What principle is used in electrophoresis?

Electrophoresis is based on the principle of moving charged molecules through a medium under the influence of an electric current. When an electric field is applied, molecules such as proteins or nucleic acids will migrate towards the electrode with the opposite charge. This movement occurs because charged particles experience a force in an electric field, allowing for separation based on size, charge, and shape. This technique is widely used in laboratories for analyzing biomolecules, particularly in applications like DNA fingerprinting, protein analysis, and the separation of biomolecules.

The other options describe different separation techniques. The separation of molecules based on boiling point relates to distillation, which relies on vaporization. Filtering particles through a porous membrane involves techniques like ultrafiltration or microfiltration and does not utilize an electric field for separation. Absorption on a solid surface pertains to chromatography methods, which separate compounds based on their differential affinities to stationary and mobile phases, distinct from the electrical principles governing electrophoresis.