<Li> For every NADH and FADH that are produced in the citric acid cycle, 2.5 and 1.5 ATP molecules are generated in oxidative phosphorylation, respectively . </Li> <Li> At the end of each cycle, the four - carbon oxaloacetate has been regenerated, and the cycle continues . </Li> <P> Two carbon atoms are oxidized to CO, the energy from these reactions is transferred to other metabolic processes through GTP (or ATP), and as electrons in NADH and QH . The NADH generated in the citric acid cycle may later be oxidized (donate its electrons) to drive ATP synthesis in a type of process called oxidative phosphorylation . FADH is covalently attached to succinate dehydrogenase, an enzyme which functions both in the CAC and the mitochondrial electron transport chain in oxidative phosphorylation . FADH, therefore, facilitates transfer of electrons to coenzyme Q, which is the final electron acceptor of the reaction catalyzed by the succinate: ubiquinone oxidoreductase complex, also acting as an intermediate in the electron transport chain . </P> <P> The citric acid cycle is continuously supplied with new carbon in the form of acetyl - CoA, entering at step 0 below . </P>

What are the key substrates and products of tca cycle