Answer:
Cell membrane or plasma membrane is the semi-permeable outer layer surrounding the components of the cell.
It is important to the cell as it provides important properties to the cell as it separates the aqueous interior of the cell from the external environment, helps in cell–cell contact, in surface recognition, signaling and transport.
The plasma membrane is made up of different types of molecules like phospholipids, proteins, cholesterol, carbohydrates providing flexibility to the layer so, the model of membrane is known as fluid mosaic model.
The primary constituent of membrane is a lipid molecule called Phospholipids which is made up of glycerol molecules attached to a phosphate group and forms a hydrophilic head while long fatty acyl chains attached to the head froms hydrophobic tails.
It is the fatty acid chains which provide hydrophobic nature to the cell membrane. These layers are arranged in the form of bilayer with head towards outside while tails inside.
Along with phospholipid membrane posses peripheral and integral proteins which helps in transport of the molecules across membrane.
