Question

A ganglioside may contain all of the following except A. a ceramide structure. B. glucose or galactose. C. phosphate. D. one or more sialic acids. \(\mathbf{E},\) sphingosine

Short answer

A. A ceramide structure B. Glucose or galactose C. Phosphate D. One or more sialic acids E. Sphingosine Answer: E. Sphingosine

Step-by-step solution

Understand the composition of gangliosides

Gangliosides are a type of glycosphingolipid that contains a ceramide structure with one or more glycosidically-linked sialic acids. They are important components of cell membranes, especially in the nervous system. The typical components of a ganglioside include a ceramide structure, sugar moieties (usually glucose or galactose), phosphate, and one or more sialic acids.

Compare the options to the typical ganglioside composition

Based on the composition mentioned in Step 1, let's go through the given options one by one: A. A ceramide structure - Gangliosides indeed contain a ceramide structure. B. Glucose or galactose - These sugars are commonly found in gangliosides. C. Phosphate - Phosphate is also a component of gangliosides. D. One or more sialic acids - Sialic acids are characteristic of gangliosides, giving them their unique properties.

Identify the option not found in gangliosides

The only component in the list that is not mentioned in the typical ganglioside composition is: E. Sphingosine

Conclusion

Based on the comparison, the correct answer to the question is \(\mathbf{E},\) Sphingosine, as it is not a component of gangliosides.