Every organism is made of the smallest single unit called a cell. The cell is the tiniest part. It makes up tissues, then tissue system, organs, and so on an individual. That tiniest cell can be single or multi-cellular. It comprises of many components inside it which made up an entire cell they are – Mitochondria, Golgi Apparatus, Cell Membrane, Cell Wall (only in plants), Endoplasmic Reticulum (ER), Nucleus, etc. These cell organelles have different functions and serve different purposes.
Cell Membrane vs Plasma Membrane
The main difference between Cell Membrane and Plasma Membrane is that Cell Membrane holds up the entire cell component within itself while the Plasma Membrane accounts for only some cell organelles or sometimes a complete cell. Cytokinesis is the division of cell membrane, so does cell membrane takes part in the process, but unlikely Plasma Membrane does not always a part of the process.
Cell Membrane is the outermost covering present in a cell. It is present to safeguard the entire cell component present in it. It is present in both plant and animal cells. It has some projections called cilia which helps in the Movement as well as transporting food. It also helps in protecting the cell and its components from foreign invaders.
Plasma Membrane is the outermost covering of any cell sometimes or a cell organelle. It helps in protecting the cell organelles from bursting. It is believed that Cell Membrane is a type of Plasma Membrane. It is mainly present in Mitochondria and Chloroplasts, which is why they are known as double cell organelles of a cell.
Comparison Table Between Cell Membrane and Plasma Membrane
| Parameters of Comparison | Cell Membrane | Plasma Membrane |
| Location | Cell Membrane is said to cover all the cell contents inside it. | It constitutes the particular cell organelles or a cell. |
| Feeding and Movement | For the movement and feeding, it has cilia. | It is absent in them. |
| Tonicity | It helps in controlling it | Not usually helps that. |
| Protection from Invaders | It protects from the invaders. | It does not protect from the invaders. |
| Cytokinesis | It plays a part in cytokinesis. | Not always it takes part in cell division. |
| Signal Transduction | The first step and receiver in the process | Not the first step always. |
| Antimicrobial Targets | Always | Not Always |
What is Cell Membrane?
The outermost covering of the cell (except in Plant Cells, as they have additional coverage of rigid Cell Walls) is known as Cell Membrane. While we look at the composition of the cell membrane, there are many theories and models on the structure of the Cell Membrane, but the best fitted and accepted model of Cell Membrane is given by Singer and Nicolson.
The name of the model given by them is named as Fluid Mosaic Model, which stated that Cell Membrane is made up of a bilayer of phospholipids and proteins, along with glycoproteins and glycolipids.
Some of the functions of Cell Membrane are discussed below –
- It helps in the regulation of substances in or out within the cell.
- Protects cell from foreign invaders and pathogen.
- It plays an important role in the signal functioning of the cell.
- It acts as a selective barrier and only lets permeable things pass in and out.
What is Plasma Membrane?
Plasma Membrane constitutes the outer covering of the cell organelles. Plasma Membrane is a very thin layer. It is usually 5-10nm in size. Plasma Membrane is quite evident through a microscope.
The composition of the plasma membrane is that it is made up of carbohydrates, proteins, lipids and is said to be a living and metabolically active layer. Plasma Membrane remains the same throughout its life. No changes are observed in thickness or composition.
The additional projections called cilia are absent in the plasma membrane, so does it usually does not take part in the cytokinesis. The functions of the Plasma Membrane depend on where it is present. Some of the functions of the Plasma Membrane is given below –
- It acts as a barrier between the cell components and the cell organelle.
- Only selective molecules are allowed to pass through it.
- It does play a role in the cell signalling and communication between the cells as it helps them to smoothly facilitate through it.
Main Differences Between Cell Membrane and Plasma Membrane
- Cell Membrane is the outer covering of the cell, while Plasma Membrane is the outer covering for cell organelles.
- The Cell Membrane helps in maintain the tonicity of a cell, while the Plasma Membrane does not usually participate in this.
- Cell Membrane helps in guarding the cell against foreign invaders while it is the opposite for the Plasma Membrane as it does not function that way.
- Cell Membrane uses its projections called cilia which helps the cell in Movement as well as feeding, while Plasma Membrane does not have any cilia present on them.
- Cell Membrane is divided by the process called cytokinesis which is an important step in cell division and takes part in it, while Plasma Membrane does not always participate in cytokinesis.
- Cell Membrane is said to be the first receiver of the transduction signal and the first participant, whereas Plasma Membrane is not the first receiver as well as not always take part.
- Cell Membrane is an easily targeted place by antimicrobial agents, while Plasma Membrane is not usually easily targeted by antimicrobial agents.
Conclusion
Both the membranes Cell and Plasma Membrane are the important part of a cell. Both are considered as the protective layers, one for the cell and another for the cell organelles. The membranes are said to be semi-permeable and allow only selective materials, molecules, and substances to move in and out from them. They also help in preventing any damage to the cell through electric shocks.
Cell Membrane helps in protecting the cell from invaders and is an easy target for antimicrobial agents, while Plasma Membrane does not help in protection also. It is difficult to target it through antimicrobial agents.
Although they have almost the same functions and roles, and both the terms are used synonymously to one another. But still, there will remain some substantial differences from each other.
References
- https://pubs.acs.org/doi/abs/10.1021/ac301776j
- https://ieeexplore.ieee.org/abstract/document/6268438/
- https://www.sciencedirect.com/science/article/pii/S0006349593815315
- https://journals.biologists.com/jeb/article/200/23/2927/7650/Cell-membrane-lipid-composition-and-distribution