Final answer:
The movement of the polypeptide from the P site to the A site during translation is known as translocation, a process that is part of the peptide chain elongation and is powered by GTP hydrolysis.
Step-by-step explanation:
The movement of the polypeptide chain from the tRNA in the P site to the tRNA in the A site during translation is called translocation. This process involves the ribosome moving along the mRNA molecule so that the tRNAs shift from the A site to the P site and then to the E site, where the tRNA is eventually ejected from the ribosome. As new charged tRNAs enter the A site, the polypeptide chain grows by forming peptide bonds between amino acids, and the whole complex moves along the mRNA. This movement and the associated processes are driven by the hydrolysis of GTP, which is catalyzed by elongation factors.