Thursday, March 8, 2012
A transfer RNA (tRNA) is a small RNA (ribonucleic acid) molecule, about 80 nucleotides long that acts as a carrier of specific amino acids during protein synthesis. A molecule of transfer RNA, which is specific for a particular amino acid, binds to that amino acid. The sequence of three nucleotides that make up the anti-codon on the tRNA recognize and bind to the codon on the messenger RNA, which is complexed with a ribosome on which a polypetide chain developing. The amino acid is thus guided into the proper position on the ribosome-mRNA complex to be enzymatically added to the polypeptide chain. There is at least one tRNA for each kind of amino acid.