Plasmolyzed cells Lab
TITLE: Please provide a descriptive title.
OBJECTIVES:
Demonstrate the effect of a salt solution on plant cells.
Construct an inference as to how diffusion occurs in elodea cells.
Distinguish between the terms: diffusion, osmosis, plasmolysis, and turgor.
INTRODUCTION:
Provide information on diffusion, osmosis, hypotonic, hypertonic, and isotonic solutions. Hypothesize what will happen
when plant cells are placed in a salt solution. Hypothesize what will happen when plant cells are placed in distilled water.
PRE-LAB:
Research TERMS: Plasmolysis and Turgor
MATERIALS:
Create a list of materials by going through the procedures.
PROCEDURES:
1. Place a leaflet from the growing tip of an elodea plant on a slide and make a wet mount using only water that the elodea
has been living in.
a. Observe under both low and high power. Draw the cells under low and high power.
b. Note how the contents of the cytoplasm appear at this time under high power.
c. Label the cell wall, plasma membrane, and chloroplasts.
2. Use a clean dropper to add a drop of a 5% salt solution along one edge of the cover slip. Place a piece of paper towel
along the opposite edge of the cover slip.
a. After several minutes, observe the cells and draw them under low and high power.
b. Note any changes in the cytoplasm of the cells under the high power.
c. If the plasma membrane and the cell contents have shrunk away from the cell wall, the cell has plasmolyzed.
d. Diagram a plasmolyzed cell. Label the cell wall, plasma membrane, and chloroplasts.
3. Add a drop of tap water to the wet mount, using the previous paper towel procedure.
a. Allow the leaflet to sit in distilled water for several minutes.
b. Observe the cells and again draw them under low and high power.
c. Note any changes in the cytoplasm of the cells.
OBSERVATIONS:
Create designated areas for your drawings and descriptions of the elodea leaves under the various conditions.
DISCUSSION:
Summarize your results for each situation. Do the results support your hypothesis? Explain any results that were
unexpected.
POST-LAB QUESTIONS:
1. Describe in detail which structure actually controls what will or will not enter the cell. Sketch this structure.
2. Explain how the immersion in salt water changes the contents of the elodea cells.
3. Propose how oxygen leaving a red blood cell enters a muscle cell.
4. Discuss how water enters the bloodstream after a person drinks a glass of water.
5. Distinguish what best describes the process of waste products of a heart cell (like urea that is responsible for the yellow
color of urine) leaving and entering the bloodstream.
6. Relate what you did in lab to a sunflower plant wilting on a hot summer day.
7. When the sunflower is seen the next morning, it is no loner wilted but stands firm and strong. Explain what has
happened.
8. Evaluate your original hypotheses and determine if your observations agree with your hypothesis. Explain why.
9. Based on the observations, what conclusions can you make?