What gas is released as a byproduct of the Krebs cycle?

The gas released as a byproduct of the Krebs cycle is carbon dioxide (CO2). During this cycle, which occurs in the mitochondrial matrix, acetyl-CoA from glycolysis is processed through a series of enzymatic reactions. As a result, high-energy electron carriers such as NADH and FADH2 are generated, which are crucial for the electron transport chain.

Importantly, during the Krebs cycle, two molecules of CO2 are produced for each acetyl-CoA that enters the cycle. This CO2 is released into the cellular environment and then expelled from the organism as a waste product during respiration. This process is essential for the overall metabolism of aerobic organisms, as it not only helps in energy production but also in maintaining the necessary balance of gases in the body.

In contrast to the other gases listed, such as oxygen (O2), which is consumed in cellular respiration, nitrogen (N2), which is largely inert and unreactive in biological systems, and hydrogen (H2), which is not a byproduct of the Krebs cycle, CO2 is the correct gas that is actively produced during cellular respiration in the Krebs cycle.