Glycolysis and fermentation reactions occur in the cytoplasm. While the excess pathways, beginning with pyruvate oxidation, transpire in the mitochondria. Nearly all of the eukaryotic mitochondria can just use oxygen as the final electron acceptor for respiration. Pyruvate goes into the mitochondrial matrix and is oxidized to acetyl-CoA in the existence of oxygen then to CO2 through the citric acid cycle. The electron move chain and ATP synthase are positioned on the mitochondrial interior membrane
