Here's why:
* NAD+ is a key electron carrier: It plays a crucial role in both glycolysis and the Krebs cycle, accepting electrons (and essentially hydrogens) from the breakdown of glucose.
* Reduced to NADH: When NAD+ accepts a hydrogen ion (H+) and two electrons, it is reduced to NADH.
* Electron transport chain: NADH carries these electrons to the electron transport chain, where they are used to generate a proton gradient that powers ATP synthesis (the process of making energy).
While other coenzymes like FAD (flavin adenine dinucleotide) also participate in accepting hydrogens, NAD+ plays a far more central role in the overall process of aerobic respiration.
