# Explain how the ultrastructure of a hepatocyte (liver cell) is adapted for its role in detoxification and metabolic processing.

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

## Mark scheme (4 marks)

1. Abundant smooth endoplasmic reticulum (SER) provides a large surface area for enzymes involved in detoxification (e.g. cytochrome P450 enzymes) / breakdown of lipid-soluble toxins
2. Large number of mitochondria supply the ATP required for the many energy-demanding metabolic reactions (e.g. gluconeogenesis, urea synthesis, active transport)
3. Numerous peroxisomes contain catalase and oxidases that oxidise toxic substances (e.g. hydrogen peroxide, ethanol) / break down H₂O₂ to water and oxygen
4. Large nucleus with prominent nucleolus / polyploidy common — reflects high level of transcriptional activity needed to produce the wide variety of metabolic enzymes; OR extensive rough ER and Golgi apparatus for synthesis and processing/secretion of plasma proteins (e.g. albumin, clotting factors)

## Key terms

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

## Related

- [Revision notes for IB DP Biology Higher 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-how-the-ultrastructure-of-a-d23876a2) · Published by Druglandscape Ltd.