elodeaLab: Diffusion and Osmosis in Elodea Cells

Questions and Predictions:

1. What is the difference between a hypertonic solution and a hypotonic solution?



2. What will happen to plant cells that are placed in a hypertonic solution?




Obtain two leaves from an elodea plant that is grown in aquarium water. Place one of the leaves on a slide and observe the cells under a microscope. You should be able to identify the chloroplasts and an empty space in the middle of the cells which is the vacuole.

Soak the other leaf in a salt water solution and observe the cells under the microscope. Compare the cells to the first slide.


Sketch your slides, showing how the cells appeared in each solution.






Analysis: Describe in your own words what happened to the elodea cells.



Images of elodea Cells in an isotonic solution and in a hypertonic solution.

elodeaelodea in salt water

Notes: Most students will understand that salt will cause the cell to shrink, what is surprising is that the cell itself does not get smaller, but the vacuole gets smaller. Chloroplasts that were found near the edge of the cell wall will collapse into the center of the cell because the vacuole is empty.