The PCR (CIE International A-level Biology)

This lesson explains how the polymerase chain reaction (PCR) is used to clone and amplify DNA fragments as part of the recombinant DNA technology process. The PowerPoint has been designed to cover point 19.1 © of the CIE International A-level Biology specification and there is a particular emphasis on the use of Taq polymerase as opposed to human DNA polymerase

A quick quiz competition is used to introduce the PCR abbreviation before students are encouraged to discuss the possible identity of the enzyme involved and to recall the action of this enzyme. Students will learn that this reaction involves cyclical heating and cooling to a range of temperatures so the next part of this lesson focuses on each temperature and specifically the reasons behind the choice. Time is taken to examine the key points in detail, such as why Taq polymerase has to be used as it is not denatured at the high temperature as well as the involvement of the primers. This process is closely linked to other techniques like electrophoresis which is covered in a later lesson and ties are continuously made throughout the lesson