During which phase of cellular respiration is most of the CO2 produced?

The Krebs cycle, also known as the citric acid cycle or tricarboxylic acid (TCA) cycle, is the phase of cellular respiration during which the majority of carbon dioxide (CO2) is produced. This cycle occurs in the mitochondrial matrix and involves a series of enzymatic reactions that oxidize acetyl-CoA, which is derived from carbohydrates, fats, and proteins.

As the cycle progresses, each turn generates CO2 as a waste product. Specifically, for every acetyl-CoA molecule that enters the cycle, two CO2 molecules are released. This happens during the decarboxylation steps of the cycle, where carbon atoms from the acetyl group are oxidized and release CO2. Since cellular respiration is designed to harness energy from organic molecules, the production of CO2 in the Krebs cycle is a critical part of metabolic processes, reflecting the breakdown of these macromolecules.

The other phases mentioned do not contribute significantly to CO2 production. Glycolysis, which occurs in the cytoplasm, primarily breaks down glucose into pyruvate without releasing CO2. The electron transport chain focuses on the transfer of electrons and the production of ATP without direct CO2 production. Fermentation, an anaerobic process, involves