# Explain how clonal selection and clonal expansion lead to the production of plasma cells during an adaptive immune response.

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

## Mark scheme (4 marks)

1. An antigen is presented to / recognised by a specific B lymphocyte (or T helper cell) that carries a complementary receptor
2. Clonal selection is the process by which only the B lymphocyte(s) with the complementary receptor are selected / activated
3. Clonal expansion is the rapid mitotic division of the selected B lymphocyte, producing a large clone of genetically identical cells
4. Some of the cloned cells differentiate into plasma cells, which secrete large quantities of specific antibodies

## Key terms

- [clonal selection](https://www.gradenine.co.uk/glossary/clonal-selection)
- [clonal expansion](https://www.gradenine.co.uk/glossary/clonal-expansion)
- [plasma cell](https://www.gradenine.co.uk/glossary/plasma-cell)

## 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)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/explain-how-clonal-selection-and-clonal-85b1b762) · Published by Druglandscape Ltd.