A-LevelBiologyGas exchange9700/12 · May/June 2023 · Q361 Mark
Which statement about gas exchange between air in the alveoli and blood in the pulmonary capillaries is correct?
AThe oxygen concentration in the capillaries leaving the pulmonary artery is higher than the oxygen concentration in the alveoli.
BGases must diffuse across the endothelium of the pulmonary capillaries and the endothelium of the alveoli.
CThe elastic fibres in the alveoli walls allow the alveoli to expand to increase the surface area available for diffusion into the pulmonary capillaries.
DBreathing out reduces the carbon dioxide concentration gradient between the blood in the pulmonary capillaries and the air in the alveoli.
✓ Correct answer
C: The elastic fibres in the alveoli walls allow the alveoli to expand to increase the surface area available for diffusion into the pulmonary capillaries.
Practise more questions on this topic
Oracle Prep sorts past-paper questions by topic, so you can drill Gas exchange and see which topics are most likely to come up next.
Sign up free →