Restriction Enzyme Digestion: How does it work? Why is it useful?

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In this activity related to plant biotechnology, learners use restriction enzymes to cut up DNA from a virus called Bacteriophage λ, a process known as restriction digestion. After overnight digestion, the reaction is stopped by addition of a loading buffer. The DNA fragments are separated by electrophoresis, a process that involves application of an electric field to cause the DNA fragments to migrate into an agarose gel. The gel is then stained with a methylene blue stain to visualize the DNA bands and may be photographed. This lab will help learners understand what a DNA restriction enzyme is and how it works, how to use a micropipette, how to separate DNA using electrophoresis, and how to use a restriction digestion map to identify a sample DNA. This lesson guide includes background information, safety precautions and notes, and questions with answers for learners. For safety reasons, adult supervision is recommended.

Quick Guide

Preparation Time:
1 to 7 days

Learning Time:
1 to 7 days

Estimated Materials Cost:
Over $20 per group of students

Age Range:
Ages 11 - adult

Resource Types:
Activity, Experiment/Lab Activity, Lesson/Lesson Plan


Materials List (per group of students)

  • Four microtubes
  • Microtube rack
  • 20-µl micropipette (or 10-µl micropipette) and sterile tips
  • Waterproof pen
  • Beakers or foam cups with crushed ice
  • 20 µl of 0.4 µg/µl λ DNA
  • 2.5 µl BamHI restriction enzyme
  • 2.5 µl EcoRI restriction enzyme
  • 2.5 µl HindIII restriction enzyme
  • 10 µl distilled water
  • Gloves
  • 500-ml beaker
  • Electrophoresis chamber
  • Power supply
  • 20 µl 10X loading dye
  • 1.0% agarose gel
  • Container with TBE solution
  • 37°C water bath w/ floating rack
  • 60°C water bath or saucepan on a hot plate
  • Cooler with crushed ice
  • Freezer (non frost-free, if possible)
  • Camera if desired
  • Distilled water
  • 0.002% methylene blue stain


  • Engineering and Technology
    • Engineering
      • Bioengineering/Biomedical Engineering
    • Technology
      • Agriculture and Biotechnology
  • Life Sciences
    • Cells
      • Cell Structure and Function
    • Diversity of Life
      • Viruses and Bacteria
    • Heredity and Genetics
      • DNA Structure and Function
      • Genetic Engineering
  • Physical Sciences
    • Chemistry
  • The Nature of Science
    • The Scientific Process
      • Conducting Investigations
      • Gathering Data
      • Formulating Explanations
      • Communicating Results


To use this activity, learners need to:

  • see
  • see color
  • read
  • touch

Learning styles supported:

  • Involves teamwork and communication skills
  • Involves hands-on or lab activities


Components that are part of this resource:

This resource is part of:

Access Rights:

  • Free access


  • Stephens, Janice ; Leach, Jan


  • All rights reserved, The American Phytopathological Society, 2011