All living organisms need Water
Water is a transparent liquid that makes the world’s oceans, lakes, rivers, streams, rain and the main ingredient fluids of organisms. Chemical formula is H2O. Water molecule contains one oxygen atom and two hydrogen atoms which are linked by covalent bonds.
It is a liquid at standard temperature and pressure. It co-exists on the Planet Earth in it’s solid form as ice or gaseous form as vapor. There is a cloud, snow, hoar, fog and dew. Under the influence of solar radiation surface water continuously evaporates into the atmosphere (the water cycle). There it condenses (creating a rainy or snowy clouds in the atmosphere) in the form of precipitation (rain, snow, hail, dew, frost and fog). Then it returns to Earth, transferring such a large mass on the continents. We call it global hydrological cycle, so in many ways influences on the climate.
At atmospheric pressure and a temperature between 0 ° C (when freezing) and 100 ° C (when boiling), pure or distilled is a colorless liquid, odorless and tasteless. It is emphasized by the fact that it’s density in the solid state is less than the density of liquid. The density is greatest at 3.98 ° C. Ice density is lower and it’s floating on water. Ice volume was increased to 9% by volume of the same mass of liquid.
The viscosity is increased by lowering the temperature. As the mass of liquid surface on Earth is huge with small changes in temperature, sea and lake, behind the atmosphere can hold up and again release into the atmosphere large amounts of heat, which is caused to the surface of the Earth there is no sudden and large changes in temperature as well as on the Moon or Mercury. Vapor in the atmosphere, partially absorb microwave and infrared radiation of soil and reduce temperature fluctuation. Slowly heating and cooling must cause the milder climate of coastal regions.
Sea is called the water of seas and oceans. It contains significant amounts of dissolved salts (more than 35 g / L). Because of the presence of calcium and magnesium in the form of chloride and sulfate, the sea is very hard liquid. Corrodes metals, concrete and some types of stone. It is extremely salty taste, but can be used for drinking obtained desalination of salty lake or sea (desalting).
The natural water containing calcium bicarbonate (Ca (HCO3) 2), calcium chloride and calcium sulfate is referred to as hard. Drinking water, groundwater, borehole and surface water is clear and totally transparent liquid odorless and colorless. For the sake of good taste should contain dissolved oxygen, carbon dioxide and soluble salts (NaCl, NaHCO3) and others. If contain the pathogenic bacteria, organic matter, nitrate, nitrite, ammonia and iron salts (which enable the development of algae), manganese salt (give a bad taste), or other harmful substances, must be purified before use by oxidation with oxygen from the air and disinfected with chlorine or ozone.
It covers 71% of the Earth’s surface. On Earth, 96.5% of the crust of the Planet is in the seas and oceans, 1.7% in groundwater, 1.7% in glaciers and ice caps of Antarctica and Greenland, a small fraction in other large bodies and 0.001% in the air as vapor, clouds (formed of ice and liquid suspended in the air) and precipitation. Only 2.5% of this water is fresh and 98.8% of that liquid is in the ice (except ice in the clouds) and groundwater. Less than 0.3% of all the fresh water in rivers, lakes and the atmosphere and an even smaller amount of the Earth’s fresh water (0.003%) is contained within biological bodies and finished products. A quantity of this liquid is in the Earth’s interior.
Life and Water
An essential component of living organisms (moisture content up to 90%) and is necessary for the life of all living organisms. In some organisms makes 99% of it’s mass. It is a good solvent supplying plants and minerals necessary for photosynthesis. In the human body as the main component of body fluids supplies all organs with nutrients and removes waste products from the body. All biological processes take place exclusively in an aqueous medium, although there are organisms that can survive long term state of complete dehydration. Metabolism, growth and reproduction of these organisms begin only after rehydration. Biological macromolecules (proteins, nucleic acids, polysaccharides) include tightly bound water, which is necessary for it’s biologically active conformation. It is not only a solvent in which the enzymes function, but also a direct metabolite, the substrate hydrolysis in all. By-product in many biosynthetic reactions.
A living organism continuously taken and released water, which is called the water cycle. Aquatic organisms alternate water diffusion. For terrestrial plants that the exchange takes place predominantly physical mechanisms (capillary forces in the bud, transpiration). Land animals and man must drink it or had obtained food containing water. Water lose urine, feces, breath and perspiration. The excretion of metabolic water is necessary because it allows the body to get rid of useless and harmful substances soluble in water. Sweating is in many organisms part of the process of thermoregulation.