Gel Electrophoresis

• The backbone of DNA consists of a sugar and phosphate
• DNA is negatively charged and RNA is positively charged, so they repel each other
• A well refers to a hole of a specific size
• In gel electrophoresis, the positive and negative electrodes are located at opposite ends of the gel box
• The gel slab is oriented in the gel box so that the wells are closest to the negative electrode.
• PCR is used to amplify DNA samples
• Only one DNA sample can be loaded into each well in a gel
• A DNA ladder is a mixture of known DNA fragments of specific sizes
• Gel electrophoresis separates DNA based on size because the gel is a matrix.
• Steps in Gel electrophoresis :

  1. Set-up gel
  2. load DNA samples
  3. run the samples
  4. visualise DNA
• A band in a gel can only be visualised if the gel has been stained with a dye.