Final answer:
The last event during the elongation phase of translation is when the tRNA molecule translocates from the P site to the E site, which is then followed by its release from the ribosome.
Step-by-step explanation:
During the elongation stage of translation, several key events occur in sequence within the ribosome. Initially, a charged tRNA carrying an amino acid binds to the A site. After this binding, a peptide bond forms between the amino group of the new amino acid in the A site and the carboxyl group of the growing polypeptide chain attached to the tRNA in the P site. This bond formation is catalyzed by peptidyl transferase. The ribosome then translocates the tRNAs: the tRNA holding the growing peptide chain moves from the A site to the P site, and the tRNA that was in the P site, now without an amino acid, moves to the E site. The last event during elongation is therefore when the tRNA molecule translocates from the P site to the E site, where it is subsequently released from the ribosome.