AP BIOLOGY

Detailed explanation-1: -After a photon hits the photosystem II (PSII) reaction center, energy from sunlight is used to extract electrons from water. The electrons travel through the chloroplast electron transport chain to photosystem I (PSI), which reduces NADP+ to NADPH (Figure 3).

Detailed explanation-2: -photosynthetic NADP+ reduction The light reactions of photosynthesis use energy from photons to generate high-energy electrons. These electrons are used directly to reduce NADP+ to NADPH. NADPH is a relatively stable molecule and can pass on its hydrogen atom to other molecules in chemical reactions.

Detailed explanation-3: -NADP+ is reduced during the light-dependent reactions of photosynthesis. NADP+ is an electron carrier that accepts high-energy electrons and transports them to the Calvin cycle where they will be used to reduce carbon dioxide and produce organic molecules.

Detailed explanation-4: -NADPH will travel to the Calvin cycle, where its electrons are used to build sugars from carbon dioxide. The other ingredient needed by the Calvin cycle is ATP, and this too is provided by the light reactions.

Detailed explanation-5: -The reaction center chlorophyll of photosystem I transfers its excited electrons through a series of carriers to ferrodoxin, a small protein on the stromal side of the thylakoid membrane. The enzyme NADP reductase then transfers electrons from ferrodoxin to NADP+, generating NADPH.