Biology Exam Discussion (and suggested answers!)

[Opengangs]

Disappointed that I got 18/20 for mc -- changed my answers for both of them in the last minute. sad

[Chrispy365]

Have amended by answer to question 11 - thanks for the feedback guys!

Both B and T cells can form clones by clonal proliferation. HOWEVER; whilst B-cells can recognise specific antigens, T-cells only recognise them in the context of MHC - a special protein (a little beyond the scope of the syllabus)... So based on the wording of the question, I don't think C) is technically correct either. I think it is just the *most* correct.

Would question 13 possibly be D, as with the DNA replication it was the new strand being formed and so would have the complimentary bases of the original DNA sequence?

[naomisirmai]

Thanks so much!! Just for question 20 I couldn't really pick between A and D and ended up going with A - can someone please explain why it would be D because I don't really understand?

Sure!
A = the rate of enzyme activity is decreasing
D = the substrate concentration is decreasing

D makes sense, as the substrate is being transformed into products by the reaction, which are then removed.
A doesn't make sense, as the question stated specifically that the experiment was *valid* - meaning that the variables were properly controlled to test the effect of substrate concentration. For the rate of enzyme activity to decrease, conditions would have to change, meaning that the experiment would not be valid.

Hope that answers your question!

[Daniyahasan]

Would anyone Pls do suggested answers for communication

[Opengangs]

For treatment vs. prevention, could you talk about bacterial strains being resistant to antibiotics? Thus, treatment only works well in a shorter timespan, as opposed to prevention.

[elysepopplewell]

Thank you times a million to Naomi for providing her insight!! Naomi's schedule is stupidly busy (did you know she studies Med?) and she made time to go through these, even though it took a little longer than we anticipated!

Feel free to keep chatting everyone!

Disappointed that I got 18/20 for mc -- changed my answers for both of them in the last minute. sad

I know that frustration, but that is still an incredible MC mark!

[Respawn in 3]

What do you guys think the cut off for a band 6 will be?

Honestly, I can see it potentially being around 84-86 this year, usually it's around 80/81

[Livchum]

Disappointed that I got 18/20 for mc -- changed my answers for both of them in the last minute. sad

Feeling your pain as well.

[Rainbowhippocampus]

Hey did anyone else put sugar phosphate backbone for franklin? 

[adelaidecruz]

Does anyone know what a raw of mark 88-89 could possibly align to? Thanks

[Paul.I]

Does anyone know what a raw of mark 88-89 could possibly align to? Thanks

Check hsc raw marks database. I am going to assume about a 93 or a 94. It really just depends on the band 6 cut off this year

[Kzaka]

Sure!
A = the rate of enzyme activity is decreasing
D = the substrate concentration is decreasing

D makes sense, as the substrate is being transformed into products by the reaction, which are then removed.
A doesn't make sense, as the question stated specifically that the experiment was *valid* - meaning that the variables were properly controlled to test the effect of substrate concentration. For the rate of enzyme activity to decrease, conditions would have to change, meaning that the experiment would not be valid.

Hope that answers your question!

I thought this differently tho. It never states it was an experiment to test the effect of concentration. Also because that graph shows product produced in each 10min period, the decrease in products means that the rate of reaction is not constant, otherwise the amount of product every 10min produced should stay the same right?
Plez prove me wrong tho, I do think A is unlikely but it made sense to me

[pikachu975]

13 they might accept 2 answers it was such a broad question

[liya1234]

I thought this differently tho. It never states it was an experiment to test the effect of concentration. Also because that graph shows product produced in each 10min period, the decrease in products means that the rate of reaction is not constant, otherwise the amount of product every 10min produced should stay the same right?
Plez prove me wrong tho, I do think A is unlikely but it made sense to me

This is what I was thinking in the exam! They both make sense to me (Thanks for the explanation for why it would be D naomi!) if you think about the experiment in different ways as I don't think they specified what exactly they were testing? I don't remember the exact question though so not sure

[Chrispy365]

With the genotype question that was a multiple choice from 2001 and the answer was ABG, abG, ABg, and abg so why is the answer different this time?