What is the fate of pyruvate generated from glycolysis?

The fate of pyruvate generated from glycolysis depends on the oxygen availability: 1) In aerobic conditions, pyruvate is converted into acetyl-CoA, which enters the citric acid cycle for ATP production. 2) In anaerobic conditions, pyruvate is converted into lactate (in muscle cells) or ethanol and CO2 (in yeast) via fermentation. Both fermentation pathways regenerate NAD+, which is essential for glycolysis to continue producing ATP. This ensures energy production even when oxygen is limited.