Fatty acids are a diverse group of carboxylic acids composed of a long hydrocarbon chain and a carboxyl functional group. Chemically, they are classified primarily by the number of carbon atoms in their chain and the degree of saturation. Saturated fatty acids possess no double bonds between the carbon atoms, giving them straight chains, while unsaturated fatty acids contain one or more double bonds, which often introduce kinks into the molecular structure. These molecules are fundamental components of biological systems, serving critical roles in energy storage, the structural integrity of cellular membranes, and participation in numerous biochemical signaling pathways. Their varying structures dictate their physical properties and metabolic fates, making them key molecules in lipid metabolism across biological life.