LC BIOLOGY- OSMOSIS AND DIFFUSION

Selectively Permeable Membrane

allows some but not all molecules to pass through

Diffusion

the spreading out of molecules from an area of high concentration to an area of low concentration

Osmosis

the movement of water molecules across a semi-permeable membrane from an area of high water concentration to an area of low water concentration

Solvent

liquid that dissolves other substances

Solute

substance that has been dissolved

Solution

mixture of solvent and solute

Turgor Pressure

the outward pressure of the cytoplasm and vacuole against the cell wall of a plant

Plasmolysis

the loss of water from the cytoplasm and the movement of the cell membrane away from the cell wall

High Salt and Sugar Concentration

• can be used to remove water from microorganisms by osmosis

• are used as food preservation techniques

To Show Osmosis

1. place bag of visking tubing almost filled with (a) distilled water, and (b) concentrated sucrose solution, in distilled water

2. bag (a) stays the same in mass and turgidity

3. bag (b) increases in mass and turgidity as water enters as a result of osmosis