2.1 Practical Investigation

HYPOTONIC Solutions

Hypotonic solutions are very dilute solutions. E.g. pure water.

The water concentration is higher in the extracellular environment, so the water is going to want to move into the cell.

The cell grows in size and becomes TURGID (plant). The animal cell keeps growing until the cell membrane ruptures (LYSIS).

ISOTONIC Solutions

Isotonic solutions are neither concentrated nor dilute. E.g. saline.

The water concentration is the same inside the cell and in the extracellular environment, so there is no net movement of water.

The cell does NOT change size.

HYPERTONIC Solution

Hypertonic solutions are very concentrated solutions. E.g. very salty or sugar water.

The water concentration is higher in the cell, so the water is going to want to move out of the cell and into the extracellular environment.

The cell shrinks in size and becomes FLACCID (plant) or PLASMOLYSED (animal).