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glutamic acid

(Encyclopedia)CE5 glutamic acid glo͞otămˈĭk [key], organic compound, one of the 20 amino acids commonly found in animal proteins. Only the l-stereoisomer occurs in mammalian proteins. Like aspartic acid, glu...

transpiration

(Encyclopedia)transpiration, in botany, the loss of water by evaporation in terrestrial plants. Some evaporation occurs directly through the exposed walls of surface cells, but the greatest amount takes place throu...

hemoglobin

(Encyclopedia)hemoglobin hēˈməglōˌbĭn [key], respiratory protein found in the red blood cells (erythrocytes) of all vertebrates and some invertebrates. A hemoglobin molecule is composed of a protein group, kn...

emphysema

(Encyclopedia)emphysema ĕmfĭsēˈmə [key], pathological or physiological enlargement or overdistention of the air sacs of the lungs. A major cause of pulmonary insufficiency in chronic cigarette smokers, emphyse...

fullerene

(Encyclopedia)fullerene, any of a class of carbon molecules in which the carbon atoms are arranged into 12 pentagonal faces and 2 or more hexagonal faces to form a hollow sphere, cylinder, or similar figure. The sm...

chlorofluorocarbons

(Encyclopedia)chlorofluorocarbons klōrˌəflo͝orˈəkärˌbənz, klôrˌ– [key] (CFCs), organic compounds that contain carbon, chlorine, and fluorine atoms. CFCs are highly effective refrigerants that were deve...

cyclopropane

(Encyclopedia)cyclopropane, C3H6, a gaseous hydrocarbon. It is a cyclic alkane, its three carbon atoms being joined together in a ring. The angle between successive carbon-carbon bonds in the ring is only 60°, muc...

mortar, in building

(Encyclopedia)mortar, in building, mixture of lime or cement with sand and water, used as a bedding and adhesive between adjacent pieces of stone, brick, or other material in masonry construction. Lime mortar, a co...

urea

(Encyclopedia)CE5 urea yo͝oēˈə [key], organic compound that is the principal end product of nitrogen metabolism in most mammals. Urea was the first animal metabolite to be isolated in crystalline form; its c...

aquarium

(Encyclopedia)aquarium, name for any supervised exhibit of aquatic animals and plants. Aquariums are known to have been constructed in ancient Rome, Egypt, and Asia. Goldfish have been bred in China for several hun...