Question

Optimum temperature conditions for photosynthesis in $C_{3}$ and $C_{4}$ plants are respectively

• A. $10^\circ C-25^\circ C$ and $30^\circ C-45^\circ C$
• B. $30^\circ C-45^\circ C$ and $10^\circ C-25^\circ C$
• C. $0^\circ C-10^\circ C$ and $10^\circ C-30^\circ C$
• D. $25^\circ C-30^\circ C$ and $40^\circ C-50^\circ C$

Answer 1

Answer: (A)

Active site of $RuBisCO$ for carboxylation and oxygenation is the same. The enzyme has more affinity for $CO_{2}$ as compared to oxygen. Active oxygenation occurs only when $CO_{2} : O_{2}$ ratio favours it.