AQA A2 Biology BIOL5 - 17th June 2015

I wrote about:

Controlling population grown due to limited resources and human impact on global warmin.
Controlling human reproduction because of harmful genetic diseases
Controlling succession to conserve habitats and species and the benifits of this to humans
Controlling the growth and development of Bacteria due to the increase in antibiotic resistance
Controlling development of other mammals (hypothesised in a recently published journal that some mammals have the potential to develope and become as intelligent as humans, e.g apes and monkeys and why we should do this [human dominance])

Ok all that chromosome stuff makes sense but
HOW DOES THE PROBE BIND?

I was a bit concerned on question 9, when it said to "use all the information given" to explain the results from electrophoresis.
It gave the lengths of the primers which attached to R and r and I felt this would have to be mentioned; it also said that shorter fragments move further and didn't identify L and N; these suggested to me that you would have to identify which of L and N was RR and which was rr.

BUT, the question only told you the lengths of the primers which were used in the PCR, and not the length of the whole alleles; in the electrophoresis I'm fairly sure it was the whole alleles that were separated and not just the parts which the primers bound to?
Therefore I didn't think it was possible to identify L and N, so I simply said: "L and N are both homozygous, one has two copies of the R allele and one has two copies of r allele, so only one band seen for each, and the alleles are of different lengths so they moved different distances along the gel. All the offspring were heterozygous so they had one R allele and one r allele, so two bands were seen but only of half the width"

can anyone back me up on this, or explain why I was wrong? It seems that other people identified the recessive allele as the one which moved further.

Wow people have interpreted essay B soooooo differently and looked at it from so many different angles

I was a bit concerned on question 9, when it said to "use all the information given" to explain the results from electrophoresis.
It gave the lengths of the primers which attached to R and r and I felt this would have to be mentioned; it also said that shorter fragments move further and didn't identify L and N; these suggested to me that you would have to identify which of L and N was RR and which was rr.

BUT, the question only told you the lengths of the primers which were used in the PCR, and not the length of the whole alleles; in the electrophoresis I'm fairly sure it was the whole alleles that were separated and not just the parts which the primers bound to?
Therefore I didn't think it was possible to identify L and N, so I simply said: "L and N are both homozygous, one has two copies of the R allele and one has two copies of r allele, so only one band seen for each, and the alleles are of different lengths so they moved different distances along the gel. All the offspring were heterozygous so they had one R allele and one r allele, so two bands were seen but only of half the width"

can anyone back me up on this, or explain why I was wrong? It seems that other people identified the recessive allele as the one which moved further.

Anyone got the exact wording for the essay questions please? Thanks

Ok all that chromosome stuff makes sense but
HOW DOES THE PROBE BIND?

Correct me if I'm wrong but didn't the question say that the primer binds to a section of DNA that is however many base pairs long. So the numbers they gave did actually represent the length of the fragments with r and R in so you could distinguish between them

Ok all that chromosome stuff makes sense but
HOW DOES THE PROBE BIND?[/QUOTE{

Simple.

God.

Can you imagine if AQA decided to go all evangelical with their mark scheme this year XD

How is muscular contraction affected when Ca 2+ ion channels close (4)
I spoke about no calcium ions to move troponin from actin binding site? looking at other people's answers on here that seems to be wrong?

I thought it said "the primer binds to a 195-bp-long fragment of r" etc. 195bp would be pretty short for a whole allele, and the other one was only 135! even without introns that would only code for a max 45 AA long peptide

Has anyone got the link for the Unofficial mark scheme? I've gone back a few pages and can't seem to find anything

B
The importance to humans of the control of reproduction, development and growth in organisms, including themselves

I think...

Thankyou! How did you find the paper?

I don't think it matters if its not the entire gene it still shows that the fragment contained R was shorter than the fragment that contained r (i think it was that way round) so from the electrophoresis you could work out which was which