Water is the Cradle of Life - General aspects of Water - Properties of Water

Life originated, evolved and is sustained by water. Therefore, water has been called the Cradle of Life. Water remains liquid over a wide range of temperature, from less than 4°C to more than 90°C.Water is the major component of the body of a living being, 70% of total and 90% of the living cells. Water is essential for growth of cells as well as various body parts. Water possesses a number of properties which are useful in maintaining living system. They are cohesion, high specific heat, and high heat of vaporization, storage of heat and maintenance of pH through formation of ions.

Water is a reagent in photosynthesis, producing oxygen and reducing powder. It is required for hydrolytic splitting of larger molecules. Water maintains turgidity of cells and their organelles. It is essential for their working. Presence of water in the area of rubbing or movement checks frictional wear during polymerization. The phenomenon is called dehydration synthesis.

Electrolytes split up into ions in water. They are not allowed to form molecules by the development of water shells over their surface. Over a cation, water molecules establish bonds with the help of oxygen atoms while over the anions they establish through hydrogen ends. The non electrolyte polar substances get dissolved in water, because they possess slightly polar groups like hydroxyl group. Water molecules establish hydrogen bonds such groups.

A number of organisms live in water. They are called aquatic organisms. Various aquatic habitats are sea, estuary, pond, lake, and rivers. Sea water has a high content of 3-5%.Nearly, pure water occurs in the vapors form in the atmosphere.

Animals or plants that live and move in water need to be much more streamlined; because the résistance to motion is viscous medium is high as it obvious that water is fairly a viscous liquid. The viscosity of water allows organisms to swim and protects the aquatic animals and plants from mechanical injuries.

Organisms can exist in water without specialized mechanical or supportive structures are needed by organisms that inhabit terrestrial environments because water is buoyant medium.

Chemically, water can be viewed variously as a covalent hydride, an oxide, or a hydroxide. It is good solvent for many substances, especially ionic and polar compounds; it is ionizing and it ionizes to give low concentration of hydroxide and hydrogen ions. It is thus both a weak acid and weak base and conducts electricity; it is good, though liable, ligand, forming hydrates.