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. Modifications for younger learners are included in a related PDF (see related resources).