Electrophoresis is a technique for separating and analyzing mixtures of proteins, DNA or RNA. Molecules are separated based on their electric charge, size and other physical characteristics. The gel may be precast and made of cellulose acetate, polyacrylamide or agarose etc. Molecules can be visualized by chemiluminescence, photodocumentation or electroblotting. For a finer degree of separation 2D electrophoresis is used.