What are the three main stages of cellular respiration?

The three main stages of cellular respiration are glycolysis, the Krebs cycle, and oxidative phosphorylation.

Glycolysis is the first step and 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. This stage does not require oxygen, making it the only step that can occur under anaerobic conditions.

The Krebs cycle, also known as the citric acid cycle, takes place in the mitochondria and processes the pyruvate produced from glycolysis. In this cycle, pyruvate is further broken down, and several high-energy electron carriers, such as NADH and FADH2, are produced, along with a small yield of ATP and carbon dioxide as a waste product.

Finally, oxidative phosphorylation, which includes the electron transport chain and chemiosmosis, is the stage where the majority of ATP is generated. Here, the electrons carried by NADH and FADH2 from the previous stages are transferred through a series of proteins embedded in the inner mitochondrial membrane, ultimately leading to the production of a large amount of ATP and water when oxygen acts as the final electron acceptor.

This sequence of processes highlights how cellular respiration efficiently converts