A scientist tests two artificial exchange membranes. Oxygen diffuses through each membrane from water into a chamber containing less oxygen. The surface area, temperature and oxygen concentration difference are the same for both membranes.
| Membrane | Thickness / mm |
|---|---|
| P | 0.12 |
| Q | 0.04 |
Explain which membrane has the greater rate of oxygen diffusion.
Calculate the ratio of the rate of oxygen diffusion through membrane Q to the rate through membrane P.
102 exam-style questions on Edexcel GCSE Biology 8.1 Exchange surfaces and diffusion, covering 8.1.1 Introduction to exchange and transport, 8.1.2 Alveoli adapted for gas exchange, 8.1.3 Factors affecting rate of diffusion, and 8.1.4 Rate of diffusion using Fick's law. Each one has a worked solution and a mark scheme showing where the marks go.