A student measures the rate of photosynthesis of pondweed at different temperatures. Above 40 ∘C40\ ^\circ\text{C}40 ∘C, the rate of photosynthesis falls quickly. Which statement explains this?
Carbon dioxide cannot dissolve in water above this temperature.
The enzymes that control photosynthesis are denatured.
Chlorophyll absorbs more light than the cells can use.
Light energy is changed into heat energy instead of glucose.
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.