Protoplasm is made by the mixture of different complex compounds. It is jelly like, translucent, viscous, colourless semi solid-living substance. All the pro perties of life are present in it. Protoplasm is divided into three parts: Plasma membrane, Cytoplasm and Nucleus.
Just beneath the cell wall there is a soft living membrane surrounding the whole protoplasm. This is called cytoplasmic membrane or cell membrane.
Plasma membrane is bi-layered. Under electron microscope there revealed a light layer between two dark layers. In the cell membrane of some epithelial cell there found some finger like out growth-these are called Microvilli(Singular : Microvillus). They increase the absorption surface of the cell. Themembrane between two adjacent cells modified in various forms to make theConnection between two cells rigid. They also make the movement of different substances between the cells easier. In many cells spaces in the cell membrane may be broader.
(a) Transportaion of different materials inside and outside the cell, (b) Absorption of different substances (mainly nutrients) from outside the cell, (c) protection of the cell body and giving the cell a definite shape.