MICROANATOMY

Detailed explanation-1: -The path of electron flow is NADH → NADH dehydrogenase complex → ubiquinone → cytochrome b-c1 complex → cytochrome c → cytochrome oxidase complex → molecular oxygen (O2). The respiratory enzyme complexes couple the energetically favorable transport of electrons to the pumping of H+ out of the matrix.

Detailed explanation-2: -Electrons from NADH enter the electron transport chain in complex I, which consists of nearly 40 polypeptide chains (Figure 10.8). These electrons are initially transferred from NADH to flavin mononucleotide and then, through an iron-sulfur carrier, to coenzyme Q-an energy-yielding process with G°´ =-16.6 kcal/mol.

Detailed explanation-3: -This being said, NADH carries one proton. During oxidative phosphorylation, NADH is oxidized and the electrons are donated to complex I in the electron transport chain while the proton is released in the mitochondrial matrix where it is pumped into the intermembrane space.