Question

Which one of the following is electron donor to $P_{680}$ during light reactions of photosynthesis?

• A. NADPH
• B. Phytochrome
• C. Chlorophyll
• D. Water

Answer 1

The correct option is D Water

Light reactions of photosynthesis occurs in thylakoid membranes. The end products are NADPH and ATP. During light reactions, photolysis of water takes place, which leads to release of electrons and these electrons can be taken by $P_{680}$, active center of photo system II. Thus, water is electron donor to $P_{680}$ during light reactions of photosynthesis. So, option D is correct and other options are incorrect.