Osmosis Experiment

Background Knowledge:

Osmosis definition:

Diffusion of water molecules through a semi permeable membrane from a higher concentration to a lower concentration until the concentration on both sides is equal.

Osmosis in animal cells:

The cell membrane is the partially permeable membrane in animal cells. If the cells were placed in distilled water they gain water, swell and burst. This is known as haemolysis.

Osmosis in plant cells:

The cellulose cell wall of plant cells is fully permeable. Therefore it’s the cell membrane of a plant cell which acts as the semi-permeable membrane, deciding what gets into and out of the cell.

When plant cells are placed in water the following happens:

• Water enters the cell, the reason is that the cell sap in the permanent vacuole is concentrated and therefore has a low water concentration compared to the water on the outside of the cell.

• The cellulose cell wall stretches slightly but most importantly it prevents the cell bursting. (Plant cell is turgid)

• The permanent vacuole fills with water, pushing the cytoplasm against the cell ...