As the most abundant inorganic substance found in living matter, water is considered to be the factor which holds the key for the prevalence of life on Earth. Though water is essential for living beings, there are several requirements for water to fulfill to allow organisms to prevail. First of all comes the physical state of it. No being could live in solid ice. No being could live in water vapor either. So it is the liquid water that does all the magic. The following chart would give you a clear understanding of the importance of water for living beings :
Property
Role
Example
Major Improtances
Liquid at room temperature
Component of protoplasm
The main constituent of cell protoplasm is water
Polarity
A powerful solvent
Most of the materials in the cell are dissolved in the protoplasm and the cell sap
Chemical property
Acts as a reactant in many biochemical processes
Photosynthesis 6H2O + 6CO2 --> C6H12O6 + 6O2
Hydrolysis Starch + H2O --> Maltose
High adhesive and cohesive forces
Maintaining turgor in cells
Cell enlargement;
Mechanical support for herbaceous plants;
Movement of guard cells;
Blooming of flowers;
Turgor movements
Other Improtances
High surface tension
Provide habitat for some aquatic insects
Waterskates live and move about on water surface
High specific heat capacity
Resists the change of temperature when a considerable amount of heat is absorbed or lost
Maintain the body temperature of Poikilotherms and other animals within a narrow range
High latent heat of vaporization
Cooling body surfaces
Sweating;
Transpiration
High latent heat of fusion
A lot of heat has to be dissipated for water bodies to freeze
Water does not freeze within cells and in water bodies
High adhesive and cohesive forces
Transportation and absorption of materials
Translocation and ascent of sap;
Absorption of minerals into plants from the soil solution
Anomalous expansion of volume on freezing
Water bodies do not freeze solid. Ice forms on the top while liquid water remains at the bottom.
Aquatic organisms are capable of surviving during winter
Transparency
Allows penetration of light
Aquatic plants and algae are allowed to grow on great depths in water
Out of approximately 100 chemical elements, about 20 are found in living organisms. (Actually not all of them are present in every organism. The elements available in each organism differ by nature) These elements could be divided into 2 major groups as Macro Elements and Micro Elements, according to their presence within organisms.
Carbohydrates are considered as the most abandunt organic matter. The things we meet up as sugars and flour in day-to-day life belong to the group of Carbohydrates. All Carbohydrates have the general formula: C x (H 2 O) y . Carbohydrates can be divided into 3 classes;
Earlier, it was believed that only living things could make organic compounds. But this belief was challenged, as the German chemist Wöhler synthesized urea, which is an organic molecule, from inorganic materials in 1828. Today we even could synthesize DNA, which is a genetic material, from inorganic materials, and hence create life.
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