What happens when a stop codon is encountered in the mRNA during translation?

• A. The ribosome continues to add amino acids to the polypeptide chain.
• B. The ribosome releases the polypeptide chain and translation terminates.
• C. The ribosome recruits a new tRNA to continue translation.
• D. The ribosome skips the stop codon and continues translation.

Answer: (B)

Verified step by step guidance

1. Understand the role of mRNA in translation: mRNA carries the genetic information from DNA to the ribosome, where it is translated into a polypeptide chain.
2. Learn about codons: Codons are sequences of three nucleotides on the mRNA that correspond to specific amino acids or signal termination of translation.
3. Identify the stop codons: In mRNA, there are three stop codons (UAA, UAG, UGA) that do not code for any amino acids but signal the end of translation.
4. Explore the function of stop codons: When a stop codon is encountered, it signals the ribosome to terminate translation, releasing the newly synthesized polypeptide chain.
5. Understand the termination process: Release factors bind to the ribosome when a stop codon is reached, facilitating the release of the polypeptide chain and disassembly of the translation complex.