The Krebs Citric Acid cycle, also known as the citric acid cycle or the tricarboxylic acid (TCA) cycle, is a key metabolic pathway that occurs in the mitochondria of eukaryotic cells. Named after the German biochemist Hans Krebs, this cycle plays a fundamental role in aerobic respiration, the process through which cells generate energy in the presence of oxygen.
The Krebs Citric Acid cycle is a series of enzymatic reactions that convert acetyl-coenzyme A (acetyl-CoA), a molecule derived from the breakdown of carbohydrates, fats, and proteins, into carbon dioxide (CO2), hydrogen atoms, and energy-rich molecules. The cycle consists of eight sequential steps, each catalyzed by a specific enzyme. These steps involve the cyclic regeneration of a four-carbon compound called oxaloacetate, which combines with acetyl-CoA to form citric acid.
Through a series of oxidation, decarboxylation, and rearrangement reactions, the Krebs Citric Acid cycle releases high-energy electrons that are captured by carriers such as NADH and FADH2. These carriers subsequently transfer the electrons to the electron transport chain, where they ultimately drive the production of adenosine triphosphate (ATP) – the cell's primary energy currency.
Furthermore, the Krebs Citric Acid cycle serves as a hub for various other metabolic pathways, supplying intermediates for processes such as gluconeogenesis (the synthesis of glucose from non-carbohydrate sources), amino acid synthesis, and lipid metabolism.
Overall, the Krebs Citric Acid cycle is a pivotal pathway in cellular metabolism, vital for the generation of ATP and the production of numerous important molecules required for various cellular processes.
