AQA AS Biology Paper 2 2021 Marking Scheme
Question Marking Guidance Mark Comments
01.1 Carboxyl; 1 Accept carboxylic acid
Question Marking Guidance Mark Comments
01.2 Type of R group
1. Unsaturated (fatty acid/hydrocarbon);
Explanation
2. Double bond (between carbons);
2
1. Accept alkene
2. Accept for ‘double bond’,
C=C
Question Marking Guidance Mark Comments
01.3 1. Add ethanol/alcohol then add water and
shake/mix
OR
Add ethanol/alcohol and shake/mix then
pour into/add water;
2. White/milky (emulsion)
OR
(emulsion) test turns white/milky;
2
1. Reject heating the emulsion
test
1. Accept ‘Add Sudan III and
mix’
1. Ignore a second shake
2. Ignore cloudy
2. Reject precipitate
2. Accept (for Sudan III) top
(layer) red
MARK SCHEME – AS BIOLOGY – 7401/2 – JUNE 2021
6
Question Marking Guidance Mark Comments
01.4 (Similarity)
1. Both have a phospholipid bilayer
OR
Both have fatty acid/hydrophobic tails pointing
in/face each other
OR
Both have phosphate/polar/hydrophilic heads
pointing out
OR
Both have protein;
(Differences)
2. No channel/carrier proteins, whereas fluid
mosaic does
OR
Protein layer outside (phospholipids), fluid mosaic
is 'dotted';
3. Cholesterol is not present whereas it is present
in fluid mosaic;
4. Glycoprotein is not present whereas it is present
in fluid mosaic;
5. Glycolipid is not present whereas it is present in
fluid mosaic;
3 max
Accept 2 marks max if
1. is not achieved
2., 3., 4., and 5.
accept first answer
refers to 1935 model
unless otherwise
stated
2. Accept for ‘no
channel/carrier’, no
intrinsic
2. Accept only one
type of protein
whereas fluid
mosaic has many
(types)
TOTAL 8
MARK SCHEME – AS BIOLOGY – 7401/2 – JUNE 2021
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Question Marking Guidance Mark Comments
02.1 Mark in pairs: 1 and 2 OR 3 and 4
1. Flattened cells
OR
Single layer of cells;
2. Reduces diffusion distance/pathway;
3. Permeable;
4. Allows diffusion of oxygen/carbon dioxide;
2
1. Reject thin cell
wall/membrane
1. Accept thin cells
1. Accept ‘one cell
thick’
4. Ignore gas
exchange
Question Marking Guidance Mark Comments
02.2 Correct answer for 2 marks = 1.10–1.15;;
Accept for 1 mark,
0.6(1) : 1 (correct FEV1 : FEC ratio)
2
Question Marking Guidance Mark Comments
02.3 1. Less carbon dioxide exhaled/moves out (of lung)
OR
More carbon dioxide remains (in lung);
2. (So) reduced diffusion/concentration gradient
(between blood and alveoli);
3. Less/slower movement of carbon dioxide out of
blood
OR
More carbon dioxide stays in blood;
Category | AQA Questions and Marking Scheme |
Authors | Qwivy.com |
Pages | 18 |
Language | English |
Tags | AQA AS Biology Paper 2 2021 Marking Scheme |
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