Electrophoresis, also called gel electrophoresis, is used to separate the macromolecules of DNA, RNA and proteins. DNA and RNA are separated according to their size and length, while proteins are separated according to their charges.
Electrophoresis is used in DNA for fingerprints for forensics, paternity testing, checking PCR reactions, disease detection and to look for evolutionary relationships among organisms. A solution of negatively charged DNA molecules are pulled through gel using an electric field. The smaller DNA molecules are pulled through the gel faster than the larger DNA molecules. This creates a series of bands that contain different sized DNA molecules. The bands that are far from the start of the gel are the ones that contain the smallest DNA fragments, while the bands that contain the largest DNA fragments are situated closest to the start of the gel.
A variety of electrophoresis gels are used to determine the information provided by proteins, and the type of gel that is used is determined by the information that is needed. Proteins contain a variety of amino acids that act as the building blocks for the structure of the proteins. The number of amino acids the proteins contain and the chemical modifications that are attached to the proteins determine their size. Proteins also have different charges based on the type of protein in question.