The cell wall and the cell membrane are two important components found in cells, but they show some different characteristics. Both the cell wall and the cell membrane protect the cell from the external environment and provide support to the cell. The cell wall is present in plant cells only, while the cell membrane is present in each cell.
The difference between the cell wall and cell membrane are as follows:
| Cell Wall | Cell Membrane |
|---|---|
| It is only present in plant cells | It is present in animals, bacteria, and human cells |
| It's thick and rigid in nature | It's thin and delicate in nature |
| It's metabolically inactive | It's metabolically active |
| It's the outermost layer found in plant cells | It's the outermost layer in animal cells |
| The cell wall grows with time and the thickness may increase within a span of time | Its thickness remains the same throughout its lifetime |
| The thickness of the cell wall can be between 0.1 μm to some μm | The thickness of a cell membrane can be between 7.5-10 nm |
| It's responsible for the protection of the cell. | It's responsible for communication with the outer environment, sexual reproduction, and cell division. |
Cell Wall
A cell wall is the outermost layer of a plant cell, it's mainly found in plant cells, some microorganisms, and bacteria. The cell wall is flexible and rigid in nature and is found outside the cell membrane. The cellulose, hemicellulose, long fiber of carbohydrates, and lignin and pectin usually make up the cell wall. It helps in regulating cell growth and protects it from physical damage as well. A cell may die due to endosmosis. Apart from this, a cell wall provides structural support and helps in maintaining its shape. Due to its textured and porous surface, it allows the entry of smaller molecules. Also, the cell wall prevents expansion or rupture in case of an increase in pressure inside the cell. The cell wall also acts as a barrier for entry for some biomolecules and even as a channel for the entry and exit of many other metabolic molecules. In some plants, the cell wall might be made up of a single layer, while in some plants there are 2 layers of the cell wall. These 2 layers provide waterproofing to the cell.
Also Read: Gram Staining
Cell Membrane
The cell membrane or also known as the plasma membrane separates the interior of the cell from the outer environment, it's the outermost layer found in animal cells. This cell membrane is a semipermeable membrane made up of proteins and lipids. The presence of cholesterol and phospholipids in the wall helps in maintaining fluidity in the cell membrane at different temperatures. This semipermeable membrane allows transportation between the outer environment and the cell. A cell membrane provides a fixed environment in the cell and also protects it from physical damage. It's the main communication channel between the cell and the outer environment, and its semipermeable nature allows the entry and exit of some selective substances only. Ion conductivity, cell signaling, and cell adhesion are some of the common processes in which cell membranes are involved.
Similarities Between a Cell Wall and a Cell Membrane
A cell wall and cell membrane might have significant differences but they also do have some similarities some of which are listed below.
- A cell wall and a cell membrane protect the cell from external mechanical stresses.
- They both provide shape and rigidity to a cell.
- A cell wall and cell membrane act as the main channel of transfer for the entry and exit of molecules.
- Both, the cell wall and cell membrane are the outermost layer of a cell.