Cell membrane
Cell Membrane

Cell Membrane: Description, 5 Functions, Structure, and Properties

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A cell membrane is a membrane that separates cells from the outside environment. This membrane serves to protect the cell nucleus and more in this article.

Cells are the simplest collection of material that is alive and it is the smallest unit of all living things.

In cells, there are several constituent elements, including cell membranes. Based on its structure, cell membranes are the outermost element of the cell array itself.

Here’s a further review of cell membranes.

Cell Membrane Description

Cell membranes are universal features that all cell types have in the form of interface layers called plasma membranes, which separate cells from the environment outside the cell.

Cell membranes serve to protect cell nucleus and survival systems that work inside the cytoplasm.

Cell Membrane Function

  • Where various chemical reactions take place.
  • Protect a part of a cell and shape a cell
  • As a receptor on stimuli intended for a cell.
  • Cell membranes can be a medium of communication between environments in cells with an outer environment of cells
  • To select various substances that enter and exit the cell.

Cell Membrane Structure

The constituent components of cell membranes are:


Phospholipids are referred to as glycerophospholipids, these phospholipids are part of the cell membrane of living beings as well as a group of lipid compounds; i.e. Along with the absence of protein, glycolipids then also cholesterol.

This phospholipid consists of four components, including:

  • Fatty acids,
  • Phosphate clusters,
  • Alco**hol containing nitrogen, as well as
  • A skeleton.


This protein itself is derived from the Greek word “Protos” which means “most importantly”. This protein is a complex organic compound with a high molecular weight, which is a polymer of amino acid monomers that is then connected to each other by the bonding of peptides.

These protein molecules contain carbon, hydrogen, oxygen, nitrogen and sometimes sulfur as well as phosphorus. This protein has an important role in the structure and function of all living cells as well as viruses.

Glycolipids and glycoproteins

Glycolipids are carbohydrate molecules that attach to fat, while glycoproteins are carbohydrate molecules that attach to protein molecules. Glycolipids and glycoproteins serve as identifiers for cells.


Oligosaccharides are a combination of monosaccharide molecules that number between 2 (two) and 8 (eight) monosaccharide molecules. So this oligosaccharide can then be or can be trisaccharides, disaccharides, and others.

This oligosaccharide experimental results from the hydrolysis process of polysaccharides and also only a few oligosaccharides that are naturally present in nature. The most widely used oligosaccharides found in nature are forms of disaccharides such as maltose, lactose and sucrose.


The cholesterol in the plasma membrane will be between phospholipid molecules and the polar part of the hydroxyl will be near the phospholipid head. Cholesterol has an important function for plasma membranes. When the environment is hot, cholesterol will play a role in inhibiting the movement of phospholipids thus preventing phospholipids from becoming too liquid,

However, when the temperature of the environment is cold, cholesterol will work by inhibiting the interaction between fats thus keeping the membrane from freezing and maintaining a fairly liquid membrane structure. Cholesterol is found in animal cell membranes, while in plant cell membranes, its function is replaced by sterols.

Cell membrane properties

Cell membranes have dynamic and asymmetric properties.

  • Cell membranes have dynamic properties because they have water-like structures that allow lipid molecules and proteins to move.
  • Cell membranes have asymmetric properties because the composition of proteins and lipids on the outside is not the same as the composition of proteins and lipids on the inside of cells.

Based on its capabilities, the nature of cell membranes is divided into 3 types:


That is the nature of the membrane that does not allow any substance outside the cell to enter the cell.


It is a trait that all substances can pass through cell membranes to get into cells. Usually this trait belongs to a cell membrane that breaks down or closes to death until the cell cannot survive.


A condition in which only certain substances that cells need can enter the cell. Usually normal cell membranes have semipermeable properties.

Last Updated on September 30, 2020 Reviewed by Market Health Beauty Team

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