A gas-permeable bag containing respiring animal cells is placed in a sealed chamber. The membrane allows oxygen and carbon dioxide to diffuse. The surface area and thickness of the membrane and the temperature remain constant.
The table shows the concentrations of the gases inside and outside the bag.
| Time in minutes | Oxygen outside the bag in % | Oxygen inside the bag in % | Carbon dioxide outside the bag in % | Carbon dioxide inside the bag in % |
|---|---|---|---|---|
| 0 | 8.0 | 2.0 | 0.5 | 5.0 |
| 10 | 6.5 | 3.0 | 2.0 | 4.0 |
Use the data to explain how the net rate of diffusion of each gas changes from 0 minutes to 10 minutes.
The cells then stop respiring and the bag is left in the sealed chamber for a long time. Predict what will happen to the net movement of each gas.
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.