Final answer:
Osmolarity measures the total solute concentration in a solution while tonicity describes the effect of a solution on cell volume through osmosis. Hypotonic, isotonic, and hypertonic refer to tonicity conditions that can cause a cell to swell, remain unchanged, or shrink, respectively, depending on whether the solution’s osmolarity is lower, equal to, or higher than the cell's cytoplasm.
Step-by-step explanation:
Osmolarity and tonicity are important concepts that explain the behavior of cells in different solutions. Osmolarity is a measure of the total concentration of solute particles in a solution, while tonicity refers to how a solution can affect cell volume by osmosis. Solutions can be described as hypotonic, isotonic, or hypertonic relative to the cytoplasm of a cell.
In a hypotonic solution, the extracellular fluid has a lower osmolarity than the cell's cytoplasm, leading to water entering the cell, potentially causing it to swell and potentially lyse. Conversely, in a hypertonic solution, the extracellular fluid has a higher osmolarity leading to the loss of water from the cell, causing it to shrink. Lastly, an isotonic solution has the same osmolarity as the cell's cytoplasm, leading to no net movement of water and no change in the cell's volume.
Tonicity is influenced by the osmolarity but it specifically relates to the effect on cell volume. Thus, while osmolarity is a measurement of solute concentration, tonicity describes the potential for water movement across a cell membrane based on the osmolarity of the solution compared to the cell's internal environment.