A scientist grows two groups of seedlings in mineral solutions.
Group C receives a complete mineral solution. Group M receives the same solution but without magnesium ions.
After three weeks, the scientist measures the chlorophyll concentration and the rate of oxygen production from 100 cm2 of leaves from each group. Both groups are measured at the same temperature and carbon dioxide concentration and in bright light.
| Group | Chlorophyll concentration in leaves (μg cm−2\mu\text{g cm}^{-2}μg cm−2) | Rate of oxygen production (cm3 h−1\text{cm}^3\ \text{h}^{-1}cm3 h−1) |
|---|---|---|
| C | 32 | 6.4 |
| M | 8 | 1.6 |
Explain the difference in the rate of oxygen production between groups C and M.
The scientist then adds magnesium ions to the solution for group M. After new leaves have grown, the scientist repeats the measurement using the same method.
Predict how the rate of oxygen production by group M will change. Justify your prediction.
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.