The Cell Wall Purpose and Function

What is a Cell Wall ? A membrane of the cell that forms external to the cell membrane whose main role is to give cells rigidity, strength and protection against mechanical stress. It is found in cells of plants, bacteria, archaea, fungi, and algae. Animals and most protists do not have cell walls. The purpose of a cell wall is to control what organelles enter and exit the cell. In other words it likes to protect the cell membrane from viruses.

Cell Walls Function Structural and mechanical support.  maintain and determine cell shape.  resist internal turgor pressure of cell.  control rate and direction of growth.  ultimately responsible for plant architecture and form.  regulate diffusion of material through the apoplast.  carbohydrate storage - walls of seeds may be metabolized.  protect against pathogens, dehydration, and other environmental factors.  source of biologically active signaling molecules.  cell-cell interactions.

Cell Wall Purpose  The purpose of a cell wall is to control which molecules enter and exit the cell, as well as to provide structure and protection.

Structure  Made of 2 or more layers Outer - gluey pectin Primary Layer- made of cellulose Secondary - in woody plants

Layers of the cell wall The cell wall is composed of cellulose, polysaccharides, and proteins.