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The key difference between the plasma membrane and cell wall is that the plasma membrane is present in almost all type of cells while the cell wall is present in plant cells, bacteria, fungi and algae.
Plasma Membrane vs. Cell Wall
The cell is a structural and functional unit of life. It is made up of many organelles which have their specific structure and function. Plasma membrane and cell wall are two important membranous structures of a cell that play many important roles. They provide shape, protection and rigidity, etc. to the cell. They act as cytoplasmic bridges which help in intercellular communication and transfer etc. Although they both are membranous structures and have many similar functions, but there is a large number of differences that exist between them. The plasma membrane is also called as cell membrane while there is no other name for the cell wall. The plasma membrane is present in almost every type of cell while the cell wall is present in just plant cells, bacteria, fungi and algae. The plasma membrane is a living and inner cover of the cell while the cell wall is an outer most and nonliving cover of the cell.
What is Plasma Membrane?
Plasma Membrane is also called as Plasma Lemma or Cell Membrane. It is a membranous structure that is present in almost every type of cell. It is the inner covering that covers the cytoplasm of the cell and is semi-permeable in nature which means that it is able to transfer some items from it and stops the movement of others. So, it is playing its role in homeostasis because it maintains the internal environment of the cell to a constant level. The plasma membrane is a thin structure 5-10nm wide and mostly made up of phospholipids, cholesterol, carbohydrates and proteins. It also has receptors that help in intercellular communication. The plasma membrane is a living membrane and needs proper nutrition. It shrinks during drought conditions.
- It plays many important functions in the cell, i.e.
- It provides protection to the protoplasm.
- It helps in intercellular communication.
- It allows the passage of some specific material through it so, maintains the internal environment of the cell and protects it from harmful material.
- In some cells, cell membrane has different types of projections like flagella and pili, etc. that help in movement and reproduction respectively.
What is Cell Wall?
The cell wall is the outermost covering of the cell that is present in Plant, fungi, bacteria and algae. It is not present in each type of cell. It covers the plasma membrane and is fully permeable in nature. So, it allows the movement of small size molecules and stops the entry of large size material. A cell wall is a thick membrane 4-20um wide and its thickness keeps on increasing with time due to deposition of more material. It is made up of chitin in fungi, cellulose in plants and peptidoglycan in bacteria. So, its composition varies from organism to organism. It is nonliving in Nature and does not need any nutrition.
- It provides protection to the cell from the harsh external environment.
- It maintains osmotic pressure in the cell.
- It provides shape and rigidity to the cell.
- It stops the entry of large size material into the cell.
- It also prevents the cell from being toxic.
- The plasma membrane is a membrane that covers the cytoplasm of the cell while the cell wall is an outer membrane of the cell that surrounds the plasma membrane.
- The plasma membrane is present in almost every type of cell wall is present in plants, algae, bacteria and fungi, etc.
- The plasma membrane is also known as a cell membrane or plasma lemma while there is no other name for the cell
- The plasma membrane is a thin structure 5-10nm wide while the cell wall is a thick structure 4-20um wide.
- The thickness of the plasma membrane remains same throughout the life of the organism whereas the thickness of the cell wall keeps on increasing with time.
- The plasma membrane is a living membrane and requires proper nutrition while cell wall is a nonliving membrane and does not require any nutrition.
- The plasma membrane is semi-permeable in nature, but the cell wall is fully permeable.
- The plasma membrane is composed of proteins, lipids and carbohydrates while the composition of cell wall varies from organism to organism.
- Plasma membrane has flexibility and able to change its shape as needed while the cell wall is rigid and does not has flexibility.
- Plasma membrane provides Intercellular communication, permeability and signal reception, while the cell wall provides rigidity, shape and maintain osmotic pressure in the cell, etc.
From the above discussion, it is concluded that Plasma membrane is a thin, living, semi-permeable membrane of the call that covers the cytoplasm and provides protection, Intercellular communication, permeability and signal reception, etc. to the cell whereas, cell wall is a thick, non living, fully permeable membrane of the cell that covers the plasma membrane and provides protection rigidity, shape and maintains osmotic pressure in the cell.