The Biological Importance of Water

The Biological Importance of Water

Water is the most important chemical on the earth for living organisms

to survive. This is because of its two unique bio-chemical and

physical properties. It’s a very important component of cells

averaging between 70-95% of the mass of any cell. Although it’s a

simple molecule, the hydrogen bonding of it makes it more difficult to

separate. Also because of its liquid property it provides a medium for

other molecules and ions to mix in. Water has some surprising

properties despite its very simple molecule.

Water is an excellent solvent for ions and polar molecules. When a

chemical dissolves in water, the water molecules are attracted to the

molecules, which have an uneven charge such as sugars and glycerol.

The chemicals in the solution move around and react with other

chemicals in the water. The majority of reactions in living organisms

take place in aqueous solutions.

Non-polar substances, however, do not dissolve in water and therefore

if they are surrounded by water, they are pushed together by water

because the water molecules are attracted to each other. These are

known as hydrophobic (water hating) which is important in protein and

membrane structure. It also adds stability to these structures.

Water has a high heat capacity. When the temperature of water

increases a large amount of energy is required. Therefore large areas

of water, such as oceans and lakes, are slow in changing temperature

unlike the environment surroundings around them. This is due to energy

being required in breaking the hydrogen bonds, which prevent the

movement of molecules. Large amounts of energy are required to convert

water to gas and it is also and for transfer of evaporation as it is

useful in cooling the body. The large water content in cells and

tissues help them to maintain a stable temperature acting as a buffer.

A large amount of energy must be transferred from water before it is

converted from a liquid to a solid form. This makes it highly unlikely

water will freeze which makes it ideal for organisms to live in.