# Describe the journey of an oxygen molecule from the trachea to the bloodstream, naming the structures it passes through in the correct order.

> Eduqas GCSE Biology — 1.2.2 The respiratory system · Describe · 4 marks

## Mark scheme (4 marks)

1. Oxygen passes from the trachea into the bronchi
2. Oxygen passes from the bronchi into the bronchioles
3. Oxygen reaches the alveoli (from the bronchioles)
4. Oxygen diffuses across the alveolar wall / thin membrane into the blood / capillaries

## Key terms

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

## Related

- [Revision notes for Eduqas GCSE Biology](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" 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/describe-the-journey-of-an-oxygen-04b7e848) · Published by Druglandscape Ltd.