Gel electrophoresis preparation
To perform a gel electrophoresis experiment you need:
- Semi-solid, porous gel matrix
- DNA or RNA sample
- Loading buffer
- Dye
- Molecular weight standard samples or "ladders"
Semisolid, porous gel matrix: This is usually an agarose or polyacrylamide gel. In the virtual lab this gel is already prepared inside the gel electrophoresis machine.
DNA or RNA sample: Isolated, treated DNA or RNA, of a sufficient quantity to be visible in a gel electrophoresis experiment.
Loading buffer: Loading buffer contains a color reagent to help visualize how far the DNA or RNA has traveled during gel electrophoresis. Loading buffer also makes the sample heavier, so it will sink to the bottom of the gel.
It typically contains the following chemicals:
- Coloring reagent, for example, xylene cyanol, cresol red, bromophenol blue, or orange G
- High viscosity reagent, for example, Ficoll, sucrose, or glycerol to make the sample more viscous and heavier
- Water to dilute the above-mentioned reagents
Dye: Fluorescent or colored dyes that bind to nucleic acids are added to the gel mixture during preparation. Alternatively, the gel can be soaked in dye solution after the electrophoresis is completed.
Molecular weight standard samples: These are run alongside the DNA or RNA sample to provide a size reference. They are also known as "ladders".