Glucose catabolism glycolysis in detail.ppt

1. Carbohydrate
Metabolism

2. Overview of
Metabolism

3. The Fate of Glucose
Exercising muscle
Yeast
The fate of glucose is
varies with physiological
conditions, tissues, and
organisms.

4. Glycolysis
Glykys = Sweet, Lysis = splitting
During this process one molecule of glucose (6 carbon molecule)
is degraded into two molecules of pyruvate (three carbon
molecule).
Free energy released in this process is stored as 2 molecules of
ATP, and 2 molecules of NADH.
Glucose + 2NAD+ = 2Pyruvate + 2NADH + 2H+ Go = -146
kJ/mol 2ADP + 2Pi = 2ATP + 2H2O Go = 2X(30.5 kJ/mol) = 61
kJ/mol

Go (overall) = -146+61 = -85 kJ/mol
In standard condition, glycolysis is an exergonic reaction which
tends to be irreversible because of negative Go.

5. → It is also called as Embden-Meyerhof Pathway (EMP)
→ it is defined as the sequence of reactions converting
glucose or glycogen to pyruvate or lactate with
production of ATP.
→ Enzymes takes place in cytosomal fraction of the
cell.
→ major pathway in tissues lacking mitochondria like
erythrocytes, cornea, lens etc.
→ it is essential for brain which is dependent in
glucose for energy.

6. Fate of glucose in living systems
Glucose + 6O2 = 6CO2 + 6H2O Go= -2840 kJ/mol
Glucose + 2NAD+ = 2Pyruvate + 2NADH + 2H+  Go = -146 kJ/mol
5.2% of total free energy that can be released by glucose is
released in glycolysis.

8. There are 10 enzyme-catalyzed reactions in glycolysis.
There are two stages
Stage 1: (Reactions 1-5) A preparatory stage in which glucose is
phosphorylated, converted to fructose which is again forphorylated
and cleaved into two molecules of glyceraldehyde-3-phosphate. In
this phase there is an investment of two molecules of ATP.
Stage 2: (Reactions 6-10) The two molecules of glyceraldehyde-3-
phosphate are converted to pyruvate with concomitant generation of
four ATP molecules and two molecules of NADH. Thus there is a net
gain of two ATP molecules per molecule of Glucose in glycolysis.
Importance of phosphorylated intermediates:
1. Possession of negative charge which inhibit their diffusion through
membrane.
2. Conservation of free energy in high energy phosphate bond.
3. Facilitation of catalysis.

9. Overview of glycolysis

12. Preparatory Phase

13. pg 526
Reaction 1: phosphorylation

14. Reaction 1: phosphorylation

15. Reaction 2: isomerization
aldose ketose

16. Reaction 2: isomerization

17. Reaction 3: phosphorylation

18. Reaction 3: phosphorylation

19. Reaction 4: cleavage

20. Reaction 4: cleavage

21. Reaction 5: isomerization

22. Reaction 5: isomerization

23. Keeping Track of Carbons
glucose
G3P

25. Reaction 6: oxidation

26. Reaction 6: oxidation

27. Reaction 7: substrate level phosphorylation

28. Reaction 8: shift of phosphoryl group

29. Reaction 8: shift of phosphoryl group

30. ~Fig 14-8

31. Reaction 9: dehydration

32. Reaction 10: substrate level phosphorylation

33. https://www.youtube.com/watch?v=EfGlznwfu9U
Energy
investment
Cleavage
Energy
Harvest
Summary