VCE Biology Question Thread

[Unblemished]

I was just wondering what exam score I would be required to get a 45+ study score. I tried reading the distributions report but it didn't really help me.

[RazzMeTazz]

I was unsure of the answers to the attached questions:

 For Question 8 the correct answer is D.

For Question 7 (which relies on information provided in question 6) the correct answer is B.

But if two parents heterozygous for the autosomal recessive condition of albinium (Aa) reproduced, wouldn't the chance of a child having albinism be 1/4 and a chance of a child being normally pigmented be 3/4. Hence wouldn't the chance of the heterozygote parents having a child with albinism and one with normal pigment be = 1/4 × 3/4 = 3/16?

Thankyou

[Deshouka]

Hi
Does signal transduction occur when a lipid soluble hormone binds to the receptor in the cytoplasm?
Thanks!

[Unblemished]

I was unsure of the answers to the attached questions:

 For Question 8 the correct answer is D.

For Question 7 (which relies on information provided in question 6) the correct answer is B.

But if two parents heterozygous for the autosomal recessive condition of albinium (Aa) reproduced, wouldn't the chance of a child having albinism be 1/4 and a chance of a child being normally pigmented be 3/4. Hence wouldn't the chance of the heterozygote parents having a child with albinism and one with normal pigment be = 1/4 × 3/4 = 3/16?

Thankyou

For question 8, it cannot be A because there is 100% of the population present so the alleles cannot be lethal. C is incorrect as there was no change in population percentage, meaning there was no change in what was favoured. B is a possibility, but unlikely as genetic drift is the unpredictable change in allele frequency and the question states the mice are laboratory mice. So, D is the most likely correct answer.

[Jason12]

what are some structural differences between neanderthals and homo sapiens and Australopithecus and homo sapiens? Am I correct in saying that all were bipedal?

[RazzMeTazz]

For question 8, it cannot be A because there is 100% of the population present so the alleles cannot be lethal. C is incorrect as there was no change in population percentage, meaning there was no change in what was favoured. B is a possibility, but unlikely as genetic drift is the unpredictable change in allele frequency and the question states the mice are laboratory mice. So, D is the most likely correct answer.

Thankyou!

[RazzMeTazz]

what are some structural differences between neanderthals and homo sapiens and Australopithecus and homo sapiens? Am I correct in saying that all were bipedal?

Structural differences between Australopithecus and Homo Sapiens are:
1.) Larger rounded skull in Homo Sapiens (as a result of increased brain size)
2.) Smaller teeth and jaws in Homo Sapiens (to make room for increasing size of the brain in the skull)
3. Greater leg to arm length in Homo Sapiens for efficient bipedal locomotion.
4.) Flatter faces in Homo Sapiens

Sorry I don't know many structural differences between Neanderthals and Homo Sapiens, except for the fact that Neanderthals has bigger brains so I'm assuming a larger skull?

[RazzMeTazz]

For this question (attached below) I answered divergent evolution but the correct answer convergent evolution.

I assumed this would be the case since both animals evolved from mammals.

 Is it said to be convergent evolution as they have similar adaptations (such as the pointed snout?) but then again they have different adaptations as well, with the Tachyglossus aculeatus having course fur and being covered with spines whlst the Myremocophaga tridactyla is covered with short fur?

Could anyone please explain why I am wrong

[howlingwisdom]

For this question (attached below) I answered divergent evolution but the correct answer convergent evolution.

I assumed this would be the case since both animals evolved from mammals.

 Is it said to be convergent evolution as they have similar adaptations (such as the pointed snout?) but then again they have different adaptations as well, with the Tachyglossus aculeatus having course fur and being covered with spines whlst the Myremocophaga tridactyla is covered with short fur?

Could anyone please explain why I am wrong

I think that because of the fact that they are present on different continents (Australia and South America) suggests that convergent evolution took place. Both organisms were exposed to similar selection pressures and lived in similar environments, hence structures that are similar to both organisms formed.

Edit: responding to your course fur vs short fur comment, I think that there would be some features that are different to both animals (because not all the selection pressures that the organisms are exposed to would be the same, for instance, a colder climate would have selected for a courser fur, whereas a hotter climate selects for short fur.) But the the initial development of fur would have probably occurred due a selection pressure in the past that selected for fur in both organisms. I hope this helps you somewhat!

[katiesaliba]

A question on the VCAA 2009 exam 2 is as follows:
Explain why apoptosis sometimes occurs during the cell cycle represented in the above diagram.

I answered as follows:
Specialised cells do not undergo mitosis.

But this wasn't an answer on the assessment report. Is my reasoning incorrect?

Also, has anyone else found the 2009 vcaa exam 2 short answer quite difficult? I hated the questions 

[dankfrank420]

Apoptosis is defined as programmed cell death, so it results in destroying cells that are sometimes not required/ceased to function.

I don't see how you came to your answer.

[katiesaliba]

Apoptosis is defined as programmed cell death, so it results in destroying cells that are sometimes not required/ceased to function.

I don't see how you came to your answer.

I know this, but specialised cells don't undergo mitosis. Therefore, they would be destroyed via apoptosis...unless they undergo some other kind of programmed cell death? 

[RazzMeTazz]

I know this, but specialised cells don't undergo mitosis. Therefore, they would be destroyed via apoptosis...unless they undergo some other kind of programmed cell death? 

I was taught that specialised cells never leave G1 phase and are in a 'resting' phase known as G0. So I guess they don't need to undergo apoptosis in order to prevent them from partaking in the cell cycle and dividing
Sorry, I'm not sure if this helps.

[katiesaliba]

I was taught that specialised cells never leave G1 phase and are in a 'resting' phase known as G0. So I guess they don't need to undergo apoptosis in order to prevent them from partaking in the cell cycle and dividing
Sorry, I'm not sure if this helps.

Thanks! It's just that when I went to a TSFX lecture they explicitly said that cells that do not divide undergo apoptosis...well, at least I THINK that was said :|

[RazzMeTazz]

Thanks! It's just that when I went to a TSFX lecture they explicitly said that cells that do not divide undergo apoptosis...well, at least I THINK that was said :|

Oh okay I get what you mean then. I probably would have arrived at the same answer for that question then :/