DNA ELECTROPHORESIS

STUDENT HANDOUT

Page 2


Part B -- Practice Loading a gel:

(If you have completed Part A skip steps #1-3 below)

 

  1. Add 10 µl of colored solution to your tube which contains 2 µL of loading dye.
  2. A total of 12 µL was added to each of your tubes. To check that your measurements were accurate, set the gel loading pipettor (green plunger: 10-50 µL size) to 12 µL and try to withdraw the total contents of your tube into the pipettor tip. (There should be no fluid left behind in the tube.)
  3. Return the contents in the pipettor tip to your reaction tube and centrifuge a few seconds to pool the solutions at the bottom of the tube. (Steps #1 and 2 are important; you will need to practice them several times!)
  4. Using the proper techniques demonstrated in the video and by your instructor, load the entire contents of your tube into your assigned well in a practice agar gel.
  5. Prepare four new tubes with 10 µL of solution plus 2 µL Loading dye and practice loading a gel inside the gel box.
  6. After all of the wells in your gel are loaded, have your instructor turn on the electrophoresis apparatus and observe what happens. (It will take about 10 minutes to see the results.)
  7. Make a quick drawing of your results

 

Questions: Part A

  1. Why did you place each solution on the side of the tube rather than at the bottom?

     

     

  2. What is the function of the loading dye?

 

Questions: Part B

  1. Why is it important to remove all of the contents of your tubes before attempting to load a gel?

     

  2. Can you explain what process is causing the production of air bubbles in the tank?

     

  3. Can you explain why you see the color separation in the gel?