What is the monosaccharide of sucrose

MonosaccharidesCarbohydratesMonosaccharides are the simplest carbohydrates. Well-known representatives are, for example, glucose (grape sugar), fructose (fruit sugar) and galactose (slimy sugar). Structurally, a distinction is made between aldoses (aldehydes) and ketoses (ketones). Monosaccharides have three or more carbon atoms and they almost invariably contain chiral carbon atoms. Condensation creates disaccharides, trisaccharides, oligosaccharides and polysaccharides. Monosaccharides are essential for life on earth. In pharmacy, they are used, among other things, as sweeteners, flavor corrections, as quick energy suppliers and as auxiliary substances.

synonymous: simple sugar


Pure monosaccharides are available in specialist shops, for example in pharmacies and drug stores. The best-known simple sugars include glucose (grape sugar), fructose (fruit sugar) and galactose (slimy sugar).

Structure and properties

Monosaccharides are the simplest → carbohydrates ("sugars"), which consist of carbon (C), hydrogen (H) and oxygen (O) atoms. The organic compounds have the general formula C.n(H2O)n. There are exceptions, for example deoxyribose. Derivatives such as amino sugars can contain other chemical elements such as nitrogen (N).

Depending on the number of carbon atoms, a distinction is made between trioses (3), tetroses (4), pentoses (5), hexoses (6), heptoses (7) and so on. The most important of them belong to the pentoses and hexoses.

Depending on whether it is aldehydes or ketones, one speaks of aldoses or ketoses. Simple sugars can be open or as rings.

With the exception of dihydroxyacetone, monosaccharides contain chiral carbon atoms. For example, glucose has four centers of chirality and there are 16 isomers. With the Fischer projection these can be easily distinguished. The designation D- (Dextro, right) and L- (Levo, left) refer to the configuration of the chiral C atom that is furthest away from the carbonyl group (C = O). So the glucose, mannose and galactose are all isomers of each other.

Condensation turns the simple sugars into disaccharides (e.g. sucrose, lactose), trisaccharides (e.g. raffinose), oligosaccharides and polysaccharides such as starch, xylan and celluloses.

Because of the hydroxyl groups, monosaccharides are usually readily soluble in water and are mostly in the form of crystalline powders.




  • Erythrosis
  • Erythrulosis
  • Threose


  • Arabinose
  • Deoxyribose
  • Lyxosis
  • Ribose
  • Ribulose
  • Xylose (wood sugar)
  • Xylulose


Examples: aldoses

The following figure shows examples of aldoses:


Some monosaccharides have a sweet taste. Many can be metabolized by the body and serve as energy sources.

As carbohydrates, the monosaccharides are among the most important biomolecules and they are indispensable for life on earth, for example for the production and storage of energy (e.g. glycogen, starch), for the structure of living things (e.g. celluloses), for the structure of the Nucleic acids and for metabolism.

Areas of application see also

Carbohydrates, disaccharides, polysaccharides

  • Medicinal product information (CH)
  • European Pharmacopoeia PhEur
  • Specialist literature
  • Textbooks of chemistry and biochemistry

Conflicts of Interest: None / Independent. The author has no relationships with the manufacturers and is not involved in the sale of the products mentioned.

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This article was last changed on 10/18/2020.
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