<Li> 2 NADH + H from glycolysis: 2 × 1.5 ATP (if glycerol phosphate shuttle transfers hydrogen atoms) or 2 × 2.5 ATP (malate - aspartate shuttle) </Li> <Li> 2 NADH + H from the oxidative decarboxylation of pyruvate and 6 from Krebs cycle: 8 × 2.5 ATP </Li> <Li> 2 FADH from the Krebs cycle: 2 × 1.5 ATP </Li> <P> Altogether this gives 4 + 3 (or 5) + 20 + 3 = 30 (or 32) ATP per molecule of glucose </P>

Where does the glucose come from that is metabolized in cellular respiration