Monosaccharide (redirected from Monosaccaride)

monosaccharide: see carbohydrate.

---

monosaccharide

Any of the simple sugars that serve as building blocks for carbohydrates. They are classified based on their backbone of carbon (C) atoms: Trioses have three carbon atoms, tetroses four, pentoses five, hexoses six, and heptoses seven. The carbon atoms are bonded to hydrogen atoms (−H), hydroxyl groups (−OH; see functional group), and carbonyl groups (−C=O), whose combinations, order, and configurations allow a large number of stereoisomers (see isomer) to exist. Pentoses include xylose, found in woody materials; arabinose, found in gums from conifers; ribose, a component of RNA and several vitamins; and deoxyribose, a component of DNA. Important hexoses include glucose, galactose, and fructose. Monosaccharides combine with each other and other groups to form a variety of disaccharides, polysaccharides, and other carbohydrates.

---

Monosaccharide

A class of simple sugars containing a chain of 3–10 carbon atoms in the molecule, known as polyhydroxy aldehydes (aldoses) or ketones (ketoses). They are very soluble in water, sparingly soluble in ethanol, and insoluble in ether. The number of monosaccharides known is approximately 70, of which about 20 occur in nature. The remainder are synthetic. The existence of such a large number of compounds is due to the presence of asymmetric carbon atoms in the molecules. Aldohexoses, for example, which include the important sugar glucose, contain no less than four asymmetric atoms, each of which may be present in either d or l configuration. The number of stereoisomers rapidly increases with each additional asymmetric carbon atom.

A list of the best-known monosaccharides is given below:

Aldose monosaccharides having 8, 9, and 10 carbon atoms in their chains have been synthesized. See Carbohydrate