What are the three stages of cellular respiration?

The three stages of cellular respiration consist of glycolysis, the Krebs cycle (also known as the citric acid cycle), and the electron transport chain.

Glycolysis is the initial step that occurs in the cytoplasm, where glucose is broken down into two molecules of pyruvate, generating a small amount of ATP and NADH in the process. It sets the stage for the next phases by providing the necessary substrates.

The Krebs cycle takes place in the mitochondria and processes the pyruvate produced from glycolysis. It generates more ATP, along with electron carriers NADH and FADH2, which are crucial for the subsequent stage.

Finally, the electron transport chain, also located in the mitochondria, utilizes the electrons from NADH and FADH2 to create a proton gradient across the mitochondrial membrane. As protons flow back into the mitochondrial matrix through ATP synthase, ATP is produced in a process known as oxidative phosphorylation.

Understanding these three stages is fundamental because they illustrate how organisms convert glucose into usable energy, demonstrating the efficiency and interconnectedness of metabolic pathways.