For High School Teachers
  From DNA to Organism: A Study in DNA Function for the High School Biology Classroom

Module 2: DNA and genes

Teacher suggestions for Module 2: Gel electrophoresis


  • 1 block set up and a PowerPoint presentation.

     What you need to set up

  • Agarose (1.25g/ group)
  • Scales/weighing dishes
  • 1X TAE buffer (125ml/group)
  • 100ml graduated cylinder for TAE
  • Microwave
  • 250ml flasks (1/group)
  • Gel casting trays/combs
  • Electrophoresis Rigs
  • Power supplies for electrophoresis
  • 2.0ml microcentrifuge tubes (3/group)
  • Loading buffer/ dye (15ml/ group)
  • 100 base pair ladder (10ml/ group)
  • 2 X 1– 10ml pipettes, 2 X 10– 100ml pipettes

     What each student group needs

  • DNA samples from PCR
  • 3 x 1.5ml microcentrifuge tubes
    Pre lab 10 minutes

           The prelab for this section consists of a brief review of PCR from the previous day followed by an explanation of what electrophoresis is. A quick tour of the room, as far as what equipment is out and how it will be used, would also be helpful for the students.

     lab 45 minutes

           The lab itself consists of the students following the provided protocol to load their samples into the gels. After the gels are loaded, the PowerPoint presentation is used to explain what is going on the gels. The gels should be done close to the end of the block and can be removed, and stained or wrapped in plastic wrap and placed in the refrigerator until the next day (if using prestained gels).

    Post lab 5 minutes

           The post lab for this section consists of clean up of materials and removal of the gels from the electrophoresis chambers. Depending on the staining procedure used, the gels can either be put into the stain or placed into the refrigerator until the next day.


           The homework for this section of the lab consists of a letter back to Dr. Berkowitz explaining the results of the three sections that they just completed (DNA extraction, PCR, and electrophoresis). The letter should include brief summaries of each of the three procedures and explanations of why they were used. Also in the letter should be an explanation of what the final conclusion of this module is, i.e., whether or not the mutant plant has functioning copies of the AKT-1 gene.