A level Biology Topic 1 - Importance of Water

IMPORTANCE OF WATER
Properties of Water =
 Cohesion
 Adhesion
 High Specific Heat Capacity
 Polar Solvent
Cohesion =
When 2 water molecules stick together, due to the hydrogen bonds, this enables
water to flow.
IMPORTANT OF COHESION –
 Allows water to move up the xylem in transcription.
 Allows the transport molecules in plants and animals.
 Gives water a high surface tension.

Adhesion =
Water molecules attracted to different polar substances.
IMPORTANCE OF ADHESION –
 Allows water to move up a plant in the xylem.
 Allows polar substances to dissolve in water.
 Allows for capillary action.

High Specific Heat Capacity =
All those hydrogen bonds within water are great at absorbing energy, meaning
water therefore requires a lot of heating in order to increase its temperature.
Water requires lots of energy to increase temperature.

Polar Solvent =
Great solvent – tiny charges [DELTA MINUS/PLUS] in its molecules attract other
molecules in effect dissolving them.
Water is a good solvent because it has polar properties, it can form hydrogen
bonds with other charged on other polar molecules, which can dissolve in water.
IMPORTANCE OF POLAR SOLVENT –
 Solubility