the three main stages of cellular respiration are: 1. glycolysis - starts cellular respiration by breaking glucose down into pyruvate (small amount of ATP is made as well)
2. citric acid cycle (krebs cycle) - completes the breakdown of glucose by decomposing a derivative of pyruvate to carbon dioxide. also, this stage supplies oxidative phosphorylation with electrons. (small amount of ATP is made as well)
3. oxidative phosphorylation - mostly ATP is produced during this stage, more specificallychemiosmosis. electron transport chains are used during this stage, but that is not the sole purpose of oxidative phosphorylation.