Trouble with TRIALS? Post Here! Help here!

[kenhung123]

OK guys its getting close. We are bringing up many trials now. I will try my best to explain questions you guys don't get and also post questions I find difficult. It would be great if we can share good questions/tricky ones as we can identify the harder questions without doing every single trial.

[kenhung123]

Cladograms - I don't know much about these, anyone can explain what information I can obtain from these and how to read one?
[IMG]http://img251.imageshack.us/img251/6332/bioquestion1.th.jpg[/img]
[IMG]http://img251.imageshack.us/img251/9544/bioanswer1.th.jpg[/img]

[Studyinghard]

yep ur right. its probably a STAV or a NEAP? those exams from what I heard are written by only one person and they are bound to make mistakes.

[kenhung123]

NEAP I think anyway can you explain question 1?

[Harbourmastah]

Here my question

TSSM 08:
Q:
"The most common mutation which causes FRDA is a large area containing many copies of a GAA triplet-repeat sequence in the first intron of the FRDA gene. What effect will this mutation have on the protein?

A:
There will be no effect on the protein and the repeat is located in an intron which is not translated

Since alleles code for proteins and the GAA triplet repeat is the mutation which causes FRDA, how can it not affect the translated protein? Surely the extent of the repeat must have lead to some sort of change in the protein otherwise how can individuals show symptoms of the disease?

[Harbourmastah]

Cladograms - I don't know much about these, anyone can explain what information I can obtain from these and how to read one?
[IMG]http://img251.imageshack.us/img251/6332/bioquestion1.th.jpg[/img]
[IMG]http://img251.imageshack.us/img251/9544/bioanswer1.th.jpg[/img]

A monophyletic group is defined as a group consisting of a single common ancestor and all its descendants.

[kenhung123]

Here my question

TSSM 08:
Q:
"The most common mutation which causes FRDA is a large area containing many copies of a GAA triplet-repeat sequence in the first intron of the FRDA gene. What effect will this mutation have on the protein?

A:
There will be no effect on the protein and the repeat is located in an intron which is not translated

Since alleles code for proteins and the GAA triplet repeat is the mutation which causes FRDA, how can it not affect the translated protein? Surely the extent of the repeat must have lead to some sort of change in the protein otherwise how can individuals show symptoms of the disease?

You are absolutely correct. The key word is intron and they are most likely intending to make you say something like no effect because its a non coding region. I think when they were writing the question they did not keep in mind that if its the non coding region how can a faulty protein be produced and cause the disease. Correct me if I'm wrong

[shinny]

Here my question

TSSM 08:
Q:
"The most common mutation which causes FRDA is a large area containing many copies of a GAA triplet-repeat sequence in the first intron of the FRDA gene. What effect will this mutation have on the protein?

A:
There will be no effect on the protein and the repeat is located in an intron which is not translated

Since alleles code for proteins and the GAA triplet repeat is the mutation which causes FRDA, how can it not affect the translated protein? Surely the extent of the repeat must have lead to some sort of change in the protein otherwise how can individuals show symptoms of the disease?

You are absolutely correct. The key word is intron and they are most likely intending to make you say something like no effect because its a non coding region. I think when they were writing the question they did not keep in mind that if its the non coding region how can a faulty protein be produced and cause the disease. Correct me if I'm wrong

Looks like they overstepped their own knowledge. Mutations in introns CAN cause changes to the protein as they have a regulatory role in the protein synthesis process, but I think this outside the scope of VCE. I don't think VCAA would give such a question.

[kenhung123]

Cladograms - I don't know much about these, anyone can explain what information I can obtain from these and how to read one?
[IMG]http://img251.imageshack.us/img251/6332/bioquestion1.th.jpg[/img]
[IMG]http://img251.imageshack.us/img251/9544/bioanswer1.th.jpg[/img]

A monophyletic group is defined as a group consisting of a single common ancestor and all its descendants.

Thanks for your help. I also have a question about relatedness represented in a cladogram.
[IMG]http://img3.imageshack.us/img3/8284/bioquestion.th.jpg[/img]
Which matters more vertical distance or horizontal distance in terms of relatedness?

[Harbourmastah]

Thanks for the help guys

yeah i see what you mean

i would say B because the South African Wild dog and the East African wild dog diverged the earliest in the cladogram

In terms of relatedness, i think the point of divergence between the two species is the most important. However I'm not too sure about this one...

[kenhung123]

I thought any diagram when they both diverge to 2 species from 1 common ancestor it means they are more closely related than when 1 species diverge to a new branch species and the diverge to a common ancestor which then diverges into 2 new species? I was expected the south african wild dog and east african wild dog to be more close due to this confusion.

[cipherpol]

For the below question, I got A, but the answer is actually B. can someone explain?

[kenhung123]

Test cross heterozygote at 2 gene loci would produce (HhWw x hhww)
Making HW, Hw, hW, hw x hw
HhWw Hhww hhWw hhww
So B is correct

[cipherpol]

Ah, I see. I thought they meant cross 2 heterozygous. Thanks for that.

[Edmund]

Thanks for your help. I also have a question about relatedness represented in a cladogram.
[IMG]http://img3.imageshack.us/img3/8284/bioquestion.th.jpg[/img]
Which matters more vertical distance or horizontal distance in terms of relatedness?

B,C are out (From similar ancestor)

'A' would be the least related because they evolved from a much earlier ancestor.

Therefore horizontal distance matters more (Sorry if I mixed horizontal and vertical)

EDIT: Fixed quote