# Explain the role of memory cells in the secondary immune response.

> IB DP Biology Standard Level (2023 syllabus) — C3.2 Defence against disease · Explain · 4 marks

## Mark scheme (4 marks)

1. Memory cells are long-lived lymphocytes produced during the primary immune response (after first exposure to an antigen).
2. Memory cells persist in the body for many years, allowing rapid recognition of the same antigen upon re-exposure.
3. On re-exposure to the same antigen, memory cells proliferate rapidly and differentiate into large numbers of effector cells (plasma cells / cytotoxic T cells).
4. This produces a faster and larger antibody titre / immune response compared with the primary response, eliminating the pathogen before symptoms develop.

## Key terms

- [memory cells](https://www.gradenine.co.uk/glossary/memory-cells)
- [secondary immune response](https://www.gradenine.co.uk/glossary/secondary-immune-response)

## Related

- [Revision notes for IB DP Biology Standard Level (2023 syllabus)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-the-role-of-memory-cells-23e2e7ca) · Published by Druglandscape Ltd.