MUSCLE PHYSIOLOGY

Detailed explanation-1: -One reaction of glycolysis removes 4 high-energy electrons, passing them to an electron carrier called NAD+. Each NAD+ accepts a pair of high-energy electrons and becomes an NADH molecule. The NADH molecule holds the electrons until they can be transferred to other molecules.

Detailed explanation-2: -As a result, there is a net gain of two ATP molecules during glycolysis. During this stage, high-energy electrons are also transferred to molecules of NAD+ to produce two molecules of NADH, another energy-carrying molecule.

Detailed explanation-3: -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-4: -NADH donates two electrons to NADH dehydrogenase. At the same time, the complex also pumps two protons from the matrix space of the mitochondria into the intermembrane space. The two electrons are now transferred to the mobile carrier protein known as ubiquinone.