Which technique is utilized to analyze the size of molecules for protein separation?

• A. Western blotting
• B. Electrophoresis
• C. Mass spectrometry
• D. Chromatography

Answer: (B)

Electrophoresis is a technique commonly used to analyze the size and charge of molecules, particularly proteins and nucleic acids. In this method, an electric current is applied to a gel matrix containing the sample. Molecules migrate through the gel at different rates based on their size and charge; smaller molecules move faster and farther than larger ones.

This technique allows researchers to separate proteins based on their molecular weight and to assess their size. The results can be visualized after staining the gel, enabling quantification and identification of the proteins present.

While Western blotting is indeed a method used to detect specific proteins after electrophoresis, it involves additional steps such as transferring proteins to a membrane and using antibodies for visualization. Mass spectrometry is primarily used for determining the molecular mass of compounds, and chromatography serves various separation and purification purposes but does not directly analyze size in the same straightforward way as electrophoresis does.