HSC Biology Marathon 2015 (1 Viewer)

[Fiction]

I'd have to say that it is recessive as there has been a huge gap where the trait has not been present, it is definitely not dominant as it has only appeared three times and the chances of it being sex linked is relatively low as only 1/7 of the males born have the trait and they have a 50% chance of getting it.

What?

It's not sex-linked because as both males and females can be affected, then it must be on the X chromosome. Then if you look at the female in generation IV, for the affected characteristic to be sex-linked, her father must also be affected since the characteristic occurs on the X chromosome and her mother must be either a carrier or an affected individual. Neither her parents are affected, therefore the characteristic cannot be sex-linked.

 

[obliviousninja]

Hello children

 

[BlueGas]

Hello children

Hello there, sorry to put you under pressure already but why don't you take a shot at the above pedigree question?

 

[DepressedPenguino]

Here is a question:

Evolution:
A) is a gradual change in the chemistry of the environment
B) is a gradual change in the physical makeup of the environment
C) is the response of organisms to changes in the environment where the fittest survive
D) was invented by Charles Darwin and has been in use since 1859

 

[BlueGas]

Here is a question:

Evolution:
A) is a gradual change in the chemistry of the environment
B) is a gradual change in the physical makeup of the environment
C) is the response of organisms to changes in the environment where the fittest survive
D) was invented by Charles Darwin and has been in use since 1859

A and B are definitely wrong, because there's two types of evolution, there's Punctuated Equilibrium (when changes happen rapidly) and gradualism (where changes happen gradually over time), so saying evolution happens gradually is not entirely correct. D may also be wrong because he may have invented evolution, but Wallace also proposed a similar theory to evolution. So we're left with C and that seems to be most likely the correct answer.

 

[DepressedPenguino]

A and B are definitely wrong, because there's two types of evolution, there's Punctuated Equilibrium (when changes happen rapidly) and gradualism (where changes happen gradually over time), so saying evolution happens gradually is not entirely correct. D may also be wrong because he may have invented evolution, but Wallace also proposed a similar theory to evolution. So we're left with C and that seems to be most likely the correct answer.

yep that's correct

 

[BlueGas]

yep that's correct

Is this a past HSC question? Because even though C is most likely to be the correct answer, the last part of the answer refers to natural selection.

 

[DepressedPenguino]

Question:

In a species of plants there are three possible flower colours: red, blue and purple. When plants with red flowers are crossed with plants with purple flowers the resulting offspring have either red flowers or purple flowers. What is this mode of inheritance called?

A) Sex linkage
B) Recessive
C) Codominant
D) Dominant

 

[DepressedPenguino]

Is this a past HSC question? Because even though C is most likely to be the correct answer, the last part of the answer refers to natural selection.

yeah idk :/ but i dont think natural selection is a "response" tho.

 

[BlueGas]

Question:

In a species of plants there are three possible flower colours: red, blue and purple. When plants with red flowers are crossed with plants with purple flowers the resulting offspring have either red flowers or purple flowers. What is this mode of inheritance called?

A) Sex linkage
B) Recessive
C) Codominant
D) Dominant

Tricky question, all I know that is that the inheritance can't be co-dominant because if it was, the offspring should have both colours in their appearance, but in this case, they are either red or purple.

 

[BlueGas]

Question:

In a species of plants there are three possible flower colours: red, blue and purple. When plants with red flowers are crossed with plants with purple flowers the resulting offspring have either red flowers or purple flowers. What is this mode of inheritance called?

A) Sex linkage
B) Recessive
C) Codominant
D) Dominant

Anyone know the answer to this question?

 

[brianchau3]

Question:

In a species of plants there are three possible flower colours: red, blue and purple. When plants with red flowers are crossed with plants with purple flowers the resulting offspring have either red flowers or purple flowers. What is this mode of inheritance called?

A) Sex linkage
B) Recessive
C) Codominant
D) Dominant

The answer is C;

- You can pretty much cancel out A) as the question says nothing on females/males (I don't think they can do that to us...)
- B) is wrong as well, as you can't have two plants, heterozygous or homozygous(recessive) red/purple and produce offspring of both colours (punnet squares! heterozygous means theres a dominant gene in there and homozygous recessive would ultimately produce a mix of both recessive genes)
- D) is the same reasoning as why B) is wrong!

If you think about it, they aren't going to say three colours (ie; red, purple, blue) if it has no impact on the question (this is my logic, I doubt it would work for every single question in the hsc).

Hope that helped!

 

[BlueGas]

The answer is C;

- You can pretty much cancel out A) as the question says nothing on females/males (I don't think they can do that to us...)
- B) is wrong as well, as you can't have two plants, heterozygous or homozygous(recessive) red/purple and produce offspring of both colours (punnet squares! heterozygous means theres a dominant gene in there and homozygous recessive would ultimately produce a mix of both recessive genes)
- D) is the same reasoning as why B) is wrong!

If you think about it, they aren't going to say three colours (ie; red, purple, blue) if it has no impact on the question (this is my logic, I doubt it would work for every single question in the hsc).

Hope that helped!

Yeah the answer is C, but the question is worded poorly in my opinion. "The resulting offspring has either red OR purple", by using OR that means it only has ONE of them at a time, if it said AND instead of OR, then that means they would have both colours in their appearance, and the answer would definitely be C.

 

[DepressedPenguino]

Anyone know the answer to this question?

from my answer sheet, it is C

 

[DepressedPenguino]

How does the amino acid attached to the tRNA gets accumulated onto another amino acid (attached to another tRNA) during translation? Is it through an enzyme? If so, anyone knows the name of it?

 

[brianchau3]

How does the amino acid attached to the tRNA gets accumulated onto another amino acid (attached to another tRNA) during translation? Is it through an enzyme? If so, anyone knows the name of it?

What you are talking about is during protein synthesis (inside the ribosome), I believe this process is known as dehydration (removal of a water molecule). The amino acids form peptide bonds to each other, hence joining together to form an unfolded amino acid chain (since the bonds are peptide bonds, i'm pretty sure this can also be called a polypeptide bond!). The unfolded polypeptide bond then leaves the ribosome whilst folding into a protein!

I believe the amino acids processed by an anticodon, which I THINK is an enzyme.

Hope i'm right!

 

[BlueGas]

How does the amino acid attached to the tRNA gets accumulated onto another amino acid (attached to another tRNA) during translation? Is it through an enzyme? If so, anyone knows the name of it?

Each type of amino acid is attached to it's specific tRNA, so if it is already attached to one and gets accumulated onto another, it has to be specific to the next one too. An enzyme called aminoacyl-tRNA synthetase, attaches amino acids to tRNA molecules.

 

[DepressedPenguino]

Each type of amino acid is attached to it's specific tRNA, so if it is already attached to one and gets accumulated onto another, it has to be specific to the next one too. An enzyme called aminoacyl-tRNA synthetase, attaches amino acids to tRNA molecules.

Yeah i understand how the amino acid gets attached to the trna (with aminoacyl-tRNA synthetase) but idk how the amino then gets transferred to the other amino acid (which is attached to the tRNA)

 

[BlueGas]

Yeah i understand how the amino acid gets attached to the trna (with aminoacyl-tRNA synthetase) but idk how the amino then gets transferred to the other amino acid (which is attached to the tRNA)

Where have you read this?

 

[DepressedPenguino]

Where have you read this?

everywhere.. it is part of the polypeptide synthesis process. it was shown by my bio teacher but she didnt explain on the transference of amino acid