Which cycle operates in the mitochondria of mammals under aerobic conditions?

The Citric Acid Cycle, also known as the Krebs Cycle or TCA Cycle, operates in the mitochondria of mammals under aerobic conditions. It plays a crucial role in cellular respiration by processing acetyl-CoA derived from carbohydrates, fats, and proteins.

During this cycle, acetyl-CoA enters the cycle and combines with oxaloacetate to form citrate. Throughout a series of enzymatic reactions, citrate undergoes transformations that lead to the production of NADH and FADH2, high-energy electron carriers that are used in the subsequent Electron Transport Chain to generate ATP. The cycle also releases carbon dioxide as a waste product, which is eliminated from the body through respiration.

The operation of the Citric Acid Cycle is intricately tied to the availability of oxygen because it relies on the reduced cofactors (NADH and FADH2) produced to drive ATP synthesis in the electron transport chain, which generates most of the ATP in aerobic organisms. Thus, when oxygen is available, the efficient energy extraction from fuel sources is maximized, highlighting the significance of the Citric Acid Cycle in aerobic metabolism.