What is plasmalemma?
What is plasmalemma?
The protoplasm of the living cell remains surrounded by a bi-layered selectively permeable membrane known as plasmalemma or cell membrane.
"Plasmalemma" is another, less common term for the cell membrane or plasma membrane. It functions as the outermost boundary of all living cells, separating the interior (cytoplasm) from the external environment. Here's a closer look at its key aspects:
Structure
- Double phospholipid bilayer: This forms the basic framework, with water-loving heads facing outwards and inwards, while water-hating tails form the inner layer.
- Embedded proteins: These provide various functions, like transport, communication, and enzyme activity.
- Carbohydrates: Attached to some proteins and lipids, forming glycoproteins and glycolipids, these play a role in cell communication and recognition.
Functions
- Selectively permeable barrier: Controls the movement of molecules in and out of the cell, allowing essential nutrients in and waste products out.
- Cellular communication: Provides docking sites for hormones and other signaling molecules, enabling communication with other cells.
- Cell shape and movement: Helps maintain cell shape and facilitates cell movement through interactions with the outside environment.
- Protection: Shields the cell from harmful substances and pathogens.
Importance
The plasmalemma is crucial for maintaining the internal environment of a cell, which is essential for all life processes. Its selective permeability, communication functions, and protective role are fundamental for cell survival and function.
Usage
While "plasmalemma" is technically accurate, "cell membrane" or "plasma membrane" are the more commonly used terms in scientific and biological contexts. However, you may encounter "plasmalemma" in older literature or specialized studies.
