Do stop codons code for amino acids?

Do stop codons code for amino acids?

• A. Yes; they code for amino acids
• B. They signal termination
• C. No; they signal termination
• D. They code for start codons

Answer: (C)

Stop codons do not code for amino acids. In translation, most codons specify a particular amino acid, but three codons have a signaling role: they terminate the process. When the ribosome reads a stop codon, release factors bind and trigger release of the finished polypeptide from the tRNA, ending translation. The three stop codons are UAA, UAG, and UGA, and there is no corresponding tRNA for them. In contrast, the start codon is AUG, which marks the beginning of translation and also encodes methionine. So, signaling termination is the correct idea for stop codons.

Stop codons do not code for amino acids. In translation, most codons specify a particular amino acid, but three codons have a signaling role: they terminate the process. When the ribosome reads a stop codon, release factors bind and trigger release of the finished polypeptide from the tRNA, ending translation. The three stop codons are UAA, UAG, and UGA, and there is no corresponding tRNA for them. In contrast, the start codon is AUG, which marks the beginning of translation and also encodes methionine. So, signaling termination is the correct idea for stop codons.