VCAA 2012 BIO EXAM

[Scooby]

Yeah, they're both right, but transgenic is more specific 

[~kitty~]

Doesn't molecular clock determine the time since species diverged from a recent common ancestor i.e  determine evolutionary relationships? I don't think it's used to date fossils. I said A index fossil

i think i did the same about the index fossils- isnt it also because they're commonly found around the world?

[boss11]

what do you think the A+ cut off mark will be? 65?

[HighLatency]

It's intervening with the evolutionary process because people who are found to have the mutated allele might be discriminated against as a partner and therefore not pass their alleles for the disease on to the next generation, etc 

Yeah, I had B for 5

It isn't limited to humans and that's a lot of guesswork :|
Tbh I could get a genetic screen for shits and gigs :/

[Scooby]

Yeah, still, preventing individuals with a particular allele from breeding isn't an example of genetic screening, it's selective breeding.

The results of genetic screening could mean that certain organisms are preventing from breeding, but that itself isn't genetic screening

I guess we'll just have to wait for a few companies to put out some answers 

[vox nihili]

1. B
2. C
3. C
4. A
5. C*
6. A
7. D
8. B
9. C
10. B
11. D
12. A
13. C
14. A
15. D
16. D
17. A
18. D
19. B
20. C
21. B
22. D
23. D
24. A
25. B

These were my answers. Question five has been given an asterix because after extensive discussion it seems likely that it is incorrect. It should be B, we think. These have been looked at by a number of students on the Biology Facebook group and agreed upon by most. (http://www.facebook.com/groups/189957917735884/)

[itsdanny]

what do you think the A+ cut off mark will be? 65?

I am going to say 59~61.

[itsdanny]

Question five has been given an asterix because after extensive discussion it seems likely that it is incorrect. It should be B, we think. These have been looked at by a number of students on the Biology Facebook group and agreed upon by most.

Well I put my answer down for B, as I didn't find C correct for some apparent reason at the time.

[Highacheiver]

question, what did everyone do for the chance of child having syndacytyl? did we know if she was homozygous ore heterozygous?

[vox nihili]

Question five has been given an asterix because after extensive discussion it seems likely that it is incorrect. It should be B, we think. These have been looked at by a number of students on the Biology Facebook group and agreed upon by most.

Well I put my answer down for B, as I didn't find C correct for some apparent reason at the time.

C seemed relatively reasonable, but I couldn't find a reason for B to be correct at all. The idea is that C is incorrect because the cells could be aneuploid (something I thought of during the exam, but couldn't understand why B would be correct). The reason that B is correct is ridiculously complex. It's based on a highly specific type of asexual reproduction in plants wherein the seeds replace fertilised cells. So, in that particular genus and in very few other genera, reproduction can occur that way.

[itsdanny]

question, what did everyone do for the chance of child having syndacytyl? did we know if she was homozygous ore heterozygous?

For some odd reason, I interpreted that question really bad, and thought the stem question was wrong. I thought it had originally said, the father and mother were normal, and so they must have been recessive for Syndactyly, although yet the daughter and the father were affected, so it didn't make sense to me... messed up on that one bad! No chance for that 75/75 now haha!

[Highacheiver]

question, what did everyone do for the chance of child having syndacytyl? did we know if she was homozygous ore heterozygous?

For some odd reason, I interpreted that question really bad, and thought the stem question was wrong. I thought it had originally said, the father and mother were normal, and so they must have been recessive for Syndactyly, although yet the daughter and the father were affected, so it didn't make sense to me... messed up on that one bad! No chance for that 75/75 now haha!

dont worry about it! im sure you'll make up the marks somewhere else! what do you think the answer would be? i was so confused!

[vox nihili]

question, what did everyone do for the chance of child having syndacytyl? did we know if she was homozygous ore heterozygous?

For some odd reason, I interpreted that question really bad, and thought the stem question was wrong. I thought it had originally said, the father and mother were normal, and so they must have been recessive for Syndactyly, although yet the daughter and the father were affected, so it didn't make sense to me... messed up on that one bad! No chance for that 75/75 now haha!

dont worry about it! im sure you'll make up the marks somewhere else! what do you think the answer would be? i was so confused!

It's autosomal dominant. Ruby's mother is normal. Therefore she's homozygous recessive (let's call that ss)
Therefore Ruby, who has the trait must be (Ss)
Jonah is normal (ss)
So, punnet square, Ruby crossed with Jonah Ss x ss
There's a 1/2 chance that the child will have it.

[emxrang]

for Q17.
the people saying index fossil are incorrect due to this statement.

index fossils are only found within a "restricted depth of sedimentary rock strata". however the question clearly stated that it lived for approximately 50 million years.
50 million years is a very very long time and they would be found in many layers.
so index fossil is probably wrong.

Carbon 14 is clearly wrong
DNA hybridisation only reveals amount of similarity between two gene sequences. this isnt the case.

leaving c.

[vox nihili]

for Q17.
the people saying index fossil are incorrect due to this statement.

index fossils are only found within a "restricted depth of sedimentary rock strata". however the question clearly stated that it lived for approximately 50 million years.
50 million years is a very very long time and they would be found in many layers.
so index fossil is probably wrong.

Carbon 14 is clearly wrong
DNA hybridisation only reveals amount of similarity between two gene sequences. this isnt the case.

leaving c.

I don't think that this is correct. Index fossils are accurate for more than 500 million years. That statement is incorrect.

C is definitely incorrect. An index fossil is much more likely to experience longevity than any form of biomolecule. You are right about the other two, but molecular clock is definitely wrong. Index fossil is the correct response.