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': 'Micro RNA is transcribed bya) RNA polymerase Ib) RNA polymerase IIc) RNA polymerase IIId) DNA Polymerasee) Drosha \nSelect and explain. \nA. ab, B. ad, C. be, D. ce', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Micro RNA (mi-RNA) are typically 21-25 nucleotides in length and are generated by nucleolytic processing of the products of distinct genes/transcription units. These precursors are single-stranded but have extended intramolecular secondary structure.\nMost mi-RNA are processed from RNA polymerase II transcripts of severed hundred to thousands of nucleotides in length called Pri-miRNA (primary transcript). Within these long transcripts are sequency that fold into a hairpin structure. A nuclear RNAase specific for dsRNA called Drosha acts with a nuclear ds-RNA binding protein called DGCR in human (Pasha in Drosophila) and cleaves the hairpin region out of long precursor RNA generating a pre-miRNA.', 'role': 'assistant'}]