The biological membrane consists of:
Lipids: The lipids present in the membrane are in the form of phospholipids which form a continuous bilayer which form the structural framework (backbone) of the plasma membrane. The phospholipids are amphipathic in nature i.e ; they contain both polar and non polar groups. The hydrophilic “polar” head are directed towards the water phase and are associated with the proteins while the hydrophobic “non polar” tails remain associated with each other.
Proteins: Two types of proteins are found in the biological membranes. Integral (Intrinsic) proteins which remain tightly bound to the phospholipid layer by strong bonds and the Peripheral (extrinsic) proteins which remain loosely attached to the surface of the membrane.
The proteins can be compared to ice bergs floating in a sea of phospholipids. The biological membranes are considered to the quasi-fluid structures in which the lipids and intrinsic proteins are arranged in a mosaic manner.