Final answer:
The two notation systems for fatty acids are alpha and omega, with omega-minus labeling identifying the position of double bonds relative to the end of the carbon chain opposite the carboxyl group, and alpha indicating the position of double bonds from the carboxyl end.
Step-by-step explanation:
The two notation systems for fatty acids are alpha and omega (Alpha and Omega). These notations are used to describe the structure and characteristics of fatty acids, including the position of carbon atoms and the presence of double bonds.
Systematic IUPAC nomenclature numbers start from the carbonyl-carbon (C=O). For example, stearic acid is expressed as 18:0, indicating eighteen carbons and zero double bonds, while oleic acid is 18:1(9), signaling eighteen carbons and one double bond at the ninth carbon.
In omega-minus (w-#) labeling, the carbon atoms are numbered from the end opposite to the carboxyl group (-COOH) with the last carbon labeled as w-1, next as w-2, and so on. For instance, alpha-linolenic acid is known as an omega-3 fatty acid because the first double bond occurs at the third carbon from the omega end (methyl group).