The stepwise oxidation of sugars begins with glycolysis. Each of the 10 steps of glycolysis is catalyzed by a different enzyme. Note that step 4 cleaves a six-carbon sugar into two three-carbon sugars, so that the number of molecules at every stage after this doubles. As indicated, step 6 begins the energy-generation phase of glycolysis, which causes the net synthesis of ATP and NADH molecules. (See 10 steps of glycolysis for a more detailed diagram). Glycolysis is also sometimes referred to Embden-Meyerhof pathway.  Fair Use and Copyright info