A horse runs up a steep slope. In some leg muscle cells, oxygen is being used faster than it can be delivered, so the cells respire anaerobically.
Which statement best explains why more glucose is needed than during aerobic respiration to make the same number of ATP molecules?
A large proportion of the chemical energy remains in the lactic acid formed.
Oxygen normally adds chemical energy to each glucose molecule before respiration.
Anaerobic respiration transfers all the energy from glucose as heat.
The glucose molecules contain less energy when the oxygen supply decreases.
92 exam-style questions on AQA GCSE Biology 4.2 Respiration, covering 4.2.1 Aerobic and anaerobic respiration, 4.2.2 Response to exercise, and 4.2.3 Metabolism. Each one has a worked solution and a mark scheme showing where the marks go.