1.The plasma membrane defines the shape nd size of the cell.
2.The plasma membrane protects the cytoplasm from external environment.
3.The plasma membrane plays a crucial role in maintaining the balance of the cell.
4.It functions as a mechanical barrier that protects the internal contents of the cell.
5.The membrane determines what substances are to be allowed entry or exit from the cell.
6.It provides for flow of information amongst different cells of the same organisms.
hope this helps u:))