The Biological Importance of Water

The Biological Importance of Water

Water is a substance whose molecule is made from two hydrogen atoms

and one oxygen atom (H20) and that is in a liquid state at room

temperature. This is covalent bonding, where two hydrogen atoms share

their electron with one oxygen atom. As the oxygen atom has more

positively charged protons than the hydrogen is has pulls on the

shared electrons more strongly than the hydrogen atoms. The oxygen

atom therefore has a slightly negative charge while the hydrogen a

slightly positive charge. Therefore because the hydrogen and oxygen

atoms are different in size and electronegativity the water molecule

is non-linear and dipolar. When two water molecules get close to one

another, the oppositely attracted parts of the molecules attract each

other. This type of attraction is called hydrogen bonding. This

polarity means that individual water molecules can from hydrogen bonds

with up to four other water molecules. Although these individual

hydrogen bonds are weak, together they make water a much more stable

substance. To break this structure would mean breaking all the

hydrogen bonds ad that would require a large amount of energy. This

sticky nature of water molecules explains many of its properties and

its called cohesion.

Water’s cohesive and adhesive properties mean that it is viscous,

making it a useful lubricant in biological systems such as the

synovial fluid which lubricates many vertebrate joints. Also the

continuous column of water is able to move up the xylem because of

cohesion between water molecules and adhesive between water and the

walls and the xylem vessels. The cohesive forces between the...

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...Substances with molecules of a

similar mass to water, such as ammonia and methane, are all gases at

room temperature but water is a liquid. It is the polarity of water

molecules and the fact that they can from hydrogen bonds which is the

key to water’s special properties. It boils at 100ºC and melts at 0ºC.

Water is probably the fundamental reason for life on Earth. Every

living thing depends on it to survive which is why water is so

important. As well as being essential to life, water also has many

other uses. Some of these include being a very good solvent, for

washing or even as habitats and environments. Water's abundance and

requirements towards life already make it special but there are even

more properties of water as a result of the hydrogen bonds between

water molecules that make water vital for living things.