| Class of RNA |
Cell Type |
Location of Function in Eukaryotic Cells* |
Function |
| Ribosomal RNA (rRNA) |
Bacterial and eukaryotic |
Cytoplasm |
Structural and functional components of the ribosome |
| Messenger RNA (mRNA) |
Bacterial and eukaryotic |
Nucleus and cytoplasm |
Carries genetic code for proteins |
| Transfer RNA (tRNA) |
Bacterial and eukaryotic |
Cytoplasm |
Helps incorporate amino acids into polypeptide chain |
| Small nuclear RNA (snRNA) |
Eukaryotic |
Nucleus |
Processing of pre-mRNA |
| Small nucleolar RNA (snoRNA) |
Eukaryotic |
Nucleus |
Processing and assembly of rRNA |
| MicroRNA (miRNA) |
Eukaryotic |
Nucleus and cytoplasm |
Inhibits translation of mRNA |
| Small interfering RNA (siRNA) |
Eukaryotic |
Nucleus and cytoplasm |
Triggers degradation of other RNA molecules |
| Piwi-interacting RNA (piRNA) |
Eukaryotic |
Nucleus and cytoplasm |
Suppresses the transcription of transposable elements in reproductive cells |
| CRISPR RNA (crRNA) |
Prokaryotic |
— |
Assists destruction of foreign DNA |
| *All eukaryotic RNAs are synthesized in the nucleus. |