Water is origin of life.
All living things are made up of certain chemical compounds. These compounds can be classified as organic and inorganic. The most important organic compounds are proteins, carbohydrates, lipids, and nucleic acids. But here, we will discuss the most important inorganic compound: water. In the bacterial cell, the percentage of water is 70%, so in the eukaryotic cells.
WATER IN HUMAN BODY
Humans body is composed of about 65 to 89% water. Bones contain about 20% water, while brain cells comprise 85% water. Almost all the reactions occurring in the human body require an aqueous medium...All enzymes of the bodywork in the water...Without water, enzymes cannot function, and all the reactions in the body would cease. It is also used as a raw material in photosynthesis.
HEAT CAPACITY OF WATER
Water has a high heat capacity. Due to this reason, water acts as a thermal stabilizer. Water absorbs a maximum of heat with a minimum change in its own temperature.
WATER AS A POLAR SOLVENT
Water is a polar solvent. It is also known as a universal solvent. Due to its polar nature, lipids are insoluble in water; thus, they maintain cell membranes that make compartments in cells.
HEAT OF VAPOURIZATION
Water has a high heat of vaporization. It is the amount of heat required to convert liquid water into steam. Its amount is 574 kcal per kilogram. Due to its high heat of vaporization, it provides a cooling effect. In plants, cooling is produced when water is transpired, while in humans, the cooling effect is produced by perspiration.
PROTECTION
Water also protects the body against protists. It also acts as a lubricant and protects against friction. For instance, tears protect the eyes from the rubbing of eyelids. Water also forms a cushion around organs that help to protect organs from trauma.
IONIZATION OF WATER
Water molecules can be ionized to form hydrogen and hydroxyl ions. The reaction is reversible, but equilibrium can be maintained. At room temperature; 25 degrees Celcius, the concentration of hydrogen and hydroxyl ion is equal. Pure water contains about 10^-7 mol per liter of each ion.
PH OF PURE WATER
PH of pure water is 7. But it can be affected by changes in chemical components present in it.
WATER AS AN ENVIRONMENTAL COMPONENT
As water is present in living organisms, it is also a major portion of the EARTH. It is present in lakes, rivers, sea, oceans, ice caps, glaciers, and groundwater. Marine life is impossible without water. The water in the sea and oceans can not be used for drinking purposes. Freshwater is only about 1% of the total water present on earth.
The system in which living and non-living organisms exchange materials and transfer energy within the water is HYDROSPHERIC ECOSYSTEM. Saltwater oceans are the largest ecosystem on the earth, forming about 71% of its surface.
Although water seems quite transparent, it absorbs a considerable amount of light energy that sustains life. Even in the clearest water, the intensity of light decreases rapidly with depth, so at a depth of 600 feet or more, a little light is left to support photosynthesis.
The aquatic ecosystem's nutrients tend to be concentrated near the bottom sediments supporting life where light levels are too low to support photosynthesis......
Appropriate temperature is present in water to carry out all metabolic processes...
A small amount of water is also present in the air in the form of water vapors. The pH of unpolluted rainwater is 5.6. Due to the presence of Carbon dioxide in the atmosphere, the natural rain itself forms carbonic acid. The rainwater has a pH of less than 5 is considered purely acidic. In the atmosphere, SOx and NOx are transformed by chemical reactions into sulphuric acid and nitrous acid. These acids get mixed with rainwater and make it acidic. The acid deposition includes both wet( rain, snow, fog) or dry, acidic deposition.
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