Notes describes glycolysis in details

1. METABOLISM OF
CARBOHDRATE 1
EXCELLENT COLLEGE
HEALTH AND AND ALLIED
SCIENCES

2. 1.Metabolism
The sum of the chemical and pysical changes
ocurring in tissue,constiting of anabolism,those
reactions that convert small molecules into
large,and catabolism,those reactions that convert
large molecules into small.

3. The three main purposes of metabolism are:-
1. The conversion of food to energy to run
cellular processes.
2.The conversion of food/fuel to building blocks
for proteins, lipids, nucleic acids, and some
carbohydrates.
3.The elimination of nitrogenous wastes.

4. 2.Catabolism
Is the set of metabolic pathways that breaks
down molecules into smaller units that are either
oxidized to release energy or used in other
anabolic reactions.
Catabolism breaks down large molecules
(such as polysaccharides, lipids, nucleic acids and
proteins) into smaller units (such as
monosaccharides, fatty acids, nucleotides, and
amino acids, respectively).
Catabolism is the breaking-down aspect of
metabolism.

5. 3.Anabolism
Is the set of metabolic pathways that construct
molecules from smaller units.
These reactions require energy, known also as
an endergonic process.

6. CARBOHYDRATE
METABOLISM.
Refers to various biochemical processes
responsible for the metabolic
formation,breakdown, and interconversion of
carbohydrates in living organisms.

7. GLYCOLYSIS
Glycolysis
Is the metabolic pathway that converts glucose
C6H12O6, into pyruvate, CH3COCOO− + H+.
In glycolysis, glucose (a six-carbon sugar) is split
into two molecules of the three-carbon sugar
pyruvate.
Glycolysis can occur with or without oxygen.
In the presence of oxygen, glycolysis is the first
stage of cellular respiration.

8. • In the absence of oxygen, glycolysis allows
cells to make small amounts of ATP through
the process of fermentation.
• Glycolysis takes place in the cytosol of the
cell's cytoplasm.

9.  Glycolysis takes place in the cytosol of cells.
 Glucose enters the Glycolysis pathway by conversion to
glucose-6-phosphate.
 Initially there is energy input corresponding to cleavage
of two ~P bonds of ATP.
H O
OH
H
OHH
OH
CH2OPO3
2−
H
OH
H
1
6
5
4
3 2
glucose-6-phosphate

10. • Glycolysis is a series of reactions
• Below are the 10 steps of glycolysis.

11. 1. Glucose is phosphorylated by ATP to form
glucose 6-phosphate and ADP.
The reaction is catalyzed by the enzyme
hexokinase.

13. 2.Glucose 6-phosphate is converted to
fructose 6-phosphate by
phosphoglucoisomerase.

16. 3.Fructose 6-phosphate is phosphorylated by
ATP to form fructose 1,6-bisphosphate and
ADP.
The enzyme catalyzing this step is
phosphofructokinase

19. 4.Aldolase splits fructose 1,6-bisphosphate (a
six-carbon molecule) into two three-carbon
molecules, glyceraldehyde 3-phosphate and
dihydroxyacetone phosphate.

21. 5.Glyceraldehyde 3-phosphate is the only
molecule that can be used for the mrest of
glycolysis
However, the dihydroxyacetone phosphate
formed in the previous step can rapidly be
converted to glyceraldehyde 3-phosphate by
triose phosphate isomerase.

23. 6.Glyceraldehyde 3-phosphate is converted to
1,3-bisphosphoglycerate.
The reaction is catalyzed by
glyceraldehyde 3-phosphate dehydrogenase
and uses inorganic phosphate and NAD+.
The other product is NADH.

25. 7.The newly created high-energy phosphate
bond of 1,3-bisphosphoglycerat is now used
to synthesize ATP.
Phosphoglycerate kinase catalyzes the
transfer of the phosphoryl group from the 1,3-
bisphosphoglycerate to ADP, generating ATP
and 3-phosphoglycerate.

27. 8.
3-Phosphoglycerate is converted to 2-
phosphoglycerate by phosphoglycerate
mutase.
Thus the reaction is a movement of the
phosphate group to a different carbon atom
within the same molecule(isomerisation).

29. 9. Enolase catalyzes the dehydration of 2-
phosphoglycerate to form phosphoenolpyruvate
(PEP).
This reaction converts the low-energy
phosphate ester bond of 2-phosphoglycerate
into the high-energy phosphate bond of PEP.

31. 10. In the last reaction, pyruvate kinase
catalyzes the physiologically irreversible
transfer of the phosphoryl group from PEP to
ADP to form ATP and pyruvate.

34. Importance of glycolysis.
1.Pentose phosphate pathway.
2.Glycogen synthesis also starts with glucose-
6-phosphate at the beginning of the glycolytic
pathway.
3.Glycerol, for the formation of triglycerides
and phospholipids, is produced from the
glycolytic intermediate glyceraldehyde-3-
phosphate.

35. 4.Various post-glycolytic pathways:
5.Fatty acid synthesis
6.Cholesterol synthesis
7.The citric acid cycle which in turn leads to:
8.Amino acid synthesis
9.Nucleotide synthesis
10.Tetrapyrrole synthesis