As you know that lipid is a biomolecule so it will be an organic compound include carbon, hydrogen, oxygen, phosphate and nitrogen. As you must have seen in your childhood that when water is mixed with oil, it does not dissolve, it remains insoluble in water, it is an example of lipids. Lipids are insoluble in water whereas lipids are soluble to non-polar solvents.
Lipids are a mixture of fatty acids and glycerol. When fatty acids are combined with glycerol via ester bonds, lipids are formed. Another name for glycerol is trihydroxy propane. Sometimes the test does not give the name of glycerol and gives its other name, trihydroxy propane.
Fatty acid are carboxylic acid with hydrocarbon side chain. Fatty acids consist of a carboxylic acid(COOH) and a long carbon chain called the R-chain. The R-chain in fatty acids is called hydrophobic which prefers to stay away from water and carboxylic acid(COOH) is called hydrophilic which prefers to stay near water.
There are two types of fatty acids, first saturated fatty acid and second unsaturated fatty acid, when we talk about saturated fatty acid then it does not have double bond present in it has single bond present. The melting point of saturated fatty acids is high. They are solid at room temperature. palmitic acid and stearic acid are the example of saturated fatty acids. This question has come up many times in the exam that how many carbons are present in palmitic acid including carboxylic acid(COOH). So, you should know that there are 16 carbons present in palmitic acid including COOH otherwise 15 carbon is present in palmitic acid.
When we talk about unsaturated fatty acid, it has double bond present and its melting point is low, due to which it becomes like oil at room temperature. Oleic acid and linoleic acid are the examples of unsaturated fatty acid. Unsaturated fatty acid contains double bond or triple bond, due to which it is good for our health. As polyunsaturated fatty acids are present in chips. It’s good for health.
Classification of lipids
lipids are Bradly classified into simple, compound and derived lipids. Which are subdivided into different groups.
Ester of fatty acid with alcohol.
Neutrals fat:- They do not have much complexity; they are made up of fatty acids and glycerol Triglyceride requires a reaction of 1 glycerol and 3 fatty acids.
Waxes:- It is mainly present in aquatic plants. It helps the plant to float in the water. Wax is present in the outer membrane of the plant which reduces the rate of transpiration. Wax is also present in animal which is called ceruminous gland.
They are esters of fatty acid with alcohol containing additional groups. They are further divided as follows:-
Phospholipids:- phospholipids contain phosphate, fatty acid, alcohol and additional group. Most of the phospholipids are found in the cell membrane. Lecithin is an example of phospholipids that are actually found in the cell membrane. Lecithin acts as a surfactant. If we talk about the structure of lecithin, then fatty acids, glycerol, phosphate and choline need to be composed to form lecithin.
Glycolipid:- Glycolipids are made up of fatty acids, sphingosine and carbohydrates. Sphingosine is an amine alcohol containing the NH2 group. Glycolipids are basically of two types, first cerebroside which is present in cell membrane and second ganglioside which is present in ganglions.
Lipoprotein:- these are the lipids that contain protein. Lipids conjugated with protein. They are also found in milk and eggs. It is good for our body as well as bad.
Derived lipids they are not made up of fatty acid, glycerol and alcohol. They are modification of fatty acids. These are the derivatives obtained on the hydrolysis of group 1 and group 2 lipids which possess the characteristics at lipids.