Question

Some of the lipid groups appear similar, but changing a few components significantly alters their biological properties. identify the similarities and differences between glycerophospholipid and sphingolipid structures.

Answer 1

In cells there are two classes of phospholipids, glycerophospholipids and sphingophospholipids.

Glycerophospholipids have two fatty acids attached to a glycerol molecule, since the third hydroxyl group of this alcohol is esterified with a phosphate, in turn attached to a second alcohol. The combination of glycerol with two fatty acids and phosphate results in a molecule called phosphatidic acid, which forms the basic structure of glycerophospholipids.

Sphingophospholipids contain ceramide, which is a molecule formed by the union of two fatty acids with a serine (which replaces the glycerol present in glycerophospholipids). The union of a serine with one of the fatty acids forms the amino alcohol called sphingosine or sphingol. Serine is formed by the aggregation of a fatty acid with sphingosine. The sphingophospholipid in the cells is sphingomyelin, originated from the union of ceramide with phosphorylcholine.

Despite the differences. both exhibit two large non-polar hydrophobic tails (two fatty acids) and a polar hydrophilic head comprising glycerol, phosphate and the second alcohol. For such characteristics phospholipids are amphipathic molecules.

Answer 2

Both glycerophospholipids and sphingolipid structures are asymmetrically distributed in the two layers of the phospholipid bilayer. Sphingolipids are membrane lipids that have a ceramide backbone while glycerophospholipid has glycerol present in its membrane lipids. Sphingolipids may or may not be present.