The fate of pyruvate depends on the species and the presence or absence of oxygen. If oxygen is present to drive subsequent reaction, pyruvate enters the mitochondria, where the citric acid cycle (als...The fate of pyruvate depends on the species and the presence or absence of oxygen. If oxygen is present to drive subsequent reaction, pyruvate enters the mitochondria, where the citric acid cycle (also known as the Krebs Cycle) (Stage 2) and electron transport chain (Stage 3) break it down and oxidize it completely to CO2 and H2O . The energy released builds many more ATP molecules, though of course some is lost as heat. Let's explore the details of how mitochondria use oxygen to make more AT
