Krebs cycle

Or citric acid cycle, a central pathway for the metabolism of fats, carbohydrates, and amino acids.


A series of chemical reactions occurring in the mitochondria, during which energy is produced from metabolism of carbohydrates, fats and amino acids and the complete oxidation of acetyl CoA is accomplished.


Aseries of eight chemical reactions that begins and ends with the same substance; energy is liberated for direct substrate phosphorylation of ATP from ADP and P.; carbon dioxide is formed and hydrogen atoms are removed and carried by NAD and FAD to the electron transport system; does not directly utilize oxygen but requires its presence.


The aerobic pathway for oxidation of carbohydrates, protein, and lipids to C02, H20, and energy.


Located in the mitochondria. This is a central cyclic pathway where a two-carbon acetyl group is joined to a four-carbon oxaloacetate to form citrate. As the cycle turns, two molecules of CO2 carbon dioxides are produced, as are four reducing equivalents.


Krebs cycle is a metabolic pathway that is instrumental in obtaining energy from macronutrients. In this cyclic pathway, oxaloacetate, produced from pyruvate, accepts the 2 carbons of acetate from acetyl CoA (produced primarily from carbohydrates and fats via glycolysis and beta-oxidation, respectively) producing the 6-carbon molecule citrate. Following several steps, citrate is ultimately converted back to the 4-carbon molecule oxaloacetate with the loss of 2 carbons as carbon dioxide. The oxaloacetate is now available to accept 2 more carbons from acetyl CoA and continue the cycle. Also produced in Krebs cycle is guanosine triphosphate (GTP) and the energy- producing equivalents NADH + H+ and FADH2. Like adenosine triph-oshate (ATP), GTP possesses a high-energy bond that when cleaved can produce free energy similarly to that of ATP NADH + H+ and FADH2 are further metabolized via the electron transport system to produce ATP.


Complex sequence of enzyme-catalyzed reactions occurring in cells, through which sugars, fatty acids, and amino acids are broken down to produce carbon dioxide and high-energy electrons linked to coenzymes. The electrons carried by the coenzymes then enter the electron transport system, which generates a large quantity of adenosine triphosphate (ATP). Also called Krebs citric acid cycle; tricarboxylic acid (TCA) cycle.


A complex cycle of enzyme catalyzed reactions, occurring within the cells of all living animals, in which acetate, in the presence of oxygen, is broken down to produce energy in the form of ‘ATP (via the electron transport chain) and carbon dioxide. The cycle is the final step in the oxidation of carbohydrates, fats, and proteins; some of the intermediary products of the cycle are used in the synthesis of amino acids.


A series of key cellular chemical reactions starting and ending with oxaloacetic acid. Also called the citric acid or tricarboxylic acid cycle, it produces energy in the form of adenosine triphosphate (ATP) and is the last stage in the biological oxidation of fats, proteins, and carbohydrates. Named after Sir Hans Kreb, a German biochemist working in England in 1900, who won the Nobel Prize for his discovery.


A complicated series of reactions in the body involving the oxidative metabolism of pyruvic acid and liberation of energy. It is the main pathway of terminal oxidation in the process of which not only carbohydrates but proteins and fats are utilized.


 


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