The lungs of an adult human contain about 480 million alveoli. The mean surface area of one alveolus is 2.4×105μm22.4 \times 10^5 \mu\text{m}^22.4×105μm2 .
1 m2=1×1012μm2 1 \text{ m}^2 = 1 \times 10^{12} \mu\text{m}^2 1 m2=1×1012μm2Calculate the total surface area of all of the alveoli in the lungs of an adult human. Give your answer in m2\text{m}^2m2 .
The outer surface of the body of an adult human has a total area of about 1.8 m2 . Explain why an adult human exchanges gases at the alveoli rather than across the outer surface of the body.
58 exam-style questions on AQA GCSE Biology 1.3 Transport in cells, covering 1.3.1 Diffusion, 1.3.2 Osmosis, and 1.3.3 Active transport. Each one has a worked solution and a mark scheme showing where the marks go.