What are the chemical substances that compose the plasma membrane?

Ans) The major constituents of the plasma membrane are phospholipids, proteins and carbohydrates. The phospholipds, amphipathic molecules, are regularly organized in the membrane according to their polarity: two layers of phospholipids develop the lipid bilayer with the polar part of the phospholipids pointing to the outside of the layer and the non polar phospholipid chains in the interior. Proteins can be originated embedded in the lipid bilayer and there are also some carbohydrates bound to proteins and to phospholipids in the outer face of the membrane.