This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Transcription, Subject name: Biochemistry
[{'content': "What is present on the 3' end of all functional, mature tRNAs? \nSelect and explain. \nA. The cloverleaf loop, B. The anticodon, C. The sequence 5'CCA3', D. The codon", 'role': 'user'}, {'content': "Answer: C \nExplanation: 5' end of the tRNA is always base paired, and 3' end is free or attached to an amino acid. 3' end of all the tRNA ends with the same sequence, i.e. CCA. This trinucleotide sequence is post-transcriptionally added to the tRNA by the enzyme CCA tRNA nucleotidyl transferase.", 'role': 'assistant'}]