A laboratory model has a folded, thin membrane separating two liquids. The liquid on one side has a higher concentration of dissolved particles than the liquid on the other side. Both liquids are continually replaced as particles diffuse across the membrane.
rate of diffusion∝surface area×concentration differencethickness of membrane \text{rate of diffusion} \propto \frac{\text{surface area} \times \text{concentration difference}}{\text{thickness of membrane}} rate of diffusion∝thickness of membranesurface area×concentration differenceExplain how the folded membrane, its thickness and the replacement of the liquids affect the rate of diffusion. In your answer, refer to surface area, diffusion distance and concentration difference.
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.