Which statement best explains the effect of temperature on the rate of photosynthesis?

• A. The rate of photosynthesis is highest at very low temperatures.
• B. The rate of photosynthesis is not affected by temperature changes.
• C. The rate of photosynthesis increases with temperature up to an optimum point, after which it decreases due to enzyme denaturation.
• D. The rate of photosynthesis decreases steadily as temperature increases.

Answer: (C)

Verified step by step guidance

1. Understand the relationship between temperature and enzyme activity: Photosynthesis relies on enzymes like Rubisco to catalyze reactions. Enzymes are sensitive to temperature changes, which can affect their efficiency.
2. Recognize the concept of an optimum temperature: Enzymes function best within a specific temperature range, known as the optimum temperature. Below this range, enzyme activity is slower due to reduced molecular movement, and above this range, enzymes may denature and lose functionality.
3. Analyze the effect of increasing temperature: As temperature rises, molecular collisions increase, leading to a higher rate of enzyme activity and, consequently, a higher rate of photosynthesis. This continues until the optimum temperature is reached.
4. Understand enzyme denaturation: Beyond the optimum temperature, excessive heat can cause enzymes to lose their three-dimensional structure (denaturation), reducing their ability to catalyze reactions and decreasing the rate of photosynthesis.
5. Conclude that the rate of photosynthesis increases with temperature up to an optimum point, after which it decreases due to enzyme denaturation. This explains why the correct answer is: 'The rate of photosynthesis increases with temperature up to an optimum point, after which it decreases due to enzyme denaturation.'