It is the number of solute molecules and not the molecular size that is important in osmosis. Osmoregulation and osmotic balance are important bodily functions, resulting in water and salt balance.

Osmosis occurs to equalize the number of solute molecules across a semi-permeable membrane by the movement of water to the side of higher solute concentration. Osmolarity is measured in units of milliequivalents or milliosmoles, both of which take into consideration the number of solute particles and the charge on them.

osmoregulation — mechanism by which water and solute concentrations are maintained at desired levels. osmotic balance — balance of the amount of water and salt input and output to and from a biological system without disturbing the desired osmotic pressure and solute concentration in every…. semi-permeable membrane — membrane that allows only certain solutes to pass through. mole — gram equivalent of the molecular weight of a substance.