|
Common Carbohydrates |
|
Name |
Derivation of name and Source |
|
Monosaccharides |
|
Glucose |
From Greek word for sweet wine; grape
sugar, blood sugar, dextrose. |
|
Galactose |
Greek word for milk--"galact",
found as a component of lactose in milk. |
|
Fructose |
Latin word for fruit--"fructus",
also known as levulose,
found in fruits and honey; sweetest sugar. |
|
Ribose |
Ribose and Deoxyribose are found in the backbone
structure of RNA and DNA, respectively. |
|
Disaccharides - contain two monosaccharides |
|
Sucrose |
French word for sugar--"sucre",
a disaccharide containing glucose and fructose; table
sugar, cane sugar, beet sugar. |
|
Lactose |
Latin word for milk--"lact";
a disaccharide found in milk containing glucose and galactose. |
|
Maltose |
French word for "malt";
a disaccharide containing two units of glucose; found
in germinating grains, used to make beer. |
|
Common Polysaccharides |
|
Name |
Source |
|
Starch |
Plants store glucose as the polysaccharide starch.
The cereal grains (wheat, rice, corn, oats, barley) as well as
tubers such as potatoes are rich in starch. |
|
Cellulose |
The major component in the rigid cell walls in
plants is cellulose and is a linear polysaccharide polymer with
many glucose monosaccharide units. |
|
Glycogen |
This is the storage form of glucose in animals
and humans which is analogous to the starch in plants. Glycogen
is synthesized and stored mainly in the liver and the muscles. |
|
Carbohydrates
- Classification
|
Classifications:
There are a variety of interrelated classification schemes.
The most useful classification scheme divides the carbohydrates
into groups according to the number of individual simple sugar
units. Monosaccharides contain a single unit; disaccharides
contain two sugar units; and polysaccharides contain many
sugar units as in polymers - most contain glucose as the monosaccharide
unit.
|
|
Carbohydrates |
|
Monosaccharides |
Disaccharides |
Polysaccharides |
|
Glucose |
Sucrose |
Starch |
|
Galactose |
Maltose |
Glycogen |
|
Fructose |
Lactose |
Cellulose |
|
Ribose |
|
|
|
Glyceraldehyde |
|
|
|
 |
|
Number of Carbons:
Monosaccharides can be further classified by the number of
carbons present.
Hexoses (6-carbons) are by far the most prevalent.
|
Number of Carbons |
|
Six = Hexose |
Five = Pentose |
Three = Triose |
|
Glucose |
Ribose |
Glyceraldehyde |
|
Galactose |
|
|
|
Fructose |
|
|
|
|
Functional Groups:
Aldoses contain the aldehyde group - Monosaccharides
in this group are glucose, galactose, ribose, and glyceraldehyde.
Ketoses contain the ketone group - The major sugar
in this group is fructose.
Reducing: Contain a hemiacetal or hemiketal group.
Sugars include, glucose, galactose, fructose, maltose, lactose
Non-reducing: Contain no hemiacetal groups. Sucrose
and all polysaccharides are in this group.
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