Final answer:
Termination of the polypeptide chain elongation occurs when a stop codon enters the A site, not the P site, of the ribosome, making the original statement false.
Step-by-step explanation:
The statement that elongation of the polypeptide chain is terminated when a stop codon enters the P site of the ribosome is false. Termination of translation occurs when a stop codon (UAA, UAG, or UGA) enters the A site of the ribosome. When the stop codon aligns with the A site, it is recognized by release factors, which prompt the addition of a water molecule to the carboxyl end of the P-site amino acid.
This results in the detachment of the P-site amino acid from its tRNA, releasing the completed polypeptide chain. The ribosomal subunits then dissociate from the mRNA and are ready for another round of protein synthesis.