What structural feature is contained in sphingomyelins?  Group of answer choicesan amide bonda glycerol backbonean estertwo fatty acids

Sphingomyelins are a type of sphingolipid found in animal cell membranes, especially in the membranous myelin sheath that surrounds some nerve cell axons. They include the following structural features:

1. An Amide Bond: Sphingomyelins contain an amide bond. This bond is formed between the fatty acid chain and the sphingosine backbone.

2. Two Fatty Acids: Sphingomyelins contain two fatty acid chains. One is part of the sphingosine backbone, and the other is attached to the sphingosine backbone via the amide bond.

3. No Glycerol Backbone: Unlike glycerophospholipids, sphingomyelins do not contain a glycerol backbone. Instead, they have a sphingosine or sphingoid backbone.

4. No Ester Linkages: Sphingomyelins do not contain ester linkages. The fatty acid chain is attached to the sphingosine backbone via an amide bond, not an ester bond.

So, the correct answer is that sphingomyelins contain an amide bond and two fatty acids. They do not contain a glycerol backbone or an ester.