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2.2 Animal tissues, organs and organ systems

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Question 78

Scientists measured features affecting gas exchange in the lungs of two adults, R and S.

MeasurementAdult RAdult S
Number of alveoli4.8 × 1083.2 × 108
Mean surface area of one alveolus in m21.5 × 10-71.2 × 10-7
Mean thickness of an alveolar wall in μm\mu\text{m}μm0.51.0
Volume of fresh air reaching the alveoli in dm3 per minute6.07.5
a.

Calculate the total gas exchange surface area for adult S as a percentage of the total gas exchange surface area for adult R.

[3]
b.

Explain why oxygen may diffuse into the blood more slowly in adult S than in adult R, even though more fresh air reaches the alveoli of adult S each minute.

[3]
Markscheme

2.2 Animal tissues, organs and organ systems Questions

  1. GCSE
  2. /Biology
  3. /2.2 Animal tissues, organs and organ systems

304 exam-style questions on AQA GCSE Biology 2.2 Animal tissues, organs and organ systems, covering 2.2.1 The human digestive system, 2.2.2 The heart and blood vessels, 2.2.3 Blood, 2.2.4 Coronary heart disease: a non-communicable disease, 2.2.5 Health issues, 2.2.6 The effect of lifestyle on some non-communicable diseases, and 2.2.7 Cancer. Each one has a worked solution and a mark scheme showing where the marks go.

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