Fatty acids (FAs) are long hydrocarbon chain molecules with a terminal carboxylate group, originating from the organism or food. Their nomenclature, structure, and properties depend on the length of hydrocarbon chain, degree of unsaturation, and position of double bond(s). The process of FA synthesis occurs in the cytosol, whereas the process of β-oxidation of FA takes place in the mitochondrial matrix. Saturated FAs are synthesized by the enzyme system FA synthase, while synthesis of unsaturated FA involves elongase and desaturase activity. The final products of FA β-oxidation are acyl CoA, FADH2, and NADH.