Water as Component of Cell:
• 85-90% of a cell (protoplasm) is composed of water.
• In some structures like seeds, spores, cysts water percentage is very low i.e.
10%.
• Reason for this low percentage is this that they are produced under special
conditions and are meant for special purpose i.e. reproduction or perennation etc,
which does not require much water.
Water as a Solvent:
• Water is excellent solvent.
• Therefore it is important for all processes of life.
• The solvent potential of water is due to the dipolar nature of its molecules.
• Water is essential for transporting of solutes.
• It is also important for cooling the plants and animals by evaporation.
• It is also important in photosynthesis (food preparing process).
Water as a Metabolite:
• Water also acts as metabolite as all the chemical reactions, occurring in cells,
take place in aqueous medium.
• Water is also required for hydrolysis.