Biochemistry. The first step in the degradation of carbohydrates to gain energy in the cell. Glycolysis is the initiating metabolic pathway for the degradation of glucose in all living cells. One molecule of glucose (6 C-atoms) is converted into 2 molecules of pyruvate (3 C-atoms), which can be either degraded aerobically in cellular respiration (end products carbon dioxide and water) or fermented. Energy is gained in form of 2 ATP and 2 NADH per molecule of glucose in the glycolytic pathway.