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Carbohydrates
Carbohydrate
• hydrate of carbon – Cn(H2O)m
• Glucose -blood sugar- C6H12O6 or C6(H2O)6
• Sucrose -table sugar- C12H22O11 or C12(H2O)11
• Not all carbohydrates have this exact form
– old habits die slow or sometimes never at all
Monosaccharides
• Formula CnH2nOn
• One carbon is either an aldehyde or ketone
• The suffix ose indicates that the molecule is a carbohydrate
• Use prefix to indicate number of carbons tri , tetr, pent, hex
• Aldose – contain an aldehyde group• Ketose – contain a ketone group
Monosaccharides
• Aldohexoses
Aldohexosesaldehyde function
six carbons
carbohydratesor
saccharides
other examples: ketotetrose, aldotriose, ketopentose
Fischer Projections
• Emil Fischer (late 1800’s)
– Side groups come out of the plane (towards you)– Vertical groups go back away from you
HHO
CHO
HHO
CH2OH
H OH
CHO
H OH
CH2OH
OHH
CHO
HHO
CH2OH
HO H
CHO
H OH
CH2OH
A B C D
Naming Aldotriose and aldotetrose
Remember ET goes home left at T
Naming AldoPentose
RAXL – Ribose, Araginose, Xylose, Lyxose
Right – Top – Middle – Top/Middle
Naming Aldohexoses
• All Altrose Gladly Make Gum in Gallon Tanks
• Bottom – all right
• 2 up – 4x4
• 3 up – 2x2 like Noahs Ark
• 4 up – alternate
R/S and D/L
• R = D - dextrorotatory• S = L - levarotatory• D – A monosaccharide with the
Penultimate OH group on the right in a Fischer Projection
• L - A monosaccharide with the penultimate OH group on the left in a Fischer Projection
OK, so what’s a penultimate????
Ketoses
• Note:
The ketone is located
on carbon #2
triose
tetrose
pentoses
hexoses
*
*
Penultimate is the nextTo last carbon
Amino Sugars
• Contain an NH2 group instead of an OH
• 1st three are common in nature
Cyclic structure of monsacharides
• It’s the hemiacetal reaction all over
• We draw them as Haworth Projections
• Practice practice practice
From yahoo images
Reactions of Monosacharides
• Practice
From yahoo images
The two Most Significant Sugars
• Ketose– D-Fructose– Known as “fruit
sugar”– Found combined with
glucosein the disaccharide sucrose
HO
D-fructose
CH 2O H
CH 2O H
O H
O
OH
•Aldose -D-glucose
-The most important monosaccharide -White solid -Formula C6H12O6
- Sugar used in our bodies
CH2OH
C
C
C
C
C
OH
OH
H
OH
H
O
H
HO
H
H
1
2
3
4
5
6
Multiple Sugars
• Monosaccharides – Single Carbohydrate unit• Disaccharides - two monosaccharides combined• Oligosaccharides - three to ten monosaccharides• Polsaccharide – More than ten monoscharides
Three Disaccharides
• Sucrose
• Lactose
• Maltose
Disaccharides
• Sucrose– A disaccharide– One D-glucose and
one D-Fructose– Connected by two anomeric carbons:
C-1 on glucose and C-2 on fructose linkages:α linkage on glucose andβ linkage on fructose
D-glucose
O
D-fructose
*
Disaccharides
• Sucrose– Anomeric C are tied-up
on both sugars
– No oxidation can occurno hemi-acetals
– Sucrose is a non-reducing sugar
– Hydrolyzed by enzymes to form a mixture ofglucose and fructose - “invert sugar”
D-glucose
O
D-fructose
*
Disaccharides
• Sucrose
α-D-glucose
O
CH2OHHO
OH
HOCH2
O
O
OHHO
HO
HOCH2
β-D-fructose
α-C-1
β-C-2
*
Disaccharides
• Lactose– A disaccharide
– One D-galactose andone D-glucose
– Connected by an β linkagebetween D-Galactose C-1 and D-Glucose C-4
– Known as an β-1,4 linkage– Found in mammalian milk
D-galactose
O
D-glucose
*
Disaccharides
O
OH
OHHO
ΟΗ
HOCH2 O
OH
OHHO
HO
HOCH2+
O
OH
OHHO
HOCH2
O
O
OHHO
ΟΗ
HOCH2
Galactose
β-D-galactose α-D-glucose
β-1,4 linkage
Lactose
Disaccharides
• Maltose– A disaccharide
– Two D-glucose monomers
– Connected by an α linkagebetween C-1 and C-4
– Known as an α-1,4 linkage (two D-glucose molecules)
– An ingredient in most syrups– “Malt sugar”
D-glucose
O
D-glucose
*
Disaccharides
O
OH
OHHO
HO
HOCH2 O
OH
OHHO
HO
HOCH2+
O
O
OHHO
HO
HOCH2
O
OH
OHHO
HOCH2Maltose
α-D-glucose α-D-glucose
α-1,4 linkage
Polysaccharides
• Starch - Amylose– Many units of α-D-glucose– Linkages are α-1,4 (same as Maltose)
– Between 1000-2000 glucoseunits (polyglucose)
– Random coils or helix
*
Polysaccharides
• Starch - Amylopectin– Also many units of α-D-glucose– Linkages are α-1,4 and α-1,6– Lots of branching– 20 to 25 glucose monomers in
the straight chain and then branching– A total of 105 to 106 glucose molecules– Use Iodine (I2) to test for starches
*
Polysaccharides
• Glycogen– Animal energy storage (about 400 g in us)
– α-D-glucose polymer– Similar to amylopectin but smaller chains– Linkages are α-1,4 and α-1,6 (branching)– 10 to 20 glucose monomers in the
straight chain and then branching– A total of 105 to 106 glucose molecules
*
Polysaccharides
• Cellulose– Linear polymer of D-glucose– Linkages are β-1,4 !– The most abundant molecule in
living tissues– Cotton is about 95% cellulose– 300 to 3000 glucose units– Form fibrous rods
*
Polysaccharides
• Cellulose– We cannot digest cellulose
• β glucose linkages!
• Many bacteria and fungihave necessary enzyme
• Ruminant mammals carrythese bacteria
• Termites also have necessarymicroorganisms
*
O
O
O
HOCH2
OH
OH
OH
OH
HOCH2
)(O O
OHOCH2
OH
OH
OH
OH
HOCH2
)
(Starch
alpha linkage Cellulose beta linkage