Which event signals termination of translation?

• A. Start codon signals the beginning
• B. A tRNA charging event occurs
• C. The stop codon is recognized and translation terminates
• D. The release factor binds at the stop codon to terminate translation

Answer: (C)

The event signaling translation termination is the encounter of a stop codon on the mRNA. When the ribosome reaches a stop codon, there are no tRNAs to pair with it, so release factors are recruited to recognize the stop codon and promote hydrolysis that releases the completed polypeptide and disassembles the ribosome. In other words, stop codon recognition serves as the signal to stop; the binding of release factors is the mechanism that carries out termination once that signal is encountered.