Plasma membrane is also known as plasmalemma, Biomembrane and cell membrane. It limits the boundary of cell.
According to deep study plasma membrane is made of mainly four biomolecules. These are proteins lipids carbohydrates and cholesterol. Singer and Nicolson in 1972 gave the first structure of biomembrane.
Function of cholesterol…..It works as an stabilizer for lipid molecules. It is present between lipid molecules.
Function of carbohydrates……. It is cell messanger. It is present in outer side is plasma membrane and also helps in cell to cell interaction.
LIPIDS…In plasma membrane mainly phospholipid are present. They are bilayer. They have polar head which are hydrophilic and hydrocarbon tail which are hydrophobic.
PROTEINS……There are two types of proteins present in the plasma membrane. They are (1) Intrinsic proteins or Tunnel proteins or Integral proteins. (2) Peripheral proteins or Extrinsic proteins.
Intrinsic proteins… They're totally or half buried proteins in lipid layer. They help in transport of substance in and out of cell. It maintains the permeability of the membrane. It also helps in tissue formation.
Extrinsic proteins…… They're found in the peripheral region of plasma membrane. They help in tissue formation and transport of materials.