Cellular compartment
As various cell compartments shall be referred within a cell in biology. In contrast to the term organelle ', which always refers to a single object (such as a mitochondrion ), the term compartment for the sum of all similar cellular spaces used. A cell can thus have many mitochondria, but only a mitochondrial compartment. Also, the cytoplasm is a compartment, but no organelle. Other compartments of eukaryotes are formed by the components of the endomembrane system, the cell nucleus and in plants of plastids and the vacuole.
Compartments are usually separated by biomembranes, but also areas of the cell that are not separated by a biomembrane may represent compartments that are heterochromatic and the euchromatic compartment in the cell nucleus. With the help of the proposed by Eberhard Schnepf Kompartimentierungsregel compartments of the plasmatic or not the plasmatic phase can be assigned.
Importance of cell compartments
The cell is divided into different reaction chambers ( compartments ), so that in a confined space different metabolic reactions are possible. Create different microenvironments. Many of the organelles have biomembranes. The biomembranes represent a demarcation smallest areas for environment and allow through their controllable permeability selective permeability. In such separate compartments thus can run different operations, such as detoxification processes, biochemical reactions that would interfere with the chemistry of the entire cell or another.
Examples of compartments are of the interior of the endoplasmic reticulum, the stroma of the chloroplasts, the matrix of the mitochondria, the vacuoles in plant cells or the interiors of the thylakoids. A special form is also the lytic compartment.
Through the membranes of the different compartments in addition concentration can be set up. That is, be different, the concentrations of solutes (such as ions, such as potassium ions or calcium ions) on the two sides of the membrane. This concentration gradient can be used, eg of proteins to synthesize substances or in exchange for other ions ion transport through the membrane.
The presence of an intracellular compartments allows division of work, is made possible by a unique differentiation and increase in performance of the specialized cells. Compartmentalization is therefore at the cellular level, the evolutionary prerequisite for the emergence of complex, differentiated organisms.
The subdivision of the cell into the reaction spaces ( compartmentalization ) also permits a considerable acceleration of metabolic reactions. Concentrating the cell Metabolitteilchen smaller due to the lower partial spaces leads to an increase in diffusion distances and the collision probability of the conversion in the reaction (see, Fick's law ).
But many prokaryotic cells have compartments. One of the most studied is the Periplasmic space of Proteobacteria, which is located between the cytoplasmic membrane and outer membrane. This compartment contains, among other things, the cell wall.
The cell interior of Planctomycetes is also highly compartmentalized, without having previously known details about the function of each demarcated spaces. Another bacterial compartment, which is found in green non sulfur bacteria, are chlorosomes, which contain the light-absorbing pigments of phototrophic bacteria.