Final answer:
The termination stage of protein synthesis is when the ribosome meets a stop codon, leading to polypeptide release and ribosomal subunit dissociation.
Step-by-step explanation:
Termination Stage of Protein Synthesis
The termination stage of protein synthesis is a critical phase in the process of translating an mRNA sequence into a polypeptide chain. It occurs when the ribosome encounters a stop codon (UAA, UAG, or UGA). At this point, release factors recognize these codons and instruct the peptidyl transferase to add a water molecule to the carboxyl end of the terminal amino acid. This action leads to the release of the polypeptide chain from the tRNA in the P-site. Subsequently, the ribosomal subunits dissociate from the mRNA, allowing them to participate in new rounds of protein synthesis. The mRNA is eventually degraded, and its nucleotides are recycled for future transcription reactions.