Question

Photorespiration is favoured by:

• A. high $O _{2}$ and low $CO _{2}$
• B. high $CO _{2}$ and low $O _{2}$
• C. high temperature and low $O_{2}$
• D. high humidity and temperature

Answer 1

Answer: (A)

high $O _{2}$ and low $CO _{2}$

Answer 2

Oxygen is a competitive inhibitor of $CO _{2}$ fixation. Increase in $O _{2}$ concentration would favour the uptake of oxygen by Rubisco leading to increase in photorespiration.