🧪 Part 1: Multiple Choice & Analysis

1. Which factor would have the GREATEST limiting effect on photosynthesis in a greenhouse at 35°C with bright artificial lights?

Temperature

Light intensity

Carbon dioxide concentration

Water availability

2. A student measures oxygen production in aquatic plants at different light intensities. At which point would the rate of photosynthesis plateau?

When light becomes the limiting factor

When CO₂ or temperature becomes the limiting factor

When all chloroplasts are damaged

When water temperature drops below 10°C

3. Which of these adaptations would you expect in plants from shaded forest floors? (Select all that apply)

Larger leaves with more chlorophyll

Thicker waxy cuticles

More efficient light-harvesting complexes

Reduced number of stomata

4. The light-independent reactions of photosynthesis occur in the _____________ and require _____________ from the light-dependent reactions.

a) _____________ b) _____________

📝 Part 2: Application & Explanation

5. A farmer notices that crop yield decreases significantly during a particularly hot summer (average 38°C). Using your knowledge of photosynthesis, explain why high temperatures reduce plant productivity.

6. Compare and contrast the light-dependent and light-independent reactions of photosynthesis. Include location, inputs, outputs, and energy requirements.

7. A student investigates the effect of CO₂ concentration on photosynthesis using pondweed. Describe how you would set up this experiment and identify two variables that must be controlled.

🔬 Part 3: Analysis & Evaluation

8. Explain why C4 plants (like maize) are more efficient than C3 plants (like wheat) in hot, dry conditions. Include reference to photorespiration in your answer.

9. A greenhouse owner wants to maximise photosynthesis rates. Suggest three environmental modifications they could make and justify each suggestion using scientific principles.

10. In the space below, draw and label a chloroplast showing where the light-dependent and light-independent reactions occur. Include at least 4 key structures.