How does rubisco "decide" whether to act as an oxygenase or a carboxylase? A) Rubisco has 10 times more affinity for O₂ than CO₂; therefore, it favors O₂ fixation. B) If O₂ is relatively abundant, rubisco acts as a carboxylase. C) If O₂ predominates, rubisco fixes it and the Calvin-Benson cycle occurs. D) Photorespiration is more likely at low temperatures. E) As the ratio of CO₂ to O₂ falls in the leaf, the reaction of rubisco with O₂ is favored, and photorespiration proceeds.

Question

Quizplus · Accepted Answer

Rubisco's activity is influenced by the relative concentrations of CO2 and O2. When the ratio of CO2 to O2 decreases, rubisco is more likely to fix O2, leading to photorespiration.

How Does Rubisco "Decide" Whether to Act as an Oxygenase