Immunity (Edexcel A-level Biology A)

This fully-resourced lesson explains how individuals develop immunity and includes a focus on the different types (active, passive, natural, artificial). The engaging PowerPoint and accompanying resources have been designed to cover point 6.12 of the Pearson Edexcel A-level Biology A specification and there is also a description and discussion of herd immunity to increase the relevance to the current epidemic with COVID-19.

The lesson begins with a series of exam-style questions which challenge the students to demonstrate and apply their understanding of the immune response as covered in the previous lessons on topics 6.8 & 6.9. In answering and assessing their answers to these questions, the students will recognise the differences between the primary and secondary immune responses and are then encouraged to discuss how the production of a larger concentration of antibodies in a quicker time is achieved. The importance of antibodies and the production of memory cells for the development of immunity is emphasised and this will be continually referenced as the lesson progresses. The students will learn that this response of the body to a pathogen that has entered the body through natural processes is natural active immunity. Moving forwards, time is taken to look at vaccinations as an example of artificial active immunity. Another series of questions focusing on the MMR vaccine will challenge the students to explain how the deliberate exposure to antigenic material activates the immune response and leads to the retention of memory cells. A quick quiz competition is used to introduce the variety of forms that the antigenic material can take along with examples of diseases that are vaccinated against using these methods. The eradication of smallpox is used to describe the concept of herd immunity and the students are given time to consider the scientific questions and concerns that arise when the use of this pathway is a possible option for a government. The remainder of the lesson looks at the different forms of passive immunity and describes the drawbacks in terms of the need for a full response if a pathogen is reencoutered.