Cellular respiration includes following 3 processes:
1) Glycolysis
2) Citric acid cycle or TCA or Kreb's cycle
3) Electron Transport Chain (ETC)
In glycolysis, a 3 carbon compound known as pyruvate is produced from glucose. Each glucose molecule produces 2 pyruvate molecules. Each pyruvate molecule then enters a complex known as Pyruvate dehydrogenase complex wherein the pyruvate molecule further undergoes oxidative decarboxylation to produce a 2 carbon compound known as Acetyl-CoA.
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The Acetyl-CoA then enters citric acid cycle or TCA or Kreb's cycle wherein this Acetyl-CoA and oxaloacetate are oxidized to produce CO₂ molecules in eight steps. Each glucose molecule is capable of producing six CO₂ after the completion of citric acid cycle. Since one glucose molecule produces 2 pyruvate molecules then it means <u>a pyruvate molecule will be able to produce three CO₂.</u>
Two pyruvate molecules enters into the citric acid cycle and during the stage of pyruvate oxidation , one carboxyl molecules detaches from each pyurvate group thereby forming carbon dioxide and leaving behind a molecule consisting of two carbon for further processes. Hence, in one complete CAC two carbon dioxide molecules are released from two pyruvate molecule. This means that One pyruvate molecule will generate one molecules of CO2 after completing the citric acid cycle
