The Krebs Cycle represents a series of eight enzymatic reactions occuring in the mitochondrion, generating the energy requested by the production of adensoine triphosphate molecules. The Krebs Cycle occurs in all aerobic organisms. Krebs Cycle reactions oxidizes two carbon molecules into carbon dioxide.
The following chemical reaction recaps Krebs Cycle:
`3NAD + FAD + ADP + acetyl CoA + HPO_4^(2-)-> 2CO_2 + CoA + 3NADH^+ + FADH^+ + ATP`
In Krebs Cycle the glucose is broken down to produce ATP, the whole cycle being an aerobic process, requiring the presence of oxygen.
In Krebs Cycle, oxaloacetate represents reactant and final product, creating the metabolic loop. In the first reaction of Krebs Cycle, citric acid is formed when oxaloacetate condenses with acetyl coenzyme A. The acetyl coenzyme A is provided by fatty acids oxidation or pyruvate decarboxylation or breakdown of certain amino acids.
Krebs Cycle produces one guanosine triphosphate molecule (GTP), two molecules of carbon dioxide and electrons that produce one molecule of `FADH_2` and three molecules of NADH.