Di-, Poly-Carbohydrates


General names for carbohydrates include sugars, starches, saccharides, and polysaccharides. The term saccharide is derived from the Latin word " sacchararum" from the sweet taste of sugars.

Monosaccharides contain one sugar unit such as glucose, galactose, fructose, etc.

Disaccharides contain two sugar units. In almost all cases one of the sugars is glucose, with the other sugar being galactose, fructose, or another glucose. Common disaccharides are maltose, lactose, and sucrose.

Polysaccharides contain many sugar units in long polymer chains of many repeating units. The most common sugar unit is glucose. Common poly saccharides are starch, glycogen, and cellulose.



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.


adapted from www.elmhurst.edu

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