Encyclopedia > Cytosol

  Article Content

Cytosol

The cytosol (as opposed to cytoplasm, which also includes the organelles) is the internal fluid of the cell, and a large part of cell metabolism occurs here. Proteins within the cytosol play an important role in signal transduction pathways, glycolysis, and act as intracellular receptors and ribosomes. In prokaryotes, all chemical reactions take place in the cytosol. In eukaryotes, the cytosol contains the cell organelles. In plants, the amount of cytosol can be reduced due to the large tonoplast (central vacuole) that takes up most of the room of the cell.

The cytosol is not a "soup" with free-floating particles, but highly organized on the molecular level. The cytosol also contains the cytoskeleton. It is made of fibrous proteins and (in many organisms) maintains the shape of the cell, anchors organelles, and controls internal movement of structures, e.g., transport vesicles.

As the concentration of soluble molecules increases within the cytosol, an osmotic gradient builds up toward the outside of the cell. Water is flowing into the cell, making it larger. To prevent the cell from bursting apart, molecular pumps in the plasma membrane, the cytoskeleton, the tonoplast or a cell wall (if present) are used to counteract the osmotic pressure.



All Wikipedia text is available under the terms of the GNU Free Documentation License

 
  Search Encyclopedia

Search over one million articles, find something about almost anything!
 
 
  
  Featured Article
Sakhalin

... area of 78,000 km² (24,560 sq. miles). The capital of Sakhalin is Yuzhno Sakhalinsk[?] (Japanese: Toyohara (豊原)), a city of about 200,000 which has ...

 
 
 
This page was created in 43.4 ms