2016 WJEC A2-Level Biology, BY5

But with E, which was the first stage, the bivalents weren't at the equator so it couldn't have been at metaphase surely, thought that C or whatever it was was the metaphase 1

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sorry man - I meant they join up at prophase I and remain as bivalents at metaphase I before they get pulled apart at anaphase I. This was just my thought process so thought that each block = one bivalent. Could most certainly be wrong

I agree, but there was 12 blocks so surely diploid is 24, and therefore haploid is 12?

What did you guys put for the Q about the Ebola Virus and how it makes amino acid and protein sequence? The 4 mark one after the first Q?

What did people put for why the white clover became a different species?

mRNA travels to ribosome. Each ribosome has two attachment sites. Each tRNA is bonded to a specific amino acid. tRNA with complimentary anti codon pairs up with first codon on mRNA. Ribosomes mover right. Second tRNA with anticodon complementary to second codon on ribsome attaches at second attachment site. Condensation reaction occurs between the two adjacent amino acids forming a peptide bond.

sorry man - I meant they join up at prophase I and remain as bivalents at metaphase I before they get pulled apart at anaphase I. This was just my thought process so thought that each block = one bivalent. Could most certainly be wrong

i thought that one was weird. I put they were isolated from wild clover. There were different selection pressure and different mutations, resulting in a different gene pool, resulting in change of phenotype. For example pollen no longer compatible with other types of clover so can no longer interbreed to produce fertile offspring.

Okay thanks me too! Although I spent a lot of time talking about Reverse Transcriptase...? I thought it might have used that to make cDNA. I then described translation and then transcription... Sorry other way around!

I didn't put that but it might be right. I think only an explanation of translation was required though as if I remember correctly the question was along the lines of: 'how does the virus make polypeptides by translation'.

Hey guys
why did grazing change the frequency of allele E? and why was the original glycoprotein smaller than the changed one?

Also I got 0.5555... so rounded 0.56%, hope 2s.f. was ok I don't think rounding to 1 would be a good idea, you're losing a lot of accuracy going from .55555... to 1 aren't you. almost 2x actual value and when would you ever round to 1 s.f. in a science exam?

For E I said it increased. I said the normal sequence contained a stop codon, but this was replaced by amino acid codon in the new one, so the amino acid chain was longer.

thanks, where did the stop codon come from i feel like im missing out on something big

Grade boundaries this year anyone?

Guys what did you get for the photosynthetic efficiency calculation question?

I got 0.5 recurring. Will i get 2 marks for that and the working out? Some people got 1% so im not sure if we had to round it

i did something similar! i put that decomposition is slower in peat bogs as the ph is not the optimum for the enzymes that decomposers secrete so it denatures or something along those lines