Question

What factor determines the binding of carbon dioxide to the active site of RuBisCO?

(a) Intensity of sunlight

(b) Number of chloroplasts

(c) Opening and closing of stomata

(d) Relative O2 and CO2 concentration

This question was addressed to me in a national level competition.

My doubt stems from Higher Plants Photosynthesis topic in division Photosynthesis in Higher Plants of Biology – Class 11

Answer 1

The correct option is (d) Relative O2 and CO2 concentration

Easiest explanation: The active site of RuBisCO can bind to both oxygen and carbon dioxide. It has a higher affinity for carbon dioxide. Hence, the relative concentrations of carbon dioxide and oxygen decide the binding of carbon dioxide.