Two equal bundles of mammalian muscle fibres are supplied with glucose. Each bundle is stimulated to complete the same number of contractions in 10 minutes10\ \text{minutes}10 minutes. The contractions of the two bundles have the same total ATP requirement.
The table shows the results.
| Measurement | Bundle A | Bundle B |
|---|---|---|
| oxygen used / μmol\mu\text{mol}μmol | 24.0 | 12.0 |
| carbon dioxide produced / μmol\mu\text{mol}μmol | 24.0 | 12.0 |
| lactic acid produced / μmol\mu\text{mol}μmol | 0.0 | 60.0 |
| glucose used / μmol\mu\text{mol}μmol | 4.0 | 32.0 |
Explain how the results show that bundle B carried out both aerobic respiration and anaerobic respiration.
Explain why bundle B used more glucose than bundle A, even though the contractions had the same total ATP requirement.
The oxygen supply to bundle B is then increased until oxygen is no longer in short supply.
Explain how this change would affect the rate of lactic acid production.
98 exam-style questions on Edexcel GCSE Biology 8.3 Respiration, covering 8.3.1 Aerobic and anaerobic respiration. Each one has a worked solution and a mark scheme showing where the marks go.