Explain6 marksChallenge
The human lung contains millions of alveoli surrounded by a network of capillaries. Explain how the structure of the alveoli and the associated capillaries is adapted to maximise the rate of gas exchange with the blood.
CAIE A Level Biology 9700 · Gas exchange
Gas exchange: explain question
How this question is marked
6 marks, so the mark scheme is looking for about 6 separate creditworthy points. Making the same point twice in different words earns it once.
Explain means: Give the reasons or the mechanism: why or how something happens. Link each point to the next with because, so or which means. A list of facts with no links usually loses the reasoning marks.
More Gas exchange questions
- 4 marks · Describe how the structure of each of the following tissues in the human gas exchange system is adapted to its function: ciliated…
- 5 marks · An oxygen molecule enters the trachea during inhalation. Describe the pathway it takes to reach the blood in the pulmonary capillaries…
- 5 marks · A student inhales a breath of air. Describe the path taken by an oxygen molecule from the trachea to the blood in the lungs, and explain…
- 4 marks · A scientist examines a section of lung tissue under an electron microscope. The image shows the alveolar wall consisting of a very thin…
- 5 marks · A person inhales a breath of air containing oxygen molecules. Describe the path taken by an oxygen molecule from the trachea to the blood…
- 4 marks · A lung biopsy sample examined under an electron microscope reveals that the alveolar walls consist of a single layer of extremely…
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.