Oxidative phosphorylation occurs in the electron transport chain, where the high-energy electrons generated during the citric acid cycle also known as the Krebs cycle or TCA cycle are used to produce ATP.Starting with one molecule of acetyl-CoA in the citric acid cycle, the following high-energy molecules are produced:1. 3 molecules of NADH each produced during the isocitrate dehydrogenase, -ketoglutarate dehydrogenase, and malate dehydrogenase reactions 2. 1 molecule of FADH2 produced during the succinate dehydrogenase reaction 3. 1 molecule of GTP produced during the succinyl-CoA synthetase reaction In the electron transport chain, each NADH molecule generates approximately 2.5 ATP molecules, and each FADH2 molecule generates approximately 1.5 ATP molecules. The GTP molecule can be converted to ATP through substrate-level phosphorylation.So, the net number of ATP molecules generated through oxidative phosphorylation starting with one molecule of acetyl-CoA in the citric acid cycle is: 3 NADH 2.5 ATP/NADH + 1 FADH2 1.5 ATP/FADH2 + 1 GTP= 7.5 ATP + 1.5 ATP + 1 ATP= 10 ATP molecules