Which part of cellular respiration is primarily responsible for the production of CO2?

The Krebs Cycle, also known as the citric acid cycle, plays a critical role in cellular respiration by being the primary step where carbon dioxide (CO2) is produced. During this cycle, acetyl-CoA, derived from glycolysis and the breakdown of fatty acids, enters the cycle and is oxidized through a series of enzymatic reactions. As carbon-containing compounds are processed, two carbon atoms are released as CO2 for each acetyl-CoA that enters the cycle.

This process is essential for cellular metabolism, as it not only generates CO2 but also produces high-energy molecules such as NADH and FADH2, which are later utilized in the electron transport chain to produce ATP. While glycolysis does produce a small amount of CO2 through the conversion of pyruvate in some organisms, the majority of the gas is generated during the Krebs Cycle. The electron transport chain primarily focuses on ATP production rather than the release of CO2, and lactic acid fermentation occurs in anaerobic conditions where CO2 is produced in minimal amounts and is not a central feature of the process. Thus, the Krebs Cycle is unequivocally identified as the main contributor to CO2 generation in cellular respiration.