Final answer:
Fatty acids are carboxylic acids found in lipids, distinguished by their saturation with hydrogen. Saturated fatty acids have no double bonds, while unsaturated fatty acids may be monounsaturated with one double bond, or polyunsaturated with multiple double bonds. The degree of unsaturation affects properties like melting points.
Step-by-step explanation:
Fatty Acids and Saturation
Fatty acids are carboxylic acids that serve as the structural components of fats, oils, and other lipids, with the exception of steroids. There are more than 70 naturally occurring fatty acids, which usually have an even number of carbon atoms, typically ranging from 12 to 20, and are generally unbranched. The saturation of a fatty acid refers to the presence of carbon-to-carbon double bonds in its structure. Fatty acids without any double bonds are considered saturated, while those with one or more double bonds are unsaturated. Saturated fatty acids, like stearic acid, have no carbon-to-carbon double bonds and are saturated with hydrogen atoms.
Types of Unsaturated Fatty Acids
Unsaturated fatty acids can be further categorized into monounsaturated and polyunsaturated fatty acids. A monounsaturated fatty acid contains one double bond within its carbon chain, such as oleic acid. A polyunsaturated fatty acid, like linoleic acid or alpha-linolenic acid, has two or more double bonds. The number of double bonds impacts the physical properties of the fatty acid, such as its melting point. Unsaturated fatty acids typically have lower melting points than their saturated counterparts with the same number of carbon atoms.