AP BIOLOGY

Detailed explanation-1: -The energy released by reactions of oxygen and reduced compounds such as cytochrome c and (indirectly) NADH and FADH2 is used by the electron transport chain to pump protons into the intermembrane space, generating the electrochemical gradient over the inner mitochondrial membrane.

Detailed explanation-2: -NADH is the electron donor in this system. It initiates the electron transport chain by donating electrons to NADH dehydrogenase (blue). 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.

Detailed explanation-3: -The energy generated from the oxidation of NADH to NAD+ and the transfer of electrons through the redox reactions is used to transfer protons from the mitochondrial matrix to the intermembrane space.

Detailed explanation-4: -The nitrogenous base in NADH has one more hydrogen ion and two more electrons than in NAD+. NAD+ is used by the cell to “pull” electrons off of compounds and to “carry” them to other locations within the cell; thus it is called an electron carrier.

Detailed explanation-5: -The electrons flow through the electron transport chain, causing protons to be pumped from the matrix to the intermembrane space.