What happens to water outside the cell when the interior is saltier than its surroundings? Is it hypotonic or hypertonic?

Answer 1

If the interior of the cell has a higher concentration of salt than its surroundings, then the solution around it would be considered hypotonic. Tonicity essentially refers to the concentration of the solute in a solution, and the prefix hypo- means low, so hypotonic means that the solution has a lower concentration. If a cell is placed in a hypotonic solution, then water will enter the cell from the solution because the system is working to make the concentration equal on both sides. Since the solute (in this case salt) cannot cross the cell membrane, so the only way for the system to make the concentration equal on both sides is for water to come into the cell, which dilutes the solution in the cell and increases the concentration of the solution outside the cell, eventually making the concentrations equal.