This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
[{'content': 'All are the processing reaction in tRNA, except: \nSelect and explain. \nA. CCA tailing, B. Methylation of bases, C. Poly A tailing, D. Trimming of 5’ end', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Post-transcriptional modification of tRNA precursor:\n\nStandard bases (A, U, G, C) undergo methylation, reduction, deamination, rearranged glycosidic bond.\nCleavage and attachment of CCA terminal at 3’ end takes place in cytoplasm.\nMethylation of tRNA takes place in nucleus.\n\nNote:-\xa0Poly A tailing is a processing step of mRNA primary transcript.\nReference- Harper 30th edition', 'role': 'assistant'}]