VCE Biology Question Thread

[sweetcheeks]

Hey guys, these are some questions I got wrong back in term 2 when completing a practice exam set by the school, any help would be appreciated:
1) Suggest a property of ATP that makes it suitable to its function (1 mark)
2) Why do living things need to undergo production of ATP continuously? (1 mark)
My answer: ATP is required by cells for metabolic activity, without ATP living things would not be able to live
3) Why do plants need to produce ATP in respiration when they produce ATP in photosynthesis? (1 mark)
My answer: ATP produced in photosynthesis is not sufficient like that of aerobic respiration. ATP from the light dependent stage of photosynthesis is also used immediately in the light independent stage.

Did I have to mention 36-38 ATP molecules are produced in aerobic respiration to obtain the mark, or was my answer wrong?
4) Describe two passive plant defences and how each deters pathogens (2 marks)
- Thick cork/bark. Pathogens cannot penetrate out surface of plant (correct)
- Sap. Covers plant openings ensuring pathogens cannot enter plant through openings (wrong)
5) Suggest one active physical plant defence and how it works to deter pathogens (1 mark)
Chemicals and oils secreted by plants which repel vectors of disease (wrong)
6) Why are most protective chemicals produced after the invasion of the pathogen has been detected?
Didn't answer because time was up

Thank you

Q1) ATP is able to be continually cycled from ATP to ADP back to ATP
Q2) I would make it clearer and say something along the lines of 'ATP is able to provide the energy required for vital metabolic processes to occur' make sure to mention that it provides energy
Q3) Not 100% sure about this one. It is a bit difficult to interpret. I read it as that the ATP produced in photosynthesis is required to manufacture the glucose and couldn't be harnessed by the plant. I feel that your answer is a good one.
Q4) Plants can also have thick waxy cuticles to stop the entry of pathogens, especially through leaves
Q5) Plants have the ability, using hormones like abscisic acid, to drop leaves that have become infected
Q6) The chemicals produced require a large investment of energy and materials to make and continually need to be replenished. It would be a huge strain on the organism to be continually making these chemicals, so they are only made when a pathogen is detected to minimise the energy produced. Some of these chemicals can have the tendency to disrupt normal functions of organisms (could be due to the shifting of energy and materials, their presence may act as hormones).

[vox nihili]

Hey guys, these are some questions I got wrong back in term 2 when completing a practice exam set by the school, any help would be appreciated:
1) Suggest a property of ATP that makes it suitable to its function (1 mark)
2) Why do living things need to undergo production of ATP continuously? (1 mark)
My answer: ATP is required by cells for metabolic activity, without ATP living things would not be able to live
3) Why do plants need to produce ATP in respiration when they produce ATP in photosynthesis? (1 mark)
My answer: ATP produced in photosynthesis is not sufficient like that of aerobic respiration. ATP from the light dependent stage of photosynthesis is also used immediately in the light independent stage.

Did I have to mention 36-38 ATP molecules are produced in aerobic respiration to obtain the mark, or was my answer wrong?
4) Describe two passive plant defences and how each deters pathogens (2 marks)
- Thick cork/bark. Pathogens cannot penetrate out surface of plant (correct)
- Sap. Covers plant openings ensuring pathogens cannot enter plant through openings (wrong)
5) Suggest one active physical plant defence and how it works to deter pathogens (1 mark)
Chemicals and oils secreted by plants which repel vectors of disease (wrong)
6) Why are most protective chemicals produced after the invasion of the pathogen has been detected?
Didn't answer because time was up

Thank you

Seems like there's a little bit of confusion about Q3 still, so I'll jump in on that one.

ATP is produced during photosynthesis in order to produce glucose. This is done because you can't store ATP, but you can store glucose. So when there's plenty of sun around, photosynthesis occurs to capture that energy and store it away. Then when it's needed, you just break down the glucose et voilà, you now have energy.

Do we need to know about polarisation, depolarisation, repolarisation & hyperpolarisation?
Thanks in advance

Yep

Hey everyone,
Does anyone know whether you have to know about CaCl2 being involved in the heat shock process (when transforming bacteria)?
Thank you!

Nope, don't need to know

[solution]

Why does greater variation in mitochondrial DNA in african humans indicate that homo sapiens originated from Africa?
Is it because greater variation = more time to mutate = homo sapiens appeared in Africa before any other place?

Also, can someone explain the answers to this question?
There is still some debate about what the hobbit is. Two explanations have been proposed.
Explanation 1 – The hobbit belongs to a species of small-brained dwarf humans.
Explanation 2 – The hobbit is a Stone Age Homo sapiens with a disease that stunts brain development.
f. i. Suggest one piece of evidence that would support explanation 1.

If adult and child fossils of Homo floresiensis were found that had skulls indicating all had the same small brain characteristic.

f. ii. Suggest one piece of evidence that would support explanation 2.
If fossils were found in the same area and had normal sized skulls.
If adult and child fossils of Homo sapiens were found in the same area and had skulls indicating child brain size much larger than that of the fossil called Homo floresiensis.

[gameboy99]

Could somebody with their experience rank these exams in order of difficulty:
NEAP
Lisachem
STAV
Insight
TSSM
TSFX
Engage
(or any other company papers)
*If you haven't tried some of these papers, then just leave it out on your list

Also, is purchasing exam pro book worth it for biology??

Thanks! 

[vox nihili]

Why does greater variation in mitochondrial DNA in african humans indicate that homo sapiens originated from Africa?
Is it because greater variation = more time to mutate = homo sapiens appeared in Africa before any other place?

Also, can someone explain the answers to this question?
There is still some debate about what the hobbit is. Two explanations have been proposed.
Explanation 1 – The hobbit belongs to a species of small-brained dwarf humans.
Explanation 2 – The hobbit is a Stone Age Homo sapiens with a disease that stunts brain development.
f. i. Suggest one piece of evidence that would support explanation 1.

If adult and child fossils of Homo floresiensis were found that had skulls indicating all had the same small brain characteristic.

f. ii. Suggest one piece of evidence that would support explanation 2.
If fossils were found in the same area and had normal sized skulls.
If adult and child fossils of Homo sapiens were found in the same area and had skulls indicating child brain size much larger than that of the fossil called Homo floresiensis.

Your answer is quite right. You get more variation within the population because it's existed for longer and thus had more time to mutate.





The evidence provided in those answers is reasonably poor to be honest. No wonder you're asking about it!
I'd probably just ignore it tbh.
What they're basically saying is that if you found fossils on Flores with normal head size, this would be an indication that H.floresiensis is not a separate species, but rather an example of a genetic abnormality in the local H.sapiens population, causing short stature. Of course, this evidence is reasonably weak, because it could just mean that H.floresienesis and H.sapiens co-existed on the same island (as H.sapiens did with both H.erectus and H.neanderthalensis). 

[blacksanta62]

Q1) ATP is able to be continually cycled from ATP to ADP back to ATP
Q2) I would make it clearer and say something along the lines of 'ATP is able to provide the energy required for vital metabolic processes to occur' make sure to mention that it provides energy
Q3) Not 100% sure about this one. It is a bit difficult to interpret. I read it as that the ATP produced in photosynthesis is required to manufacture the glucose and couldn't be harnessed by the plant. I feel that your answer is a good one.
Q4) Plants can also have thick waxy cuticles to stop the entry of pathogens, especially through leaves
Q5) Plants have the ability, using hormones like abscisic acid, to drop leaves that have become infected
Q6) The chemicals produced require a large investment of energy and materials to make and continually need to be replenished. It would be a huge strain on the organism to be continually making these chemicals, so they are only made when a pathogen is detected to minimise the energy produced. Some of these chemicals can have the tendency to disrupt normal functions of organisms (could be due to the shifting of energy and materials, their presence may act as hormones).

Thank you so much especially with Q6)
I know this is a big ask, but could you (or anyone else) explain why my answer for Q4) was wrong.
Thanks vox nihili  

[plsbegentle]

Could somebody with their experience rank these exams in order of difficulty:
NEAP
Lisachem
STAV
Insight
TSSM
TSFX
Engage
(or any other company papers)
*If you haven't tried some of these papers, then just leave it out on your list

Also, is purchasing exam pro book worth it for biology??

Thanks! 

My own opinion:
STAV
VCAA
NEAP
LISACHEM
ENGAGE
TSSM and TSFX (havent tried any of these exams yet)

There's enough resources online or through ur school, i havent bought much for bio expect the required materials and notes from past students.So i would say no, but its really up to you if u want extra practice.

EDIT: this is from hardest to easiest

[Gogo14]

Would complete selelction have a greater effect on dominant or recessive traits in a population?
dominant, because it can potentiall wipe all of the alleles in a generation; whereas recessive alleles can be carried by heterozygotes to next generations
Not sure if right or how to articulate it properly

[vox nihili]

Would complete selelction have a greater effect on dominant or recessive traits in a population?
dominant, because it can potentiall wipe all of the alleles in a generation; whereas recessive alleles can be carried by heterozygotes to next generations
Not sure if right or how to articulate it properly

What do you mean complete selection?

[Gogo14]

What do you mean complete selection?

Nature of Biology defines complete selection basically as selective pressures against a phenotype resulting in it not being able to breed

[HasibA]

Nature of Biology defines complete selection basically as selective pressures against a phenotype resulting in it not being able to breed

is the q you did from an exam or from NoB? shouldn't be on an exam.... never heard of complete selection, in that way at least

[plsbegentle]

do we need to know all the technologies in selective breeding for the exam (artificial insemination,sperm sorting and embryo transfer)?
thanks 

[ezferns]

Hi everyone,

I'm preparing for Bio 3/4 next year and I've got a question about cellular respiration.

The following is what I think the three net stages look like (please correct me if I'm wrong):

Glycolysis
C₆H₁₂O₆ + 2 ADP+P + 2 NAD --> 2C₃H₄O₃(Pyruvate) + 2 ATP + 2 NADH + 2H

Krebs Cycle
2C₃H₄O₃ + 2ADP+P + 8NAD + 2FAD --> 6 CO₂ + 2ATP + 8NADH + 2 FADH₂

My question is: the Krebs cycle starts off with 8 Hydrogens but ends up with 12. Where did these other Hydrogens come from?

Thanks

[sweetcheeks]

do we need to know all the technologies in selective breeding for the exam (artificial insemination,sperm sorting and embryo transfer)?
thanks 

It states in the study design

human intervention in evolutionary processes:
– application of gene technologies including gene cloning, bacterial transformations, stem cell differentiation, genetic screening, gene therapy and DNA pro ling
– selective breeding as a method of affecting and limiting the gene pool.

Judging by that I would say that you wouldn't need to know what you have listed, rather be prepared to answer questions relating to a scenario that may incorporate one of the methods.

[Gogo14]

is the q you did from an exam or from NoB? shouldn't be on an exam.... never heard of complete selection, in that way at least

NoB

Hi everyone,

I'm preparing for Bio 3/4 next year and I've got a question about cellular respiration.

The following is what I think the three net stages look like (please correct me if I'm wrong):

Glycolysis
C₆H₁₂O₆ + 2 ADP+P + 2 NAD --> 2C₃H₄O₃(Pyruvate) + 2 ATP + 2 NADH + 2H

Krebs Cycle
2C₃H₄O₃ + 2ADP+P + 8NAD + 2FAD --> 6 CO₂ + 2ATP + 8NADH + 2 FADH₂

My question is: the Krebs cycle starts off with 8 Hydrogens but ends up with 12. Where did these other Hydrogens come from?

Thanks

My advice is don't memorise chemical equations and specifics, but rather know inputs and outputs of each stage of aerobic cellular respiration. TBH teachers and examiners don't care about that level of detail