What are the light-dependent reactions of photosynthesis responsible for?

What are the light-dependent reactions of photosynthesis responsible for?

• A. Producing oxygen as the primary product.
• B. They are responsible for the production of ATP and NADPH.
• C. They capture carbon dioxide from the air.
• D. They store energy in glucose.

Answer: (B)

The light-dependent reactions are about turning light energy into chemical energy that the cell can use later. In these reactions, energy from absorbed light drives electrons through an electron transport chain in the thylakoid membranes. This flow of electrons powers the pumping of protons across the membrane, creating a proton gradient that ATP synthase uses to synthesize ATP. Electrons are also transferred to NADP+, forming NADPH. Water is split to replace the electrons, releasing oxygen gas as a byproduct. The ATP and NADPH produced here are then used in the Calvin cycle to fix carbon and ultimately make glucose. So the main outputs of the light-dependent reactions are ATP and NADPH, with oxygen released as a byproduct.

The light-dependent reactions are about turning light energy into chemical energy that the cell can use later. In these reactions, energy from absorbed light drives electrons through an electron transport chain in the thylakoid membranes. This flow of electrons powers the pumping of protons across the membrane, creating a proton gradient that ATP synthase uses to synthesize ATP. Electrons are also transferred to NADP+, forming NADPH. Water is split to replace the electrons, releasing oxygen gas as a byproduct. The ATP and NADPH produced here are then used in the Calvin cycle to fix carbon and ultimately make glucose. So the main outputs of the light-dependent reactions are ATP and NADPH, with oxygen released as a byproduct.