An animal cell and a plant cell were immersed in a hypotonic solution. Both cells received water by osmosis. The animal cell has ruptured but the plant cell has not. Evaluate this.

This situation can be explained by the structural differences between animal and plant cells.

1. Hypotonic Solution: A hypotonic solution is one in which the concentration of solutes (like salt or sugar) is lower outside the cell than inside the cell. In this case, water will move from the area of lower solute concentration (outside the cell) to the area of higher solute concentration (inside the cell) to try to establish equilibrium. This process is known as osmosis.

2. Osmosis in Animal Cells: Animal cells do not have a rigid cell wall, so when they are placed in a hypotonic solution, water enters the cell, causing it to swell. If too much water enters, the cell may burst, or rupture. This is known as lysis.

3. Osmosis in Plant Cells: Plant cells, on the other hand, have a rigid cell wall in addition to their cell membrane. When a plant cell is placed in a hypotonic solution, water also enters the cell, causing it to swell. However, the rigid cell wall provides support and prevents the cell from bursting. Instead, the cell becomes turgid, or firm, which is actually the normal state for a healthy plant cell.

So, in this case, the animal cell has ruptured because it lacks the rigid cell wall that provides support and prevents over-expansion. The plant cell, with its rigid cell wall, has remained intact despite the influx of water.