Which enzyme is critical for the production of ATP during oxidative phosphorylation?

ATP synthase is essential for the production of ATP during oxidative phosphorylation, which occurs in the mitochondria. This enzyme couples the energy derived from the electron transport chain to the synthesis of ATP from ADP and inorganic phosphate (Pi). As electrons are transferred through the complexes of the electron transport chain, protons are pumped across the mitochondrial membrane, creating a proton gradient. This gradient generates a potential energy difference across the membrane, known as the proton motive force.

ATP synthase harnesses this stored energy as protons flow back into the mitochondrial matrix through the enzyme, leading to the phosphorylation of ADP into ATP. This process is integral to cellular respiration, enabling cells to generate a significant amount of ATP, which fuels various cellular activities. Without ATP synthase, the conversion of the energy stored in the proton gradient into usable energy in the form of ATP would not occur efficiently.