Glycolysis

Cytoplasm; glucose → 2 pyruvate; net 2 ATP, 2 NADH₂

Transition reaction

Matrix; pyruvate → Acetyl CoA + CO₂ + NADH₂

Krebs cycle

Matrix; 2 ATP, 6 NADH₂, 2 FADH₂, 4 CO₂ per glucose

Electron transport chain

Inner membrane; NADH₂ → ~3 ATP, FADH₂ → ~2 ATP

Final electron acceptor

Oxygen → water (via cytochrome oxidase)

Alcoholic fermentation

Plants/yeast: pyruvate → ethanal → ethanol + CO₂

Lactic acid fermentation

Animals: pyruvate → lactic acid

RQ = 1.0 / 0.8 / 0.7

Carbohydrate / Protein / Lipid substrate

BMR

Minimum energy needed at complete rest

Oxygen debt

Extra O₂ needed after exercise to restore normal state

Myoglobin

Stores O₂ in muscle; releases it after haemoglobin