Monosaccharide

Monosaccharides are the simplest form of carbohydrates, consisting of one sugar and are usually colorless, water-soluble, and crystalline solids. Some monosaccharides have a sweet taste. Monosaccharides are the building blocks of disaccharides such as sucrose and polysaccharides (such as cellulose and starch).

Structure

Monosaccharides are classified by the number of carbon atoms they contain: triose (3), tetrose (4), pentose (5), hexose (6), heptose (7), and so on. The chemical formula for all of these monosaccharides is CnH2nOn. Monosaccharides are further classified by functional group: aldose for aldehyde, or ketose for ketone.

Classification

Monosaccharides can be classified into two types: aldoses and ketoses. Aldoses have an aldehyde functional group at the end of the carbon chain and ketoses have a ketone functional group in the middle of the carbon chain.

Functions

Monosaccharides are the major source of fuel for metabolism, being used both as an energy source (glucose being the most important in nature) and in biosynthesis. When monosaccharides are not immediately needed by many cells they are often converted to more space-efficient forms, often polysaccharides. In many animals, including humans, this storage form is glycogen, especially in liver and muscle cells. In plants, starch is used for the same purpose.

See also

• Disaccharide
• Polysaccharide
• Carbohydrate
• Glucose
• Fructose

Monosaccharide

• 
  DL-Glucose
• 
  Existence in solution
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  Structure of D-pentoses
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  Structure of D-hexoses