Which enzyme synthesizes ATP during oxidative phosphorylation?

ATP synthase is the enzyme responsible for synthesizing ATP during oxidative phosphorylation, which occurs in the mitochondria of eukaryotic cells. This process is a key part of cellular respiration, where energy stored in the form of a proton gradient across the inner mitochondrial membrane is harnessed to convert adenosine diphosphate (ADP) and inorganic phosphate into ATP.

During oxidative phosphorylation, electrons are transferred through a series of protein complexes in the electron transport chain, ultimately leading to the pumping of protons from the mitochondrial matrix into the intermembrane space. This creates an electrochemical gradient, also known as the proton motive force. ATP synthase utilizes this proton motive force as protons flow back into the matrix through the enzyme, driving the phosphorylation of ADP to form ATP.

Other enzymes listed do not participate in ATP synthesis during oxidative phosphorylation. Hexokinase is involved in the glycolytic pathway, catalyzing the phosphorylation of glucose to glucose-6-phosphate. Pyruvate kinase is also part of glycolysis, catalyzing the conversion of phosphoenolpyruvate to pyruvate while generating ATP in the process. Citrate synthase plays a role in the citric acid cycle, catalyzing the formation of