How are coenzymes used in the process of aerobic respiration?

Coenzymes contrary to their name aren't enzymes but are synthesised from vitamins. Their overall purpose is to bind to the active site of a specific enzyme to aid the binding of the complemenatry substrate, so therefore without them the enzyme wouldn't be able to fulfill it's purpose.

Coenzymes are reversibly oxidised and reduced with a loss and gain of hydrogen. In Glycolysis, the link reaction and the Krebs cycle the coenzmyes FAD and NAD are reduced; gaining the hydrogens given off by organic molecules (compounds made from carbon and hydrogen) being broken down by enzymes. Then once we reach oxidative phosphorylation these coenzymes are reoxidised by electron carriers in the inner membrane of the mitochondria. This released 'energy' which allows the electron carriers to actively pump H+ ions across the inner membrane into the intermembrane space of the mitochondria, creating a proton gradient which drives ATP synthase to produce ATP. These reoxidised NAD and FAD molecules are then recycled back to the beginning of the process in glycolysis allowing the aerobic respiration cycle to occur once again. Coenzymes like NAD and FAD allow this process to continue repeatedly as long as there is oxygen present.