Lipids and Fatty Acids - Practice Questions & MCQ

Lipids and Fatty Acids

• Lipids are a diverse group of compounds that are made up of carbon, hydrogen and oxygen.
• They are hydrophobic in nature due to their fatty acid component.
• Fatty acids are hydrocarbon chains to which carboxyl group is attached. 
• The number of carbons in the fatty acid may range from 4 to 36.
• Different fatty acids have different length, degree of unsaturation (number of double bonds) and properties such as melting point, fluidity etc. 
• The length of the fatty acids determines their melting point. As the length increases, the melting point increases.
• Fatty acids are amphipathic molecules, that is, they have both hydrophilic (carboxylic acid) and hydrophobic (hydrocarbon) component.
• But they are largely non-polar (hydrophobic) due to large hydrocarbon chains. 
• If there are only single bonds between neighbouring carbons in the hydrocarbon chain, the fatty acid is said to be saturated. 
• Saturated fatty acids are saturated with hydrogen; in other words, the number of hydrogen atoms attached to the carbon skeleton is maximized. 
• For example, Stearic acid.
• When the hydrocarbon chain contains a double bond, the fatty acid is said to be unsaturated. For example, Oleic acid.