A technician grows equal quantities of algae in transparent culture vessels at 25 ∘C25\ ^\circ\text{C}25 ∘C. Gas containing either 0.04% or 0.20% carbon dioxide is bubbled through the cultures.
The technician changes the light intensity and measures the volume of oxygen produced each minute.
| Light intensity (lux) | Rate at 0.04% carbon dioxide (cm3 min−1\text{cm}^3\ \text{min}^{-1}cm3 min−1) | Rate at 0.20% carbon dioxide (cm3 min−1\text{cm}^3\ \text{min}^{-1}cm3 min−1) |
|---|---|---|
| 1000 | 0.8 | 0.8 |
| 2000 | 1.6 | 1.6 |
| 4000 | 2.4 | 3.2 |
| 8000 | 2.4 | 5.6 |
The technician concludes that making the lamps still brighter will continue to increase the rate of photosynthesis in both cultures.
Evaluate the technician's conclusion. Use the results and your knowledge of limiting factors.
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.