# Explain how the structure of a neutrophil is related to its function in the immune response.

> IB DP Biology Standard Level (2023 syllabus) — B2.3 Cell specialisation · Explain · 4 marks

> Neutrophils are the most abundant white blood cells in human blood and are typically the first immune cells to arrive at a site of infection.

## Mark scheme (4 marks)

1. Neutrophils have a multi-lobed (polymorphic) nucleus, allowing the cell to squeeze through narrow gaps between capillary endothelial cells (diapedesis) to reach infected tissue.
2. Neutrophils contain numerous lysosomes (granules) packed with hydrolytic / digestive enzymes, enabling them to destroy pathogens after phagocytosis.
3. Neutrophils carry out phagocytosis: the flexible cell surface membrane allows pseudopodia to form, engulfing pathogens into a phagosome.
4. Neutrophils have many mitochondria to supply ATP required for the energy-demanding processes of movement (chemotaxis) and phagocytosis.

## Key terms

- [neutrophil](https://www.gradenine.co.uk/glossary/neutrophil)

## Related

- [Revision notes for IB DP Biology Standard Level (2023 syllabus)](https://www.gradenine.co.uk/learn)
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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-how-the-structure-of-a-e148f8a6) · Published by Druglandscape Ltd.