# Explain how vesicle formation from fatty acid membranes could have contributed to the origin of the first cells.

> IB DP Biology Standard Level (2023 syllabus) — A2.1 Origins of cells · Explain · 4 marks

> Early Earth conditions included the presence of simple organic molecules such as fatty acids in aqueous environments. Fatty acids can spontaneously form membranous structures when placed in water.

## Mark scheme (4 marks)

1. Fatty acids are amphipathic molecules that spontaneously self-assemble into vesicles (or bilayer membranes) in aqueous conditions
2. Vesicle formation creates a selectively enclosed internal environment / separates internal chemistry from the external environment
3. Enclosure of self-replicating molecules (e.g. RNA) within vesicles would have concentrated reactants and allowed proto-metabolic reactions to occur
4. Vesicles can grow and divide, passing enclosed molecules to daughter vesicles, providing a basis for heredity / reproduction

## Key terms

- [vesicle](https://www.gradenine.co.uk/glossary/vesicle)
- [fatty acid](https://www.gradenine.co.uk/glossary/fatty-acid)

## 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-how-vesicle-formation-from-fatty-9744d848) · Published by Druglandscape Ltd.