introduction of Carbohydrates,Classification function and structural elucidation or constitution of carbohydrates

1. CHEMISTRY OF CARBOHYDRATES
PRESENTED BY:
MR.MOTE G.D.
AGCOP,SATARA
1

2. OBJECTIVES
Introduction and Definition
Isomerism in Sugars
Classification
Important Carbohydrates
Biomedical Importance of Carbohydrates
2

3. INTRODUCTION
Hydrates of carbon
Saccharides — sugars
Some contain N and S
Synthesized in
Plants
Animals
3

4. DEFINITION
Carbohydrates are polyhydroxylated compounds having at
least 3 carbon atoms and a potentially active carbonyl group
which may be an aldose or a ketose group.
Examples are: glucose, ribose.
4

5. GLUCOSE
CHO
C OHH
C HHO
C OHH
C OHH
CH2OH
D-Glucose
5

6. ANOMERIC CARBON ATOM
The carbon atom which is part of the carbonyl group
Alpha( )α and Beta( )β anomers differ from each other only in
respect to configuration around anomeric carbon atom.
6

7. 7

8. ISOMERISM IN SUGARS
 Isomers/Stereo-isomers: Compounds having the same
chemical formulae but differing in the arrangement of their
atoms in space and having different physical properties are
called isomers.
8

9. Mutarotation
Defination:The optical rotation is changes gradualy until
constant rotation is attained this phenomenon is also known
as Mutarotaion
e.g: glucose is dissolved in water,its optical rotation gradualy
changes from 111° to 52.5 when solution is allowed to stand
Key features:
All reducing sugars exhibit mutarotation
The phenomenon of mutarotation occures slowly in aqueous
medium
Mutarotation study can be done by changing NMR,IR,Mass
Spectra
9

10. EPIMERS
Monosaccharides which differ in configuration around one
specific C-atom are called epimers of one another
C-2 epimers
glucose and mannose
C-4 epimers
glucose and galactose
10

11. H C O
H C OH
HO C H
H C OH
H C OH
CH2OH
D-GLUCOSE
H C O
HO C H
HO C H
H C OH
H C OH
CH2OH
D-MANNOSE
CARBON-2 EPIMERS
11

12. CARBON-4 EPIMERS
H C O
H C OH
HO C H
H C OH
H C OH
CH2OH
D-GLUCOSE
H C O
H C OH
HO C H
HO C H
H C OH
CH2OH
D-GALACTOSE
12

13. Carbohydrates
Monosaccharides Oligosaccharides Derived
Disaccharides Carbohydrates
Aldoses Ketoses
Oxidation
Polysaccharides Reduction
Amino sugars
Homopolysaccharides Deoxy sugars
CLASSIFICATION OF CARBOHYDRATES
13

14. MONOSACCHARIDES
No of C-atoms Potentially active
carbonyl group
Trioses
Tetroses
Pentoses Aldoses Ketoses
Hexoses
Heptoses “These carbohydrates cannot
Octoses be hydrolyzed into simpler compounds”
14

15. Aldehyde CHO Ketone C O15

16. Reducing and Non-Reducing Sugars
Reduction is the chemist’s term for electron gain
A molecule that gains an electron is thus……
“reduced”
A molecule that donates electrons is called a……
“reducing agent”
A sugar that donates electrons is called a……
“reducing sugar”
The electron is donated by the carbonyl group
Benedict’s reagent changes colour when exposed to a
reducing agent
16

17. 17

18. Benedict’s Test
 Benedict’s reagent undergoes a
complex colour change when it
is reduced
 The intensity of the colour
change is proportional to the
concentration of reducing sugar
present
 The colour change sequence is:
 Blue…
 green…
 yellow…
 orange…
 brick red
18

19. The carbonyl group - monosaccharides
The carbonyl group is “free”
in the straight chain form
But not free in the ring
form
BUT remember – the ring
form and the straight chain
form are interchangeable
So all monosaccharides are
reducing sugars
All monosaccharides reduce
Benedict’s reagent
19

20. The carbonyl group –
disaccharides - sucrose
 In some disaccharides e.g.
sucrose both of the carbonyl
groups are involved in the
glycosidic bond
 So there are no free carbonyl
groups
 Such sugars are called non-
reducing sugars
 They do NOT reduce
Benedict’s reagent
20

21. The carbonyl group –
disaccharides - sucrose
 The subunits of sucrose
(glucose and fructose) are
reducing sugars
 If sucrose is hydrolysed the
subunit can then act as
reducing sugars
 This is done in the lab by acid
hydrolysis
 After acid hydrolysis sucrose
will reduce Benedict’s
reagent
21

22. OLIGOSACCHARIDES
These are the condensation products of 2 to 10
monosaccharide units
Disaccharides: These are the condensation products of two
monosaccharide units e.g. sucrose, lactose.
22

23. POLYSACCHARIDES
These are the condensation products of more than 10 molecules of
monosaccharide units
They include starch, glycogen.
Stores of fuel
Structural elements of cells
23

24. POLYSACCHARIDES
Homopolysaccharides
Heteropolysaccharides
*Starch
*Glycogen Glycoseaminoglycans
*Cellulose Mucilages
*Dextrins *Hyaluronic acid
*Heparin *Agar
*Chondoitin SO4 *Vegetable
*Serum mucoids gums
*Blood gp *Pectins
polysaccharides *Hemicellulose
24

25. DERIVED CARBOHYRATES
Oxidation Reduction Amino Deoxy
Products Products Sugars Sugars
Gluconic acid Glycerol Glucosamine
Glucuronic acid Ribitol Galactoseamine
Glucaric acid Mannoseamine
Deoxyribose
“These are derived from carbohydrates by various chemical
reactions”
25

26. OH
H
OHOH
H
CH2OH
HH
OH
H
HOH
H
CH2OH
HH
DEOXYRIBOSE SUGARS
26

27. IMPORTANT CARBOHYDRATES
MONOSACCHARIDES
PENTOSES
Ribose:
Found in nucleic acids
Forms structural elements of nucleic acid and coenzymes
Intermediates of pentose phosphate pathway
ATP, NAD, NADP, flavoproteins etc
27

28.  HEXOSES
Glucose
 Found in fruits, fruit juices, hydrolysis of starch, maltose
and lactose.
 Body sugar and the principal one used by the tissues
 Excess in the blood is called hyperglycemia and presence in
urine (glucosuria) indicates diabetes mellitus
Cataract due to sorbitol
28

29. Fructose
Latin word for fruit — "fructus"
Found in fruit juices, honey
Released by the hydrolysis of inulin
 Main nutritional source of energy for the spermatozoa and is
found in the seminal fluid
Can be converted to glucose in the liver
It is the sweetest sugar
Lack of enzymes of metabolism can lead to essential fructosuria
29

30. Galactose
Greek word for milk--"galact", found as a component of
lactose in milk
Formed by the hydrolysis of lactose
Synthesized in the lactating mammary gland
Constituent of glycolipids and glycoproteins
Can be converted to glucose in the liver
Accumulation can lead to galactosemia and cataract
(galactitol)
30

31. 31

32. OLIGOSACCHARIDES
Sucrose
 Known as table sugar
 -D-glucose ------ -D- fructoseα β
 -1 -2α β
Sucrose
α-D-glucopyranosyl-(1 2)-β-D-fructofuranoside
32

33. Commonly known as malt sugar.
 Present in germinating grain.
 Produced commercially by hydrolysis of starch.
Maltose
33

34. Formation of maltose
34

35. Commercially known as milk sugar.
Bacteria cause fermentation of lactose forming lactic acid.
 When these reaction occur ,it changes the taste to a sour one.
Lactose
35

36. Formation of lactose
36

37. Glycosidic linkage between glucose
37

38. HOMOPOLYSACCHARIDES
Starch
 Main storage form of glucose in plants
 Polysaccharide units
• Amylose (20—28%)
• Amylopectin 72—80%)
 Polymer of -D-glucoseα
 -1 4 glycosidic linkageα
 At branching points -1 6 linkageα
 No free aldehyde group
 Found in wheat, rice, corn, potatoes38

39. Starch
39

40. Form Linear Branch
Linkage α-1,4
(some α-
1,6)
α-1,4; α-
1,6
Polymer units 200-2,000 Up to
2,000,000
Molecular
weight
Generally
<0.5 million
50-500
million
Gel formation Firm Non-
gelling to
soft
Characteristics of Amylose and Amylopectin
Characteristic Amylose Amylopectin
40

41. Glycogen
 Known as animal starch
 Present in the liver and muscle
 Both -1 4 and -1-6 linkages are foundα α
 More branched structure than starch
Gives red color with iodine
41

42. Glycogen
42

43. Reactions of Monosacharides
OH
H
CH2OH
H
OH
H
OH
OH
H
D-Glucose
CHO
C OHH
C HHO
C OHH
C OHH
CH2OH
D-Glucose
CH2OH
C OHH
C HHO
C OHH
C OHH
CH2OH
D-Sorbitol
NaBH4
Reduction:
43

44. Reactions of monosacharides
Oxidation:
CHO
C OHH
C HHO
C OHH
C OHH
CH2OH
D-Glucose
O
COOH
C OHH
C HHO
C OHH
C OHH
CH2OH
Gluconic Acid
OC
C OHH
C HHO
CH
C OHH
CH2OH
lactone
NaBH4
CH2OH
C OHH
C HHO
C OHH
C OHH
CH2OH
D-Sorbitol44

45. Reactions of Monosacharides:
OH
H
CH2OH
H
OH
H
OH
OH
H
D-Glucose
H3C C O
C OH3C
Acetic anhydride
CH3CN
HOAc
H
CH2OAc
H
OAc
H
CH2OAc
OAc
H
Penta-o-acetyl-D-Glucose
CHO
C OHH
C HHO
C OHH
C OHH
CH2OH
D-Glucose
CH3OH
HCl H
CH2OH
H
OH
H
OH
OH
H
OCH3
H
Methyl glucopyranoside
Glycoside formation:
Acetylation Reaction:
45

46. Reactions of Monosacharides
O
H
H
H
OH
H
OH
H
HO
D-Glucose
CH2OH
H
H2SO4
Heat
O
C
O
HHOH2C
5-Hydroxymethyl Furfural
Action of acid:
Action of base:
CHO
C OHH
HC OH
C OHH
C OHH
CH2OH
2(D-Glucose)
Dil NaOH
Warm
CHO
C HHO
HC OH
C OHH
C OHH
CH2OH
D-Mannose
CH2OH
C O
HC OH
C OHH
C OHH
CH2OH
D-Fructose
46

47. Reactions of Monosacharides:
Fermentation:
C6H12O6 C2H5OH+2CO2
Glucose ethylalcohol
47

48. Constitution of Glucose:
 Molecular formula: C6H12O6
 Pressence of Aldehude Group:glucose reacts with phenyl hydrazine to form phenyl hydrazone.this
reaction indicate the pressence of a carbonyl group.
 Pressence of 5-OH groups:when glucose reacts with acetic anhydride in presence of pyridine to
form glucose pentaacetate is formed .this indicates presence of Hydroxyl group
 Presence of straight chain of carbon atoms:when glucose is reduced with hydrogen in the presence
of nickel catalyst gives sorbitol and reduction with HI gives n-hexane .this reaction indicates that the
six carbon atoms present in glucose.
 Open chain structure of Glucose:
1. glucose contains a straight chain of six carbon atom
2. One end of carbon atom is aldehyde and other is alcohol
3. Remaining four carbon atom carries a hydrogen atom and hydroxyl group.
48

49. STRUCTURAL ELUCIDATION OF
GLUCOSE
49

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78. 78

79. Fructose:
Preparation:fructose may be prepared in the laboratory by
hydolysis of sucrose with dilute sulphuric acid
C12H22O11 +H2O C6H12O6+C6H12O6
Sucrose water glucose fructose
79

80. Reactions of fructose:
1. Reaction with hydrogen cyanide:Fructose yields a
cyanohydrin with hydrogen cyanide gives fructose
cyanohydrin
CH2OH
C O
HC OH
C OHH
C OHH
CH2OH
D-Fructose
HCN
CH2OH
C OH
HC OH
C OHH
C OHH
CH2OH
Fructose cyanohydrin
NC
80

81. Reaction with hydroxylamines
Fructose reacts with hydroxylamine to yeild an oxime
CH2OH
C O
HC OH
C OHH
C OHH
CH2OH
D-Fructose
NH2OH
CH2OH
C NOH
HC OH
C OHH
C OHH
CH2OH
Fructose oxime
81

82. Reaction with phenylhydrazine
On treatment with equimolar quantities of phenyl hydrazine gives
phenyl hydrazone
CH2OH
C O
HC OH
C OHH
C OHH
CH2OH
D-Fructose
C6H5NHNH2
CH2OH
C NNHC6H5
HC OH
C OHH
C OHH
CH2OH
Fructose phenyl hydrazone
82

83. Reduction:
CH2OH
C O
HC OH
C OHH
C OHH
CH2OH
D-Fructose
2H
CH2OH
C OHH
C HHO
C OHH
C OHH
CH2OH
Sorbitol
CH2OH
C HHO
C HHO
C OHH
C OHH
CH2OH
Mannitol
83

84. Oxidation:
CH2OH
C O
HC OH
C OHH
C OHH
CH2OH
D-Fructose
Br2
COOH
(CHOH)3
COOH
CO2 + H2O
Trihydroxy glutaric acid
84

85. Acetylation:
CH2OH
C O
HC OH
C OHH
C OHH
CH2OH
D-Fructose
5(CH3CO)2O
CH2OOCH3
C O
HC OOCH3
C OOCH3H
C OOCH3H
CH2OOCH3
Fructose pentacetate
85

86. Reaction with alcohol
CH2OH
C O
HC OH
C OHH
C OHH
CH2OH
D-Fructose
CH3OH
CH2OCH3
C O
HC OH
C OHH
C OHH
CH2OH
Fructoside
86

87. STRUCTURAL ELUCIDATION OF
FRUCTOSE
87

88.  Fructose also known as levulose or fruit sugar is found in
many fruits and in honey.
 It occur in combination with glucose in cane and beet sugars.
The most important source of fructose is the polysaccharide
inulin.
 Commercially, fructose is obtained by the hydrolysis of
inulin.
 Crystalline D-fructose melts at 1040
c, it is the sweetest of the
sugars, but is seldom used in pure form .it exibits
mutarotation; the specific rotation values of alfa- and beta –
and equilibrium mixture are -210
, 133.50
and -92.30
; respetively.
88

89.  Fructose responds most of the usual properties of the ketonic
and hydroxyl groups.
 A very important property of the fructose is that although it
has no aldehydic group ,it reduces fehling solution and Tollen’s
reagent.
 This reducing property of fructose is said to be due to the
presence on an α-hydroxy ketonic group which is readily
oxidised by fehling and Tollen’s reagent.
Tartaric acid
89

90.  Fructose from an insoluble calicium fructosate with lime
water (difference from glucose) . This fact is utilised in
the separation of glucose and fructose by the hydrolysis
of sucrose.
CONSTITUTION OF FRUCTOSE :
 From the qualitative and quantitative analysis ,fructose
is found to have its molecular formula as C6H12O6
 Fructose is found to have five hydroxyl groups on five
different carbon atoms .
90

91.  Fructose forms a cyanohydrin and an oxime
indicating the presence of carbonyl group, since
fructose on oxidation with nitric acid gives a mixture
of tartaric acid and glycolic acid (each having lesser
number of carbon atoms), the carbonyl group is ketonic
in nature.
 The formation of glycolic and tartaric acids
indicates that the ketonic group is present at second
position.
91

92.  On reducing with sodium amalgam and
water, fructose gives hexahydric acid and
sorbitol and mannitol.
 Which on further reduction with
hydriodic acid and red phosphorus gives
2-iodohexane and n-hexane which suggest
that in fructose molecule the six carbon
atoms are present in a straight chain.
92

93.  Fructose on treatment with hydrogen cyanide gives
cyanohydrin which on hydrolysis followed by reduction
hydriodic acid and red phosphorus give n-
butylmethylacetic acid, CH3CH2CH2CH2CH(CH3).COOH
 The formation of this compound again indicates that the
ketonic group present at second position .The straight chain structure of fructose may be written as
n-butylmethylacetic acid
Fructose93

94. Tartaric acidGlycolic acid
Fructose
94

95.  CONFIGURATION OF FRUCTOSE:
 Since the above structure has three asymmetric carbon
atoms it may exist in eight (2
3
=8) optical isomers.
 The exact configuration of the fructose is established by that
it forms the same osazone as glucose indicating there by
that the configurations of C3to C6 atoms of fructose is same as
that of glucose.
 Hence the complete open-chain formula of fructose may be
written as below.
95

96.  RING STRUCTURE OF FRUCTOSE:
 Fructose exhibits mutarotation and forms two methyl
fructosides. That is α and β forms.
 The commercial and natural free fructose is most probably β-
isomer with a pyranose ring. But the fructose found in sucrose
(a disaccharide) and inulin (a polysaccharide) is present inn
furanose ring which during hydrolysis is converted into more
stable pyranose form.
 Lastly , since the fructose is laevorotatory and has D-
configuration of glucose ,it is denoted by D(-)-fructose.
D-Fructose96

97. STRUCTURAL ELUCIDATION OF
SUCROSE
97

98.  Sucrose is the commonest sugar known. The most common
sources are sugar cane and sugar beets and other sources are
maple saps, honey and fruit juices.
 The use of sugar is as food in various forms.
 The molecular formula is C12H22O11
 On hydrolysis with acids or enzymes, sucrose gives equal
parts of glucose and fructose; which thus constitute the two
monosaccharides units of sucrose.
98

99.  Sucrose neither reacts with phenylhydrazine nor reduce
Fehling’s solution indicating that the carbonyl group of the both
monosaccharides involved in linkage.
 The glucose linked via its to the of fructose.
 Sucrose is hydrolysed by maltase but not by emulsin , thus
indicating an alfa-D –glucose unit.
 Sucrose is also hydrolysed by an enzyme takainvertase thus
indicates the beta-D-fructofuranose unit in sucrose.
99

100. The identities of these products demonstrate that the glucose portion
is a pyranoside(1:5 linkage) and that the fructose portion is a
furanoside(2:5 linkage)
100

101. Confirmation of Sucrose
 The structure of sucrose has been confirmed by several physical and
chemical evidences.
 Determination of stereochemistry of D-glucoside and D-fructoside
linkage is complicated by the fact that both linkages are hydrolyzed at
the same time.
 The structure of sucrose has been confirmed by X-ray analysis
 The X-ray analysis of susrose sodium bromide dihydrate confirmed
the stereochecal configuration found chemically ,and also the five
membered ring of fructose.
101

102. Periodic acid method :
 Periodate oxidation conforms the structure of sucrose by
following reaction.
 When sucrose is treated with three moles of periodic acid ,
one mole of formic acid and one mole of a tetra-aldehydes are
formed .

 The Latter compound on oxidation with bromine water follwed
by acid hydrolysis yields a mixture of glyoxylic , glyceric and
hydroxypyruvic acids.
102

103. 103

104. STRUCTURAL ELUCIDATION OF
LACTOSE
104

105. Lactose occures in mammalian milk, e.g.,cow’s milk
contains 4 to 6 % and human milk conains 5 to 8% of this
sugar.
Lactose molecular formula is C12H22O11
 Lactose reduces on fehling’s solution, Tollen’s solution
and benedict’s solution, it forms an osazone and exhibits
mutarotation. Therfore, lactose must possess at least one
carbonyl group which is not involved in he disaccharide
linkage.
105

106.  On acidic or enzymatic (lactase) hydrolysis lactose gives
equimolar amounts of glucose and galactose.
106

107. Since lactose is hydrolysed only by lactase(identical with
emulisin) the two monosaccharide units are linked
through beta –glycosidic linkage. This is also indicated by
its low specific rotation.
Lactose
107

108.  When lactose is methylated, it yields methyl
heptamethyl lactose which, on vigorous hydrolysis,
yields 2,3,6-tri-o-mehyl-D-glucose and 2,3,4,6-
tetra-O-methyl-D-galactose.
 The formation of these products reveals that
glucose is the reducing half.
108

109. When lactose is oxidised by bromine water, it yields
lactobionic acid which, on methylation and hydrolysis yields
2,3,5,6-tetra-O-methyl-D-gluconic acid and 2,3,5,6-tetra-O-
methyl-D-galactose.
109

110.  The formation of these products reveals that in lactose
C-1 of glucose is linked to C-4 of galactose.
 This further reveals that glucose is a reducing part and
D-galactose in non-reducing part in lactose.
 The point of linkage (C-4) of galactose unit is further
confirmed by osazone formation.
110

111.  When lactosazone is subjected to acid hydrolysis, it
yields D-galactose and D-glucosazone.
 This reaction show that in lactose it is the glucose unit
which possesses a reducing group
111

112. Conformation structure of lactose.
112

113. Structural elucidation of maltose:
113

114. Maltose:
It is also known as malt sugar
It is diasachride obtained by careful hydrolysis of starch in
aqueous acid
Maltose is also formed in one stage of the fermentation of of
starch to ethyl alcohol,here hydrolysis is catalysed by enzyme
diastase
Maltose is white crysatlline solid,m.p.160-165°c
It is soluble in water and is dextrorotatory
114

115. Constitution of maltose
 Molecular formula of maltose has been found to be C12H22O11
 maltose is reducing sugar because it reduces
Benidicts,Tollen’s and Fehling reagent.
 It reacts with phenyl hydrazine to form osazone
 When maltsoe is oxidized in presence bromine to form
monocarboxylic acid(maltonic acid)
 When maltose is hydrolyzed in aqueous acid it yields two
molecules of glucose
 C12H22O11 C6H12O6 + C6H12O6
115

116. Constitution of maltose
Methylation of maltonic acid followed by acid hydrolysis
gives 2,3,4,6 tetra-o-methyl-D-glucose and 2,3,5,6-tetra-o-
methyl-D-gluconic acid indicates that in first product having
free OH group at 5th
position and second product having free
OH group at 4th
position which are involved in glycosidic
linkage.
Presence of free OH group indicates reducing sugar
116

117. General methods employed for
elucidation of polysacharides
1) Acid hydrolysis
2) Acetolysis
3) Enzyme hydrolysis
4) Methylation
5) Periodic oxidation
6) Molecular weight determination
117

118. General methods employed for
elucidation of polysacharides
1) Acid hydrolysis:A polysaccharide on treatment with acid
undergoes complete hydrolysis to yield monosacharide
units which can be identified by chromatographic
technique.e.g.paper chromatography
2) Acetolysis:in this method,a polysacharide is subjected to
simultaneous acetylation and hydrolysis
118

119. General methods employed for
elucidation of polysacharides
3) Enzyme hydrolysis:Enzyme are specific in their action,their
for their action on polysacharide gives idea about the
configuration of glycosidic linkage
4) Methylation:methylation of polysacharide is done by
adding barium oxide and methyl iodide to the solution of
polysachrides. the completion of methylation is confirmed
by the absence of hydroxyl bond in the infrared
spectrum.methylation of sugar gives information about the
point of attachment of the sugar units through the
glycosidic linkage
119

120. General methods employed for
elucidation of polysacharides
5) Periodic oxidation:it is most important method for
establishing the mode of linkage in di and polysacharides.it
yeilds different products in 1-2 linkage,1-3 linkage,1-4
linkage,1-6 linkage.
This method involves the oxidation of the polysachride
molecule followed by reduction to yield fragments that
reveal the mode of linkgae present in original polysacharide
120

121. General methods employed for
elucidation of polysacharides
6) Molecular weight determination:it gives information about
number of sugar molecule in polysachride.the various
physical and chemical methods which are used for
measuring the molecular weight of
polysacharides.e.g.viscosity, osmotic pressure,
sedimentation, light scattering,X-ray,electrophoresis.
121

122. Constitution of cellulose
Molecular formula (C6H10O5)n
When cellulose is hydrolysed with hydrochloric acid gives D-
glucose.this reaction reveals that cellulose is made up of
glucose unit
As methylation,acetlyation and nitration of cellulose produce
a trisubstitution product
Fully methylated cellulose,when subjected to hydrolysis
yeilds 2,3,6 tri-o-methyl-D-glucose .it reveals that the three
free hydroxyl groups in each glucose
When cellulose is dissloved in water it produces colloidal
solution,this reveals that cellulose is a linear molecule
122

123. Constitution of starch
Molecular formula (C6H10O5)n
When cellulose is hydrolysed with hydrochloric acid gives D-
glucose.this reaction reveals that cellulose is made up of
glucose unit
As methylation,acetlyation and nitration of cellulose produce
a trisubstitution product
Fully methylated cellulose,when subjected to hydrolysis
yeilds 2,3,6 tri-o-methyl-D-glucose .it reveals that the three
free hydroxyl groups in each glucose
Starch is hydrolysed by the enzyme called diastase to
maltose.this reveals that starch contains maltose unit.
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124. 124
Sr.No starch cellulose
1. Reserve food material in plant It chief component of wood
2 It can be seperated into two
component,amylose and
amylopectin
It is single component
3. Amylose and amylopectin linked
through α-glycosidic linkage
It contains D-glucose interconnected by B-
glucoside linkage
4. Amylose chain acquire helical
structure
Cellulose acquire rope like structure
5. It gives blue color with Iodine It doesnot give blue color with iodine

125. 125

126. GLYCOSIDES
A glycoside is an organic compound, usually of plant origin,
that is composed of a sugar portion linked to a non-sugar
moiety. The sugar portion is called glycone, while the non-
sugar portion is called aglycone .
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127. GLYCOSIDES
The linkage between the sugar and the
aglycone is an acetal linkage.
Types of Glycosides :
According to atoms involved in the
glycosidic linkage:
1- O-glycosides
2- C-glycosides
3- S-glycosides
4- N-glycosides
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128. GLYCOSIDES
 Cardiac glycosides Digitalis useful in
Congestive cardiac failure. They contain
Steroid as aglycone.
128

129. BIOMEDICAL
IMPORTANCE
OF
CARBOHYDRATES
129

130. BIOMEDICAL IMPORTANCE
 Glucose — most important carbohydrate
 Glucose can be converted into
• glycogen
• ribose
• galactose
 Glycoproteins — molecular targeting
 Antibodies and blood clotting factors
 Structural components of cell membranes
130

131. Neuronal adhesion in development of nervous system
(protein-glycan-heparan-sulfate)
 Constituents of extra cellular matrix
 Diseases associated with carbohydrates
• Diabetes mellitus
• Galactosemia
• Lactose intolerance
• Glycogen storage diseases
131

132. 132