Which molecule acts as a high-energy electron carrier produced during the light reactions?

Which molecule acts as a high-energy electron carrier produced during the light reactions?

• A. NADPH
• B. ATP
• C. ADP
• D. NADP+

Answer: (A)

During the light-dependent reactions, energy from light drives electrons through the photosynthetic electron transport chain and ultimately reduces NADP+ to NADPH. This NADPH is a high-energy electron carrier because it holds energized electrons that can be donated in the next stage of photosynthesis to power the reduction of carbon dioxide in the Calvin cycle. NADP+ is the oxidized form that accepts electrons; ATP is produced to provide energy for various steps, but it does not carry electrons. ADP is simply the lower-energy precursor to ATP. So, NADPH is the molecule that acts as the high-energy electron carrier produced during the light reactions.

During the light-dependent reactions, energy from light drives electrons through the photosynthetic electron transport chain and ultimately reduces NADP+ to NADPH. This NADPH is a high-energy electron carrier because it holds energized electrons that can be donated in the next stage of photosynthesis to power the reduction of carbon dioxide in the Calvin cycle. NADP+ is the oxidized form that accepts electrons; ATP is produced to provide energy for various steps, but it does not carry electrons. ADP is simply the lower-energy precursor to ATP. So, NADPH is the molecule that acts as the high-energy electron carrier produced during the light reactions.