1) The Krebs cycle breaks down pyruvic acid in the mitochondrion, producing carbon dioxide, NADH, and FADH2. 2) The electron transport chain uses the high-energy electrons from NADH and FADH2 to convert ADP to ATP via ATP synthase. 3) Cellular respiration completely breaks down glucose to produce 36 ATP molecules, while glycolysis alone produces only 2 ATP.