The three stages of cellular respiration include glycolysis, electron transport chain and citric acid cycle, also known as Krebs cycle or tricarboxylic acid cycle. Cellular respiration refers to the set of biochemical processes involved in the synthesis of adenosine triphosphate, or ATP, which provides the essential energy for an organism to survive.
In glycolysis, glucose molecules that are stored in nutrients and ingested into the body are broken into pyruvates, which are in turn converted to acetyl CoA during the citric acid cycle. The electron carriers NADH and FADH2, which are produced during this stage, undergo oxidation in the electron transport chain. At the end of the third stage, 36-38 ATPs are produced.