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
Nohern blot is used for the separation of which of the following? 
Select and explain. 
A. mRNA, B. DNA, C. Protein, D. tRNA
A: mRNA
Answer: A: mRNA 
Explanation: Nohern blotting is used to estimate the gene expression estimating the expression of mRNA.