Which molecule is reduced to create NADPH during photosynthesis?

During photosynthesis, NADP+ (Nicotinamide adenine dinucleotide phosphate) serves as an essential electron carrier. The process of reducing NADP+ occurs primarily in the light-dependent reactions of photosynthesis. When light energy is captured by chlorophyll, it leads to the excitation of electrons, which are then transferred through a series of proteins in the thylakoid membrane. This flow of electrons ultimately results in the reduction of NADP+ to NADPH by accepting these electrons, along with a proton (H+).

NADPH then acts as a reducing agent in the Calvin cycle (light-independent reactions) where it provides the necessary electrons and hydrogens to help convert carbon dioxide into glucose. This process is critical as NADPH is required for the synthesis of organic molecules during the fixation of carbon.

In contrast, the other molecules listed either do not participate directly in the reduction process of creating NADPH or serve different functions. For example, NADH is primarily involved in cellular respiration and does not play a direct role in photosynthesis. ATP acts as an energy currency, powering various cellular processes without being directly reduced in the same manner as NADP+. FADH2 is also involved in cellular respiration and does not contribute to the