AQA GCSE Biology Unit 2 - 24th January 2012 Unofficial Markscheme

I dont remember particular questions, but I know I put;

A "B" when you had to choose between A,B or C.

11.6cm (out of the four options).

0.18% (for the energy passed on).

10 minutes for 1b.

You know the question where you put B... What was it actually about? Thanks

I think he was talking about the insulin one. Where you had to select a drug.

1 c) Circle the two actions when body temperature falls. (Shivering and vasoconstriction).
2a) Control variables- mass of crushed apple/ amount of drops of liquid
b) Drops can be different sizes (volumes)
c) Amylase does not break down cell wall like water (1)
Pectinase enzyme digests cell wall (pectin in the cell wall according to wiki) (1)
Energy in boiling water causes the cell wall to break apart (1)
d) 11.6 cm^3
ii) Pectinase enzyme is denatured at high temperatures but boiling the apple still has the same effect.
3a) Drug B- kills pancreatic cells which means even less insulin is produced than before (which is why it only has negative effect on some diabetics)
b) Careful attention to diet
Pancreatic cell transplants
4a) Cloudy means less light so less photosynthesis so less CO2 used
b) Magnesium
5a) 0.18%
b) Heat
c) Shorter food chains more efficient as there are less energy losses. Heron only gets 2 out of the 25,000kJ of energy absorbed.
d) Microorganisms consume the dead animals and plants (1) causing decay. They then used the biomass for respiration (1) which released carbon dioxide into the atmosphere (1)- replacing CO2. CO2 then used in photosynthesis (1) to be returned to the food chain.
6a) Water moves through the semi-permeable membrane by osmosis (1) (from the dilute solution to the more concentrated sugar solution(1)) causing the solution level to rise (1).
b) Would still increase (1) but at a slower rate the solution is less concentrated so smaller concentration gradient (1).
7a) Gene
ii) Ribosomes
b) A combination of three bases (1) codes for different amino acids (1). Amino acids then join together to create the protein which codes for blue eyes (1)
c) Different amino acids in structure
ii) Different coloured eyes
8) Bone marrow (advantages)
Does not kill embryos (1)
It is a simple operation (1)
Can still cure heart and blood diseases (1) and futire possibilities (1)
Embryonic stem cells (advantages):
Is not painful to patient (1)
Can develop into any type of cell so can cure more diseases (1)
Conclusion (1)

1a) As temperature decreases frostbite occurs quicker (1 mark)
b) 10 minutes (maybe 9??) (1 mark)
1 c) Circle the two actions when body temperature falls. (Shivering and vasoconstriction). (2 marks) ( /5marks)

2a) Control variables- mass of crushed apple/ amount of drops of liquid (1 mark)
b) Drops can be different sizes (volumes) (1 mark)
c) Amylase does not break down cell wall like water (1)
Pectinase enzyme digests cell wall (pectin in the cell wall according to wiki) (1)
Energy in boiling water causes the cell wall to break apart (1) (3 marks)
d) 11.6 cm^3 (1 mark)
ii) Pectinase enzyme is denatured at high temperatures (1) but boiling the apple still has the same effect (1). (2 marks) ( /8 marks)

3a) Drug B- kills pancreatic cells which means even less insulin is produced than before (which is why it only has negative effect on some diabetics) (2 marks)
b) Careful attention to diet (1)
Pancreatic cell transplants (1) (2 marks) ( /4marks)

4a) Cloudy means less light so less photosynthesis (1) so less CO2 used (1) (2 marks)
b) Magnesium (1 mark) ( /3 marks)

5a) 0.18% (2 marks)
b) Heat (1 mark)
c) Shorter food chains more efficient as there are less energy losses (1). Heron only gets 2 out of the 25,000kJ of energy absorbed (1). (2 marks)
d) Microorganisms consume the dead animals and plants (1) causing decay. They then used the biomass for respiration (1) which released carbon dioxide into the atmosphere (1)- replacing CO2. CO2 then used in photosynthesis (1) to be returned to the food chain. (3 marks only) ( / 9marks)

6a) Water moves through the semi-permeable membrane by osmosis (1) (from the dilute solution to the more concentrated sugar solution(1)) causing the solution level to rise (1). (3 marks)
b) Would still increase (1) but at a slower rate the solution is less concentrated so smaller concentration gradient (1). (2 marks) ( / 5marks)

7a) Gene (1 mark)
ii) Ribosomes (1 mark)
b) A combination of three bases (1) codes for different amino acids (1). Amino acids then join together to create the protein which codes for blue eyes (1) (3 marks)
c) Different amino acids in structure (1 mark)
ii) Different coloured eyes (1 mark) ( /7 marks)

8) Bone marrow (advantages) (5 marks)
Does not kill embryos (1)
It is a simple operation (1)
Can still cure heart and blood diseases (1) and futire possibilities (1)
Embryonic stem cells (advantages):
Is not painful to patient (1)
Can develop into any type of cell so can cure more diseases (1)
Conclusion (1) ( /5 marks)

How sure are you about the answer highlighted in bold? that's what i put, but i'm not too sure

It sound weird but I can't think of what else it could be- none of my friends have out anything else!

1a) As temperature decreases frostbite occurs quicker (1 mark)
b) 10 minutes (maybe 9??) (1 mark)
1 c) Circle the two actions when body temperature falls. (Shivering and vasoconstriction). (2 marks) ( /5marks)

2a) Control variables- mass of crushed apple/ amount of drops of liquid (1 mark)
b) Drops can be different sizes (volumes) (1 mark)
c) Amylase does not break down cell wall like water (1)
Pectinase enzyme digests cell wall (pectin in the cell wall according to wiki) (1)
Energy in boiling water causes the cell wall to break apart (1) (3 marks)
d) 11.6 cm^3 (1 mark)
ii) Pectinase enzyme is denatured at high temperatures (1) but boiling the apple still has the same effect (1). (2 marks) ( /8 marks)

3a) Drug B- kills pancreatic cells which means even less insulin is produced than before (which is why it only has negative effect on some diabetics) (2 marks)
b) Careful attention to diet (1)
Pancreatic cell transplants (1) (2 marks) ( /4marks)

4a) Cloudy means less light so less photosynthesis (1) so less CO2 used (1) (2 marks)
b) Magnesium (1 mark) ( /3 marks)

5a) 0.18% (2 marks)
b) Heat (1 mark)
c) Shorter food chains more efficient as there are less energy losses (1). Heron only gets 2 out of the 25,000kJ of energy absorbed (1). (2 marks)
d) Microorganisms consume the dead animals and plants (1) causing decay. They then used the biomass for respiration (1) which released carbon dioxide into the atmosphere (1)- replacing CO2. CO2 then used in photosynthesis (1) to be returned to the food chain. (3 marks only) ( / 8marks)

6a) Water moves through the semi-permeable membrane by osmosis (1) (from the dilute solution to the more concentrated sugar solution(1)) causing the solution level to rise (1). (3 marks)
b) Would still increase (1) but at a slower rate the solution is less concentrated so smaller concentration gradient (1). (2 marks) ( / 5marks)

7a) Gene (1 mark)
ii) Ribosomes (1 mark)
b) A combination of three bases (1) codes for different amino acids (1). Amino acids then join together to create the protein which codes for blue eyes (1) (3 marks)
c) Different amino acids in structure (1 mark)
ii) Different coloured eyes (1 mark) ( /7 marks)

8) Bone marrow (advantages) (5 marks)
Does not kill embryos (1)
It is a simple operation (1)
Can still cure heart and blood diseases (1) and futire possibilities (1)
Embryonic stem cells (advantages):
Is not painful to patient (1)
Can develop into any type of cell so can cure more diseases (1)
Conclusion (1) ( /5 marks)

For 4A i put that as the carbon dioxide level was higher than day 2, this was because that it was cloudy so the plants respire more and produced carbon dioxide

I agree with your answers, but 7b you need to refer back to the diagram to get full marks, so you need to include some sort of reference to it.

Plants take in Carbon dioxide don't they?