2. Lecture 1 Function of carbohydrate
Lecture 2 The classification of carbohydrates
Lecture 3 Glycolysis
Lecture 4 The fates of pyruvate
Lecture 5 Gluconeogenesis
Lecture 6 The pentose phosphate pathway of
glucose oxidation
Lecture 7 Citric acid cycle
4. Carbohydrate, (C-H2O)n = “Carbon + Water”
What are Carbohydrates (saccharides)?
Carbohydrate is an organic compound with the
general formula Cm(H2O)n, which consists of carbon,
hydrogen and oxygen, the last two in the 2:1 atom ratio.
Carbohydrates are hydrates of carbon, hence their name.
6. Upland cotton produces the most widely used
natural fibers, cellulose (polysaccharide)
Cellulose:
the most abundant organic
compounds in the biosphere
1015 kg of cellulose is
synthesized and degraded
on earth each year
11. Function of Carbohydrates
Source of energy
Structure (cotton fibers: cellulose )
Building blocks
Cellular recognition
12. Lecture 2 The classification of carbohydrates
（Saccharides ）
13. • The generic name of the simplest carbohydrates.
• Monosaccharides can not be hydrolysised to give
smaller carbohydrates.
1 Monosaccharide
14. Triose 3 carbons
Tetrose 4 carbons
Pentose 5 carbons
Hexose 6 carbons
Heptose 7 carbons
Monosaccharides can be classified
according to the number of carbons:
22. 3 Polysaccharide
An alternative name for glycan ;
Any linear or branched polymer consisting of
monosaccharide residues. Important polysaccharides
include glycogen, starch and cellulose .
24. Amylose
It can be made of several thousand glucose units.
In amylose, the 1st carbon on one glucose
molecule is linked to the 4th carbon on the next
glucose molecule (α(1→4) bonds).
Amylose is soluble in water.
25. Amylopectin
Glucose units are linked in a linear way with α(1→4)
glycosidic bonds. Branching takes place with α(1→6)
bonds occurring every 24 to 30 glucose units.
It is not soluble in water.
29. In glycolysis, a molecule of glucose is broken down in a
series of enzyme-catalyzed reactions to yield two
molecules of the three-carbon compound pyruvate .
During the sequential reactions of glycolysis, some of
the free energy released from glucose is conserved in
the form of ATP and NADH.
30. First stage of carbohydrate metabolism.
Glycolysis was first discovered by Gustav Embden and
Otto Meyerhof and Parnus. Glycolysis is named as
EMP
Simple sugars are broken down to pyruvate
No oxygen needed.
All life uses this process.
There are 10 steps in glycolysis.
31. 1 The Reaction of the glycolysis (Two Phases)
Preparatory phase（step①-⑤）：
Phosphorylation of glucose and its
conversion to glyceraldehyde 3-
phosphate
Payoff phase（step⑥-⑩）：
Oxidative conversion of glyceraldehyde 3-
phosphate to pyruvate and the coupled
formation of ATP and NADH
32. (1) Phosphorylation of Glucose
or glucokinase
Transfer of a phosphoryl group from ATP to glucose
42. (10) Transfer of the Phosphoryl Group from
Phosphoenolpyruvate to ADP
Transfer of a high-energy phosphoryl group to ADP, yielding ATP
43.
44.
45. For each molecule of glucose that passes
through the preparatory phase (a), two
molecules of glyceraldehyde 3-phosphate are
formed; both pass through the payoff phase
(b), Pyruvate is the end product of the
second phase of glycolysis.
46. For each glucose molecule, two ATP are
consumed in the preparatory phase and four
ATP are produced in the payoff phase, giving
a net yield of two ATP per molecule of
glucose converted to pyruvate.
47. The glycolytic breakdown of glucose is the
sole source of metabolic energy in some
mammalian tissues and cell types
(erythrocytes, renal medulla, brain, and
sperm, for example).
Many anaerobic microorganisms are
entirely dependent on glycolysis.
48. ATP and NADH Formation Coupled to Glycolysis
During glycolysis some of the energy of the
glucose molecule is conserved in ATP, while
much remains in the product, pyruvate. The
overall equation for glycolysis is
49. Regulation of glycolysis
Three glycolytic reactions(the reactions catalyzed
by hexokinase, PFK-1, and pyruvate kinase) are
irreversible.
1. Phosphofructokinase （PFK）
Inhibited by：ATP，Citrate
Activated by：AMP， 2,6-bisphosphate（F-2,6-BP）
55. Lactic acid fermentation
Under anaerobic conditions, reduction of pyruvate
provides a means of reoxidizing the NADH produced
in the glyceraldehyde-3-phosphate dehydrogenase
reaction of glycolysis converted to lactate.
