Ritu Jangid posted an Question
January 04, 2021 • 09:50 am 30 points
  • Life Sciences

Yield of atp.. please explain me the net atp production in the respective cycles.. it is quite confusing..

Yield of ATP At this point the yield of ATP is 4 moles per mole of Glucose as it passes through the Krebs cycle. This is not much more than the 2 moles which would have been produced from glycolysis NADH and FADH, are energy ich molecules Their oxidation is highly exergonic and is coupled with the production of ATP from ADP Oxidation of 1 mole NADH produces 3 moles ATP Oxidation of 1 mole FADH, produces 2 moles ATP Thus, total ATP yield = (10 x 3) (2 x 2) + 4= 38 moles ATP per mole Glucose. The complete oxidation of one molecule of glucose produce 38 ATP molecules of which 8 ATP molecule are produced in glycolysis 6 ATP molecule s in oxidative phosphorylation and 24 ATP molecule in Krebs cycle. The reaction of pyruvate to acetyl Co-A is an exergonic process (AG°= -33.4K J. Mo- or -8.0 Kcal mol-). More energy release to come in the ETC. when the 4 NADH & 1 FADH2 produced by pyruvate dehydrogenase complex and citric acid cycle are reoxidized by the ETC, considerable quantities of ATP are produced.

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    Yogita Basnal

    Celluar respiration has 3 main steps. But if we include pyruvate decarboxylation also as a separate step in cellular respiration then there are overall 4 steps mentioned as under: 1) Glycolysis 2) Pyruvate decarboxylation 3) TCA or Citric acid cycle or Kreb cycle 4) Oxidative Phosphorylation. Glycolysis: During glycolysis from 1 glucose molecule, 2 ATP are used whereas 4 ATP molecules are produced so net ATP yield is 2 ATP. Apart from this, 2 NADH are also produced. So, during glycolysis overall we get 2 ATP and 2NADH from 1 glucose molecule. Pyruvate decarboxylation: During glycolysis 2 pyruvate molecules are produced from 1 glucose molecule. These pyruvate molecules are oxidatively decarboxylated in PDH complex. 2 pyruvate molecules produce 2 acetyl CoA molecules and 2 NADH at the end of pyruvate decarboxylation. TCA cycle/ tricarboxylic acid cycle/ Kreb cycle: The acetyl CoA produced as mentioned above then enters mitochondrial matrix. 1 acetyl CoA produces 3 NADH, 1 FADH2 and 1ATP/GTP so that means 2 acetyl CoA will produce 6 NADH, 2 FADH2 and 2 ATP/GTP. So in total we get, 2+2+6 = 10 NADH 2 FADH2 and 2+2 = 4 ATP Also, when 1 NADH undergoes Oxidative Phosphorylation then it produces 3 ATP so the total 10 NADH will produce = 10 x 3 = 30 ATP When 1 FADH2 undergoes Oxidative Phosphorylation then it produces 2 ATP so the total 2 FADH2 will produce = 2 x 2 = 4 ATP 4 ATP we get directly during the entire cellular respiration so, the total ATP yield from cellular respiration will be 30 + 4 + 4 = 38 ATP. The diagram is attached.


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