A technician used five similar bean plants. Each plant was kept under controlled conditions, and its rate of photosynthesis was measured as the volume of carbon dioxide taken up per hour.
| Trial | Light intensity in arbitrary units | Carbon dioxide concentration (%) | Temperature (°C) | Carbon dioxide uptake (cm³ h⁻¹) |
|---|---|---|---|---|
| 1 | 100 | 0.04 | 25 | 18 |
| 2 | 400 | 0.04 | 25 | 34 |
| 3 | 400 | 0.10 | 25 | 52 |
| 4 | 400 | 0.10 | 15 | 29 |
| 5 | 400 | 0.10 | 40 | 16 |
Explain the difference in carbon dioxide uptake between trials 1 and 2.
Explain the difference in carbon dioxide uptake between trials 2 and 3.
Explain the differences in carbon dioxide uptake between trials 4, 3 and 5.
87 exam-style questions on Edexcel GCSE Biology 6.1 Photosynthesis, covering 6.1.1 Photosynthetic organisms as producers, 6.1.2a Limiting factors on the rate of photosynthesis, 6.1.2b Interactions of limiting factors on photosynthesis, and 6.1.3 Inverse square law and light intensity. Each one has a worked solution and a mark scheme showing where the marks go.