What are the two types of lipids that are part of the cell membrane?
Posted July 28, 2022
The two types of lipids that are part of the cell membrane are phospholipids and sterols. While they are similar to other lipids in that they dissolve readily in organic solvents, what sets these two membrane lipids apart from other lipids is their distinctive amphiphilic properties. In addition to a lipophilic region, the membrane lipids also have a hydrophilic region that is attracted to soluble water. This amphiphilic property of phospholipids and sterols is what makes them perfect as membrane lipids.
- Phospholipid molecules have 2 long fatty acid chains attached like tails to one part of a glycerol head. The fatty acid chains are repelled by water but readily dissolve in organic solvent, which gives the phospholipid its lipophilic character. A negatively charged phosphoryl group is attached to another part of the glycerol head. This portion of the phospholipid is hydrophilic and dissolves readily in water, imparting the molecule with its distinctive amphiphilic character.
- In sterols, a complex hydrocarbon ring structure acts as the lipophilic region that is repelled by water but dissolves in organic solvent. A hydroxyl grouping in the molecule acts as the hydrophilic or water-soluble region.