What is the function of a stop codon?

A stop codon serves a critical role in the process of translation, which is the synthesis of proteins from messenger RNA (mRNA). Its primary function is to signal the termination of the translation process. When the ribosome encounters a stop codon during protein synthesis, it instructs the ribosome to release the newly formed polypeptide chain, thereby concluding the translation of the mRNA into a protein.

This mechanism ensures that proteins are synthesized to their proper lengths and that the genetic information encoded in the mRNA is accurately translated into functional proteins. The stop codon does not initiate translation, nor does it code for the addition of amino acids or regulate RNA splicing—these processes are governed by different elements of molecular biology. The specific role of the stop codon in terminating translation is essential for maintaining the integrity and functionality of proteins.