Kids Research Express

Glycosides, class of complex chemical compounds in plants. They are broken down by plant enzymes into sugars, among which glucose is generally included, and into other substances. The term glucoside is often used synonymously with glycoside, but in its more specific meaning it refers to glycosides that yield glucose. Each glycoside in a plant is hydrolyzed (converted in a reaction with water) by an enzyme, usually a specific enzyme found in the same plant. The enzyme emulsin, however, causes hydrolysis of several glycosides. The enzymes and glycosides are stored in separate plant cells until the reaction products of the glycosides are needed and the enzymes are activated. Glycosides are believed to serve several purposes in the plant. Glycosides are bitter tasting, and it is believed that they help keep birds and insects from eating seeds and fruit before they are fully grown, by which time the glycosides have been converted to sweet sugars. When a plant tissue is bruised, the

Glucose, monosaccharide sugar,  C 6 H 12 O 6 . It is found in honey and the juices of many fruits; the alternate name grape sugar is derived from the presence of glucose in grapes. It is the sugar most often produced by hydrolysis of natural glycosides . Glucose is a normal constituent of the blood of animals (see Sugar Metabolism ). Glucose is a white crystalline solid, less sweet than ordinary table sugar. Solutions of glucose rotate the plane of polarization of polarized light to the right; hence the alternative name dextrose (Latin dexter, “right”). Glucose crystallizes in three different forms. The degree of rotation of polarized light is different for each form. Glucose is formed by the hydrolysis of many carbohydrates, including sucrose, maltose , cellulose , starch , and glycogen. Fermentation of glucose by yeast produces ethyl alcohol and carbon dioxide. Glucose is made industrially by the hydrolysis of starch under the influence of dilute acid or, more commonly, u