Osmosis is defined as the movement of solvent particles from their higher concentration to their lower concentration i.e., from hypotonic solution to hypertonic solution through a semipermeable membrane. Diffusion is defined as the movement of solute as well as solvent molecules from the region of their higher concentration to the region of their lower concentration. There is no role of semipermeable membrane. Plasmolysis is defined as the rupture or bursting of a cell when it is kept in hypotonic solution due to the movement of solvent particles in the cell.