Plasma membrane and cell membrane are often confused to be similar terms. However, they are quite different from each other. The plasma membrane encloses the organelles of the cell, whereas, the cell membrane encloses the entire cell components.
Read on to know what is cell membrane and plasma membrane, cell membrane and plasma membrane function and the difference between the cell membrane and the plasma membrane.
Cell membrane is the outermost layer of the cell that surrounds all the components of a cell, including different organelles. It is found in both plant cell and animal cells. However, the plant cells have a cell wall that surrounds the cell membrane.
The cell membrane acts as a boundary separating the cellular contents with the outside environment. It consists of a phospholipid bilayer with integral proteins that provides a pathway for the movement of molecules across the membrane. The membrane allows only a certain molecules to pass through it because of the hydrophobic lipids present
Cell Membrane Function
Following are the important cell membrane function:
- It regulates the entry and exit of substances in the cell.
- Protects a cell from bacteria, viruses and other invading pathogens.
- It also plays a major role in cell-signalling.
- Provides a selective barrier which allows only a certain molecules to enter and exit the cell.
Also Read: Fluid Mosaic Model
Plasma membrane surrounds the organelles of the cells. It forms a barrier between cell organelles and the outside environment. A plasma membrane plays different roles depending upon its location. For eg., a plasma membrane encloses the cytoplasm as well the organelles of the cell. It is a tough, rigid and flexible layer made up of proteins, lipids, and carbohydrates.
Plasma Membrane Function
Following are the important plasma membrane function:
- The plasma membrane forms a barrier between the cell organelles from the outside environment.
- It allows only a certain molecules to pass through it.
- It facilitates communication and signalling between the cells.
Difference Between Cell Membrane and Plasma Membrane
Following are the important difference between cell membrane and plasma membrane:
It surrounds the entire components of the cell.
It surrounds only the cell organelles.
It regulates the tonicity of the cell.
|It does not regulate the tonicity of the cell.|
|Cell membrane can be transformed to stimulate movement and feeding in organisms such as Paramaecium.||
Plasma membrane cannot be modified.
It contains initial receptors for signal transduction and is the first step in cell signalling.
|It is not the first step in cell signalling. However, it is involved in the process.|
|Always protects the cell from bacteria and viruses.||
Does not always protect the cell from outside invaders.
Plays an important role in cytokinesis during cell division.
|Do not play a key role in cytokinesis during cell division.|
|Cilia are present and are involved in feeding and movement.||
Cilia are absent.
Is a target for antimicrobials.
Is not a target for antimicrobials.
Key Points on Cell Membrane and Plasma Membrane
- The cell membrane is a type of plasma membrane that encloses the cell and all its components.
- Both the membranes are selectively permeable and regulate the entry and exit of components.
- The cell membrane is the only membrane involved in cytokinesis.
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Frequently Asked Questions
Is plasma membrane and cell membrane the same thing?
No, plasma membrane and cell membrane are not the same. Plasma membrane is the membrane surrounding the organelles. On the contrary, cell membrane is the membrane that surrounds the entire cell.
What is the function of plasma membrane?
The plasma membrane protects the cell from its surroundings. It is a selectively permeable membrane that regulates the entry of certain ions and molecules.
Do eukaryotic cells possess plasma membrane?
Both eukaryotic and prokaryotic cells possess plasma membrane.
Do animal cells possess a plasma membrane?
The animal cell do possess a plasma membrane.
What is the composition of plasma membrane?
The plasma membrane is composed of a phospholipid bilayer with integral proteins. The lipid bilayer consists of a polar head and a non polar tail.