VCE Biology Question Thread

[grannysmith]

VCAA 2003 BIOL EXAM 2

Q7. c. Suggest one reason why all species of trilobites became extinct.

My answer: Emergence of an ice age froze all the water bodies in which trilobites lived, killing all members of the trilobite species.

VCAA's answer: A global climate change must have occurred to make all species of trilobites extinct.

Some students mentioned a climate change without any indication of the global nature of the change and therefore were
not awarded a mark.

Would my answer be plausible?

[dankfrank420]

For clonal selection:

How do we know when to used the APC --> TH cell --> B cell pathway or simply the antigen binds to antibodies on the B cell?

No, transcription occurs in a 3' to 5' creating a pre-mRNA strand of 5' to 3'

I thought it was the other way around?

[psyxwar]

For clonal selection:

How do we know when to used the APC --> TH cell --> B cell pathway or simply the antigen binds to antibodies on the B cell?

I thought it was the other way around?

Nah he's right. The strand is always MADE 5' to 3'. This means the DNA has to be read 3' to 5' due to the anti-parallel nature of it.

[vox nihili]

For clonal selection:

How do we know when to used the APC --> TH cell --> B cell pathway or simply the antigen binds to antibodies on the B cell?

To activate a B-cell, it must bind the antigen directly. The APC/T_H cell "pathway" is just about support and about setting the B-cells up to respond to particular types of invader.

[RazzMeTazz]

Would all genes show polymorphism? because the term polymorphism is defined in my textbook as "variation in a trait owing to the presence of more than one allelic form of a gene in the gene pool"

As all genes pretty much have alternative forms (alleles) ?

[Reus]

Nah he's right. The strand is always MADE 5' to 3'. This means the DNA has to be read 3' to 5' due to the anti-parallel nature of it.

I'm always right

[anat0my]

Just curious, how many practice exams do you guys do in a day?

[dankfrank420]

Nah he's right. The strand is always MADE 5' to 3'. This means the DNA has to be read 3' to 5' due to the anti-parallel nature of it.

Is this the same for DNA replication?

I'm always right

Just checking

[Reus]

Just curious, how many practice exams do you guys do in a day?

I've only done 6 for bio so far, which is the most across all my subjects.

[vox nihili]

Nucleic acids, no matter the type, can only be made 5' to 3'. So that means that whatever the enzyme is, it can only read 3' to 5' be it RNA pol, DNA pol or reverse transcriptase.

[dankfrank420]

Nucleic acids, no matter the type, can only be made 5' to 3'. So that means that whatever the enzyme is, it can only read 3' to 5' be it RNA pol, DNA pol or reverse transcriptase.

Cheers for the clarification.

[RazzMeTazz]

Would it be correct to say that the founder effect and bottleneck effect are types of genetic drift?

[anat0my]

I've only done 6 for bio so far, which is the most across all my subjects.

For a second I thought you meant 6 a day haha.

Also, does anyone have any good exam techniques? I complete my exams in the conventional way of MC > Short answer.

[anat0my]

Would it be correct to say that the founder effect and bottleneck effect are types of genetic drift?

Aren't they the result of genetic drift? Not sure.

[RazzMeTazz]

Aren't they the result of genetic drift? Not sure.

Ohh okay thanks that makes more sense now!