A

Ceramide is formed by just two components—sphingosine (a long-chain amino-alcohol) and one fatty acid—without any extra phosphate or sugar head-groups. Because of this minimal composition it is universally described as “the simplest sphingolipid,” i.e., a simple lipid rather than a compound or derived form [Castro et al., 2014, PMID 24513486; Goñi & Alonso, 2014, PMID 25233422].