Main Difference
Osmosis and diffusion are the scientific term used in chemistry and biology. Diffusion is the movement of molecules form the region of a higher concentration to a region of lower concentration. Osmosis is the movement of molecules from the region of higher concentration to a region of lower concentration through semi permeable or selectively permeable membrane or layer.
Diffusion
Diffusion is the movement of molecules form the region of a higher concentration to a region of lower concentration. If a bottle of perfume is kept open in a room, its fragrance will spread in the whole room due to diffusion of molecules. Diffusion takes place in gases as well in liquids. It is independent of solute potential.
Osmosis
Osmosis is the movement of molecules from the region of higher concentration to a region of lower concentration through semi permeable or selectively permeable membrane or layer. Osmosis takes place in liquids only. Osmosis is dependent upon solute potential.
Key Differences
- Both osmosis and diffusion are movement of molecules from higher to lower concentration but in osmosis the movement is through semi permeable membrane.
- Osmosis take place in liquids only while diffusion take place in gases and liquids as well.
- Semi permeable membrane is must for osmosis but for diffusion semi permeable membrane is not needed.
- Diffusion can operate in any medium while osmosis can operate only in liquids.
- Diffusion depends upon free energy of diffusing substance while osmosis depends upon of degree of free energy reduction of one solvent over another.
- Osmosis is opposed by turgor pressure while in diffusion turgor pressure don’t normally operate.
- Osmosis is dependent upon solute potential while diffusion is independent of solute potential.
- Osmosis depends upon the no of the particles of other substance dissolved in liquid while diffusion of a substance is dependent upon the presence of the other substances.