Factors affecting Diffusion
Biology: Edexcel IGCSE, topic 2.1.15
Factors Affecting Diffusion
The rate of diffusion can speed up or slow down based on the following factors:
Concentration gradient
- The concentration gradient is linked to the difference in concentration between two areas.
- The bigger the difference in concentration between two areas, the greater the concentration gradient and the faster the rate of diffusion.
Temperature
- The higher the temperature, the faster the rate of diffusion.
Membrane surface area
- The larger the surface area of the membrane that a substance is diffusing through (e.g. the membrane around a cell), the faster the rate of diffusion.
Distance
- The greater the distance a substance has to diffuse across, the more time taken.
- For example, a thicker membrane creates a larger distance, so diffusion across it will take longer.
Test yourself on Factors affecting Diffusion
Which factor does NOT affect the rate of diffusion across a membrane?
What would happen to the rate of diffusion if the concentration got steeper and the temperature rose?