Describe the process of glycolysis

Glycolysis is the first of four steps in cellular respiration, and involves the breakdown of one glucose molecule into two molecules of pyruvate. A 6C glucose molecule is first phosphorylated, using the phosphate from two molecules of ATP, to form hexose bisphosphate. Hexose bisphosphate splits into two molecules of triose phosphate, each of which are then oxidised to pyruvate. This oxidation step involves the removal of hydrogen atoms and phosphate groups from the triose phosphate, producing reduced NAD (NADH) and two molecules of ATP, respectively. As there are two triose phosphate molecules in total, a net gain of two ATP molecules and two NADH molecules is seen. In anaerobic respiration, respiration ceases at this point, with an overall gain of two ATP molecules. However, in aerobic respiration, the pyruvate and NADH molecules can pass out of the cytoplasm into the mitochondrial matrix, where they can be further involved in the Krebs cycle and electron transport chain.