# Explain how the structure of the cell wall in prokaryotic cells is related to its functions.

> IB DP Biology Standard Level (2023 syllabus) — A2.2 Cell structure · Explain · 4 marks

## Mark scheme (4 marks)

1. The cell wall is composed of peptidoglycan (murein), a mesh-like polymer of sugars and amino acids
2. The rigid, cross-linked structure of peptidoglycan provides mechanical strength, maintaining the shape of the cell
3. The cell wall prevents the cell from bursting (lysis) by withstanding the internal turgor pressure / osmotic pressure when the cell is in a hypotonic environment
4. The porous nature of the cell wall allows water, ions, and small molecules to pass through freely, so the wall does not restrict nutrient uptake

## Key terms

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

## 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-the-structure-of-the-1ac45f03) · Published by Druglandscape Ltd.