Water is the place that the first cells started and the medium most life processes take place in.
Water plays many essential roles in living things.
Water is a very good example of how understanding the structure and properties of very small units such as atoms and molecules can create a chain of explanation built on scientific reasoning and observation. These ideas can then be used to explain a great deal of biologically significant patterns.
Water has a very special structure. This is due to the atoms that make up a water or (H2O) molecule and how they bond together. Atoms contain an equal number of negative charges and positive charges. These are in their electrons and the protons in the nucleus. They balance each other out so an atom has in effect no net charge.
Each hydrogen atom has only 1 electron so there are two electrons around the hydrogen atoms in the water molecule. The oxygen atom has 6 electrons in its outermost shell. This outer shell shares its charges with the two electrons from the hydrogen atoms to form what are called strong covalent bonds. However the strong pull of the oxygen atom means the probability of the electrons being positioned closer to the oxygen atom is high.
This means that the oxygen end of the water molecule has more electrons in it than the two hydrogen ends.
The whole molecule develops what we call a polarity shown
by the δ + and δ – signs.
This means that water molecules tend to rotate and attract each other to form what are called hydrogen bonds. These are weak compared to the covalent bonds but are in fact very important.
