Question

Which of the following order in the process of translation, is true?

• A. AA enters the ribosome through the E site, binds to the polypeptide chain at the A site and leaves through the P site.
• B. AA enters ribosome through P site, binds to the polypeptide chain at E site and leaves through the A site.
• C. AA enters the ribosome through A site, binds to the polypeptide chain at P site and exits through the E site.
• D. AA enters the ribosome through A site, binds to the polypeptide chain at E site and exits through the P site.

Answer 1

The correct option is C AA enters the ribosome through A site, binds to the polypeptide chain at P site and exits through the E site.

The A site, which is the aminoacyl tRNA site, recognises the incoming amino acyl-tRNA molecule. This is followed by a peptide bond formation between this amino acid and the growing polypeptide chain attached to the tRNA at the P site (peptidyl-tRNA site). This growing polypeptide chain is then transferred to the tRNA at the A site, followed by translocation of the peptidyl-tRNA from the A site to the P site so that the empty tRNA can now leave the ribosome through the E site (exit site). This cycle repeats until the polypeptide chain is fully formed.