Which metabolic cycle produces CO2 as a byproduct?

The citric acid cycle, also known as the Krebs cycle or TCA cycle, is a crucial metabolic pathway that takes place in the mitochondria of cells. The primary function of this cycle is to generate energy through the oxidation of acetyl-CoA, which is derived from carbohydrates, fats, and proteins.

During the citric acid cycle, several reactions occur that lead to the decarboxylation of intermediates, meaning that carbon dioxide (CO2) is released as a byproduct. Specifically, for each turn of the cycle, two carbon atoms from acetyl-CoA are released as CO2. This process is essential not only for energy production but also for the regeneration of electron carriers, which are necessary for the electron transport chain to produce ATP.

In contrast, glycolysis primarily converts glucose into pyruvate, producing some ATP and NADH but not releasing CO2. The Cori cycle involves the conversion of lactic acid back into glucose in the liver, also not producing CO2 as a byproduct. The urea cycle is involved in the detoxification of ammonia into urea for excretion but does not produce CO2 directly as a byproduct of its reactions.

This makes the citric acid cycle unique among these