Biology

Difference between plasma membrane and cell wall

Main difference

The main difference between the plasma membrane and the cell wall is that the plasma membrane is present in almost all cell types, 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 that have their specific structure and function. The plasma membrane and the cell wall are two important membranous structures of a cell that perform many important functions. They provide shape, protection, rigidity, etc. to the cell. They act as cytoplasmic bridges that help in intercellular communication and transfer, etc. Although both are membranous structures and have many similar functions, there are a large number of differences between them. The plasma membrane is also called the cell membrane, while there is no other name for the cell wall.The plasma membrane is present in almost all types of cells, while the cell wall is present only in plant cells, bacteria, fungi and algae. .

Comparative chart

Plasma membrane Cellular wall
The inner membranous covering of the cytoplasm is known as the plasma membrane. The outermost covering of the cell is known as the cell wall.
Other name
The plasma membrane is also known as the cell membrane and the plasma lemma. The cell wall has no other names.
Presence
It is present in almost all types of cells. The cell wall is present only in plant cells, bacteria, fungi, and algae.
Nature
It is living in nature. It is not living in nature.
Structure
It is a thin structure 5-10 nm wide. It is a thick structure 4-20um wide.
Visibility
It can be seen with an electron microscope. It can be seen with an optical microscope.
Location
It is the inner covering of the cytoplasm. It is the outermost covering of the cell and covers the cell membrane.
Permeability
The plasma membrane is semi-permeable in nature. The cell wall is completely permeable.
Composition
It is made up of proteins, lipids and carbohydrates. It is composed of chitin (fungi), cellulose (plant) and peptidoglycan (bacteria).
Receivers
The plasma membrane has receptors that aid in intercellular communication. The cell wall has no receptors.
Flexibility
It has the flexibility and the ability to change its shape as needed. The cell wall is neither flexible nor rigid and has a fixed shape.
Changes over time
Its thickness remains the same throughout the life of the body. It increases in thickness over time.
Features
The plasma membrane provides protection, intercellular communication, permeability and reception of signals, etc. It provides rigidity, shape and maintains the osmotic pressure in the cell, etc.
What is the plasma membrane?

The plasma membrane is also called the plasma lemma or cell membrane. It is a membranous structure that is present in almost all cell types. It is the inner covering that covers the cytoplasm of the cell and is semi-permeable in nature, which means that it can transfer some elements from it and stop the movement of others. So it is playing its role in homeostasis because it keeps the internal environment of the cell at a constant level. The plasma membrane is a thin structure 5 to 10 nm wide and is composed primarily 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. Shrinks during drought conditions.

Features

  • It performs many important functions in the cell, i.e.
  • Provides protection to protoplasm.
  • Helps in intercellular communication.
  • It allows the passage of some specific material through it, thus maintaining the internal environment of the cell and protecting it from harmful materials.
  • In some cells, the cell membrane has different types of projections like flagella and pili, etc. that aid in movement and reproduction respectively.

What is the cell wall?

The cell wall is the outermost covering of the cell that is present in plants, fungi, bacteria and algae. It is not present in all types of cells. It covers the plasma membrane and is completely permeable in nature. Therefore, it allows the movement of small molecules and stops the entry of large material. A cell wall is a thick membrane 4-20um wide and its thickness keeps increasing over time due to the deposition of more material. It is composed of chitin in fungi, cellulose in plants, and peptidoglycan in bacteria. So, its composition varies from one organism to another. It does not live in nature and does not need nutrition.

Features

  • Provides cell protection from harsh external environment.
  • It maintains the osmotic pressure in the cell.
  • Provides shape and rigidity to the cell.
  • Stops oversized material from entering the cell.
  • It also prevents the cell from being toxic.
Key differences
  1. 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.
  2. The plasma membrane is present in almost every type of cell wall; it is present in plants, algae, bacteria and fungi, etc.
  3. The plasma membrane is also known as the cell membrane or plasma lemma, while there is no other name for the cell.
  4. The plasma membrane is a thin structure 5-10 nm wide, while the cell wall is a thick structure 4-20 mm wide.
  5. The thickness of the plasma membrane remains the same throughout the life of the organism, while the thickness of the cell wall continues to increase over time.
  6. The plasma membrane is a living membrane and requires proper nutrition, while the cell wall is a non-living membrane and requires no nutrition.
  7. The plasma membrane is semi-permeable in nature, but the cell wall is completely permeable.
  8. The plasma membrane is made up of proteins, lipids, and carbohydrates, while the composition of the cell wall varies from one organism to another.
  9. The plasma membrane has the flexibility and ability to change its shape as needed, while the cell wall is rigid and has no flexibility.
  10. The plasma membrane provides intercellular communication, permeability and reception of signals, while the cell wall provides rigidity, shapes and maintains the osmotic pressure in the cell, etc.
Final Thought

From the above discussion, it is concluded that the plasma membrane is a thin, living and semi-permeable membrane of the so-called that covers the cytoplasm and provides protection, intercellular communication, permeability and reception of signals, etc. to the cell whereas, the cell wall is a thick, non-living and totally permeable membrane of the cell that lines the plasma membrane and provides protection, rigidity, forms and maintains the osmotic pressure in the cell.

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