During elongation, what happens?

• A. The ribosome disassembles.
• B. The chain of amino acids grows longer as amino acids are added.
• C. The mRNA is transcribed into DNA.
• D. The stop codon is encountered.

Answer: (B)

During elongation, the growing polypeptide chain gets longer as amino acids are added one by one to the end of the chain. The ribosome reads each codon on the mRNA, tRNAs bring the matching amino acids, and a peptide bond forms to attach each new amino acid to the chain. This cycle repeats, moving the ribosome to the next codon and extending the protein until a stop codon signals termination. At that point translation ends and the ribosome disassembles. The other options describe events from different stages: disassembly happens at termination, transcription (DNA to RNA) is not part of elongation, and the stop codon is encountered only during termination, not during elongation.