Lab mr. Galloway name: date

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LAB Mr. Galloway

NAME: __________________________ DATE: _____________________

Experiment: Elodea (Anacharis) Plant Cells
[Homeostasis, Osmosis, Photosynthesis]
Experimental Method:
Observe - Examine the Elodea (freshwater) plants, especially the leaves

Question - What might happen if a pond’s solute concentration changes?

Gather - Research data on post-hurricane sea water contamination of ponds

Hypothesize - If salt water from the Gulf mixes with inland ponds,
then the fresh water plants’ cells will undergo plasmolysis.

Test - Leaves tested in aquarium, saline, and distilled water.
(You will perform this experiment in the lab today.)

Analyze - (This is for you complete at the end of this lab.)

Conclude - (This also is for you to complete.)

Background Information (Spiritual Application Review)

Spiritual Application: Elodea’s common name is “Anacharis” meaning “increased GRACE / GIFT (charis)” in Greek. Just as our Creator God gave plants to continually provide life-giving air (oxygen) to His nephesh (thinking / feeling) creatures, God has also given us the Holy Spirit as the source of new, eternal life through the second birth spiritually when a person is “born-again”. By the way, the New Testament Greek word for spirit is pneuma, which means air or wind. Therefore, without the new, spiritual, second birth, no person can have eternal life. Jesus said the choice is yours (John 3). The Good News (Gospel) is that Jesus did all the work necessary for us, through His sinless life, sacrificial death, and resurrection. None of our tainted “good” works are of any value to earn or buy eternal life.
Elodea (Elodea Canadensis) is a common plant that grows in fresh water ponds, lakes, and is often used in freshwater aquariums. Remember that plant cells contain both a cell membrane and a cell wall. They also often contain a large water vacuole.
Homeostasis involves the maintenance of a stable set of conditions inside an organism’s cell(s).
Osmosis has important implications for organisms and their cells. Because cells contain mostly water, the water concentration of the environment in which they reside is very important. If cells are exposed to water concentrations that are different from their internal environment, they may loose or gain water. The exaggerated picture at the right shows three beakers with isotonic, hypertonic, & hypotonic solutions.
Photosynthesis in water plants provides food for the plant and much of the oxygen needed by the bacteria and animals in the pond or aquarium where they live. If changes in the salt (or many other solutes in the solution) concentrations in the water hindered the plants’ ability to perform photosynthesis, then the interdependent system of life in that habitat would be affected as well.


A. Elodea in AQUARIUM Water

1. Prepare a wet mount of an Elodea leaf with aquarium water. To do this, use a soaked

“Q-Tip” to place a drop of aquarium water towards one end of the slide. Using forceps remove a small leaf from the tip of an Elodea plant and lay it flat in the drop of water. Cover with a cover slip.
2. Observe the leaf at 40X and record your observations.
3. Increase the magnification to 100X, observe and record your observations.

B. Elodea in 10% SALT Solution

1. Remove the slide from the stage of the microscope.

2. Soak a “Q-Tip” in 10% salt solution & put 2 drops on the slide at the left edge of the cover slip. To make a 10% sea salt solution, mix 10 grams of NaCl with100 ml of distilled water.
3. Tear off a small piece of paper towel and place the torn edge on the slide at the right edge of the cover slip. The piece of towel should begin to soak up water, drawing the salt solution under the cover slip as it does so. (See the figure below)
4. Return the slide to the microscope stage and observe the cells at 40X and 100X. Record your observations.

C. Flushing Out the Salt Solution with DISTILLED Water

1. Remove the slide from the stage of the microscope.

2. Place 3-5 drops of distilled water on the slide at the cover slip.
3. Draw the water through with a piece of paper towel.

4. Observe the cells at 40x and 100x. Record your observations.

Remove the slide from the microscope stage, clean it and the cover slip, then put them away carefully. The cover slip is very sharp.


• Prepare sketches of your observed Elodea cells under each set of conditions

(aquarium water, 10% salt solution, and distilled water).

• Label the magnification under which the plant cells are being observed (40x or 100x).

• Label the sketches to note the cell structures that you can identify.

• Be sure to note any changes in the color, size, and shape of the cells.

  1. Elodea in AQUARIUM Aqueous Solution

Low Power (______ x) High Power (______ x)

  1. Elodea in 10% SALT Solution

Low Power (______ x) High Power (______ x)

  1. C. Elodea in Distilled Water (0% Salt Solution)

Low Power (______ x) High Power (______ x)


  1. What was the shape of your Elodea cells in Aquarium water?

  2. What happened to your cells as the salt water flowed under the cover slip?

  1. What happened to the cells when the salt water was flushed out with distilled water?
    Why do you thiink this happen?

  2. Why do you think the cell walls not change shape very much?

  3. Which of the solutions were
    a. Isotonic -
    b. Hypotonic -
    c. Hypertonic -

  4. Did any of the solutions cause cells to undergo cytolysis or plasmolysis? Explain why or why not.
Copy & paste this link to your Web browser for an excellent animation of the dynami

Page of LAB Bio-Logic 10th Experiment: Homeostasis,Osmosis, Photosynthesis Mr. Galloway

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