Word Study
nucleoside
CIDE DICTIONARY
nucleoside, n.
A type of molecule found in all living organisms, present mostly in chemically combined form as a component of nucleic acids, and also in smaller amounts in free form, consisting of a pentose sugar bound to a purine or pyrimidine base; two types of nucleoside, ribonucleoside and deoxyribonucleoside , are present. The most common bases present in nucleosides are adenine, cytosine, uracil, guanine, and thymine, and to a lesser extent hypoxanthine and other bases are found. The most commmon ribonucleosides composed from these bases are called adenosine, cytidine, uridine, and guanosine. The forms esterified with orthophosphoric at the 5-position of the pentose are called nucleotides . The nucleotides form the monomer units which are combined into DNA and RNA, which carry the genetic information required for reproduction in all known organisms. [PJC]
OXFORD DICTIONARY
nucleoside, n. Biochem. an organic compound consisting of a purine or pyrimidine base linked to a sugar, e.g. adenosine.
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