Biological Significance Of Water

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The Biological Significance of Water


Water is the basis for life. Fortunately, it is the most available compound on earth. The compound is made up of the two different elements: hydrogen and oxygen. Water has a formula of H2O. Two hydrogen atoms are combined with an oxygen atom by sharing electrons via a process called covalent bonding.
It is polarised and the molecules form weak hydrogen bonds between them selves
Although it is a simple compound it has a complex set of properties. It has been argued that nearly everything about water is somehow unusual or contradictory.

For example, liquid water contracts when cooled until it reaches a temperature of around 4°C. This is the temperature where it reaches its maximum density. When the temperature drops below 4°C it begins to expand. This continues even when it changes state into ice. This is due to the more open arrangement of the water molecules in the ‘ice lattice’. This explains why ice floats; ice is less dense than water. It is also why pond and sea life can survive underneath a thick layer of ice. The surface ice insulates the water below it.

The specific heat capacity of water is very high. Much energy is needed to break the hydrogen bonds, which restrict the movement of water molecules. This results in aquatic environments to have more stable temperatures than terrestrial surroundings do.
Ponds, seas, lakes and even cells and bodies of organisms are relatively slow to change temperature. Larger animals have a yet further stable temperature than smaller animals, since they have more water in them, which slows down the loss or gain of heat.
Even more energy is needed to turn this liquid water to a gas.

Another important property that water has is that it has very high surface tension. It is higher than any other substance except for Mercury. The reason for this is that at the surface of the water, the hydrogen bonds are orientate...