Editing Ribonucleotide (section)

===General structure===

[[File:AMP structure.svg|200px|thumbnail|class=skin-invert|Structure of adenosine 5'-monophosphate (AMP)]]
[[File:GMP chemical structure.png|200px|thumbnail|class=skin-invert|Structure of guanosine 5'-monophosphate (GMP)]]
[[File:Uridinmonophosphat protoniert.svg|200px|thumbnail|class=skin-invert|Structure of uridine 5'-monophosphate (UMP)]]
[[File:CMP chemical structure.png|200px|thumbnail|class=skin-invert|Structure of cytidine 5'-monophosphate (CMP)]]

The general structure of a ribonucleotide consists of a phosphate group, a ribose sugar group, and a nucleobase, in which the nucleobase can either be adenine, guanine, cytosine, or uracil. Without the phosphate group, the composition of the nucleobase and sugar is known as a nucleoside. The interchangeable nitrogenous nucleobases are derived from two parent compounds, purine and pyrimidine. Nucleotides are [[heterocyclic compounds]], that is, they contain at least two different chemical elements as members of its rings.{{citation needed|date=July 2024}}

Both RNA and DNA contain two major purine bases, adenine (A) and guanine (G), and two major pyrimidines. In both DNA and RNA, one of the pyrimidines is cytosine (C). However, DNA and RNA differ in the second major pyrimidine. DNA contains thymine (T) while RNA contains uracil (U). There are some rare cases where thymine does occur in RNA and uracil in DNA.<ref name=Nelson08 />

Here are the 4 major ribonucleotides (ribonucleoside 5'-monophosphate) which are the structural units of RNAs.
{| class="wikitable"
|-
! Nucleotide !! Symbols !! Nucleoside
|-
| Adenylate (adenosine 5'-monophosphate)  || A, AMP || Adenosine
|-
| Guanylate (guanosine 5'-monophosphate) || G, GMP || Guanosine
|-
| Uridylate (uridine 5'-monophosphate)  || U, UMP || Uridine
|-
| Cytidylate (cytidine 5'-monophosphate) || C, CMP || Cytidine
|}