Unit 10: Biological Molecules and Biochemical Processes L3 Applied Science (new specification)

Unit 10- Biological Molecules and Biochemical Processes-


Water
Water is a small, simple molecule consisting of 2 Hydrogen atoms and an oxygen
atom (H2O) which are bonded together with a covalent bond, meaning they share
their electrons to create a strong electrostatic attraction.
The charges of the atoms in water are partial as you can see in the diagram, the
delta symbol in front of the + and -. This is because the electrons are not shared
evenly because oxygen is more electronegative than hydrogen, therefore oxygen
has a greater pull on the electrons than the hydrogen. Water is described as a
polar molecule because of its partially charged atoms.




https://alevelbiology.co.uk/notes/water-structure-properties/
In addition to this, water is also structured through hydrogen bonds, where the
delta + (The hydrogen molecule) bonds with the delta – (The oxygen molecule).
Hydrogen bonds are essential for some of the unique properties of water. For
example, the hydrogen bonds in water cause the molecule to have a high heat of
vaporisation meaning that a large amount of heat is required for water to
become a vapour. The hydrogen bonds also allow water to remain as a liquid for
a wider range of temperatures. Hydrogen bonds in water can be seen in the
diagram below.




http:// www1.lsbu.ac.uk/
water/
water_hydrogen_bonding.html
Water is important because it helps regulate the temperature within the body
and also regulates pH levels. It does this by secreting from the body as sweat,
which is evaporated, this cools the body effectively. Water is also excellent
within the cytoplasm of a cell because it constantly stays at a liquid state at a
large variety of temperatures meaning it is good for transportation of molecules
around the cell.