What happens when a stop codon is encountered during translation?

What happens when a stop codon is encountered during translation?

• A. Translation terminates
• B. Translation continues
• C. RNA polymerase binds
• D. tRNA is degraded

Answer: (A)

When a stop codon appears, the process of building the protein ends. Stop codons don’t code for any amino acid, so no tRNA matches them. Instead, release factors bind to the ribosome at that site, triggering release of the finished polypeptide and causing the ribosome to detach from the mRNA and tRNA. This terminates translation. RNA polymerase is involved in transcription to make mRNA, not translation, so it’s not part of this step. The tRNA used during elongation is recycled rather than degraded just because a stop codon is encountered.

When a stop codon appears, the process of building the protein ends. Stop codons don’t code for any amino acid, so no tRNA matches them. Instead, release factors bind to the ribosome at that site, triggering release of the finished polypeptide and causing the ribosome to detach from the mRNA and tRNA. This terminates translation. RNA polymerase is involved in transcription to make mRNA, not translation, so it’s not part of this step. The tRNA used during elongation is recycled rather than degraded just because a stop codon is encountered.