Final answer:
A red blood cell that swells and bursts in a hypotonic solution is undergoing hemolysis. Such a solution has a lower solute concentration than within the cell, causing water to rush in and potentially rupture the cell. Cells are most stable in isotonic conditions where solute concentrations are equal inside and outside.
Step-by-step explanation:
A red blood cell that has swelled and/or lysed due to being placed in a hypotonic solution is experiencing hemolysis. This term describes the process that happens when the cell takes in more water than it expels, leading to it swelling up and eventually bursting. The state of the red blood cell refers to the balance of solute and solvent concentrations inside and outside of the cell membrane. A hypotonic solution has a lower concentration of solutes compared to the inside of the cell, causing water to flow into the cell to dilute the higher solute concentration within the red blood cell.
In contrast, in a hypertonic solution, the environment outside the cell has a higher solute concentration than inside, resulting in water leaving the red blood cell, causing it to collapse or shrink. A red blood cell is most stable in an isotonic solution, where the concentrations inside and outside of the cell are equal, maintaining its normal shape without swelling or shrinking. When a red blood cell is placed in a hypotonic solution, it will become visibly swollen and potentially rupture as the plasma membrane's capacity to expand is exceeded.
Red blood cells lack mechanisms other cells may have to prevent excessive swelling, making them susceptible to hemolysis in hypotonic environments. This process can lead to hemolytic anemia and other related issues if it occurs inside the human body. The movement of water in response to solute concentration gradients is known as osmosis and is a critical concept in cell biology.