3 sites of ribosome
There are three binding sites for tRNAs on the ribosome. In the aminoacyl site (A site), a tRNA charged with an amino acid (aminoacyl-tRNA) is presented to the messenger RNA (mRNA) being translated. The peptidyl site (P site) carries the growing peptide chain attached as a peptidyl-tRNA complex.The exit site (E site) contains empty tRNAs on their way out of the ribosome.ranslation is an iterative process, adding one amino acid to the growing polypeptide chain at each round, at a rate of 15â20 residues per second in bacteria. Amino acids are carried to the ribosome attached to the 3' end of a specific class of small RNAs, the transfer RNAs (tRNAs).