- Transfer of molecules of solvent
- From less concentrated solution to a more concentrated solution
- From higher water concentration to lower water concentration
- Through semi-permeable (permits half of molecules to transfer from one side to another) membrane
- Until the concentrations on both sides are equal
Osmosis:
- Process happens without expenditure of energy (passive process)
- Solvent that undergoes osmosis can be liquid or gas
Osmosis vs Diffusion
Diffusion
- Movement of particles from higher concentration to lower
- No semi-permeable membrane
- What entire solute is doing
- E.g. Filling entire room with perfume when sprayed
Osmosis
- Semi-permeable membrane
- Movement of solvent particles from dilute solution to the concentrated solution
- Movement of particles from lower concentration to higher concentration
- What solvent is doing
- Red blood cells flowing through water
First half of particles transferred is osmosis; if rest of particles are transferred without a semi-permeable membrane, it is diffusion
Types of Osmotic solutions
- Isotonic: Same conc. of solution both inside and outside of the cell (cell volume stays the same) FLACCID
- Hypertonic: Higher conc. of solution outside the cell than inside (cell volume decreases) PLASMOLYSED
- Hypotonic: Higher conc. of solution inside the cell than outside (cell volume increases) TURGID
Endosmosis vs Exosmosis
- Endosmosis
- Inflow of solvent from outside to inside of cell
- Exosmosis
- Outward flow of water from cell when placed in more concentrated solution(cell shrinks)
- Cell becomes plasmolysed