Editing RNA (section)

===RNAs involved in protein synthesis===
[[Messenger RNA]] (mRNA) carries information about a protein sequence to the [[ribosome]]s, the protein synthesis factories in the cell. It is [[genetic code|coded]] so that every three nucleotides (a [[codon]]) corresponds to one amino acid. In [[eukaryotic]] cells, once precursor mRNA (pre-mRNA) has been transcribed from DNA, it is processed to mature mRNA. This removes its [[intron]]s—non-coding sections of the pre-mRNA. The mRNA is then exported from the nucleus to the [[cytoplasm]], where it is bound to ribosomes and [[Translation (biology)|translated]] into its corresponding protein form with the help of [[tRNA]]. In prokaryotic cells, which do not have nucleus and cytoplasm compartments, mRNA can bind to ribosomes while it is being transcribed from DNA. After a certain amount of time, the message degrades into its component nucleotides with the assistance of [[ribonuclease]]s.<ref name=The_Cell/>

[[Transfer RNA]] (tRNA) is a small RNA chain of about 80 [[nucleotide]]s that transfers a specific amino acid to a growing [[polypeptide]] chain at the ribosomal site of protein synthesis during translation. It has sites for amino acid attachment and an [[anticodon]] region for [[codon]] recognition that binds to a specific sequence on the messenger RNA chain through hydrogen bonding.<ref name=transcriptome/>

[[File:Translation of mRNA.svg|thumb|A diagram of how mRNA is used to create polypeptide chains]]

[[Ribosomal RNA]] (rRNA) is the catalytic component of the ribosomes. The rRNA is the component of the ribosome that hosts translation. Eukaryotic ribosomes contain four different rRNA molecules: 18S, 5.8S, 28S and 5S rRNA. Three of the rRNA molecules are synthesized in the [[nucleolus]], and one is synthesized elsewhere. In the cytoplasm, ribosomal RNA and protein combine to form a nucleoprotein called a ribosome. The ribosome binds mRNA and carries out protein synthesis. Several ribosomes may be attached to a single mRNA at any time.<ref name=The_Cell>{{cite book|title=The Cell: A Molecular Approach|edition=3rd| vauthors = Cooper GC, Hausman RE | date = 2004|pages=261–76, 297, 339–44|publisher=Sinauer|isbn=978-0-87893-214-6|oclc=174924833 }}</ref> Nearly all the RNA found in a typical eukaryotic cell is rRNA.

[[tmRNA|Transfer-messenger RNA]] (tmRNA) is found in many [[bacteria]] and [[plastid]]s. It tags proteins encoded by mRNAs that lack stop codons for degradation and prevents the ribosome from stalling.<ref>{{cite journal | vauthors = Gueneau de Novoa P, Williams KP | title = The tmRNA website: reductive evolution of tmRNA in plastids and other endosymbionts | journal = Nucleic Acids Research | volume = 32 | issue = Database issue | pages = D104–08 | date = January 2004 | pmid = 14681369 | pmc = 308836 | doi = 10.1093/nar/gkh102 }}</ref>