Why are $C_4$ plants more suited to hot climates than $C_3$ plants?

• A. $C_4$ plants have a higher tolerance for cold temperatures.
• B. $C_4$ plants can perform photosynthesis without sunlight.
• C. $C_4$ plants have a specialized mechanism to minimize photorespiration.
• D. $C_4$ plants require less water than $C_3$ plants.

Answer: (C)

Verified step by step guidance

1. Understand the difference between C3 and C4 photosynthesis: C3 plants use the Calvin cycle for carbon fixation, while C4 plants have an additional step that helps them minimize photorespiration.
2. Recognize that photorespiration is a process where oxygen is taken up and carbon dioxide is released, which can be wasteful for the plant, especially under hot and dry conditions.
3. C4 plants have a specialized mechanism involving a four-carbon compound that efficiently captures carbon dioxide, even when stomata are partially closed to conserve water.
4. This mechanism allows C4 plants to concentrate carbon dioxide in specialized cells, reducing the oxygenation activity of RuBisCO, the enzyme responsible for carbon fixation, thus minimizing photorespiration.
5. In hot climates, where photorespiration is more likely to occur due to higher oxygen levels and closed stomata, C4 plants are more efficient in photosynthesis compared to C3 plants, making them better suited for such environments.