VCE Biology Question Thread

[HasibA]

http://imgur.com/a/vHAYq
can anyone helpwith the MCQ questions attached, and perhaps why what i circled was wrong?
thank you so much guys! dont seem to have written responses for them ahha

[Angelx001]

If chromosomes do not form homologous pairs during meiosis does this mean the gametes produced die?

[FatimaEl]

http://imgur.com/a/vHAYq
can anyone helpwith the MCQ questions attached, and perhaps why what i circled was wrong?
thank you so much guys! dont seem to have written responses for them ahha

Since this is an X linked trait (X^H, indicating that the trait is determined by the X chromosome) it would be reasonable to conclude that the mother (kate) would also have the trait since she is the one in charge of giving her sons the X chromosome and the father gives the Y (as im sure u know). However im not quite sure why you cant say elliot cant have the trait, maybe because its more reasonable to say the mother has it?
Hope i helped a little 

[HasibA]

Since this is an X linked trait (X^H, indicating that the trait is determined by the X chromosome) it would be reasonable to conclude that the mother (kate) would also have the trait since she is the one in charge of giving her sons the X chromosome and the father gives the Y (as im sure u know). However im not quite sure why you cant say elliot cant have the trait, maybe because its more reasonable to say the mother has it?
Hope i helped a little 

that helped heaps! thanks
anyone else can help with any of the rest- much appreciated <3

[Gogo14]

1. Really stumped with the mc in the question attached
2. How do you do the questions that give you a number of alleles and ask for the possible number of phenotypes and genotypes. I always get these wrong. Is there some trick, other than doing  a massive punnet square?

[blacksanta62]

Hey guys, I just have some questions:
1) Would it be more beneficial for me to go through past exams and nail the questions I frequently get wrong/don't fully understand (Unit 4 AOS 2, lol, it was rushed) rather than do full exams? I doubt I'll be able to get them all done. I have the checkpoints book so I can be specific to what I continiously get wrong
2) What VCAA papers are essential to do fully because a lot of the state didn't do well?
Thanks

[Gogo14]

3. This question too

Thanks

[homosapien]

(Image removed from quote.)

With this question, why isn't the answer A? (it's B by the way)

Since it's an original plasmid, wouldn't it be cut by restriction enzymes to make space for the desired gene? So 5.3-2.9 and then + 2.9 for the gene, making it 5.3kb again?

may i ask what exam this is? Looks interesting

[lasagne]

1. Really stumped with the mc in the question attached
2. How do you do the questions that give you a number of alleles and ask for the possible number of phenotypes and genotypes. I always get these wrong. Is there some trick, other than doing  a massive punnet square?

Alright, so both members of the couple have a 2/3 chance of being heterozygous for the trait; this is because they both have a sibling with the disease yet they dont have it themselves (both of the male and female's parents would be heterozygous). So 2/3 x 2/3 =4/9. If the two people are both heterozygous, the chance of them having a child with Tay Sachs is 1/4. Now multiply it in. 4/9 x 1/4 =1/9.
Hope this helps!

[Robert243]

Is it correct to say that RNA polymerase helps unzip and unwind Double stranded DNA into a single strand.In a question i just did i said that , but for the solutions it said  it help's copies DNA template and join nucleotides.

[HasibA]

Is it correct to say that RNA polymerase helps unzip and unwind Double stranded DNA into a single strand.In a question i just did i said that , but for the solutions it said  it help's copies DNA template and join nucleotides.

doesnt DNA helicase 'unzip' the DNA, whereas DNA ligase joins okazaki fragments together, and DNA polymerase replicates, 'proofreads' and check the DNA replication process?
i thought RNA polymerase wasn't for DNA replication, but rather for the synthesis or building up of Ribonucleotides?

[vox nihili]

Is it correct to say that RNA polymerase helps unzip and unwind Double stranded DNA into a single strand.In a question i just did i said that , but for the solutions it said  it help's copies DNA template and join nucleotides.

They had the same discussion on the HSC biology group last week and it turned into an absolute shit storm.


Suffice to say that you don't need to know what unwinds the DNA in transcription, so don't worry about it





Well beyond VCE:

Wikipedia says that RNA polymerase has inherent helicase activity (i.e. it has a bit that can unwind DNA). This is, unfortunately, one of those examples wherein wikipedia is wrong. It is true that there is an RNA polymerase that does have helicase activity; however, it is found in a virus that infects bacteria, so it's hardly relevant to normal transcription!

[88mimi12345]

Hey Guys!
I've been staring at this question for so long and I just don't get it
I don't understand how you would draw these translocations in part b!
Any help would be greatly appreciated, thank you!!

[instax101]

may i ask what exam this is? Looks interesting

Insight 3/4 2016

[mayonnaise]

3. This question too

Thanks

Look up the definitions of a nonsense mutation, missense mutation, and silent mutation. The ans you circled is a missense, not nonsense mutation