a commonly used technique for separating DNA and RNA mixtures based on molecular size, was used. separated to make the substance pure. The molecules are pushed by an electric field through a gel with small pores. Mixtures of different sizes pass through the pores at different speeds. Smaller molecules are more efficient and can travel farther than larger ones. Makes it possible to separate mixed substances from each other. Electrodes are placed on the device with one end of the gel having a positive charge and the other having a negative charge. Because DNA and RNA are negatively charged, they move toward a positive charge.