Chemicals of Life
- Water
- Lipids
- Carbohydrates
Structure
They are made up of glycerol and fatty acids.Gylcerol - C3H8O3 (nothing complex about it)
Fatty Acids – CH3(CH2)nCOOH
A lipids properties depends on the fatty acid, because fatty acids come in many different structural varients, whereas there is only 1 type of gylerol.
A hydrocarbon chain - A long chain(variable length) of carbon atoms with 2
hydrogen atoms attached to each one.
Carboxyl group - At the one end of the molcule is a carboxyll(COOH) group.
Methyl group - At the other end is a methyl(CH3) group.
In the hydrocarbon chain, there are 2 hydrogens attached to every carbon.
This not always true, but when it is, the molecule is said to be saturated. However, sometimes there is a double bond between the carbons, instead of a second hydrogran atom, so there are less hydrogens on the chain - making it unsaturated. Unsaturated fats are better for our health, as saturated ones tend to cause blocking of arteries. Polyunsaturated fats = 2 or more double bond per fatty acid.
Synthesis of fats and oils
Fats and oils are made of gycerol and fatty acids. 3 fatty acid molecules combine with 1 glycerol molecule. When the 2 join, condensation(water loss) occurs. Each OH group of the gycerol joins with the COOH of the fatty acid.. The bond formed is called an ester bond. 3 molecules of water are removed.
Their Function
They supply energy. They contain more energy than carbohydrates(due to little oxygen). It is because it contains more energy, that it is stored.
It conducts heat very slowly, and so acts as a good insulator again cold weather. Eg in Polar Bears
Some desert animals never have to drink, as they are very efficient at removing water from fat metabolism.
Fats are important ifor the structure of the plasma membrane.