CAIE A Level Biology 9700 · Energy and respiration
A student used a simple respirometer to investigate the respiration of germinating mung bean seeds at 25°C. Over a 40-minute period, the total volumes were: oxygen absorbed = 5.4 cm³, carbon dioxide released = 4.6 cm³. Describe the features of ATP that make it a suitable universal energy currency. Explain how the respiratory quotient (RQ) would be found from these data, and use its value to describe the likely respiratory substrates being used by the seeds.
4 marks, so the mark scheme is looking for about 4 separate creditworthy points. Making the same point twice in different words earns it once.
Describe means: Say what happens or what something is like, in order and with detail. You are not being asked why. If there is data, quote it: name the trend, then give figures with units at the points where it changes.
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