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Difference Between Cell Membrane and Plasma Membrane

Main Difference

The main difference between Cell Membrane and Plasma Membrane is that Cell Membrane encloses the whole-cell, whereas Plasma Membrane refers to enclose the organelles of the cell.

Cell Membrane vs. Plasma Membrane

The cell membrane is the boundary of the complete cell. The plasma membrane is the boundary of cellular organelles. The cell membrane protects the organism from the attack of viruses and bacteria. The plasma membrane isn’t involved in the protection against bacteria and viruses. The cell membrane is always the first receiver of signal transduction and the first step to start every process. The plasma membrane is not always the first step in the process.

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On cell membranes, cilia, pili, flagella, etc. may be present for feeding and locomotion process e.g., in paramecium cilia are present for movement. On the plasma membrane, cilia are not present on the surface for locomotion. The cell membrane is comprised of embedded proteins and lipid bilayer. The composition of the plasma membrane changes according to the requirements of the cell. The cell membrane faces the outer environment of the cell. The plasma membrane faces the inner environment of the cell.

Cell membrane act as a barrier between the internal environment of the cell and the outer environment of the cell. Plasma membrane act as a barrier between the inter environment of an organelle and the outer environment of the organelle. The cell membrane plays the main role in cell signaling. The plasma membrane only facilitates cell signaling communication. In the case of the plant cell, the cell membrane is surrounded by the cell, but in an animal cell, the only cell membrane is present. The plasma membrane doesn’t surround with any other membrane.

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Comparison Chart

Cell MembranePlasma Membrane
The cell membrane surrounds the entire cellThe plasma membrane surrounds the organelles
Helps In
Signaling, feeding, and movementHelps only in signal transduction
Antimicrobials Target
Targeted by antimicrobialsNot always targeted
Cytokinesis
Plays a vital role in cytokinesisDoesn’t play any role in cytokinesis
Tonicity
Regulates the tonicity of cellDoesn’t help to regulate the tonicity of cell

What is Cell Membrane?

The cell membrane is a sort of plasma membrane which helps to enclose the whole cell. Plant cells also possess a cell wall after the plasma membrane that encloses the whole cell. The cell wall is not present in the animals and acts as a barrier between the internal components of the cell and to the outer environment of the cell. The cell membrane is mainly comprised of the bilayer of phospholipids and other integral proteins. These integral proteins usually stretch the cell membrane so that they can make the pathways for the different molecules to cross the membrane.

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The cell membrane acts as a selectively permeable membrane because of the existence of lipids molecules which are act as hydrophobic molecules that repel the water and phosphate molecules that act as hydrophilic that don’t repel the water. The cell membrane also comprised some glycerol molecules that make a structure named as the lipid tail. Some molecules of cholesterols are also present in the composition of the cell membrane, which helps the membrane to provide support and stiffness.

In the case of some organisms, cell membrane possesses cilia like appendages which help the organism for movement and feeding. Our cell membrane plays ital roles in different functions like protection etc. The cell membrane protects the cell form many bacteria and viruses that come from the outside. It also helps to correctly maintain the tonicity of the cell by regulating the movement of water and solutes. It also assists in signal transduction. The cell membrane plays an important role in the process of cytokinesis.

What is Plasma Membrane?

The plasma membrane is a type of biomembrane which encloses the different organelles and other cellular content of an individual. The plasma membrane plays a cardinal role regarding the protection. It also plays a leading role in phosphorylation reactions. The plasma membrane creates a barrier organelles and the cell’s environment. It makes ease to maintain the signaling and communication between the cells. The plasma membrane also serves as a selectively permeable membrane as it permits some particles to pass through it. The structure of the plasma membrane is changed according to the organelle at which it surrounds.

As the plasma membrane has the ability of selective permeability and actively controls the movement of substances in or out of the organelle. In the case of molecules, the plasma membrane is choosy and differs by organelle to the organelle. At different times organelles perform various functions, and molecules need specific conditions of entry and leaving the organelles, for instance, mitochondria compared with chloroplast. The plasma membrane performs its function according to its location. The plasma membrane contains receptors for cell communication.

The plasma membrane is slightly different organelle to organelle to perform a specific function according to the demand of an organelle. For example, for aerobic respiration, pyruvate molecules need to enter inside the mitochondria, and carbon dioxide needs to enter the chloroplast during the process of photosynthesis. The plasma membrane is a rigid-flexible cover on the organelles which acts as a barrier between the organelles respective to their environment. Besides organelles plasma membrane also surrounds the cytoplasm.

Key Differences

  1. Cell membrane covers the entire cell, whereas the plasma membrane covers only the organelles or cytoplasm of the cell.
  2. Cell membrane plays a role in protecting the cell from the invaders; on the other hand, the plasma membrane doesn’t protect against the invaders.
  3. Cell wall performs functions like signal transferring, locomotion, etc.; conversely, the plasma membrane only performs the function of signaling.
  4. During cell division, the process of cytokinesis involves the role of the cell membrane; on the flip side, the plasma membrane involved in the process of phosphorylation.
  5. On cell membranes, appendages like Pilli, etc. are present, while on the plasma membranes, appendages are absent.
  6. The cell membrane is the outermost layer of the cell, although the plasma membrane is the inner layer.
  7. The cell membrane is actively targeted by the antimicrobials as compared to the plasma membrane, which is not targeted for the antimicrobials.
  8. Cell membrane plays a major role in cell signaling comparatively to the plasma membrane.

Conclusion

It is concluded that the cell membrane encloses the cell and the plasma membrane encloses the cell organelles.

Janet White

Janet White is a writer and blogger for Difference Wiki since 2015. She has a master's degree in science and medical journalism from Boston University. Apart from work, she enjoys exercising, reading, and spending time with her friends and family. Connect with her on Twitter @Janet__White