2.48 Alveoli and gas exchange
Exam question
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Which feature of the alveoli shortens the diffusion distance?
(1)Total for this question: 1 mark
2(g) GAS EXCHANGE · EXAM QUESTIONS
2.48 Alveoli and gas exchange
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2.48 Alveoli and gas exchange
Exam question
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Which gas diffuses from the blood into the alveoli?
(1)Total for this question: 1 mark
2.48 Alveoli and gas exchange
Exam question
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Describe how the alveoli are adapted for gas exchange.
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Total for this question: 4 marks
2.48 Alveoli and gas exchange
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Explain how oxygen moves from the air in an alveolus into a red blood cell.
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Total for this question: 3 marks
2.48 Alveoli and gas exchange
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Explain why blood flowing through lung capillaries keeps a steep concentration gradient for oxygen.
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Total for this question: 2 marks
2.48 Alveoli and gas exchange
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Explain why the capillaries around the alveoli are very narrow.
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Total for this question: 2 marks
2.48 Alveoli and gas exchange
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Explain why having millions of tiny alveoli is better than one large air sac.
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Total for this question: 2 marks
2.48 Alveoli and gas exchange
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Composition of air Gas Inhaled / % Exhaled / % Oxygen 21 16 Carbon dioxide 0.04 4 Nitrogen 78 78 Water vapour variable saturated Illustrative typical values, rounded. The table shows the composition of inhaled and exhaled air. Compare the percentages of oxygen and carbon dioxide.
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Total for this question: 2 marks
2.48 Alveoli and gas exchange
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Explain why the percentage of nitrogen is the same in inhaled and exhaled air.
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Total for this question: 2 marks
2.48 Alveoli and gas exchange
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Explain why exhaled air contains more water vapour than inhaled air.
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Total for this question: 2 marks
2.48 Alveoli and gas exchange
Exam question
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Composition of air Gas Inhaled / % Exhaled / % Oxygen 21 16 Carbon dioxide 0.04 4 Nitrogen 78 78 Water vapour variable saturated Illustrative typical values, rounded. Using the table, calculate how many times more carbon dioxide there is in exhaled air than in inhaled air.
(2)timesTotal for this question: 2 marks
2.48 Alveoli and gas exchange
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Emphysema destroys the walls between alveoli, forming larger air spaces. Suggest why people with emphysema are short of breath.
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Total for this question: 2 marks
2.48 Alveoli and gas exchange
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Explain why a thick fluid in the alveoli (as in pneumonia) reduces oxygen uptake.
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Total for this question: 2 marks
2.48 Alveoli and gas exchange
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Describe the direction of diffusion of oxygen and carbon dioxide at the alveolus.
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Total for this question: 2 marks
2.48 Alveoli and gas exchange
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Explain why the alveolus lining is moist.
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Total for this question: 2 marks