• The aerobic process of respiration takes place only in the presence of oxygen, but the role of oxygen is limited to the terminal stage of the process.

• During terminal oxidation, oxygen acts as final hydrogen acceptor and combines with H⁺and forms the water.

• Pyruvate is formed by glycolytic catabolism of carbohydrates in the cytoplasm.

• In fermentation, there is incomplete oxidation of glucose under anaerobic conditions.

• During the conversion of succinyl-CoA to succinic acid, a molecule of GTP is synthesised.