Science·Organisms & Life Processes·conceptual
Gas Exchange & Breathing
Describe the structure of the human gas exchange system (trachea, bronchi, bronchioles, alveoli) and explain how the mechanism of breathing — using pressure changes from rib and diaphragm movement — moves air in and out of the lungs
Suggested ages 12–13
Evidence of understanding
- Labels a diagram of the lungs showing trachea, bronchi, bronchioles, and alveoli
- Explains that breathing in lowers air pressure in the chest and air rushes in
- Describes how the structure of alveoli (large surface area, thin walls, good blood supply) aids gas exchange
Assessment prompt
If Gas Exchange & Breathing took a deep breath after running, could they explain what's happening in their lungs — how the air gets in, where the oxygen crosses into the blood, and how carbon dioxide leaves?
Standards alignment
KS3.Sci.Bio.GasExchange.1GB · uk-nc-2013
Human gas exchange system
The national curriculum in England: Key stages 1 and 2 framework document · KS3
KS3.Sci.Bio.GasExchange.2GB · uk-nc-2013
Mechanism of breathing
The national curriculum in England: Key stages 1 and 2 framework document · KS3