Respiration
In eukaryotes, glycolysis occurs in the cytosol; pyruvate oxidation and the citric acid cycle occur in the mitochondrial matrix. Glycolysis produces a net two ATP and two NADH per glucose. Carbon dioxide is released during pyruvate oxidation and the citric acid cycle, not glycolysis. NADH and FADH₂ carry electrons to the electron transport chain. Oxygen is the terminal electron acceptor in aerobic respiration and becomes water.
MAKE IT CONCRETE
Without oxygen, the chain cannot keep accepting electrons; NADH accumulates and oxidative ATP production decreases.
DON’T FALL FOR THIS
Plants respire too. Photosynthesis does not replace cellular respiration.