Basic Molecular Biology Laboratory Techniques Activities for High School

Instructor: Rachel Tustin

Dr. Rachel Tustin has a PhD in Education focusing on Educational Technology, a Masters in English, and a BS in Marine Science. She has taught in K-12 for more than 15 years, and higher education for ten years.

While the students in your classroom may not all become microbiologists, there are some fundamental molecular lab techniques that will serve them in biological sciences beyond your classroom.

Molecular Biology Techniques

While your typical high school classroom may not have access to the sophisticated and expensive equipment used in colleges, there is no reason you can't expose your students to the basic molecular lab techniques that they will need to know as a foundation for their future education. Let's explore a few activities you can use with your students.


In the field of molecular biology, electrophoresis is a common lab technique students need to be familiar with. While you may not do it with real DNA, you can still help students master the same techniques using a variety of dyes.


  • agarose
  • various dyes, such as Methyl Orange, Methyl Green, Allura Red, and Bromophenol Blue
  • electrophoresis apparatus
  • micropipettes
  • pipet tips
  • TAE for electrophoresis units


  • Explain to students that a common technique they will use in molecular biology is electrophoresis. It can be used for all sorts of activities, such as DNA analysis.
  • Students should prepare by first melting their agarose in a microwave according to package instructions.
  • Next, students should pour the agarose into their electrophoresis apparatus (making sure the comb is in place) and allow it to set, without touching it to assure it is even. Explain to students that if it hardens unevenly, it becomes difficult for the dye or DNA to move through it.
  • Once the agarose is set, have students remove the comb.
  • Next, students should add the TAE solution to their gels. TAE is the solution that allows the electricity to be conducted through the gel once the power is connected to the electrophoresis apparatus.
  • Before students load their gels with the various dyes, it is a good idea to have them practice loading gels. You can set up gels in Petri dishes with combs, and model for students how to correctly use a micropipette to load the gels. Students often struggle with keeping the plunger down on the micropipette until they remove it from the gel. If they don't do it right, they just end up sucking part of the sample back up into the micropipette.

Sample Practice Pipeting Plate

  • When students are ready, they can load the dyes into the slots left from the comb.
  • Have students connect the electrodes on their electrophoresis apparatus (red to red and black to black). They will know the electricity is running because the chemical reaction caused by the electricity and TAE solution will cause hydrogen gas to form at the black electrodes and oxygen on the red electrodes.
  • Once you have let students run their gels for about ten minutes, they can disconnect their electrodes and lay their gel on an index card or piece of white paper.

Electrophoresis Apparatus

  • Discuss with students their results. Explain that the dyes move based on their charge (just like DNA would). The dye will move toward the positive electrode if negatively charged, and to the negative electrode if positively charged.
  • Explain to students that the same principles apply if you were doing electrophoresis to DNA samples from a crime scene. The DNA will move from one end of the gel to the other because of their charge and the charge of the current.

DNA Extraction

Forensic scientists use electrophoresis to test DNA samples. However, in order to test DNA samples you first have to extract the DNA. The method below can be used to extract DNA from any soft plant or animal tissue.


  • zippered bags
  • funnels
  • jars that fit the funnels
  • cheesecloth
  • large mixing bowl
  • ice
  • shampoo
  • table salt
  • water
  • kiwis or strawberries
  • cold isopropyl rubbing alcohol
  • small test tubes
  • graduated cylinders
  • digital scale
  • stirring rods
  • test tube holders
  • pipets

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