The document summarizes the citric acid cycle (also known as the Krebs cycle or TCA cycle), which is a series of chemical reactions in the mitochondria that breaks down food molecules into carbon dioxide. It discusses how the cycle was discovered by Sir Hans Krebs, and outlines the key reactions where acetyl-CoA is oxidized, releasing carbon dioxide and producing reduced cofactors that are used to generate ATP. The citric acid cycle is an important amphibolic pathway that generates important biosynthetic intermediates and allows anaplerotic reactions to replenish cycle intermediates.

1. CITRIC ACID CYCLE
PRESENTED BY:
INCHARA R
5TH SEMESTER
MOLECULAR BIOLOGY
06/08/2019
GUIDED BY:
SADASHIVAIAH
DEPT. OF MOLECULAR
BIOLOGY
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2. CONTENTS
 Introduction
 Formation of Acetyl CoA
 Reactions of Citric Acid Cycle
 Significance
 Conclusion
 References
 Acknowledgement
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3. Sir Hans Adolf Kreb
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4. Fig 1: Citric acid cycle 4

5. Fig 2: Formation of Citrate
Reactions of Citric Acid Cycle
Citrate
synthase
Citrate synthase
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6. Fig 3: Formation of Isocitrate
OH
Aconitase Aconitase
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7. Fig 4: Oxidation of Isocitrate to α-Ketoglutarate
Isocitrate dehydrogenase Isocitrate
dehydrogenase
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8. Fig 5: Oxidation of α-Ketoglutarate to Succinyl-CoA
α-ketoglutarate
dehydrogenase
complex
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9. Fig 6: Conversion of Succinyl-CoA to Succinate
succinyl-CoA
synthetase
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10. Fig 7: Oxidation of Succinate to Fumarate
Succinate Dehydrogenase
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11. Fig 08: Hydration of Fumarate to Malate
Fumarase
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12. Fig 9: Oxidation of Malate to Oxaloacetate
L-malate dehydrogenase
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H H
H
H

13. SIGNIFICANCE
 Amphibolic pathway
 Important Biosynthetic Intermediates
 Anaplerotic Reactions
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14. CONCLUSION
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15. REFERENCES
 David L. Nelson & Michael M. Cox. 2008. Lehninger Principles Of
Biochemistry, 5th edition, W. H. Freeman & Company, New York, USA,
1303pp.
 Jeremy M. Berg, John L. Tymoczko & Lubert Stryer. 2007.
Biochemistry, 6th edition, W. H. Freeman & Company, New York, USA,
1158pp.
 Donald Voet & Judith G. Voet. 2011. Biochemistry, 4th edition, John
Wiley & Sons, Inc., New Jersey, UK, 1515pp.
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16.  http://www.biologydiscussion.com/organism/metabolism-
organism/the-krebs-cycle-notes-on-the-krebs-cycle-with-diagram-
metabolism/50314
 http://www.namrata.co/?s=tca+cycle
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17. ACKNOWLEGDEMENT
I would like to thank the dept. of Molecular Biology for
providing this opportunity to present this seminar.
I would also like to thank my guide Sadashivaiah sir for his
valuable guidance.
Thank you one and all.
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