Beginning of Essay
also called SIMPLE SUGAR, any of the basic compounds that serve as the building blocks of carbohydrates. are polyhydroxy aldehydes or ketones; that is, they are molecules with more than one hydroxyl group (-OH), and a carbonyl group (C=O) either at the terminal c ....

Middle of Essay
.... from glucose. Important sugar alcohols (alditols), formed by the reduction of (i.e., addition of hydrogen to) a monosaccharide, include sorbitol (glucitol) from glucose and mannitol from mannose; both are used as sweetening agents. Glycosides derived from are widespread in nature, especially in plants. Amino sugars (i.e., sugars in which one or two hydroxyl groups are replaced with an amino group, -NH2) occur as components of glycolipids and in the chitin of arthropods. carbohydrateClasses of carbohydrates Sources The most common naturally occurring are D-glucose, D-mannose, D-fructose, and D-galactose among the hexoses, and D-xylose and L-arabi ....