HSC Biology Question Thread

[mjorfian]

anyone know how to do q 18 of the 2010 paper? It's just a simple calculation but I can't seem to get it!

[angelahchan]

anyone know how to do q 18 of the 2010 paper? It's just a simple calculation but I can't seem to get it!

The section of the virus given to us is approx 50 nm  and since they're all some form of "13", the whole virus is probably 130 nm.
and since 1 micrometer = 1000 nm, we have to convert the nm into micrometers by dividing by 1000. therefore 130/1000= 0.13. So the answer is D.

[J.B]

Hi,
I was how recombinant DNA technology is used to make a gene probe? (2016 CSSA Trial - Code Broken)
Thanks

[Natasha.97]

anyone know how to do q 18 of the 2010 paper? It's just a simple calculation but I can't seem to get it!

Hi!



Hope this helps

[liya1234]

Hi, just wondering if we need to know about plant grafting? Also what's the difference between that and root culturing? Thanks!

[itssona]

heey im really lost,
so we have citrus greening which occurs due to the psyllid insect but we also have another citrus disease where citrus fruits borers tunnel into the rind of citrus fruits? and is this the same as fruit flies? which one should i use?

(this is for the quarantine dotpoint)

[kemi]

heey im really lost,
so we have citrus greening which occurs due to the psyllid insect but we also have another citrus disease where citrus fruits borers tunnel into the rind of citrus fruits? and is this the same as fruit flies? which one should i use?

(this is for the quarantine dotpoint)

Just select one. Probably citrus greening is best.

[kemi]

Hi, just wondering if we need to know about plant grafting? Also what's the difference between that and root culturing? Thanks!

They are both forms of plant reproductive technologies

Cutting and grafting involves inserting the stem of one plant into rhe stem of another such that they grow as one plant. The new plant will have characteristics of both of these plants (see attached picture)

Root culture is when a sample of the root tip of a plant is cultured in a liquid in a laboratory. It will develop into a clone of the original (I believe it can be done with carrots)

No need for excessive detail; just know the impacts on biodiversity, which is usually that it is decreased as certain genes are propagated while others are depleted or removed.

[caitlinlddouglas]

hey could someone please explain this answer for a multiple choice from 2015 hsc paper?
 1. An extremely high concentration of  carbon dioxide   is undesirable   in active muscle tissue because it   will:
Answer is: A) increase the pH.
----> wouldn't this cause the blood to be more alkaline, not acidic?

Also are we supposed to know the size of pathogens in relation to different cells as there was question 9 from the same paper that showed a redblood cell and a a larger cell with cell wall and membrane next to it and we were supposed to the know that the cell was a fungi?

Thanks heaps!

[blasonduo]

hey could someone please explain this answer for a multiple choice from 2015 hsc paper?
 1. An extremely high concentration of  carbon dioxide   is undesirable   in active muscle tissue because it   will:
Answer is: A) increase the pH.
----> wouldn't this cause the blood to be more alkaline, not acidic?

Also are we supposed to know the size of pathogens in relation to different cells as there was question 9 from the same paper that showed a redblood cell and a a larger cell with cell wall and membrane next to it and we were supposed to the know that the cell was a fungi?

Thanks heaps!

Yes, this is true! I believe you just looked at a different answer because 6 is B! (cause enzymes to denature)

For the other one, I believe the size of the size of the pathogen was to throw people off because the dead giveaway is the cell wall, so relative size was not needed in this question, will they do something similar but with another pathogen? Who knows!

I'd say, just know the size's of the pathogens in ascending order (which is easy because the syllabus gives them in ascending order!) But it wouldn't hurt to know all their sizes!

[angelahchan]

Hi, could someone please help me with Q7 and Q18 from the 2015 paper?
https://www.boardofstudies.nsw.edu.au/hsc_exams/2015/exams/2015-hsc-biology.pdf

I don't really understand the diagram for Q7. And for Q18 I don't get why there's 2 independent variables - because if they're determining the optimum pH isn't the pH the only thing they're changing?

[caitlinlddouglas]

Hi, could someone please help me with Q7 and Q18 from the 2015 paper?
https://www.boardofstudies.nsw.edu.au/hsc_exams/2015/exams/2015-hsc-biology.pdf

I don't really understand the diagram for Q7. And for Q18 I don't get why there's 2 independent variables - because if they're determining the optimum pH isn't the pH the only thing they're changing?

Hey haha I just did that paper too. For question 7 it's just skipped a few steps and jumped straight to where the message would have been processed by the brain and a corrective response sent for.
For the next one  I just went off the face that an independent variable is something you change so you changes he ph for four different types of enzymes ( imagine maybe that you were doing four separate experiments ) meaning there were 4 IV

[angelahchan]

Hey haha I just did that paper too. For question 7 it's just skipped a few steps and jumped straight to where the message would have been processed by the brain and a corrective response sent for.
For the next one  I just went off the face that an independent variable is something you change so you changes he ph for four different types of enzymes ( imagine maybe that you were doing four separate experiments ) meaning there were 4 IV

for 18 the correct answer is B tho - 2 IV rather than 4

[J.B]

Hi,
I was wondering how you would answer this question:
how is recombinant DNA technology used to make a gene probe? (2016 CSSA Trial - Code Broken)
Thanks

[kemi]

for 18 the correct answer is B tho - 2 IV rather than 4

So the aim was to find the optimum pH for four different enzymes.

An IV is something you can change, so in this case it is the pH and the type of enzyme = 2 IV