(Briefly) describe the four phases of aerobic respiration?

Glycolysis: Takes place in the cytoplasm and involves the oxidation of a 6-carbon glucose molecule to two 3-carbon pyruvate molecules with a net gain of ATP and reduced NAD (2 molecules of each per glucose molecule).

Link Reaction: Pyruvate enters the mitochondrion and is converted into 2-carbon Acetyl Coenzyme A. Carbon dioxide and reduced NAD also produced.

Krebs Cycle: Occurs in the mitochondrial matrix. Involves the introduction of acetyl coenzyme A into a cycle of oxidation-reduction reactions that yield some ATP by substrate-level phosphorylation and a large number of electrons carried by reduced NAD and reduced FAD (as well as carbon dioxide).

Electron Transport Chain: The electrons produced in the Krebs cycle (carried by the reduced NAD and FAD molecules) are transferred down the electron transport chain located on the mitochondrial cristae, allowing the passage of protons (also from the NADH and FADH2) across mitochondrial membranes. This is turn results in the synthesis of ATP by oxidative phosphorylation. Water is produced as a byproduct.