Essential fatty acids are required in the diet because, lacking the necessary desaturase enzymes, humans are unable to biosynthesize omega fatty acids, though we do possess the bio-machinery for their interconversion. The two closely related families of EFAs are : omega-3 (ω-3, or n-3) α-linolenic acid (18:3), and omega-6 (ω-6, n-6) linoleic acid (18:2). The EFAs serve as substrates for the biosynthesis of longer, more desaturated fatty acids (long-chain polyunsaturates).
Only sphingomyelin has a sphingosine backbone. Sphingomyelin is present in all eukaryotic cell membranes, but is mainly present in cells of the nervous system. Phospholipids, along with glycolipids and cholesterol, are a major component of all biological membranes.
tags [Biochemistry] [Molecular Biology] [eicosanoid] [phospholipid]