CARBOHYDRAT E CHEMISTRY
Dr.Almoeiz Yousif MS.c.,Ph.D.,MEE
Carbohydrates • (hydrates of carbon) • Carbo(C)……Hydrate Most have formula general Carbo(C)……Hydrate (CH 2 O ) n or H
-
C
I I
-
OH C n H 2 n O n
2 Thursday, April 23, 2020
Carbohydrate Definition
2020 , , polyhydroxyaldehyde or 23 polyhydroxyketone, or a substance that can be hydrolyzed to form these April Thursday, compounds
I (CH2O)n or H - C - OH I 3 Functions of Carbohydrates • •
Energysource Structural role
4 Thursday, April 23, 2020
Classification of Carbohydrates
2020
Monosaccharides - simple sugars , 23
Disaccharides - 2 monosaccharides April Thursday, covalently linked.
Oligosaccharides – 3 to 10 monosaccharides covalently linked.
Polysaccharides - more than 5 10 monosaccharide units covalently linked.
Monosaccharides A monosaccharide is acarbohydrate • carbohydrate (simplesugar) that cannot be hydrolyzed toa simpler also blood sugar sugar blood also • • • biologically importantonesare: Galactose Fructose Glucose : most common sugar, sugar, common most :
: fruit sugar sugar fruit : : sugar found in milk milk in found sugar :
6 Thursday, April 23, 2020
Properties of Monosaccharides
2020 , , • Simplest of carbohydrates 23
• Sweet-tasting Thursday, April April Thursday, • Dissolve in water • Straight chain or ring structure • Reducing sugars
7
Monosaccharide Classification
2020 , ,
• 1- On the basis of the numbers of 23 carbon atoms
• 2- On the basis of the functional April Thursday, group.
8
1. According to number of carbons
2020 , ,
23 • 3 carbons triose • 4 tetrose • 5 pentose (ribose) April Thursday, • 6 hexose (glucose,fructose galactose) • 7 heptose • 8 octose • 9 nonose
9
2.According to functional group
2020 , ,
Aldoses have an aldehyde Ketoses have a keto group, 23 group at one end. usually at C2.
H O April Thursday, C CH2OH
H C OH C O
HO C H HO C H
H C OH H C OH
H C OH H C OH CH OH CH2OH 2 10 D-glucose D-fructose ISOMERS: same chemical
formulae
2020
, , 23
C6H12O6 Thursday, April April Thursday,
11
ISOMERS OF MONOSACCHARIDES
2020 , ,
1) D- and L- isomers 23
Thursday, April April Thursday, = mirror images (enantiomers)
nature important: D-monosaccharides
12
2)Aldoses and Ketoses
2020
, , 23
H O April Thursday, C CH2OH
H C OH C O
HO C H HO C H
H C OH H C OH
H C OH H C OH CH OH CH2OH 2 13 D-glucose D-fructose
2020 , ,
23 Thursday, April April Thursday,
Sugars Prefer To Be Cyclic in solutions
2020
, ,
23 Thursday, April April Thursday,
15
2020
, , 23
April Thursday, 99% of Glucose in solution is found in pyranose form
16
4) and anomers
2020 , ,
23 only cyclic molecules
April Thursday,
-D-Glc
17 * OH orientation of anomeric carbon is the basis of this
classification. 2020 β anomer : Same side with the side chain( the last , carbon atom) 23 α anomer : opposite side with the side chain
April Thursday,
18
5) epimers
2020 , , EPIMERS:differ in 23 conformation around
ONE carbon April Thursday,
Man = 2-epimer of Glc Gal = 4-epimer of Glc
19
2020
, ,
23 Thursday, April April Thursday,
Gal is found in Galaltose and Mannose are lactose (milk sugar) epimers of glucose
20 Joining of
monosaccharaides
2020
, 23 • Monosaccharaides can be joined to form
disaccharides, oligosaccharides, and Thursday, April April Thursday,
polysaccharides. Important disaccharides include
lactose (galactose + glucose), sucrose (glucose +
fructose), and maltose (glucose + glucose).
21
2020
, , 23 • Important polysaccharides include branched
glycogen (from animal sources) and starch (plant Thursday, April April Thursday,
sources) and unbranched cellulose (plant sources);
each is a polymer of glucose.
22
Glycosidic bond
2020
, , 23 • a glycosidic bond or glycosidic linkage is a type of
covalent bond that joins a carbohydrate (sugar) Thursday, April April Thursday,
molecule to another .
23
Naming glycosidic bonds:
2020
, , 23 • Glycosidic bonds between sugars are named
according to the numbers of the connected Thursday, April April Thursday,
carbons, and also with regard to the position of the
anomeric hydroxyl group of the sugar involved in the
bond. If this anomeric hydroxyl is in the α
configuration, the linkage is an α-bond. 24
2020
, , 23 • If it is in the β configuration, the linkage is a β-bond.
Lactose, for example, is synthesized by forming a Thursday, April April Thursday,
glycosidic bond between carbon 1 of β-galactose
and carbon 4 of glucose. The linkage is, therefore, a
β(1→4) glycosidic bond
25 26 Thursday, April 23, 2020
27 Thursday, April 23, 2020
2020 , ,
23 Thursday, April April Thursday,
28
DISACCHARIDES
2020 , ,
23
• Sucrose Thursday, April April Thursday, • LActose • MaltosE
29 Disaccharide
2020 , , • Two joined monosaccharaides are called a disaccharide 23
and these are the simplest polysaccharides. Examples Thursday, April April Thursday, include sucrose and lactose. They are composed of two
monosaccharide units bound together by a covalent bond
known as a glycosidic linkage formed via a dehydration
reaction, resulting in the loss of a hydrogen atom from
one monosaccharide and a hydroxyl group from the other. 30
Lactose Sucrose Maltose • Two Two simplesugars together.joined linkage
monosaccharaides
(milk (milk sugar) = glucose + galactose
(table sugar) = glucose + fructose (malt (malt sugar) = glucose + glucose
to form a Disaccharides disaccharide can join with a .
glycosidic
31 Thursday, April 23, 2020
Maltose
2020 , ,
23 • Maltose is formed by joining two
glucose molecules. April Thursday,
32
Sucrose
2020
, , 23
• is formed by joining glucose and fructose. Thursday, April April Thursday,
33
Lactose
2020
, ,
23 Thursday, April April Thursday,
34 35 Thursday, April 23, 2020
Lactose Intolerance
2020 , , • Symptoms 23
• Bloating, abdominal discomfort, and April Thursday,
diarrhea
• Causes
• Lactase deficiency 36
Oligosaccharid es
• Oligosaccharides e.g.
• • 3 - Dextrin Maltotriose 10
monosaccharaides linked togetherlinked monosaccharaides
( 6 -
8 ( 3 glucose units glucose units
38 Thursday, April 23, 2020
Polysaccharides
Polysaccharides
2020
, , 23 • Polysaccharides: more than 10 monosaccharide
units linked together. Thursday, April April Thursday,
• polysaccharides are insoluble in water.
• Polysaccharides can be polymers of hexose or
pentose sugars.
40 Chitin: Glycogen: Cellulose: Starch: • animals. plants. Examples exoskeletons of insects. of exoskeletons
Polysaccharides
Structural elementthe in Storage form of glucose of glucose Storage formin
Structural element ofplants. Structural
: Polymers of glucose of Polymers : Storage form of glucose in of form Storage
41 Thursday, April 23, 2020
GLYCOGEN
GLUCOSE IS STORED AS GLYCOGEN IN
2020 , ,
LARGE AMOUNTS IN BOTH THE LIVER AND 23
SKELETAL MUSCLES Thursday, April April Thursday,
42
Structural Polysaccharides
2020 , ,
• Chitin is the major 23 element in the exoskeleton of insects
and crustacea where it April Thursday, affords protection and support.
43 44 Thursday, April 23, 2020