This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of nucleic acids, Subject name: Biochemistry
[{'content': 'Stop codon \nSelect and explain. \nA. UAG, B. UCA, C. UAC, D. AUG', 'role': 'user'}, {'content': 'Answer: A \nExplanation: They do not code for any amino acid Mark the end of protein synthesisOther stop codons are UAA UGARef: DM Vasudevan, 7th edition, page no: 599', 'role': 'assistant'}]