From Simple English Wikipedia, the free encyclopedia
TheKrebs cycle (named afterHans Krebs) is a part ofcellular respiration. Its other names are thecitric acid cycle, and the tricarboxylic acid cycle (TCA cycle).
The "Krebs cycle" is a series of chemical reactions used by allaerobic organisms in their energy conversion processes. It is important to many biochemical pathways. This suggests that it was one of the earliest parts of cellularmetabolism toevolve.[1]
The diagram below shows how this part of respiration is an ever-repeating cycle which producesATP and gives offCO2. The ATP is a molecule which carries energy in chemical form to be used in other cell processes. To summarize:
Two molecules of carbon dioxide are given off
One molecule of GTP is formed
Three molecules of NAD+ are combined with hydrogen (NAD+ → NADH)
One molecule of FAD combines with hydrogen (FAD → FADH2)
Because two acetyl-CoA molecules are produced from each glucose molecule,two cycles are required per glucose molecule. Therefore, at the end of two cycles, the products are: two ATP, six NADH, two FADH2 two QH2 (ubiquinol) and four CO2.
