What is the cell membrane?
In prokaryotic and eukaryotic cells, the cell membrane describes the envelope of the cell plasma. Thus, the cell membrane protects the cell from external influences. The basic structure of the cell membrane is the same for all cells.
The basic structure is a double fat layer (lipid bilayer). This consists of various fats (lipids), such as phospholipids and sphingolipids. The two fat layers differ in their composition of fats.
Embedded in this lipid bilayer are also different proteins. These have different functions.Some act as channels to transport substances into and out of the cell, others are receptors for different molecules. The property of how fluid, or how mobile the cell membrane is, is influenced by the presence of cholesterol.
Tasks of the cell plasma
The tasks of the cytoplasm include mass transport as well as the assembly and breakdown of proteins, enzymes, signal molecules and metabolites. Another important task is the generation of energy within the mitochondria in the form of ATP, which is required for almost all processes in the cell. In the cytoplasm, the cytoskeleton gives the cell its structure and establishes a connection to the cell environment outside the adjacent cell membrane. Cell organelles in the cytoplasm perform specialized tasks, and the fluid milieu of the cytoplasm provides an optimal environment for many biochemical reactions that must take place in a cell as part of the metabolism. The cytoplasm has a regulating effect on these reactions, connects the different cell components with each other and thus enables communication within the cell.
Color of the cell plasma
Besides water, the cytoplasm consists mainly of proteins and is generally colorless. By means of different staining techniques the structures including the cytoplasm can be stained to make them visible. The widely used hematoxylin-eosin (HE) stain stains the cytoplasm orange, but the color depends on the state of the cell: active and proliferating cells, for example, have a lot of RNA in the cytoplasm, which is stained blue-violet.