Plasma membrane and cell wall is not the similar thing. Plasma membrane, also known as cell membrane, is the outer membrane common to all living cells and it is made of a phospholipid bilayer, embedded proteins and some appended carbohydrates.

Because cell membranes are fragile, in some types of cells there are even outer structures that support and protect the membrane, such as cellulose wall of plant cells and the chitin wall of some fungi cells. Most bacteria also there an outer cell wall made of peptidoglycans and other organic substances.