CARBOHYDRATES
Di, poly-Carbohydrates Carbo MiniTopics
Review
 Elmhurst College
Classification Glucose Fructose  Chemistry Department
Carbo - Isomers Galactose Ribose  Virtual ChemBook

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.