AP BIOLOGY

Detailed explanation-1: -NADH (electron carrier) is the reduced form of NAD+ (which is an electron acceptor) and can be generated from glycolysis and other metabolic pathways. NADH is used to make lots of ATP via electron transport chain (ETC) and oxidative phosphorylation.

Detailed explanation-2: -Complex I (NADH dehydrogenase) is the first enzyme in the respiratory chain. It catalyses the electron transfer from NADH to ubiquinone that is associated with proton pumping out of the matrix.

Detailed explanation-3: -The electron transport in the inner membrane of the mitochondria is a series of protein complexes that receive electrons from NADH and FADH2. Transferring electrons through the protein complexes results in the pumping of protons into the inner membrane space, and the final acceptor is oxygen, generating water.

Detailed explanation-4: -NADH is the electron donor for the electron transport chain. The first complex to accept the donated electrons is NADH dehydrogenase.