CAIE A Level Biology 9700 · Energy and respiration

Energy and respiration: describe question

Describe5 marksChallenge

Mitochondria isolated from rat liver cells are incubated in a buffer solution containing pyruvate, ADP, and inorganic phosphate. Oxygen is supplied, and the mitochondria are actively respiring.

Describe the process by which the energy released from the oxidation of pyruvate is used to synthesise ATP. In your answer, you should name the stages and their locations, and explain the role of the inner mitochondrial membrane, including the movement of protons and the action of ATP synthase.

0 words · 5 marks

No account needed for your first marks. Your answer is used only to mark it.

How this question is marked

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.

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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