Intracellular water and the cytomatrix: some methods of study and current views

The extent to which the properties of water in cells are like those of water in dilute aqueous solutions is a question of broad significance to cell biology. A detailed answer is not available at present, although evidence is accumulating that the properties of at least a large fraction of intracellular water are altered by interactions with cell ultrastructure, notably the cytomatrix. That and related evidence also suggests that the properties, composition, and activities of the "aqueous cytoplasm" of intact cells bear little resemblance to those of the "cytosol" obtained by cell fractionation. This paper will consider some of the evidence for these possibilities and some of their potential consequences with regard to cellular structure and function.