The cell membrane is the membrane found in all cells that separate the interior of the cell from the outer environment. We know that animal cells have a membrane, but do plant cells too have a membrane?
Do plant cells have a cell membrane?
No, plants don’t have a cell membrane. Instead, it has something called a plasma membrane, and it is attached to the cell wall. So, unlike the animal cells, which have a well-defined cell membrane, plants have the cell wall and the plasma membrane. However, there are several similarities between the plasma membrane and the cell membrane.
So, let us explore more about the plasma membrane and the cell wall.
The cell wall is a complex structure that provides structural support to the plant cell. It is composed of cellulose and has two membranes.
The primary membrane is formed in the early days of cell growth. It provides basic structural support while allowing space for the cell to grow.
Once the plant cell has developed, the secondary wall forms. It is thicker and more durable than the primary wall. The cell wall protects the plant cells from intrusions by foreign elements. It is also semi-permeable and allows an exchange of specific molecules. It plays an important part in ensuring the safety of the plant cells. It forms the outer layer of the plant cell.
Thus, unlike in animals, where the cell membrane forms the outer layer, in plants, it is the cell wall.
The plasma membrane is found in the inner lining of the cell wall. It consists of both proteins and lipids. It too is semi-permeable in nature and allows the selective exchange of molecules.
The plasma membrane also consists of proteins that are involved in the transport of molecules in and out of the cell through the cell wall. It consists of different types of lipids and proteins. It primarily regulates the exchange of molecules but also helps prevent the liquids inside the cell from spilling out. It is also the site of cellulose synthesis of the plant cell.
Thus, it helps in the formation of cellulose that is required by the plant to form the cell wall.
The lipid molecules form the majority of the plasma membrane. Phospholipids are the most abundant lipids in the plasma membrane. They play an important role in the exclusion of excess water from the cell due to the presence of fatty acids which are hydrophobic and non-polar.
The lipids are structured in a bilayer with fatty acids on both sides. It prevents the unnecessary external liquids from entering the plant cells and the essential internal liquids from flowing out.
Thus, we can see that, unlike animal cells, plant cells don’t have cell membranes. Instead, they have a cell wall along with a plasma membrane. Since the plasma membrane carries out a task similar to the cell membrane in animals, it is also called the cell membrane in plants.