Question

Western blotting uses ________ to detect specific proteins.

• A. \( \text{a known DNA sequence} \)
• B. \( \text{a RNA Molecule} \)
• C. \( \text{a purified protein} \)
• D. \( \text{an antibody} \)

Hint:

Remember the Blots: Southern = DNA, Northern = RNA, Western = Protein. (Mnemonic: SNOW DROP).

Answer 1

The Correct Option is D

Concept: Western blotting, also known as protein immunoblotting, is a core technique in molecular biology.
• It is used to identify specific proteins from a complex mixture of proteins extracted from cells.
• The technique relies on the specificity of the interaction between an antigen and its antibody.

Step 1: Separation and Transfer.
First, proteins are separated by their size using gel electrophoresis (usually SDS-PAGE). These separated proteins are then moved or "blotted" from the gel onto a sturdy membrane, like nitrocellulose.

Step 2: Detection using Antibodies.
The membrane is then incubated with a primary antibody that specifically binds to the target protein. A secondary antibody, linked to a detection enzyme or fluorophore, is then added to visualize the protein. Because the entire detection process hinges on the antibody's ability to find its target, it is the essential tool for this method. Final Answer: Western blotting uses an antibody to detect specific proteins.