The Biological Importance of Water

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The Biological Importance of Water

Water is vital to all living organisms, as a constituent of cells, a

reactant in metabolic reactions, and a solvent for aquatic organisms.

Without water life on earth would not exist. Water also provides an

environment for organisms to live in. Water consists of two hydrogen

atoms and one oxygen atom forming H2O. The two hydrogen’s and the

oxygen bond together through covalent bonding, which is the sharing of

electrons.

Water molecules are polar, with negative charge on the hydroxyl ions

and positive charge on hydrogen ions. The attraction of oppositely

charged poles of water molecules cause them to group together.

Attractive forces form hydrogen bonds. The substances that are able to

dissolve in water are known as hydrophilic substances.

Water can be used as temperature stabiliser. Lots of energy is

required to heat or boil water. The boiling point of water is 100 c

and the melting point is 0 c. At room temperature water is a liquid

because of hydrogen bonds, which hold the water molecules in a liquid

state. Water has a high specific heat, which is important inside cells

where metabolic reactions are enzyme controlled and externally to

provide a constant environment for aquatic organisms. High latent

heat, which is significant in temperature control where heat is used

for vaporization of water when sweating.

Water’s maximum density is at 4 c. As water-cools the density

increases. When water is in a liquid state the hydrogen bonds are weak

and can break easily because molecules move about. When water freezes,

the water molecules are no longer free to move and the hydrogen bonds

are permanently formed. Ice floats because ice is less dense than

water. This is because in the solid state the molecules are less

closely packed than in liquid water. Fish can survive in frozen lakes

because the ice on the surface insulates the water from further

freezing. Water is also good as a lubricant.

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