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
For RNA, which blotting technique is used 
Select and explain. 
A. Western blot, B. Nohern blot, C. Southern blot, D. None
B: Nohern blot
Answer: B: Nohern blot 
Explanation: Nohern Blotting for identifying RNA : The Nohern blot is used to demonstrate specific RNA. The total RNA is isolated from the cell, electrophoresed and then blotted on to a membrane. This is then probed with radioactive cDNA .There will be RNA - DNA hybridization. This is used to detect the gene expression in a tissue. Ref :DM.VASUDEVAN.TEXTBOOK ; SEVENTH EDITION ; PAGE NO : 634.