Differentiate between hypertonic and hypotonic solution.

A hypertonic solution has a higher solute concentration (and consequently lower water concentration) compared to the cell's interior, while a hypotonic solution has a lower solute concentration (higher water concentration) than the cell. When a cell is placed in a hypertonic solution, water moves out of the cell through osmosis, causing the cell to shrink or become plasmolyzed in plant cells—a process where the cell membrane pulls away from the cell wall. Conversely, in a hypotonic solution, water enters the cell, causing it to swell and potentially burst in animal cells or become turgid in plant cells.

These concentration differences drive the net movement of water molecules across the semi-permeable cell membrane, always flowing from regions of higher water potential to lower water potential until equilibrium is reached. In practical terms, if you place a raisin in pure water (hypotonic to the raisin), it swells as water enters; if you place a fresh grape in concentrated salt solution (hypertonic to the grape), it shrivels as water exits. This concept is crucial for understanding biological processes like kidney function, intravenous fluid administration in medicine, food preservation through salting or sugaring, and how organisms maintain water balance. The third category, an isotonic solution, has equal solute concentration to the cell and results in no net water movement, maintaining cellular volume and shape.