- Glycolysis
- Means ‘splitting of sugar’; the first stage of both aerobic and anaerobic respiration, occurring in the cytoplasm. Converts 1 glucose into 2 pyruvate.
Key Steps (Summary)
- Activation: glucose is phosphorylated (using 1 ATP) to glucose-6-phosphate, isomerised to fructose-6-phosphate, then phosphorylated again (using a 2nd ATP) to fructose-1,6-diphosphate.
- Lysis: fructose-1,6-diphosphate splits into two 3-carbon glyceraldehyde-3-phosphate (triose phosphate) molecules.
- Energy-yielding stage: each triose phosphate is dehydrogenated (producing NADHâ‚‚) and phosphorylated, then passes through reactions that each generate one ATP by substrate-level phosphorylation (transferring a phosphate from the substrate directly to ADP), ending as pyruvate.
- Net yield from one glucose: 2 pyruvate + 2 ATP (net, since 2 were used to activate glucose and 4 were made) + 2 NADHâ‚‚.