Which process produces NADH while using NAD+?

The process that produces NADH while utilizing NAD+ encompasses both glycolysis and the Krebs cycle.

In glycolysis, glucose is broken down into pyruvate, and during this conversion, electrons are transferred to NAD+, reducing it to NADH. This reaction is critical as it captures energy that will later be harnessed in aerobic respiration.

Similarly, in the Krebs cycle, which occurs in the mitochondrial matrix, further oxidation of acetyl-CoA takes place. During this cycle, several reactions facilitate the reduction of NAD+ to NADH as various substrates, including citrate, isocitrate, and alpha-ketoglutarate, undergo dehydrogenation. This reduction process is essential for energy production, as NADH will later donate electrons to the electron transport chain, contributing to ATP synthesis.

Thus, both glycolysis and the Krebs cycle are integral metabolic pathways that generate NADH while utilizing NAD+, emphasizing their roles in cellular energy metabolism.