Question

1e. Which of the following rules concerning osmolarity and tonicity is NOT true? (2 points) a. The tonicity of a solution is more important than the osmolarity in clinical medicine b. A solution that is hyperosmotic to a cell will always be hypertonic c. Only Non Penetrating Particles are important when assessing the tonicity of a solution relative to a cell d. A cell will shrink when placed into a hypertonic solution e. Penetrating particles affect the osmolarity of the solution

Answer 1

Option b is the correct answer.Osmolarity can be defined as the measure of solute concentration per unit volume of the solvent and tonicity is the measure of osmotic pressure gradient between two solutions which are separated by a semipermeable membrane.Osmolarity deals with both penetrating(option e) and non penetrating solutes whereas tonicity is concerned about non penetrating solutes only(option c).A cell placed in a hypertonic solution will lose its volume and shrink (movement of solvent from cell to the solution,osmosis),hence option d.Tonicity of a solution is more important than osmolarity because tonicity is the basis for intravenous fluid therapy(option a).