Q. Which one of the following is not true about the light reactions of photosynthesis?
A) Light energy provides energy for the photolysis of water through excitation of the reaction centre of PS-II
B) The flow of electrons from water to NADP in non-cyclic electron transport produces one ATP
C) Reactions of the two photosystems are needed for the reduction of NADP
D) $P_{680}$ and $P_{700}$are the reaction centres of PS-I and PS-II respectively
Explanation
In photosystem-I, the photocentre is a special chlorophyll-a molecule called $P_{700}$, which is active in both red and far-red light, while a very small amount of special from of chlorophyll-a called $P_{680}$, constitutes the reaction centre of photo system-II. PS-II is inactive in far-red light (beyond 680 nm).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.