Q. If photosynthesising, green algae are provided with $CO_{2}$ labelled with an isotope of oxygen $(O^{18})$, later analysis showed that all of the following compounds produceds by the algae contains $\ ^{18}O$ except
A) PGA
B) RuBP
C) Glucose
D) $O_{2}$
Explanation
Oxygen evolved by the splitting of $H_{2}O$ $2H_{2}O \rightarrow 4H^{+} + 4e^{-} + O_{2}$ So, the isotopic oxygen $(O^{18})$ molecule in ${CO}_{2}$ will be incorporated into the PGA, RuBP, glucose. Isotopic $O^{18}$ is not found in oxygen liberation
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.