of NAD so that the glycolysis chain of reactions can keep going, fermentation leaves much of the glucose molecule's original energy untapped.
Where oxygen is available, oxygen rather than pyruvic acid can act as the ultimate acceptor of electrons from NADre. Thus pyruvic acid can be further broken
down to yield more energy for the production
of new ATP. This continued breakdown under aerobic conditions occurs into two stages: the oxidation of pyruvic acid to acetyl-CoA and the oxygen-requiring reactions of the Krebs citric acid cycle. Unlike anaerobic metabolism, the aerobic stages in the breakdown of glucose occur within a cell's mitochondria; however, like the
