The term cellular respiration refers to the biochemical pathway by which cells release energy from the chemical bonds of food molecules and provide that energy for the essential processes of life. All living cells must carry out cellular respiration. It can be aerobic respiration in the presence of oxygen or anaerobic respiration. Prokaryotic cells carry out cellular respiration within the cytoplasm or on the inner surfaces of the cells. More emphasis here will be placed on eukaryotic cells where the mitochondria are the site of most of the reactions. The energy currency of these cells is ATP, and one way to view the outcome of cellular respiration is as a production process for ATP.

Steps of cellular respiration:

1. Glycolysis
2. Pyruvate oxidation
3. Citric acid cycle
4. Oxidative phosphorylation