Diffusion

Diffusion

The random movement of small particles from an area of high concentration to an area of low concentration
1. Pass between small gaps between phospholipid molecules or dissolves in lipid layer
  1. Passive process, no ATP required
No membrane proteins needed
Examples
1. O2
2. CO2
3. Vitamin A,D,E
Factors affecting rate
1. Concentration Gradient
  1. Higher the concentration gradient the more likely a molecule will collide with the membrane and cross it
2. Temperature
  1. As temp increases molecules gain kinetic energy so moves faster, so collides with membrane more frequently
3. Size of molecule
  1. The larger the molecule the harder it is to fit between phospholipids
4. Lipid solubility
  1. The more lipid soluble a molecule is, the easier it is to dissolve and cross bilayer
5. Distance
  1. The longer the diffusion path, the more distance the molecule needs to travel so the longer it takes
6. Surface Area
  1. As S.A increases the more spaces for diffusion to happen

Resource summary

	Created by Fauzia Ali over 8 years ago