Using gene sequencing (Edexcel A-level biology B)

This detailed lesson describes the processes of PCR and electrophoresis to allow students to understand how gene sequencing can be used. The engaging PowerPoint and accompanying resource have been planned to cover the content of point 7.1 of the Edexcel A-level biology B specification.

The lesson begins by comparing the number of genes in the genome with the number of base pairs, to allow students to learn that the bases in the genes only accounts for about 1.5% of the genome. This challenges them to recall that most is non-coding DNA, and the importance and usefulness of these sections are explored during the lesson. Moving forward, a step-by-step guide describes the key steps in the polymerase chain reaction, and time is taken at each step to qualify the fine details such as the use of Taq polymerase instead of human DNA polymerase.

The remainder of the lesson focuses on the various uses of these DNA samples once they’ve been amplified by the PCR. The steps of the electrophoresis process are described and students will see how DNA profiling can be used in forensic science to identify criminals and for paternity tests.

Understanding and prior knowledge checks are found throughout the lesson, along with the answers, to allow students to assess their grasp of the current topic as well as their ability to identify the links with previously covered topics.