The net yield of ATP molecules in the complete oxidation of one molecule of glucose via the citric acid cycle and oxidative phosphorylation is approximately 30-32 ATP molecules. The breakdown of the process is as follows:1. Glycolysis: 2 ATP net and 2 NADH2. Pyruvate decarboxylation: 2 NADH3. Citric acid cycle: 6 NADH, 2 FADH2, and 2 ATP4. Oxidative phosphorylation: 10 NADH 2.5 ATP/NADH = 25 ATP, and 2 FADH2 1.5 ATP/FADH2 = 3 ATPTotal ATP yield: 2 glycolysis + 2 citric acid cycle + 25 oxidative phosphorylation from NADH + 3 oxidative phosphorylation from FADH2 = 32 ATPHowever, the yield can vary between 30-32 ATP molecules depending on the efficiency of the transport of NADH from glycolysis into the mitochondria.The mechanism of ATP synthesis during oxidative phosphorylation is known as chemiosmosis. In this process, the energy derived from the transfer of electrons through the electron transport chain ETC is used to pump protons H+ across the inner mitochondrial membrane from the matrix to the intermembrane space. This creates an electrochemical gradient, known as the proton motive force PMF .ATP synthesis occurs when protons flow back down this gradient through a protein complex called ATP synthase. The flow of protons through ATP synthase drives the rotation of its subunits, which in turn catalyzes the phosphorylation of ADP to form ATP. This process is known as the chemiosmotic coupling of electron transport and ATP synthesis.