uracil

One of the four bases in RNA. The others are adenine, guanine, and cytosine. Uracil replaces thymine, which is the fourth base in DNA. Like thymine, uracil always pairs with adenine. See also protein, nucleotide

A nitrogenous base normally found in RNA but not DNA; uracil is capable of forming a base pair with adenine. See also: base pair, nucleotide

(YOOR-uh-sil) One of four building blocks of ribonucleic acid (RNA), a type of nucleic acid found in all cells. In the cell, RNA is made from DNA (the other type of nucleic acid), and proteins are made from RNA.

(Abbreviation: U). One the bases found in RNA. See: uridine.