In a hypotonic solution, what happens to animal cells?

In a hypotonic solution, the concentration of solutes outside the animal cell is lower than the concentration of solutes inside the cell. This difference in concentration causes water to move into the cell through osmosis, as water flows from an area of lower solute concentration to an area of higher solute concentration to achieve equilibrium.

As water enters the cell, the cell begins to swell. Because animal cells lack a rigid cell wall, excessive swelling can lead to the cell membrane being unable to withstand the increased internal pressure. This may ultimately result in cell lysis, where the membrane ruptures, and the cell bursts. This process illustrates the critical relationship between osmotic pressure and cell stability in different solute concentrations.