Final answer:
Osmolarity refers to the solute concentration of a solution, while tonicity describes how that solution affects the volume of a cell through osmosis. Solutions with low osmolarity have more water molecules and can cause cells to swell, while solutions with high osmolarity have fewer water molecules and can cause cells to shrink. Red blood cells may undergo hemolysis when placed in a low osmolarity solution, while plant cells may shrink when placed in a high osmolarity solution.
Step-by-step explanation:
Osmolarity refers to the total solute concentration of a solution, while tonicity describes how that solution affects the volume of a cell through osmosis. In a solution with low osmolarity, there are more water molecules relative to solute particles, while in a solution with high osmolarity, there are fewer water molecules relative to solute particles.
When solutions of different osmolarities are separated by a membrane permeable to water, water will move from the side with lower osmolarity to the side with higher osmolarity. This can cause cells to shrink or swell depending on the tonicity of the solution. For example, if red blood cells are placed in a pure water solution with lower osmolarity, water will rush into the cells and cause them to swell and burst in a process called hemolysis. Conversely, if plant cells are placed in a high concentration salt solution, they will shrink as water moves out of the cells.