Discussion 1. What changes occurred in the diameter of the onion rings that were immersed in the distilled
werter and concentrated sucrose solution? State the difference in the concentration of water
molecules in the onion cells and the solutions.
(a) Distilled water
(b) Concentrated sucrose solution
2. Explain why the changes occurred in the onion rings immersed in:
(a) distilled water;
(b) concentrated sucrose solution.

In this case, it is important to have into account the properties of hypertonic (sucrose) and hypotonic (distilled water) solutions:

Sucrose solution (higher concentration of water molecules in the onion cells) >> red onion cells will shrink >> smaller diameter.Distilled water (higher concentration of water molecules in the surrounding solution) >> red onion cells will become turgid >> higher diameterOsmosis refers to the movement of a solvent (usually water molecules) across semipermeable biological membranes, which occurs from a region of higher concentration to a region of lower concentration. There are three classes of solutions that have different effects on cells due to the process of osmosis:In a hypotonic solution, the cells will become turgidIn an isotonic solution, the cells will become flaccidIn a hypertonic solution, the cells will shrink (plasmolysis)When plant cells are placed into a hypertonic solution where there is a greater concentration of solute outside the cells (as in this case sucrose solution), water molecules will move from inside the cells to outside the cells, thereby cells will shrink due to water lossMoreover, when plant cells are placed into a hypotonic solution that is diluted in comparison to the content of the cell (as in this case plant cells placed in distilled water) water molecules will move from outside the cells to inside the cells, thereby cells will become turgid.

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