UNOFFICIAL MARK SCHEME: AQA A Level Biology 20/06/2017 Paper 2

so who actually thinks they're getting an A or A*, i'm genuinely curious?

What did people say for the relative effect on biomass increase of the 3 different mycorrhizae species with normal or x2 phosphate concentration in the soil?

There is a positive marking system, so if you have enough of the other points you could potentially get full marks in the question. But if you got the equation wrong, then you would not get the mark for it - but the equation will only be worth 1 mark.

anyone got any essay predictions for paper 3???????????

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Add a few more

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Nah seriously here are a few possible titles on topics which haven't come up much in either paper:
-Biology importance of cycles (Krebs, Calvin, Nitrogen etc.)
-Biological importance of ions (Kidneys and nerve impulses didn't come up much)
-Importance of transport (Haemoglobin, Plant transport, Mass transport like heart)

Those are few at the top of my head rn, feel free to add more.

You know whoever wrote this unofficial mark scheme, did you just write down what you wrote in the exam?

As for the question which concerned the E280 A mutation and the question saying why was it not wiped out by natural selection I put because it was advantageous for another characteristic previously. (I had seen a very similar question during past paper questions so I assume it is right)

So, from what I can remember. These are the questions:

Question 1 - [7 marks]
a) Exercise increases the heart rate, explain how receptors and the nervous system are involved. [4 Marks]
b) Suggest an advantage of AMPK during exercise (diagram) [3 Marks]

Question 2 - [12 Marks]
a) Why would releasing sterile males would reduce the chance of the spread of infection in humans? [2 marks]
b) Explain how the scientists would use the mark-release-capture method to determine the population size [3 marks]
c) Explain why the treatment wasn't effective [1 Mark]
d) Explain why the transgenic mosquitoes were released in week batches? [2 marks]
e) Using all the information provided, evaluate the use of transgenic mosquitoes [4 marks]

Question 3 - [10 Marks]
a) Explain the difference between the staining [2 Marks]
b) Group B could last longer than Group A, explain why [4 marks]
c) What is the average diameter of the muscle cells [2 marks]
d) State two differences between young and adult males [2 Marks]

Question 4 - [6 Marks]
a) How does the fungi get nutrients [2 Marks]
b) Evaluate the use of AMF across all phosphate concentrations [4 Marks]

Question 5 - [6 Marks]
a) Explain why Tube 1 was set up [2 Marks]
b) Explain the results in Tube 3 [2 Marks]
c) Why is using an inhibitor of the reduction of DCPIP a way of reducing weed growth? [2 Marks]

Question 6 - [10 Marks]
a) What does reverse transcriptase do? [1 Mark]
b) What does DNA polymerase do? [1 Mark]
c) Explain why the DNA was hydrolysed [2 marks]
d) Calculate the ratio of A to B [2 Marks]
e) Why did the PCR reaction stop [2 Marks]
f) Explain why primers were added to the DNA sample [2 Marks]

Question 7 - [10 Marks]
a) What is meant by phenotype [2 Marks]
b) What gene interaction is the diagram displaying [1 Mark]
c) What are the colours of the genotypes [2 marks]
d) Genotypes/Phenotype/P Ratio [3 Marks]
e) Use H-W, find the percentage of those who are heterozygous [2 Marks]

Question 8 - [9 Marks]
a)Why wasnt the transplant given to Type 2? [2 Marks]
b) Tick the box that incorrectly describes the role of insulin [1 Marks]
c) Describe how transcription factors turn adult skin cells into iPS [2 Marks]
d) Using all the information provided, evaluate the use of iPS transplants on humans [4 Marks]

Question 9 - [6 Marks]
a) What is a gene pool? [1 Mark]
b) Describe how the two species arose via sympatric speciation [5 marks]

Question 10 - [15 Marks]
a) Calculate the percentage increase [2 Marks]
b) Why does inhibition of acetylcholinerase improve nerve communication in AD sufferers [2 Marks]
c) Give two reasons why there was a high frequency of the gene [2 Marks]
d) Why was the gene not removed by natural selection [2 Marks]
e) Why was there a variation in gene expression [2 Marks]
f) Explain the figures in the number of AD genes that had the right mutation [2 Marks]
g) Why did they decide a DNA probe was not appropriate? [2 Marks]


That's 91 Marks total. I'm unsure about 2(e) but I do remember having to talk about the graph and the effectiveness of the transgenic?

I think the PCR question was 9 marks, the one about why PCR stopped was 1 mark and I think the one about why the trained mice could last longer was 3 marks as was acetylcholinesterase?

??????????????????????????????????????????????????????
Nah seriously here are a few possible titles on topics which haven't come up much in either paper:
-Biology importance of cycles (Krebs, Calvin, Nitrogen etc.)
-Biological importance of ions (Kidneys and nerve impulses didn't come up much)
-Importance of transport (Haemoglobin, Plant transport, Mass transport like heart)

Those are few at the top of my head rn, feel free to add more.