All are essential unsaturated fatty acids except

Palmitoleic acid, oleic acid, linoleic acid, linolenic acid and arachidonic acid are the five unsatured fatty acids. Among them palmitoleic acid, oleic acid are mono unsaturated fatty acids. linoleic acid, linolenic acid and arachidonic acid are essential unsaturated fatty acids. Arachidonic acid becomes essential, if its precursor, linoleic acid is not present in the diet. It is considered as the precursor for the synthesis of prostaglondins.