What happens when a premature stop codon is encountered during translation?

When a premature stop codon is encountered during translation, the process of synthesizing the protein ceases unexpectedly. In the genetic code, stop codons signal the end of polypeptide synthesis. When a ribosome reaches a stop codon, it does not encode an amino acid; instead, release factors are invoked, prompting the ribosome to disassemble and release the newly formed polypeptide chain.

This results in a truncated protein that is often nonfunctional because it does not contain the full sequence of amino acids that would have been produced if translation had proceeded to a proper stop codon. Such premature termination can arise from mutations in the DNA that create new stop codons, leading to diseases or dysfunctional proteins.

In contrast, when a normal stop codon is encountered, the protein is completed as expected, and if the translation process runs without interruptions or errors, the protein is synthesized fully. The other options either suggest that translation continues normally or that the mRNA is degraded, neither of which accurately describes the situation when a premature stop codon is encountered in the translation process.