Final answer:
The Krebs or citric acid cycle's main function is to convert pyruvate into CO2, and generate high-energy molecules like FADH2, NADH, and ATP. It is a vital part of cellular respiration, taking place in the mitochondria, and also contributes to the metabolism of amino acids, fats, and proteins.
Step-by-step explanation:
The main function of the Krebs cycle, also known as the citric acid cycle or the tricarboxylic acid (TCA) cycle, is to convert pyruvate, derived from glucose through glycolysis, into carbon dioxide (CO2) and high-energy molecules such as FADH2, NADH, and a small amount of ATP. This biochemical pathway is crucial in cells' energy production as it constitutes a central part of cellular respiration. During the cycle, which takes place in the mitochondria of eukaryotic cells, acetyl-CoA combines with oxaloacetate to form citrate, which then undergoes a series of reactions. These reactions release energy that is captured in energy-carrying molecules ATP, NADH, and FADH2, which later enter the electron transport chain to generate a greater yield of ATP. Additionally, the Krebs cycle plays a role in amino acid metabolism and the processing of fats and proteins.
The citric acid cycle begins with the combination of acetyl-CoA and oxaloacetate, resulting in citrate. For each turn of the cycle, two molecules of CO2 are released, and energy is transferred to three molecules of NADH, one molecule of FADH2, and one molecule of ATP (or GTP).
The cycle is named after Hans Krebs, who elucidated this essential metabolic pathway and won a Nobel Prize for his discovery. All aerobic organisms share the Krebs cycle, highlighting its importance and evolutionary establishment early on for life on Earth.