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CARBOHYDRATES
Monosaccharides
Disaccharides
Polysaccharides (homo-)
Polysaccharides (hetero-)
What is a carbohydrate?
Ans: A carbohydrate is a polyhydroxy aldehyde or ketone
or a compound that gives rise to such on hydrolysis
1. It must have more than one hydroxy group
2. It must have either an aldehyde or a ketone functional group
3. It can be a large molecule made up of repeating units with
the above characteristics
What is a monosaccharide?
1. Otherwise known as a simple sugar, it’s a carbohydrate that
cannot be converted to a smaller molecule by simple hydrolysis
What is a polysaccharide?
1. Otherwise known as a complex carbohydrate, it’s a
carbohydrate molecule constructed of a smaller repeating unit,
homo (same unit) or hetero (different units).
CARBOHYDRATE TERMS
GENERAL TERMINOLOGY
1. saccharide
2. monosaccharide
3. disaccharide
4. oligosaccharide
5. polysaccharide
6. glycoside
7. triose
8. tetrose
9. pentose
10. hexose
11. Aldose
12. Ketose
13. amino sugar
14. deoxysugar
OPTICAL ACTIVITY AND ISOMERISM
1. Stereo vs structural isomers
2. Optical activity
3. Dextrorotatory (+)
4. Levorotatory (-)
5. Enantiomers
6. Epimers
7.  anomers
8.  anomers
9. D sugar
10. L sugar
11. diastereoisomers
12. Asymmetric carbon
13. Racemic mixture
14. Chiral center
STRUCTURES AND PROPERTIES
1. hemiacetal (hemiketal)
2. acetal (ketal)
3. furanose ring
4. pyranose ring
5. Fischer projection
6. Haworth projection
7. Simple sugar
8. Reducing sugar
9. Enediols
10. Mutarotation
REACTIONS OF MONOSACCHARIDES
1. oxidation
2. reduction
3. lactones
4. Uronic acids
5. Sugar alcohol
6. Glycoside formation
7. esterification
8. dehydration
BIOLOGICALLY IMPORTANT SUGARS
1. ribose
6. D fructose
2. 2-deoxy-D-ribose
7. Sucrose
3. D glucose
8. Lactose
4. D mannose
9. Maltose
5. D galactose
10. Starch
See Strategies
pp123-124
11.
12.
13.
14.
15.
Glycogen
cellulose
 amylose
amylopectin
Hyaluronic acid
SIMPLEST CARBOHYDRATE
CARBONYL GROUP
CHO
CH O
H C OH HO C H
CH2OH
CH2OH
CHIRAL CENTER
PRIMARY ALCOHOL
Anatomy of a Monosaccharide
Reducing
group
Primary
alcohol
Reducing
group
3
CHO
D orientation
C
C OH
3
CH2OH
C=O
C OH
4
CH2OH
4
CH2OH
1
2
Primary
alcohol
Aldose
1
2
Primary
alcohol
Ketose
Simplest Carbohydrate - Quiz
Name?
CH2OH
C=O
CH2OH
Dihydroxy
Acetone
Is this a polyhydroxy aldehyde?
NO
Is this a polyhydroxy ketone?
YES
Is this a carbohydrate?
YES
Is this a D sugar?
NO
Is this an L sugar?
NO
Why?
No chiral center in the molecule
OH Group Configurations
EPIMERS
GLUCO
See carbohydrate
tutorial on web
GALACTO MANNO
ENANTIOMERS
DIASTEREOISOMERS
ENANTIOMERS
CHO
CHO
CHO
H C OH HO C H HO C H
H
H C OH HO C H
H C OH HO
CH2OH
CH2OH
CH2OH
A
B
C
D-SUGARS
L-SUGARS
CHO
C OH
C H
CH2 OH
D
Isomers = 2n
n = no. of chiral cntr
n= 2
Total = 4
By specifying a sugar as D or L we need
name only half of the total
n=3
Total = 8
4
16
Anomeric carbon
RING STRUCTURE OF SUGARS
ANOMERS
OH IS ON SAME SIDE
AS RING OXYGEN
OH IS ON OPPOSITE
SIDE OF RING OXYGEN
*
*
H - C - OH
HO - C - H
O
ALPHA SUGAR
O
BETA SUGAR