The biological importance of water

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The biological importance of water

Water is an important part of life: Without it, life on earth would not exist. Water is a major component in cells, typically forming 70 to 95% of the cell's mass. In humans water is around 80% of our mass. Water also provides an environment for organisms to live in. One obvious example of water's  is that 75% of the Earth is covered in water.  Their use in all living things and it covers a huge variety of everyday functions which are important to the existence or operation of the organism. Humans are not the only ones who contain the valued material but other creatures like the jellyfish hold 96% of water as their body mass.

Water is one of the most unusual compounds on Earth. It has a variety of properties not found in any other liquid. These properties are due to its molecular composition, which is simply just 2 hydrogen atoms and one oxygen atom, making up H2O.

Water is a covalent compound. This means that water has , which are formed by sharing electrons in the outer orbits of the nuclei and proton. In the case of water however the large numbers of protons in the oxygen nucleus have a stronger attraction for these shared electrons than the relative tiny hydrogen nuclei. This pulls the electrons slightly closer to the oxygen nucleus and away from the hydrogen so that the oxygen develops a slight negative charge and the hydrogen's a slight positive charge. This makes the water molecule a slightly Polar Molecule. This slight charge gives water its various properties.

The first I will discuss is its solvent properties. One of the major functions of water in living organism is its use as a solvent. Because water is slightly ionised, other polar molecules such as salts, sugars and amino acids will dissolve readily in water. Water's property as a solvent is biologically important to life as most biochemical reactions such as respiration occur in solution. A medium, that is water, is required for the transportation, as reaction of certain substances. Blood plasma is mostly water. Blood is needed to transport vital substances around organisms. Water cannot dissolve hydrophobic substances such as fats and oils. Water can be used in this way to transport many substances: nutrients, excretory products (e.g. urea, ammonia), hormones and digestive juices can all be transported by using water as a solvent. Molecules such as starch and glycogen which are hydrophobic are not soluble and therefore are ideal for storage.

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In the digestive system many polymers and dimmers need to be broken down into smaller molecules by the process of hydrolysis. Water is used in hydrolysis reactions to separate the larger molecules into smaller ones (e.g. proteins into amino acids). Water is produced in respiration and this water can be very useful for organisms living in dry habitats. The process of photosynthesis requires water in order to create glucose.

The fact that water has an unusually high specific heat capacity makes it a very useful substance for living organisms. Water does not change temperature very easily and therefore ...

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