See: nucleotide

A ribonucleotide is a nucleotide in which a purine or pyrimidine base is linked to a ribose molecule. The base may be adenine (A), guanine (G), cytosine (C), or uracil (U). Note that thymine (T), which is found in deoxyribonucleotides, is not found as a ribonucleotides in living beings.

Monomeric unit of RNA.

A monomereric unit of RNA