DIFFUSION |
OSMOSIS |
ACTIVE TRANSPORT |
Transport of gases or dissolved substances in solution from a region of high concentration to a region of low concentration |
Transport of water through a semi-permeable membrane from a solution of high concentration to a solution of low concentration |
Transport of a substance from low to high concentration regions, using energy from the cell, through a living membrane |
1. Liquids and gases can diffuse over considerable distances |
Water only transported over a short distance |
Certain selected solutes, ions, glucose, sucrose, amino acid, etc., transported through short distances |
2. Rapid in gases, but slow in solutions of substances |
Slow process |
Rapid process |
3. Transport from high to low concentration |
Transport of water from solution of high to low concentration |
Transport of selected substances from region of low to high concentration |
4. Occurs with or without a non-living permeable membrane |
Either a living or non-living semi-permeable membrane needed |
A living selective lipo-protein membrane is essential |
5.No cell energy required |
No cell energy required |
Cell energy from ATP required |