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bacteria

(Encyclopedia)bacteria [pl. of bacterium], microscopic unicellular prokaryotic organisms characterized by the lack of a membrane-bound nucleus and membrane-bound organelles. Once considered a part of the plant king...

chromosome

(Encyclopedia)chromosome krōˈməsōmˌ [key], structural carrier of hereditary characteristics, found in the nucleus of every cell and so named for its readiness to absorb dyes. The term chromosome is usually res...

grebe

(Encyclopedia)grebe grēb [key], common name for swimming birds found on or near quiet waters in most parts of the world. Grebes resemble the loon and the duck; they have short wings, vestigial tails, and long, ind...

guanine

(Encyclopedia)guanine gwäˈnēn [key], organic base of the purine family. It was reported (1846) to be in the guano of birds; later (1879–84) it was established as one of the major constituents of nucleic acids....

phosphate

(Encyclopedia)phosphate, salt or ester of phosphoric acid, H3PO4. Because phosphoric acid is tribasic (having three replaceable hydrogen atoms), it forms monophosphate, diphosphate, and triphosphate salts in which ...

uracil

(Encyclopedia)uracil yo͝orˈəsĭl [key], organic base of the pyrimidine family. It was isolated from herring sperm and also produced in a laboratory in 1900–1901. When combined with the sugar ribose in a glycos...

Americas, antiquity and prehistory of the

(Encyclopedia)Americas, antiquity and prehistory of the, study of the origins of the aboriginal peoples of the Americas. Archaeologists believe humans had entered and occupied much of the Americas by the end of the...

Dulbecco, Renato

(Encyclopedia)Dulbecco, Renato rənätˈō dŭlbĕkˈō [key], 1914–2012, Italian-American virologist, b. Catanzaro, Italy. In 1947 he came to the United States to work with Salvador Luria at Indiana Univ. in Blo...

gout

(Encyclopedia)gout, condition that manifests itself as recurrent attacks of acute arthritis, which may become chronic and deforming. It results from deposits of uric acid crystals in connective tissue or joints. Th...

Nematoda

(Encyclopedia)Nematoda nĕmˌətōdˈə [key], phylum consisting of about 12,000 known species, and many more predicted species, of worms (commonly known as roundworms or threadworms). Nematodes live in the soil an...