SOLUTIONS
AQA CORE Science Biology - Diagnosis Test – Carbon Cycle SOLUTIONS (15 marks)
1. What conversion in carbon occurs in combustion? (circle the correct answer)
A.
B.
C.
D.
Carbon dioxide to fuel
Glucose to carbon dioxide
Fuel to glucose
Carbon dioxide to glucose
(1mark)
2. Fill in the gaps:
The carbon from carbon dioxide is used to make carbohydrates, fats and proteins to make up the
body of plants.
plants
carbon dioxide
protein
amino acid
carbon
microbes
(3 mark)
3.
What is chalk formed from and how does it contribute to the release of carbon dioxide?



Chalk is formed from fossilised sea creatures.
Rain water is slightly acidic and this reacts with the chalk and releases carbon dioxide.
Metals below carbon can be extracted by reduction using carbon, coke, or charcoal.
(3 marks)
4.
What are the two products of respiration?
Carbon dioxide and water
(2 marks)
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5. QWC: Describe how living things are involved in the constant cycling of carbon in nature.
QWC Suggested marking guidance (Total 6 marks)
Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the
standard of the scientific response. Teachers should apply a ‘best-fit’ approach to the marking.
0 marks
No relevant
content.
Level 1 (1-2 marks)
Level 2 (3-4 marks)
Level 3 (5-6 marks)
One process discussed.
The spelling, punctuation
and grammar are very
weak.
The organisms named in at least two
processes.
There is reasonable accuracy in
spelling, punctuation and grammar,
although there may still be some
errors
All processes discussed.
The answer shows almost faultless
spelling, punctuation and grammar.
Photosynthesis:

green plants and algae remove CO2 from the atmosphere – passed on when plants are eaten. Plants use CO2
to make carbohydrates, fats and proteins.
Carbon dioxide + water  glucose + oxygen
Respiration:

living organisms use oxygen to break down glucose CO2 is a waste product. Decomposers respire too
Glucose + oxygen  carbon dioxide + water
Combustion:

fossil fuels contain carbon, when we burn then CO2 is produced
Fuel + oxygen  carbon dioxide + water
(6 marks)
1
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