Which reaction in the Citric Acid Cycle produces carbon dioxide?

In the Citric Acid Cycle, carbon dioxide is produced during the oxidative decarboxylation reactions of isocitrate and alpha-ketoglutarate. During these key reactions, isocitrate is converted into alpha-ketoglutarate, and in this process, one molecule of carbon dioxide is released. Similarly, alpha-ketoglutarate is then converted into succinyl-CoA, which also results in the release of another molecule of carbon dioxide.

These decarboxylation steps are critical because they not only help to oxidize the intermediates but also play a vital role in the overall energy yield of the cycle by liberating carbon dioxide, which is a waste product of metabolism. This release of CO2 signifies the conversion of organic substrates into a form that can be further metabolized for energy, reflecting the cycle's role in cellular respiration.