How does gel electrophoresis work and what kind of information can you determine from gel electrophoresis?

Gel electrophoresis separates DNA or proteins based on size and charge by applying an electric field to move molecules through a gel matrix. Smaller molecules move faster and thus travel further in the gel. Gel electrophoresis can be used to determine the size, quantity, and purity of DNA fragments or proteins, as well as for DNA fingerprinting and genetic testing.