When a cell is placed in an isotonic solution, the cell will not exprience a change in size. This is because, an isotonic solution is one which contains two different solutions which have the same osmotic pressure across a semi-permeable membrane. This makes it possible for water to move freely across the membrane without changing the concentration of the solutes on either side of the membrane. Thus the cell will not exprience any change in size. Cells placed in an hypertonic solution will shrink because water will be moving out of the cell.
