Biochemistry : Sphingolipids

Study concepts, example questions & explanations for Biochemistry

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Example Questions

Example Question #181 : Biochemistry

Lysosomal storage diseases occur when mutations cause defects in which of the following?

Possible Answers:

Lysosome transformation

Lysosome formation

Formation of N-acetylgalactosamine derivatives

Sphingolipid biosynthesis enzymes

Sphingolipid degradation enzymes

Correct answer:

Sphingolipid degradation enzymes

Explanation:

Lysosomal storage diseases occur when mutations cause defects in sphingolipid degradation enzymes. Simply put, the key word is "degradation," which indicates the presence of a disease. No other answer choice has a key word that indicates the presence of a disease.

Example Question #2 : Sphingolipids

Which of the following is the smallest sphingolipid in terms of molecular mass? 

Possible Answers:

Sphingomyelin

Cerebroside

Ceramide

Ganglioside

Correct answer:

Sphingomyelin

Explanation:

All four of these sphingolipids differ only in the functional groups attached to the sphingosine. Ceramide has a fatty acid group; cerebroside has a monosaccharide group; ganglioside has a polysaccharide group; sphingomyelin has a phosphatidylcholine or phosphoethanolamine group. In terms of molecular mass, phosphatyidylcholine or phosphoethanolamine are the smallest as well as the least massive functional group, making sphingomyelin the sphingolipid with the smallest molecular mass. 

Example Question #3 : Sphingolipids

Ceramide is a precursor to which of the following?

Possible Answers:

Glycoshingolipids only

Sphingomyelin and glycosphingolipids

Sphingosine

Sphingolipids only

Sphingomyelin only

Correct answer:

Sphingomyelin and glycosphingolipids

Explanation:

Ceramide is formed by sphingosine. Sphingosine is formed by a long chain of sphingolipids. Both sphingomyelin and glycosphingolipids are formed from ceramide.

Example Question #4 : Sphingolipids

Which of the following is amphipathic, polar, and are formed by long-chain sphingolipids?

Possible Answers:

Palmitoyl-CoA

Sphingomyelin

Glucosamine

Ceramide

Sphingosine

Correct answer:

Sphingosine

Explanation:

Glucosamine contributes to the structure of glycosylphosphatidylinositol (GPI). Ceramide is the precursor to sphingomyelin, sphingosine is hydrolyzed to form ceramide.

Example Question #1 : Sphingolipids

The myelin sheaths of neurons typically contain large quantities of __________.

Possible Answers:

triacylglycerols

waxes

sphingolipids

cholesterol

Correct answer:

sphingolipids

Explanation:

Myelin sheaths surround nerve cell axons and are essential for proper nervous system function. They act as an electrically insulating layer and enable better propagation of action potentials. Sphingomyelin is a type of sphingolipid found in the myelin sheaths of animal cell membranes.

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