CAIE A Level Biology 9700 · Energy and respiration
The table below shows the respiratory quotients (RQ) of three different respiratory substrates.
| Substrate | RQ |
|---|---|
| Carbohydrate | 1.00 |
| Lipid (fat) | 0.70 |
| Protein | 0.85 |
A student uses a simple respirometer to investigate the respiration of germinating pea seeds. Outline how the student would use the respirometer to determine the RQ of the seeds and how the value obtained can be used to identify the respiratory substrate(s) being used.
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Outline means: Give the main points briefly. Less detail than describe, but every key step has to be there. One short line per step, in order. The marks are for coverage, not depth.
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