Final answer:
Sphingomyelins lack glycerol in their structure, instead featuring a sphingosine backbone. They are characterized by the presence of an amide bond (not an ester bond) holding the fatty acid chain to the sphingosine. The correct response is glycerol, ester bond, amide.
Step-by-step explanation:
Sphingomyelins do not contain a glycerol; they have a sphingosine backbone instead. They do not contain an ester bond. An amide bond is used to bond their single fatty acid chain to the backbone. The correct answer is:
a) Glycerol, ester bond, amide.
Sphingomyelins are a kind of sphingolipid and are also considered phospholipids due to the inclusion of phosphoric acid. They play a crucial role in the structure of the myelin sheath of nerve cells, and damage to this sheath can lead to diseases such as multiple sclerosis. Unlike glycerophospholipids that have a glycerol backbone, sphingomyelins utilize a sphingosine backbone and have a unique structural composition that includes a fatty acid and choline.