Isomerism Flashcards
2 monosaccharides differ from each other in their configuration around a single specific carbon
Epimerism
C2 epimer
HO - C - H
Mannose
C4 epimer
H - C - OH
Glucose
C4 epimer
HO - C - H
Galactose
Isomers obtained from the change of position of hydroxyl group attached to the anomeric carbon ex. a and b glucose, fructose
Anomerism
OH
hydroxyl not aligned with carbon
Alpha
OH
hydroxyl align with carbon
Beta
change in the specific optical rotation by the interconvension of a and b forms of D glucose to an equilibrium mixture
Mutarotation
OH
|
H
B - D glucose
OH
|
OH
A - D Glucose
HO - H
| |
H OH
B - D Glucose
HO - OH
| |
H OH
A - D Glucose
Monosaccharides
Disaccharides
Oligosaccharides
Polysaccharides
classification of saccharides, sugar, carbohydrates
simplest carbohydrates, 3-6 carbon atoms
Carbonyl group aldehyde or ketone
Several hydroxyl group
Colorless crystalline solids
Monosaccharides
2 monosaccharides
Disaccharides
2-10 monosaccharides
Oligosaccharide
Many monosaccharides
polysaccharides
Monosaccharides- w/ aldehyde group
Many hydroxyl
(-OH) groups
triose (3 carbon atom)
tetrose (4)
pentose (5)
hexose (6)
Aldose
Monosaccharides - w/ ketone group
Many hydroxyl
(-OH) groups
triose (3 carbon atom)
tetrose (4)
pentose (5)
hexose (6)
Ketose
O
||
C - H aldose
|
H - C - OH
|
H - C - OH
|
CH2OH
Erythrose, an aldotetrose
CH2OH
|
C = O ketose
|
H - C - OH
|
H - C - OH
|
H - C - OH
|
CH2OH
Fructose, a ketohexose
Found in fruits, corn syrup, honey
Aldohexose with formula C6H12O6
Blood sugar in body
Monosaccharide in polymers of starch, cellulose, glycogen
D - Glucose
H O
\ /
C
|
H- C - OH
|
HO - C - H
|
H- C - OH
|
H- C - OH
|
CH2OH
D - Glucose
In the body Glucose has normal blood level of 70 - 90 mg/dL
Blood Glucose level
Glucose tolerance test measures blood glucose for several hours after ingesting sugar
Blood Glucose Level
Low glucose
Hypoglycemia
Ketohexose
C6H12O6
Sweetest carbohydrate
Found in fruit, juices, honey
Converts to glucose in the honey
D - Fructose
CH2OH
|
C = OH
|
HO - C - OH
|
H - C - OH
|
H - C - OH
|
CH2OH
D - Fructose
aldohexose
C6H12O6
not found free in nature
Obtained from lactose a disaccharide
similar structure to glucose except for the - OH on C4
D - Galactose
O
||
C - H
|
H - C - OH
|
HO - C - H
|
HO - C - H
|
H - C - OH
|
CH2OH
D - Galactose
Fischer projection
Haworth projection
X-ray diffraction analysis
structure of monosaccharides
straight chain structural formula
Fischer projection
Cyclic formula or ring structure
Haworth projection
boat and chair form
X-ray diffraction analysis
- developed by Hermann Emil Fischer (German)
- represent carbohydrates
- places the most oxidize group at the top
- shows chiral carbons as the intersection of vertical and horizontal lines
Fischer projection
H O
\ /
C
|
HO -+- H
CH2OH
L glyceraldehyde
H O
\ /
C
|
H -+- OH
CH2OH
D glyceraldehyde
- developed by Walter Noman Haworth (British)
- 2 - dimensional structural anotation that specifies the 3 dimensial
- structure of a cyclic form of monosaccharides
Haworth projection
CH2OH
|
________ O
/ \
\ ________ /
Glucose Haworth Projection
prevalent form of monosaccharides with 5 or 6 carbon atoms
Cyclic structure
________ O
/ \
\ ________ /
Pyran
O
/ \
\ /
_____
Furan
Formed when the hydroxyl group on C5 reacts with the aldehyde or ketone group
Cyclic structure
