Which head group is added to sphingomyelin?

Sphingomyelin is a type of sphingolipid found in cell membranes, particularly in the myelin sheath of nerve cells. The correct head group that is added to sphingomyelin is phosphocholine. This head group consists of a phosphate group bound to choline, which plays a crucial role in the function and structural characteristics of sphingomyelin.

The presence of phosphocholine provides the molecule with amphipathic properties, which are essential for its role in forming lipid bilayers and membranes. The positively charged choline portion contributes to interactions with both other lipids and proteins, facilitating various cellular processes, including membrane stability and signal transduction.

Other choices, such as glucose, amino acids, and phosphate on their own, do not accurately define the chemical structure of sphingomyelin. While sphingolipids can have various head groups, the specific combination of sphingosine, a fatty acid, and phosphocholine distinctly characterizes sphingomyelin, linking it to its specific biological functions.