Question

For which of these is northern blotting with hybridization useful?

• A. Protein antigen
• B. RNA
• C. DNA
• D. Histone

Hint:

Remember the naming pattern: Southern blot detects DNA, northern blot detects RNA, and Western blot detects protein using antibodies.

Answer 1

The Correct Option is B

This question checks whether you know which molecule each classic blotting technique picks up, since the names Southern, northern and Western all describe a similar method applied to a different target.

1. Protein antigen: A protein has no base sequence, so a hybridization probe cannot bind it. Proteins are picked up by Western blotting using specific antibodies instead.
2. RNA: Northern blotting separates RNA on a gel, blots it onto a membrane, then hybridizes it with a labeled complementary probe. This matches the question exactly, so this option is correct.
3. DNA: DNA is the target of Southern blotting, the original method that gave the whole family of blots its naming convention.
4. Histone: Histones are proteins that package DNA, so like any protein they are detected with antibodies, not by hybridization.

The correct option is RNA, because northern blotting is built specifically to detect and roughly quantify RNA through base pairing with a labeled probe.

Let's summarize:

• Southern blot picks up DNA, northern blot picks up RNA, Western blot picks up protein.
• Hybridization needs a complementary nucleic acid sequence, which proteins such as histones or antigens simply do not have.

So northern blotting with hybridization is used to detect RNA.