Biotech 2nd Edition Sample Ch. 4 Biotechnology Sample Ch. 4 - Page 26

Laboratory 4j Using Gel Electrophoresis to Study DNA Molecules Background Gel electrophoresis is one of several ways that molecules are studied in labs. The technique uses a gel and an electric field to separate molecules based on size, shape, and/or charge. Most frequently, samples of nucleic acids (DNA and RNA) and proteins are analyzed using gel electrophoresis. DNA molecules in solution have a net negative charge due to their phosphate groups. Because of the negative charge, DNA molecules are attracted to the positive end of a “running” gel box. The agarose gel material acts as a molecular sieve separating longer DNA strands from shorter ones, thus separating the molecules based on their size. YX