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Cell Membrane vs. Plasma Membrane: What's the Difference?

Edited by Janet White || By Harlon Moss || Updated on October 27, 2023
The cell membrane and plasma membrane refer to the same structure, acting as a barrier around the cell.

Key Differences

The cell membrane and plasma membrane are terms that often cause confusion, even though they describe the same cellular structure. The primary purpose of the cell membrane is to act as a boundary, separating the internal components of the cell from its external environment. Similarly, the plasma membrane serves this exact function, protecting and encompassing the cell's inner workings.
Both the cell membrane and the plasma membrane have a unique composition. This lipid bilayer, filled with proteins and other molecules, ensures selectivity in what enters and exits the cell. Thus, whether you refer to it as the cell membrane or the plasma membrane, you're speaking about a structure that ensures cellular integrity and regulates the movement of substances.
In some contexts, the term "cell membrane" is preferred, especially in elementary biological discussions. It gives a general idea about the cell's outer boundary. In contrast, "plasma membrane" is often used in more advanced biological contexts, emphasizing the fluid-like nature of the membrane and its specific compositions and functions.
Regardless of the nomenclature - cell membrane or plasma membrane - the importance of this structure in maintaining cellular homeostasis cannot be understated. It's responsible for selective permeability, allowing certain substances in while keeping others out, ensuring the cell functions correctly.
In summary, while the terms cell membrane and plasma membrane might be used in different contexts, they refer to the identical structure, which plays a pivotal role in cellular function and maintenance. Both terms highlight the membrane's significance in biology and medicine.

Comparison Chart

Terminology Usage

Common in basic biology
Often used in advanced biology


Outer boundary of the cell
Lipid bilayer surrounding the cell


Lipids, proteins, carbohydrates
Lipids, proteins, carbohydrates


Protects the cell, regulates transport
Protects the cell, regulates transport


Yes, with plasma membrane
Yes, with cell membrane

Cell Membrane and Plasma Membrane Definitions

Cell Membrane

A protective barrier made up of a lipid bilayer.
The cell membrane's lipid bilayer allows for selective permeability.

Plasma Membrane

A fluid-like barrier surrounding the cell's contents.
The plasma membrane's structure aids in its flexibility.

Cell Membrane

Provides support and maintains the cell's shape.
The cell membrane's rigidity prevents the cell from bursting.

Plasma Membrane

Comprises lipids, proteins, and carbohydrates in a bilayer.
The plasma membrane's proteins are essential for various cellular functions.

Cell Membrane

The cell membrane is the outermost boundary of the cell.
The cell membrane ensures that the cell's contents remain enclosed.

Plasma Membrane

Ensures cellular homeostasis and protection.
Without the plasma membrane, the cell would be vulnerable to its surroundings.

Cell Membrane

Integral to processes like cell signaling and transport.
Receptors on the cell membrane detect signals from other cells.

Plasma Membrane

Dictates what enters and exits the cell.
The plasma membrane only allows specific molecules to pass through.

Cell Membrane

Regulates the entry and exit of substances in a cell.
Oxygen passes through the cell membrane to enter the cell.

Plasma Membrane

Is involved in cellular communication and recognition.
The plasma membrane contains receptors that bind to signaling molecules.


Can substances freely pass through the cell membrane?

No, the cell membrane is selectively permeable, only allowing certain substances through.

Can the cell membrane change its composition?

Yes, depending on the cell's needs, the cell membrane's composition can alter.

What's the main function of the cell membrane?

The cell membrane protects the cell and regulates substance transport.

Why is the plasma membrane sometimes called a "fluid mosaic"?

The plasma membrane is fluid-like with various proteins embedded, resembling a mosaic.

How do water molecules pass the plasma membrane?

Water molecules often use aquaporin proteins to cross the plasma membrane.

Why is cholesterol found in the plasma membrane?

Cholesterol in the plasma membrane provides stability and fluidity.

Why is understanding the plasma membrane crucial in medicine?

Understanding the plasma membrane can aid in drug delivery and understanding cellular diseases.

How does the cell membrane aid in cell recognition?

The cell membrane has glycoproteins and glycolipids that aid in cell recognition.

Are the terms cell membrane and plasma membrane used interchangeably?

Yes, though "plasma membrane" might be more common in advanced biological contexts.

Is the plasma membrane only found in animal cells?

No, the plasma membrane is present in both animal and plant cells.

Do all cells have a cell membrane?

Yes, all cells, whether prokaryotic or eukaryotic, have a cell membrane.

Are there specialized regions in the plasma membrane?

Yes, there are specialized regions like lipid rafts that have specific roles.

Are the cell membrane and plasma membrane the same?

Yes, the terms refer to the same cellular structure.

What composes the plasma membrane?

The plasma membrane consists of a lipid bilayer with embedded proteins and carbohydrates.

Why are proteins crucial in the plasma membrane?

Proteins in the plasma membrane facilitate transport, signaling, and other cellular functions.

How do small molecules cross the cell membrane?

Small molecules often diffuse across the cell membrane or use transport proteins.

Can the cell membrane repair itself?

Yes, the cell membrane can self-repair from minor damages.

What happens if the plasma membrane is compromised?

If the plasma membrane is damaged, the cell might lose its contents or become vulnerable.

Why is the cell membrane crucial for homeostasis?

The cell membrane regulates substance exchange, maintaining internal balance.

What provides the cell membrane its flexibility?

The lipid bilayer in the cell membrane gives it its flexible nature.
About Author
Written by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.
Edited by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.

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