Question

Western blotting is used for the identification of

• A. DNA
• B. RNA
• C. Protein
• D. All of the above

Answer 1

Answer: (C)

Protein

Blotting techniques are used to transfer nucleic acids from gels, after gel electrophoresis, to membranes for further analytical studies. Southern blotting is used for transfer of DNA from agarose gels to the membrane to analyze their composition. For the purpose, the agarose gel is mounted on filter-paper wick and the hybridization membrane is sandwiched between the gel and any absorbent material, which draw the transfer buffer through the gel by capillary action. The buffer flow draws the DNA molecules which are then immobilized on the membrane. Northern blotting is used for RNA analysis; the absorbent material is different in both techniques. Western blotting is the technique used to transfer proteins from acrylamide gels to membranes. For the purpose, electrophoresed protein bands from a polyacrylamide gel are transferred on to nitrocellulose or nylon membrane, to which they bind strongly. Thus, the correct answer is option C.