VCE Biology Question Thread

[Jay.C]

Hey, looking through this document has clarified some concerns but unfortunately, my previous question wasn't addressed? Would anyone please be able to answer the previous question? Thanks!

Yes! Ill try to answer it as best as i can!

So taken straight from the study design:
-requirements for photosynthesis – excluding differences between CAM, C3 and C4 plants
including: the structure and function of the chloroplast; the main inputs and outputs of the light
dependent and light independent stages
– requirements for aerobic and anaerobic cellular respiration: the location, and main inputs and
outputs, of glycolysis; the structure of the mitochondrion and its function in aerobic cellular
respiration including main inputs and outputs of the Krebs Cycle and the electron transport
chain.

So from this all you need to know for photosynthesis is structure and function of the chloroplasts. Then the main inputs and outputs of both the stages and where they occur. So you do not need to go into that much detail on all of the processes only the main inputs and outputs at each stage.

With cellular respiration the story is basically the same. You need to know both requirements for anaerobic and aerobic respiration, again where they occur and again just the MAIN inputs and outputs of each stage. VCAA does not require you to go into detail about each stage e.g. all the reactions that occur in the Krebs cycle, they just want the main parts.

It however does not hurt to know these details and will give you a greater understanding then someone that does not know these things.  I hope this answered your question!

[Maca 13]

Yes! Ill try to answer it as best as i can!

So taken straight from the study design:
-requirements for photosynthesis – excluding differences between CAM, C3 and C4 plants
including: the structure and function of the chloroplast; the main inputs and outputs of the light
dependent and light independent stages
– requirements for aerobic and anaerobic cellular respiration: the location, and main inputs and
outputs, of glycolysis; the structure of the mitochondrion and its function in aerobic cellular
respiration including main inputs and outputs of the Krebs Cycle and the electron transport
chain.

So from this all you need to know for photosynthesis is structure and function of the chloroplasts. Then the main inputs and outputs of both the stages and where they occur. So you do not need to go into that much detail on all of the processes only the main inputs and outputs at each stage.

With cellular respiration the story is basically the same. You need to know both requirements for anaerobic and aerobic respiration, again where they occur and again just the MAIN inputs and outputs of each stage. VCAA does not require you to go into detail about each stage e.g. all the reactions that occur in the Krebs cycle, they just want the main parts.

It however does not hurt to know these details and will give you a greater understanding then someone that does not know these things.  I hope this answered your question!

Ahh, OK. I checked the Study Design recently to start making my Unit 3 notes and saw this as well. Thanks for that, I guess I won't learn all those little details but I'll be aware of them. Much appreciated!!

[cosine]

It is reasonable to infer that an infection has occurred if:
A. Histamine is released by cells
B. A scab has formed on a cut on the skin
C. Bacteria are found in the large intestine
D. Pathogens are found in leg muscle tissue

Okay let's break it down. A is incorrect because histamine is released to an allergic response, so it does not necessarily mean it is an infection in the cell. C is incorrect because there are naturally occurring bacteria in our bodies (are these called Natural Flora, or are Natural Flora on located on body-surface openings?).

So im stuck between B and D. The answer is D, but who says B cannot also be true? An explanation would be awesome, cheers.

[heids]

So im stuck between B and D. The answer is D, but who says B cannot also be true? An explanation would be awesome, cheers.

Scabs automatically form over a cut to form a barrier to stop pathogens getting in, whether or not any pathogens have actually got in.  The scab is just the body's automatic clotting response to broken skin.  So just because a scab forms, doesn't mean pathogens have invaded and infection has occurred.

[cosine]

Question attached:

The answer is D. I was able to deduce A and B because I learnt the other day that only bacteria are affected by antibiotics, not fungus (what about viruses, can they be affected by antibiotics?). Also fungus is not a prokaryotic cell, so B is also out. Now C and D are tormenting me, because is this stuff even in the study design?

[cosine]

Scabs automatically form over a cut to form a barrier to stop pathogens getting in, whether or not any pathogens have actually got in.  The scab is just the body's automatic clotting response to broken skin.  So just because a scab forms, doesn't mean pathogens have invaded and infection has occurred.

Are we meant to know this or is this just common sense/logic?

[StupidProdigy]

Question attached:

The answer is D. I was able to deduce A and B because I learnt the other day that only bacteria are affected by antibiotics, not fungus (what about viruses, can they be affected by antibiotics?). Also fungus is not a prokaryotic cell, so B is also out. Now C and D are tormenting me, because is this stuff even in the study design?

I don't really think the details of option D are necessary to know. I think vcaa wanted students to be knowledgeable about the other three options and hence choose D through elimination. Your reasoning behind eliminating A is correct, and likewise your thoughts on B. Now most people would of got to c and D. In this case common sense is quite handy. Think about all the times you've seen fungi. They've normally been in a dark, shaded and humid area yeah? Like you don't find fungus in deserts right? Anyway that's how I'd reach D..

[cosine]

So I have finished all the Unit 3 exams from VCAA, where can I get some free Unit 3 ones ??

[Maca 13]

So I have finished all the Unit 3 exams from VCAA, where can I get some free Unit 3 ones ??

Hey! There was a thread posted on ATARNotes about practise exams, I hope this helps, here's the link:
Practice Exams - Where to get them for free?
 

[cosine]

Thank you Maca 13

1). When an enzyme's disulphide bridges are broken, what will happen to the enzyme?

I said the shape of the active site will obviously by altered, and hence the enzyme can no longer react and bind to it's specific substrate as it is no longer complementary.

However, should the word 'denatured' be included? Has the enzyme been denatured or not? I know if the enzyme was exposed to factors outside it's optimum range it would become denatured (besides low temperatures), so does that mean enzyme's become denatured when their overall shape is changed, and hence the bonds in the active site is are broken?

[vox nihili]

Are we meant to know this or is this just common sense/logic?

Bit of both. It is commonsense in the context of what you should know.

Thank you Maca 13

1). When an enzyme's disulphide bridges are broken, what will happen to the enzyme?

I said the shape of the active site will obviously by altered, and hence the enzyme can no longer react and bind to it's specific substrate as it is no longer complementary.

However, should the word 'denatured' be included? Has the enzyme been denatured or not? I know if the enzyme was exposed to factors outside it's optimum range it would become denatured (besides low temperatures), so does that mean enzyme's become denatured when their overall shape is changed, and hence the bonds in the active site is are broken?

Denature would be fair. I suspect that the answer is actually more complex, because of the role that disulphide bonds actually play in protein folding, but thinking with my VCE hat on, I daresay denaturation would be a fair assumption. Maybe if mahler's around he'll shed some light on this

[heids]

Are we meant to know this or is this just common sense/logic?

Hmm, a mixture.  Often I think the point with Bio is to be able to deduce stuff, but based on some base knowledge that you just 'absorb'.

So I have finished all the Unit 3 exams from VCAA, where can I get some free Unit 3 ones ??

'Finished' all?  What do you mean?  I milked VCAA exams for all their worth - as in, I shaped my notes from them, I did them countless times, I carefully examined their answer wording.  That is, I did in HHD, but not nearly enough in Bio.

I'm not a fan / Of prac-exam-spam (ooh kinda rhymes!).  For my 50 in HHD, I did one total other than VCAA, the school-enforced trial in September, because I had other things I knew would work better.  Practising your knowledge is obviously important, but it's easy to spam exams without focusing on a) whether you know all the content, and b) exactly where you can improve.  More important to me was checking that I knew everything; like try getting the study design, and writing everything you can under each dot-point with no notes, and then checking your notes afterwards.  Don't just 'do' a VCAA exam, carefully figure out how they want questions answered and exactly the sorts of questions they like asking.

VCAA exams rule the world, anyway.  See the spoiler.

I'll give you first-hand insight into company-made exams.

I was just told to write a HHD exam for Engage Ed, not a free but saleable exam (check here if you haven't already btw).  Without any knowledge of whether I'd done it before, they said, here, you have nine days to write an exam plus comprehensive answers, and we'll pay you X for it.  No training, no knowledge about my skills except that I got a good score, no incentive for high quality - just a due date and blanket fee no matter the quality.  Lucky for them, I had already spent considerably many hours studying exactly the sorts of HHD questions VCAA asks, exactly the number of marks and lines they give, etc.  But if someone asked me to write a Biology exam within 9 days - in fact I'm waiting for them to do it any day! - I would write a hopeless exam, because you really have to study and research exactly how VCAA does that subject's exam to write a well-balanced, comprehensive, clear, useful, correct exam.

Hence, they often include content out of the study design, ask weird/poorly worded questions, have wrong answers or multiple answers that could be correct in MC, and just do other weird un-VCAA-y stuff.

I can't say with other companies, but from this perspective of one company, I wouldn't rely very heavily on company exams.  They're quite possibly written under strict time-limits by people your age (I'm probably younger than you) who haven't spent much time on perfecting it, and I can tell you, VCAA-style exam writing takes skill, dedication and practice.

Hence, while they MAY be good, they may also be totally dodgy and unreliable.  Just sayin'.

[cosine]

So I just found out that my school average, 90%, according to the 2014 grade distributions, is actually not an A+. It says that 89-93 is an A Well that sucks.. Do I still have a chance at a 40+? (Not to sound like a noob, but lots of people say you need all your GA's as A+..) 

Bummed out

[heids]

So I just found out that my school average, 90%, according to the 2014 grade distributions, is actually not an A+. It says that 89-93 is an A Well that sucks.. Do I still have a chance at a 40+? (Not to sound like a noob, but lots of people say you need all your GA's as A+..) 

1.  SAC marks can scale heaps (up or down) based on cohort exam performance.
2.  Unit 3 SAC marks are worth only 20% of your overall SS; you still have 80% of your marks to decide (4 times as much as you've done already).
3.  If you are constantly looking at where you went wrong, where you lost those ten percent, and where you can make sure that you DON'T lose them in the exam, your remaining 80% will be up there.

So:
4.  Yes you do.

[cosine]

1.  SAC marks can scale heaps (up or down) based on cohort exam performance.
2.  Unit 3 SAC marks are worth only 20% of your overall SS; you still have 80% of your marks to decide (4 times as much as you've done already).
3.  If you are constantly looking at where you went wrong, where you lost those ten percent, and where you can make sure that you DON'T lose them in the exam, your remaining 80% will be up there.

So:
4.  Yes you do.

Thanks

I still don't feel that convinced though haha