The TCA cycle can be used for the complete oxidation of organic carbon in respiring organisms. This is obvious by observing that one full "turn" of the cycle releases molecules of .

The TCA cycle can be used for the complete oxidation of organic carbon in respiring organisms. This is obvious by observing that one full "turn" of the cycle releases molecules of NADH.

Explanation:

The second energy-rich molecule of cellular metabolism is NADH, it is the oxidized form of NAD+. The assessment of the energy that is released and stored during glycolysis contains the two NADH molecules that are formed in the catalysis of glyceraldehyde-3-P. The conversion of pyruvate in the six molecules into the final product of CO2 during the end of the TCA cycle causes eight other NADH molecules to be produced inside the mitochondria.