Which process describes stop codons signaling termination?

Which process describes stop codons signaling termination?

• A. Termination
• B. Initiation
• C. Elongation
• D. Translocation

Answer: (A)

Stop codons signaling termination happens during translation when a stop codon sits in the ribosome’s A site. There’s no tRNA with an anticodon that pairs with a stop codon, so release factors bind instead. These factors promote hydrolysis of the bond between the last tRNA and the polypeptide, releasing the finished protein, and then the ribosome, mRNA, and tRNA disassemble. Other stages of translation—initiation (assembly at the start), elongation (adding amino acids), and translocation (ribosome movement along the mRNA)—don’t involve signaling termination by a stop codon.

Stop codons signaling termination happens during translation when a stop codon sits in the ribosome’s A site. There’s no tRNA with an anticodon that pairs with a stop codon, so release factors bind instead. These factors promote hydrolysis of the bond between the last tRNA and the polypeptide, releasing the finished protein, and then the ribosome, mRNA, and tRNA disassemble. Other stages of translation—initiation (assembly at the start), elongation (adding amino acids), and translocation (ribosome movement along the mRNA)—don’t involve signaling termination by a stop codon.