Oxidative phosphorylation is

(d) : Oxidative phosphorylation is the synthesis of energy rich \(ATP\) molecules with the help of energy liberated during oxidation of reduced co­enzymes \((NADH, FADH_2)\) produced in respiration.The enzyme required for this synthesis is called \(ATP\) synthase. It is located in \(F_1\) or head piece of \(F_0 -F_1\) or elementary particles present in the inner mitochondrial membrane. \(F_1\) particle is capable of \(ATP\) synthesis. \(ATP\) synthase becomes active in \(ATP\) formation only when there is a proton gradient having higher concentration of \(H^+\) or protons on the \(F_0\) side as compared to \(F_1\) side.This higher concentration creates an electric potential across the mitochondrial membrane. The proton gradient and membrane electric potential together form proton motive force \((PMF)\). The flow of protons through the \(F_0\) channel which induces \(F_1\) particle to function as \(ATP\) synthase. The energy of the proton gradient is used in attaching a phosphate radicle to \(ADP\) by high­energy bond. This produces \(ATP.\)