The Biological Importance of Water for Living Organisms
Water is a chemical substance with the formula H2O which appears in nature in all three common states of matter; its most common state being liquid. Pure water is tasteless, odorless and clear. It is essential to life and is one of the most essential elements to good health - it is necessary for the digestion and absorbtion of food; helps maintain proper muscle tone; supplies oxygen and nutrients to the cells; rids the body of wastes; and serves as a natural air conditioning system.
Water is a polar molecule which is made up of one negatively charged oxygen atom and two positively charged hydrogen atoms which are joined together by covalent bonds. The water molecule shape with both hydrogen atoms occurring on the same side of the oxygen atom gives water its ability to “stick” to itself and to other surfaces. The hydrogen atoms create a positive electrical charge while the oxygen atom creates a negative charge. The attraction to one another is what causes water to form droplets. The attraction between the positive and negative bonds also means that water dissolves compounds important for survival, such as glucose gleaned from ingesting food.
One of the main roles of water in living organism is that its use as a solvent. Because water is somewhat ionised, other polar molecules such as salts, sugars and amino acids will dissolve easily in water. This permits water to be used for the transportation of such substances (notably in the bloodstream of animals and the xylem and phloem vessels found in plants). Water can be used in this way to transport many substances e.g. nutrients and excretory products by using water as a solvent. Molecules such as starch and glycogen which are hydrophobic are not soluble and therefore are ideal for storage. Temperature of water is very important. The temperature at which water freezes is 0°C (32°F) and the temperature at which it boils is 100°C (212°F). At room...
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