Plasma Membrane - Cell Membrane, Definition, Structure and Function

What is Plasma Membrane?

 

All living organism cells have a plasma membrane or cell membrane; it is the outermost component of the cell that encloses all the cellular contents.

The plasma membrane's primary role is to protect the cell from its surrounding; it separates the cytoplasm inside a cell from the extracellular fluid outside. These membranes also regulate the flow of molecules and materials in and out of the cells.

 

The plasma membrane is a biological membrane, a thin semi-permeable membrane layer, it is selectively permeable, chiefly made up of protein and lipid components, surrounding the cell. Its primary role is to protect the cell from its surrounding. Also, it controls the entry and exit of nutrients and other microscopic entities into the cell.

 

Eukaryotic; animal cell has only the cell membrane, protecting their cellular contents.

In prokaryotes, the cell membrane is the inner layer of protection surrounded by a rigid cell wall.  

 

Plasma Membrane Structure

 

Functions of Plasma Membrane

 

Major functions of the cell membrane are-

 

1. It is selective in nature; selectively permeable or semipermeable. The cell membrane controls the entry and exit of ions, biomolecules, and electrolytes into or out of a cell.

 

2. It maintains and stabilizes the appropriate environment for normal cellular activities.

 

3. Play a key role in the way to communicate between the cell and within the cell in a controlled way.

 

4. It regulates the movement of substances or flow of material into or out of a cell.

 

4.  It separates the cytoplasm inside a cell from the extracellular fluid outside means separating the cell's internal environment from the external environment.

 

5. It provides protection for cells, it protects the cell from various energy.

 

6. It acts as a receptor for certain hormones and neurotransmitters.

 

7. It separates the cell from the various compartments (separate cells from one another).

 

8. Help in maintaining the osmotic pressure.

 

9. It transports nutrients into the cell and also transports toxic substances out of the cell.