CAIE IGCSE Biology 11.1.9 Explaining Inspired & Expired Air
Practise explaining air-composition differences through cellular respiration, alveolar diffusion and humidification.
- Syllabus
- 2026–2028
- Course
- Biology 0610
Exam points
- explain lower expired oxygen because oxygen diffuses into blood and is used in aerobic respiration
- explain higher expired carbon dioxide because respiration produces it and it diffuses from blood into alveoli
- explain higher expired water vapour through evaporation from moist airway and alveolar surfaces
11.1.9—Differences in composition between question 1
[Maximum number: 3]
Explain the differences in composition between inspired and expired air.
any three from:
less oxygen and more carbon dioxide in expired air (than inspired air) ;
(as) oxygen is required for aerobic respiration ; carbon dioxide is released by respiration ; water vapour increases (as it is released by respiration) ; AVP ;
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