How is NADH related to cellular respiration and photosynthesis?

NADH is a crucial electron carrier in both cellular respiration and photosynthesis. In cellular respiration, it is produced during glycolysis and the citric acid cycle, where it stores energy by transferring electrons to the electron transport chain, ultimately leading to ATP production. In photosynthesis, NADH is generated in the light-dependent reactions and used in the Calvin cycle to help convert carbon dioxide into glucose, thereby linking energy capture to carbon fixation. Both processes highlight NADH's role in energy metabolism and the transfer of electrons.