Question

Before you five types of lipids. Represent and illustrate all of them. What are the hydrophylic and hydrophobic parts in each of them?
1) cholesterol
2) gangelioside
3) sphingomyelin
4) galactosylcerebroside
5)phosphatidylethanolamine
Thank you very much!

Answer 1

Cholestrol: It is a lipid molecule waxy, fat-like substance that's found in all the cells of the body. It involves in the biosynthesis of some hormones, vitamin D, and substances that help you digest foods. Our body has tendency to synthesise cholestrol for its use. Some food also contains cholestrol.

They are of two types: LDL and HDL

High density lipid are good lipids as it carries cholesterol from other parts of your body back to your liver.Then liver detoxify the body by eliminating the excess.

LDL are low density lipid and termed as bad lipid as high LDL level leads to a buildup of cholesterol in your arteries.

Structure: It is amphiphatic molecule. The four linked hydrocarbon rings forming the bulky steroid structure is the hydrophobic part. While hydrocarbon tail linked to one end of the steroid and a hydroxyl group linked to the other end. The -OH group containing side is hydrophillic as it is capable of formation of hydrogen bond withcarbonyl oxygen of phospholipid and sphingolipid head groups.

2. Ganglioside: They are glycosphingolipids with sialic acid.  They tend to accumulate on cellular surfaces of neuronal cells, but also present in other cells. They are present i abundance in brain and is the main component of some neuronal membranes in the central nervous system. Their participation in the transmission of impulses is one of the main function of gangliosides. Their defects may cause Tay sach disease.

Structure: sphingosine, fatty acids, hexoses, and sialic acid are the main components of ganglioside. The glycan and a lipid portion are the hydrophobic part in the ganglioside, while sialic acid are the major hydrophillicity contributing part of gangliosides.

3. Sphingomylein:  Myelin sheath that surrounds the nerve cell axons are rich in sphingomylein.It acts as insulator of nerve fibre.  Exoplasmic leaflet of the cell membrane has sphingomylein as major composition. It also played significant role in signal transduction.

Structure: The sphingomylein is comprise of  phosphocholine head group, a sphingosine, and a fatty acid. The phosphocholine is the hydrophillic part while the fatty acid represents the hydrophobic part.

4.Galactosylcerebroside: Galactosylcerebroside functions as an inhibitor of apoptosis. Overexpression of this molecule upon the cellular surface can lead to many cancer.

Structure: It is composed of Monoglycosyl and oligoglycosylceramides. The ceramide group is the hydrophillic part while the glycosyoligosachcarides are hydrophobic part.

5. Phosphatidylethanolamine: It is one of the majorly found phospholipid in the biological membrane. Their synthesis includes addition of cytidine diphosphate-ethanolamine to diglycerides, releasing cytidine monophosphate. On the other hand phosphate group is combined with choline in phosphatidylcholine, which is with ethanolamine in phosphatidylethanolamine.

The ethanolamine is the hydrophillic part while the phospholipid or glycerides are the hydrophobic part.