Osmosis
Osmosis: passive movement of water molecules from a region of lower solute concentration to a region of higher solute concentration, across a partially permeable membrane
Solute: the substance that dissolves in a solvent to produce a mixture
Solvent: the substance that is capable of dissolving one or several substances, creating a solution
--> water is considered a universal solvent
Solution: the resulting mixture of a solute and solvent
Molecules are always moving, in a solution both the water and solute molecules move around randomly
Therefore osmosis takes place naturally and without input of energy
Aquaporins are specialised integral proteins that functions as a channel for water to enter/exit the cell
--> water would otherwise has a hard time a passing through the hydrophobic center of phospholipid bilayers