Major RNA Molecules

Type of RNA Messenger RNA (mRNA) Table 8.1 Major RNA Molecules Function Used to encode the sequence of amino acids in a polypeptide. May be polycistronic (encoding two or more polypeptides) in bacteria and archaea. Encodes single polypeptides in nearly all eukaryotes (see Sections 8.2 and 8.4). Ribosomal RNA (rRNA) Along with numerous proteins, helps form the large and small ribosomal subunits that unite for translation of mRNA (see Sections 8.4 and 9.2). Transfer RNA (tRNA) ” ‘Sm‘a‘llmnuclearRNA(sn RNA) “ Carries amino acids to ribosomes and binds there to mRNA by complementary base pairing to ‘add the ammo aCIdS to the elongatIng polypeptIde (see Sections 8 4 and 9. 3). Found In eukaryotIc nucleI where multiple snRNAs Join with numerous proteins to form spliceosomes that remove introns from precursor mRNA (see Section 8. 4). MicroRNA (miRNA) Eukaryotic regulatory RNAs that function by base pairing with certain mRNAs, altering their stability and efficiency of translation (see Section 13.3). Small interfering RNA (siRNA) Eukaryotic regulatory RNA made from long double-stranded molecules that are cut into shorter pieces used to regulate mRNA stability and translation (see Section 13.3). Telomerase RNA Located in the telomerase ribonucleoprotein complex, where it acts as a template to maintain and elongate telomere length of eukaryotic chromosomes (see Section 7.4).