Article / Updated 03-26-2016
Molecules that pass muster with the cell membrane enter the cytoplasm, a mixture of macromolecules (such as proteins and RNA), small organic molecules (such as glucose), ions, and water.
Because of the various materials in the cytoplasm, it’s a colloid, or mixture of phases, that alternates from a sol (a liquid colloid with solid suspended in it) to a gel (a colloid in which the dispersed phase combines with the medium to form a semisolid material).