1. Biochemistry Lecture 10

2. Only a Small Amount of Energy Available in Glucose is Captured in Glycolysis 2  G’° = -146 kJ/mol Glycolysis Full oxidation (+ 6 O 2 )  G’° = -2,840 kJ/mol 6 CO 2 + 6 H 2 O GLUCOSE

3. Cellular Respiration: the big picture process in which cells consume O 2 and produce CO 2 provides more energy (ATP) from glucose than glycolysis also captures energy stored in lipids and amino acids evolutionary origin: developed about 2.5 billion years ago used by animals, plants, and many microorganisms occurs in three major stages: - acetyl CoA production - acetyl CoA oxidation - electron transfer and oxidative phosphorylation

4. Stage 1. Acetyl-CoA production

5. Stage 2. Acetyl-CoA Oxidation

6. Stage 3. Electron Transfer and oxidative Phosphorylation

7. Where does this all happen?

8. Stage 1. Acetyl-CoA production

9. Pyruvate Decarboxylation

10. The PDC

12. Sequence of Events in Pyruvate Decarboxylation Step 1: Decarboxylation of pyruvate to an aldehyde Step 2: Oxidation of aldehyde to a carboxylic acid Step 3: Formation of acetyl CoA Step 4: Reoxidation of the lipoamide cofactor Step 5: Regeneration of the oxidized FAD cofactor

14. Structure of CoA

16. Stage 2. Acetyl-CoA Oxidation

18. Step 1

20. Step 2

21. Sterospecificity

22. Step 3

23. Step 4

24. Step 5.

25. Succinyl-CoA Succinate Succinyl-CoA Synthetase Succinate dehydrogenase * * Carbons are scrambled at succinate * 1/2

26. Step 6.

27. Step 7.

29. Products from one turn of the cycle

30. Net Effect of the Citric Acid Cycle Acetyl-CoA + 3NAD + + FAD + GDP + P i + 2 H 2 O 2CO 2 +3NADH + FADH 2 + GTP + CoA + 3H + carbons of acetyl groups in acetyl-CoA are oxidized to CO 2 electrons from this process reduce NAD + and FAD one GTP is formed per cycle, this can be converted to ATP intermediates in the cycle are not depleted

31. Energy Yield