Describe what happens in glycolysis.

Glycolysis takes place in the cytoplasm and comprises two stages: phosphorylation and oxidation. In phosphorylation, glucose is phosphorylated using two molecules of ATP to form glucose phosphate and then hexose bisphosphate. Hexose bisphosphate is split into two molecules of triose phosphate. In oxidation, the two molecules of triose phosphate are then oxidised (they each lose a hydrogen ion) to form two molecules of pyruvate. NAD collects the H+ ions to form two molecules of reduced NAD (NADH) and four molecules of ATP are also produced by substrate-level phosphorylation. The overall yield of glycolysis is 2ATP and 2NADH per glucose molecule.