Plasma Membrane is the phospholipid layer, found in all types of cells; it helps in protecting the protoplasm and checks the passage of molecules inside the cell, Though cell wall is found in the plant cell, fungi, bacteria only and protects the cell from external shocks, and provide rigidity and shape to the cell. The cell wall is the outermost boundary of the cell (if present), and plasma membrane is present in the inner lining of the cell.
The plasma membrane is delicate thin layer while cell wall is the thick and rigid layer. Plasma Membrane is selectively permeable membrane allowing small molecules entry only; their layer is made up of lipids and proteins and few carbohydrates, while Cell wall constituents may vary from chitin, peptidoglycan, and cellulose.
Complexity in the cell becomes higher from the lower level of uni-cellularity to the higher level of multicellularity, but they share many things common. In this content, we will discuss the difference between the plasma membrane and cell wall and few of their similarities also.
Content: Plasma Membrane Vs Cell Wall
|Basis For Comparison||Plasma Membrane||Cell Wall|
|Meaning||Plasma Membrane is a delicate, thin structure of around 5-10nm wide and is visible under electron microscope, and it is present in all types of cell, helps in the passage of molecules and protects the protoplasm.||Cell Wall is a thick, rigid structure of around 4-20um wide and is visible under light microscope; it is present in plant cell, bacterial and fungal cell, helps in providing
shape and rigidity to the cell.
|Presence||Plasma Membrane is present in all types of cells.||Cell Wall is present in the plant cell, bacteria, fungi and algae.|
|Composition||Made up of lipids and proteins and carbohydrates.||Made up of cellulose (plant cell), chitin (fungi), and peptidoglycan (bacteria).|
|Structure||Thin layers and is visible only through the electron microscope.||Thick layers which are visible through the light microscope.|
|Receptors||Plasma membrane have receptors, helps in cell-cell communication.||Cell wall does not have receptors.|
|Metabolic function||Metabolically active and living.||Inactive and non-living.|
|Thickness||Same thickness throughout its life.||Thickness grows with life.|
|Nutrition||Need proper nutrition to survive.||Doesn't need any nutrition from cell but deposition instead.|
2.It separates the components present inside to outside environment.
3.Helps in cell-cell communication.
4.It allows the passage of molecules
|1.Cell wall provides rigidity to the cell, protect the cell from external shock and other mechanical forces.
2.It is responsible for cell morphology.
3.It prevents large molecule to enter into the cell.
4.Also, prevent the cell from being toxic.
5.Helps in maintaining the osmotic environment of the cell.
Definition of Plasma Membrane
Plasma Membrane is also known as Cell Membrane or Plasma Lemma, is found in all types of cell and is selectively permeable which means it does not allow every kind of material to enter into the cell. That’s why it is known to control the traffic of the molecules inside the cell, by checking the entry of molecules.
Even they are responsible for maintaining the constant internal environment in the cell cytoplasm. The plasma membrane is present below cell wall and if the cell wall is not present plasma membrane act as the outer layer.
The plasma membrane is made up of a phospholipid bilayer and small amount of carbohydrate, this layer is thin, fragile structure of only 5-10nm only and is visible in the light microscope. It is a semipermeable membrane allowing very selective molecules to pass through it and hence maintain the proper internal structure of the cell.
Plasma membrane also helps in cell-cell communication through the receptor present on the outer layer of the membrane. The plasma membrane is metabolically active and living and protects the protoplasm and its internal environment.
Definition of Cell Wall
Cell Wall is the outermost layer of the plant cell, fungal and bacterial cell, but it is absent in animal cell, hence plasma membrane act as an outermost layer of the cells. Plant cell wall is made up of cellulose, while the fungal cell is made up of chitin and bacterial cell is made up of peptidoglycan. It is very rigid and thick structure of approx. 4-20um and is visible through the light microscope.
Key Differences Between Plasma Membrane and Cell Wall
Following are the key differences between Plasma Membrane and Cell Wall:
- Plasma Membrane is also known as Plasma Lemma, or Cell Membrane is the phospholipid layer present in all types of cells, it is very fragile of only 5-10nm thickness, while Cell Wall is found in the plant cell, bacterial and fungal cell and is made up of cellulose, peptidoglycan, and chitin respectively. It has thickness 4- 20um and is rigid.
- Plasma Membrane is metabolically active and living, while Cell wall is metabolically inactive and non-living; Plasma Membrane requires nutrition to grow while Cell wall doesn’t require nutrition to grow.
- Plasma Membranes are semipermeable and have receptors which help in cell-cell communication, whereas Cell wall is completely permeable and does not have any receptors.
- Plasma Membrane protects protoplasm and checks the entry of molecules. Hence it is a semi-permeable membrane, also helps in cell-cell communication; while Cell wall provides rigidity and protection from external shock to the cell.
- Give shape to the cell.
- Provide support and rigidity for the cell.
- Regulate incoming and outgoing of the molecules.
- Provide protection.
From the above discussion, we conclude that both the layers of the cell provide protection, rigidity, and shape to the cell, though their composition is different and but their presence is worthy, as they protect the cell.