What is the Difference Between Cell Wall and Cell Membrane?

The cell wall and cell membrane are both structures that protect and support cells, but they have distinct differences. Here are the main differences between them:

1. Presence: The cell wall is present only in plants, fungi, and some bacteria, while the cell membrane is present in all living organisms, including plants, animals, and bacteria.
2. Structure: The cell wall is made up of pectin, chitin, lignin, glycoproteins, glycolipids, sugar, and cellulose, and has a thickness of 0.1 μm to several μm. In contrast, the cell membrane is a lipid bilayer composed of lipoproteins and carbohydrates, with a thickness of 7.5–10 nm.
3. Permeability: The cell wall is fully permeable to smaller molecules with a size of 30-60 kDa. On the other hand, the cell membrane is selectively permeable and controls the movement of substances into and out of the cell.
4. Functions: The main function of the cell wall is to provide protection from the external environment. The cell membrane, also known as the plasma membrane, has diverse functions, including permeability, signal reception, motility conduction, cell division, and sexual reproduction.
5. Nature: The cell wall is a thick and rigid structure with a fixed shape, providing structural support to the cells. In contrast, the cell membrane is a thin and delicate structure that is flexible and can change shape and size as needed.
6. Metabolic Activity: The cell wall is metabolically inactive and non-living in nature, while the cell membrane is metabolically active and living in nature.

In summary, the cell wall is a rigid structure found only in plant cells, fungi, and some bacteria, while the cell membrane is a flexible, selectively permeable structure present in all living cells. The cell wall provides structural support and protection, whereas the cell membrane has a wider range of functions, including controlling the movement of substances in and out of the cell.

Comparative Table: Cell Wall vs Cell Membrane

The cell wall and cell membrane are both outer layers of a cell, providing protection and structure. However, they have distinct differences in their composition, function, and permeability. Here is a table comparing the two: