Lab – Normal & Plasmolyzed Cells
Name ________________________
Purpose –
To observe osmosis in Elodea plant cells. Elodea is a common water plant. In this lab you will
look at normal Elodea plant cells and compare their insides to plasmolyzed plant cells. Plant
cells lose water (plasmolysis) when the living cells are placed in an environment where the water
concentration on the outside of the cell is less than the concentration on the inside of the cell.
Because water moves from areas of high concentration to areas of lower concentration, the water
moves out of the cell, causing its insides to shrink (plasmolysis).
Materials –
microscope
microscope slide
coverslip
elodea plant
water solution
salt solution
Procedures –
Part A- Normal Cells
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prepare a wet mount slide of an elodea leaf in regular tap water
place slide on microscope and view under low power
focus slide on medium power. Locate cells along the edge of the leaf and notice the
location of the chloroplasts in relation to the cell wall.
focus slide on high power and draw cells in space provided below
Part B – Plasmolyzed Cells
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prepare a second wet mount slide using another elodea leaf and use salt water solution
let the slide sit for 2 minutes
place slide on microscope and view under low power
focus slide on medium power. Locate cells along the edge of the leaf and notice the
location of the chloroplasts in relation to the cell wall.
focus slide on high power and draw cells in space provided below
Normal Elodea Cell
Plasmolyzed Elodea Cell
Part C – Label drawings
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When you have both drawings completed, look in your book or notes at structures of a
plant cell.
Go back to both drawings you made and label the following structures –
o Cell wall, cell membrane, chloroplasts
When finished with drawings & labels, clean up your lab station. Elodea should be
thrown in the trash – NOT in your sink!
Analysis –
1) Describe the location of the choloroplasts in a normal Elodea cell.
2) Describe the location of the chloroplasts in a plasmolyzed Elodea cell.
Use these facts to answer the following questions
 Elodea cells have a normal concentration of 1% salt water and 99% water
 Tap water used in lab has a concentration of 1% salt water and 99% water
 Salt water used in lab has a concentration of 10% salt and 90% water
 Distilled water is 100% water
3) In Part A of the lab
a) how did the concentration of water inside the cell compare to the concentration of water
outside the cell? (same, more, less)
b) did the inside of the cell gain water , lose water , or remain the same?
4) In Part B of the lab
a) how did the concentration of water inside the cell compare to the concentration of water
outside the cell? (same, more, less)
b) did the inside of the cell gain water , lose water , or remain the same?
c) how was the shape of the cell(s) affected by the water?
5) What do you think would happen to the cells if we put the Elodea in a distilled water solution?
6) In the winter, roads are sometimes salted to melt ice and snow. What does this salting do to
the vegetation along the roadside? Explain your answer in terms of osmosis.