I could be wrong, but in writing that solution I had question 3c from the 2013 VCAA paper in mind which was very similar. I think that if both cells had the same receptor then the same signal transduction pathway would be activated  leading to the same response since there are no other molecules (besides DNA) involved. Do you have a different explanation?

If you read the first part of this question again, it explains that the gene activated is the same, so would the best answer be to describe how alternative exon splicing can produce different proteins from the same gene?

[Yacoubb]

If you read the first part of this question again, it explains that the gene activated is the same, so would the best answer be to describe how alternative exon splicing can produce different proteins from the same gene?

To be honest from what I have seen on the exam for this question (briefly looked at this question), alternative splicing is probably the best answer. It is the way to account for the fact that the same genetic sequence can yield different proteins (alternative splicing of exons = different AA = different tertiary structures & 3D protein conformations). So yup :-)

[flozza]

The explanation given in 8ii is incorrect. Both BR/br and Br/bR will produce 4 phenotypes due to crossing over events. The most common phenotypes reveal the parental allele linkage. For BR/br the numbers in the table would be 47,3,3, 47 instead of 3,47,47,3.

[Alsci]

If i was to get A+ A+ A for bio, what study score are we looking at?

[Sine]

same guys lost at least 10 marks