Osmosis is crucial for maintaining cell integrity as it controls the movement of water across the cell membrane. Water moves from areas of low solute concentration to high solute concentration, balancing internal and external conditions. Proper osmosis ensures that cells do not become too turgid (swollen) or plasmolyzed (shrunken), which can affect their function and survival. Disruption in osmotic balance can lead to cell damage or death, highlighting the importance of this process in cellular health.