Compartmentalization rule
The compartmentalization rule is a theorem in cell biology that goes back to Eberhard Schnepf . It is also known as Schnepf's rule or Schnepf's theorem .
According to this rule, a biological membrane separates a plasmatic from a non-plasmatic phase . Metabolic reactions can take place in the non-plasmatic areas, the plasmatic areas and membrane-bound areas. For the plasma membrane as the outer boundary of the cell , this classification is immediately obvious: Outside the cell is the non-plasmatic phase, inside the plasmatic phase with the eponymous cytoplasm . The compartmentalization rule includes the intracellular biomembranes in this consideration: the content of the ER , the Golgi apparatus , the lysosomes , vesicles and vacuoles , the spaces between the two covering membranes of the nucleus , the mitochondria and plastids, and the content of the thylakoids in the chloroplasts belong to the non-plasmatic phase .
Exceptions to the rule of compartmentalization are rarely observed, for example in processes associated with endocytobiosis . The compartmentalization rule must not be confused with the compartmentalization hypothesis .
Application in cell biology
The compartmentalization rule allows a number of basic statements:
- Each biomembrane separates two different phases: plasmatic and non-plasmatic.
- In order to get from one plasma to another (for example from the caryoplasm to the cytoplasm ), two membranes and the intermediate, non-plasmatic phase must be crossed.
- Only phases of the same name mix in fusion processes.
- Only phases of the same name separate in vesiculation processes.
literature
- ↑ Schnepf E. 1966. In: (P. Sitte, ed.) Functional and morphological organization of the cell Springer, Berlin, Heidelberg, New York, pp 372-393.
- Hans Kleinig, Uwe Maier: Cell Biology: A Textbook . Founded by Hans Kleinig and Peter Sitte. 4th edition. Fischer, Stuttgart 1999, ISBN 3-437-26010-3 .