In the context of the pigments of photosynthesis, what role does chlorophyll play in the light-dependent reactions?

• A. It serves as the primary enzyme that reduces NADP+ to NADPH in the stroma.
• B. It splits glucose to release energy for the synthesis of ATP in chloroplasts.
• C. It absorbs photons and excites electrons, initiating electron transport and conversion of light energy to chemical energy.
• D. It fixes atmospheric CO2 into carbohydrates by catalyzing the Calvin cycle.

Answer: (C)

Verified step by step guidance

1. Understand that chlorophyll is a pigment molecule located in the thylakoid membranes of chloroplasts, primarily responsible for capturing light energy.
2. Recognize that during the light-dependent reactions of photosynthesis, chlorophyll absorbs photons (light energy), which excites its electrons to a higher energy state.
3. Note that these high-energy electrons are then transferred to the electron transport chain, initiating a series of redox reactions that convert light energy into chemical energy stored in ATP and NADPH.
4. Clarify that chlorophyll itself is not an enzyme and does not directly reduce NADP+ to NADPH; instead, it facilitates the initial step of electron excitation.
5. Distinguish chlorophyll's role from other processes: it does not split glucose or fix CO2; those functions occur in other parts of photosynthesis (glycolysis and the Calvin cycle, respectively).