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Over two thirds of the Earth today is water, and living organisms are 80% water by mass, they must retain this to survive. Water is a vital solvent and reactant in everyday life.

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Over two thirds of the Earth today is water, and living organisms are 80% water by mass, they must retain this to survive. Water is a vital solvent and reactant in everyday life. The formula for water is H20. Compared to other molecules H20 is very small. Two hydrogen atoms are covalently bonded to one oxygen atom. Covalent bonds are formed by sharing electrons in outer energy levels of atoms. The large number of protons in the oxygen nucleus has a stronger attraction for shared electrons than the hydrogen nucleus. Oxygen therefore pulls electrons slightly closer to itself so that it develops a weak negative charge represented as ?- and hydrogen develops a slight positive charge represented as ?+. This means the charge distribution is unequal and it becomes a polar molecule. Adjacent molecules of water are attracted because the negatively charges O attracts a positively charged H. The bonds between the molecules are called hydrogen bonds and they make water very stable. ...read more.


This enables insects such as pond skaters to travel across the top layer of water. Their weight isn't great enough to break the surface tension and the waxy cuticle prevents it from getting wet. If a drop of water is dropped onto a polished surface, the drop will remain intact and it will not spread whereas a drop of alcohol would spread. This serves a vital function for plants. Cohesiveness and high surface tension means that long columns of water remain intact when travelling up capillaries such as xylem. The process of transpiration can carry water to the highest leaves on trees up to 30m high. Water is also essential in sexual reproduction because it's needed to bring female and male gametes together. In pregnancy the foetus develops a water filled sack; this gives it physical and thermal stability. Water is good for transporting material an example is in the uptake of minerals by plants from the soil, transpiration then occurs in the leaves. ...read more.


The molecules therefore remain dispersed which prevent them from joining together and this is called colloidal suspension. Water is a solvent which is biologically important; in many living many organisms' biochemical reactions take place in the cytoplasm or other substances such as the blood. Water serves as a solvent which holds ions such as potassium and chloride or other organic molecules such as glucose and proteins in a liquid phrase and these molecules are transported in the solution. Water also removes excretory products from the human body such as urea and ammonia. The process of osmosis is when water moves in and out of cells depending on the concentration of solutes. Water will move from a high to a low concentration. When it enters the cell will swell until it becomes turgid. In conclusion I can prove that the importance of water in living organisms is essential. Functions such as transport, chemical reactions, temperature control, support, movement and reproduction need water to happen. Its structure is so that it allows water to have many properties. The structure and function of water in living organisms ...read more.

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