INFOGRAPHIC 3.4: WATER FLOWS ACROSS CELL MEMBRANES BY OSMOSIS
The direction of water movement across the cell membrane is determined by the solute concentration on either side. Water always moves toward the side with the higher solute concentration. In a hypotonic solution, water will flow into the cell, and in a hypertonic solution, water will flow out of a cell. The bacterial cell wall helps protect the cell from lysing in a hypotonic environment. In the presence of some antibiotics the cell wall is disrupted, leaving the cell susceptible to lysis.