Diffusion
- Created by: Jasmin
- Created on: 22-10-14 21:37
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- Diffusion
- Diffusion is the paddsive movement of particles from an area od higher concentration to an area of lower concentration
- Molecules may diffuse both ways, but the net movvement will be in the area of low concentration. This continues until particles are evenly distributed throughout the liquid or gas
- It is a passive process -no energy is needed for it to happen
- The concentration gradient is the path from an area of higher concentration to an area of lower concentration. Particles diffuse down a concentration gradient
- Particles can diffuse across a plasma membrane as long as they can move freely through the membrane. Eg - Oxygen and carbon dioxide molecules are small enough to pass easily through spaces between phospholipids
- Rate of diffusion depends on:
- 1) The concentration gradient -the higher it is, the faster the rate of diffusion
- 2) Thickeness of the exchange surface -the thinner the exchange surface (i.e. the shorter the distance particles have to travel) te faster the rate of diffusion
- 3) Surface area -the larger the surface area (e.g. of the cell membrane) the faster the rate of diffusion
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