What occurs when a ribosome encounters a stop codon during translation?

• A. The ribosome binds to another mRNA molecule.
• B. The ribosome initiates the process of transcription.
• C. The ribosome releases the polypeptide chain and disassembles.
• D. The ribosome continues to add amino acids to the polypeptide chain.

Answer: (C)

Verified step by step guidance

1. Understand the process of translation: Translation is the process by which ribosomes synthesize proteins using mRNA as a template. It involves the sequential addition of amino acids to a growing polypeptide chain.
2. Identify the role of stop codons: Stop codons are specific sequences in mRNA (UAA, UAG, UGA) that signal the termination of protein synthesis. They do not code for any amino acids.
3. Recognize the action of release factors: When a ribosome encounters a stop codon, release factors bind to the ribosome, prompting it to release the newly synthesized polypeptide chain.
4. Describe ribosome disassembly: After releasing the polypeptide chain, the ribosome components (large and small subunits) disassemble and detach from the mRNA.
5. Clarify the next steps for the ribosome: Once disassembled, ribosome subunits can be reused for translating another mRNA molecule, but they do not initiate transcription, which is a separate process occurring in the nucleus.