Inorganic molecules
Magnesium (Mg2+) is an important constituent of
chlorophyll and essential for photosynthesis. If a plant is
derived from magnesium it goes yellow and this is called
chlorosis. Mammals also need magnesium for bone
growth.
Iron (Fe2+) is a constituent of haemoglobin which
transports oxygen though red blood cells. When we don’t
have enough iron it is called anaemia.
Phosphate (PO3-) are used in making nucleotides
including ATP. They are also found in phospholipids
which make up biological membranes.
Calcium (Ca2+) is an important structural component of
bones and teeth in mammals. Plant cell walls also have a
calcium component.
Water
Water is a polar molecule which means it has a positive
and a negative end to it. This means that it can be used
as a universal solvent as all polar and ionic compounds
can dissolve in it.
Water can also form Hydrogen bonds due to its
electronegativity these bonds are strong and here is a
large number in water giving it properties vital for life.
Water is a metabolite which means it is used in many
mechanical reactions. For example hydrolysis and
condensation reactions.
Water has a high specific heat capacity which prevents
large fluctuations in water temperature and high latent
, heat of vaporisation which helps us with temperature
control as we use energy to vaporise sweat.
Water also has cohesion witch causes molecules to stick
together as well as sticking to surroundings therefore
allowing the water to be drawn up the xylem. This also
allows high surface tension allowing insects to walk on it
such as the pond skater
Water has a high-density supplying buoyancy to aquatic
organisms. Ice is less dense then water as the hydrogen
bonds are further apart. Ice is also a good insulator.
Water is transparent allowing plants to continue to
photosynthesis.
Carbohydrates
monosaccharides
Carbohydrates are also known as saccharides and there
are different types including monosaccharides,
disaccharides and polysaccharides.
Monosaccharides are single sugars and have the general
formula cn(H2O)n with the n representing the number of
carbon atoms. Monosaccharides are named after there
number of carbon atoms for example triose has 3 carbon
atoms.
Examples of monosaccharides are glyceraldehyde
(triose) ribose and deoxyribose (pentose) and a-glucose,
b-glucose, fructose and galactose (hexose)
disaccharides