What is the role of NADP in the light reactions?

NADP plays a crucial role in the light reactions of photosynthesis by acting as the final electron acceptor in the electron transport chain. During the light reactions, chlorophyll absorbs sunlight, which energizes electrons. These high-energy electrons are passed along a series of proteins, known as the electron transport chain, where their energy is used to pump protons into the thylakoid lumen, creating a proton gradient that ultimately drives the synthesis of ATP through ATP synthase.

At the end of this transport process, NADP accepts the electrons along with protons (H+) to form NADPH. This conversion is essential because NADPH serves as a reducing agent, providing the high-energy electrons required for the Calvin cycle, which is responsible for synthesizing glucose from carbon dioxide.

The other options do not accurately describe the function of NADP during the light reactions. While NADP does accept electrons, it is not involved in ATP synthesis directly (which is primarily the role of ATP synthase). Moreover, the metabolism of carbon dioxide occurs in the Calvin cycle, not in the light reactions, and electrons don’t get donated to the electron transport chain; instead, they are moved through the chain, culminating in their transfer to NADP. Thus, the defining