According to Education Portal, cytosol has no defined function, aside from simply supporting the other organelles in a cushioning fluid. However, as SparkNotes states, it is within the cytosol that many important cell functions take place, including protein synthesis. Cytosol also provides a way of distributing organelles into small groups that aide each other's functions.
Cytosol is a part of the cytoplasm. About.com Biology defines cytoplasm as all the internal components of a cell within a cell membrane but outside the nucleus. The European Molecular Biology Laboratory defines cytosol as all the parts of the cytoplasm excluding the organelles, or the space between organelles. In practice, cytosol is usually liquid and mostly water, as noted by Education Portal. SparkNotes states that cytosol often takes up more than 50 percent of the cell's volume. The fluidity and open space provided by the liquid cytosol allows for the movement of objects within the cell. Because organelles can move within the cell, they can be distributed into working units to synthesize protein, digest or store food, and maintain the shape and form of the cell. Cytosol also contains polar molecules and ions, and assists with cellular metabolism and chemical reactions within the cell.