A student measures the rate of photosynthesis of a plant at different carbon dioxide concentrations and at two temperatures. The light intensity is high and is kept the same throughout. The table shows the results. Table
| Carbon dioxide concentration in % | 0.02 | 0.04 | 0.06 | 0.08 | 0.10 |
|---|---|---|---|---|---|
| Rate of photosynthesis at 15 ∘C15\ ^\circ\text{C}15 ∘C in arbitrary units | 12 | 20 | 24 | 24 | 24 |
| Rate of photosynthesis at 25 ∘C25\ ^\circ\text{C}25 ∘C in arbitrary units | 12 | 22 | 32 | 40 | 41 |
| Which statement explains the results at 0.02% carbon dioxide? |
Temperature is limiting the rate at both 15 ∘C15\ ^\circ\text{C}15 ∘C and 25 ∘C25\ ^\circ\text{C}25 ∘C.
Temperature is limiting the rate at 15 ∘C15\ ^\circ\text{C}15 ∘C but not at 25 ∘C25\ ^\circ\text{C}25 ∘C.
Carbon dioxide concentration is limiting the rate at both temperatures.
Light intensity is limiting the rate at both temperatures.
117 exam-style questions on OCR GCSE Biology 1.4 Photosynthesis, covering 1.4.1 Photosynthesisers as biomass producers, 1.4.2 Factors affecting the rate of photosynthesis, and 1.4.3 Limiting factors in photosynthesis. Each one has a worked solution and a mark scheme showing where the marks go.