Membrane can"t work by it self. it need something to help to do it function. Below, it's a function and definition.

Name	Definition	Function
Phospholipids	Special type of lipid. Basic structure of the membrane	Act as a barrier to most water-soluble substance
Cholesterol	Small molecule, that have hydrophilic heads and hydrophobic tails, located between phospholipids molecule with their head at the membrane surface.	To avoid membrane to become closer or farther.
Glycolipid	Different structure as Glycoprotein	Help the cell to know other cell in the body
Glycoprotein	Different structure as Glycolipids	Help to communicate with something outside the cell
Protein	Has 2 types of protein. Channel and Carrier	Channel Protein: allowed ions to diffuse through the membrane Carrier Protein: change molecule and bring molecule