What role do NADH and FADH2 play in aerobic respiration?

NADH and FADH2 play a critical role in aerobic respiration as carriers of electrons. During the processes of glycolysis, the citric acid cycle (Krebs cycle), and the oxidation of fatty acids, these coenzymes are produced when nutrients such as glucose and fatty acids are metabolized. Specifically, they are generated during the reduction of NAD+ to NADH and FAD to FADH2.

These reduced forms, NADH and FADH2, then donate their high-energy electrons to the electron transport chain, a series of protein complexes located in the inner mitochondrial membrane. As the electrons move through this chain, they undergo a series of redox reactions, creating a proton gradient across the membrane. This gradient is crucial for ATP production, as protons flow back into the mitochondrial matrix through ATP synthase, driving the conversion of ADP and inorganic phosphate into ATP.

The role of NADH and FADH2 in carrying electrons is essential for the overall efficiency of cellular respiration, allowing the cell to harness the energy stored in nutrients and convert it into a usable form, ATP. Without these electron carriers, the processes of aerobic respiration would be significantly impaired, leading to decreased energy production.