Final answer:
In osmosis, water molecules move across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration. A hypertonic solution has a higher solute concentration than the cell, causing water to leave the cell and potentially shrink or burst it. A hypotonic solution has a lower solute concentration than the cell, causing water to enter the cell and potentially make it swell or burst.
Step-by-step explanation:
Osmosis occurs when there is an imbalance of solutes outside of a cell versus inside the cell. A solution that has a higher concentration of solutes than another solution is said to be hypertonic, and water molecules tend to diffuse into a hypertonic solution. Cells in a hypertonic solution will shrivel as water leaves the cell via osmosis. In contrast, a solution that has a lower concentration of solutes than another solution is said to be hypotonic, and water molecules tend to diffuse out of a hypotonic solution.