Final answer:
In a hypertonic solution, red blood cells shrink and collapse. In a hypotonic solution, red blood cells swell and may burst. Red blood cells lack mechanisms to prevent them from taking on too much or too little water.
Step-by-step explanation:
In a hypertonic solution, where the concentration of solute is higher outside the red blood cell, water will leave the cell. As a result, the red blood cell will shrink and collapse onto itself. This process is known as crenation.
On the other hand, if the red blood cell is placed in a hypotonic solution, where the concentration of solute is lower outside the cell, water will flow into the cell. This can cause the red blood cell to swell and potentially burst, a process called hemolysis.
It is important to note that red blood cells lack mechanisms to prevent them from taking on too much or too little water, making them particularly useful for studying osmolarity.