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Explain krebs cycle.

Dear Student,
 
Krebs Cycle: It is a step in cellular aerobic respiration. It is a series of chemical reaction that breaks down glucose for energy. It is also known as Citric Acid Cycle or Tricarboxylic Acid Cycle.
The over view of the cycle is mentioned below:
  • Acetyl group condenses with oxaloacetic acid and water to yield citric acid (catalysed by the enzyme citrate synthase)
  • Citrate isomerises into isocitrate
  • Two successive decarboxylation steps follow, leading to the formation of α ketoglutaric acid, followed by succinyl CoA
  • This is followed by the conversion of succinyl CoA into succinic acid (substrate level phosphorylation). In a coupled reaction, GTP is converted into GDP, simultaneously synthesising ATP from ADP.
  • Conversion of one molecule of pyruvate into acetyl CoA yields 1 molecule of CO2 and 1 NADH.
  • One Krebs cycle yields 2 CO2 + 3 NADH + 1 FADH2 + 1 ATP
  • Overall equation:
  • For continued oxidation of acetyl CoA in TCA 2 things are required:
    • Continued replenishment of oxaloacetic acid
    • Regeneration of NAD+ and FAD+ from NADH and FADH2 respectively.


Regards

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View Full Answer
The citric acid cycle (CAC) – also known as the TCA cycle (tricarboxylic acid cycle) or the Krebs cycle – is a series of chemical reactions used by all aerobic organisms to release stored energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins, into adenosine triphosphate (ATP) and carbon dioxide. In addition, the cycle provides precursors of certain amino acids, as well as the reducing agent NADH, that are used in numerous other reactions. Its central importance to many biochemical pathways suggests that it was one of the earliest established components of cellular metabolism and may have originated abiogenically.
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