Plant Cell Lab Name: __________________________________________ Purpose: Students will observe plant cells using a light microscope. Two cells will be observed, one from the skin of an onion, and the other from a common aquarium water plant (Anacharis). Students will compare both types of cells. Prelab Questions 1. What is the function of chloroplasts? 2. Name two structures found in plant cells but not animal cells. 3. Name three structures found in plant cells AND in animal cells. 4. What structure surrounds the cell membrane (in plants) and gives the cell support. Part A - Onion Cells Obtain a prepared slide of onion cells or prepare one yourself. View under the microscope and sketch the cells at each magnification. The drawings should go in section 4 of your notebook. Label the cells as they appear. under high power. Part B - Elodea Cells View a prepared slide of elodea (Anacharis), which is an aquarium plant. As the slide warms from the light of the microscope, you may see the chloroplasts moving, a process called cytoplasmic streaming. View under the microscope and sketch the cells at each magnification. The drawings should also go in section 4 of your notebook. Post Lab Questions 1. Describe the shape and the location of chloroplasts. 2. Why were no chloroplasts found in the onion cells? (hint: think about where you find onions) 3. Which type of cell was smaller - the onion cells or the elodea cells? 4. Make a Venn Diagram to show the differences and similarities between plant and animal cells. This should also go in section 4 of your notebook. Plasmolysis in Elodea Plant Cells Review the directions for the lab below. Then record your data and observations, and answer the questions at the end of the page in your lab notebook – section 4 Methods Elodea in Tap Water 1. Prepare a wet mount of an Elodea leaf with tap water. To do this, place a drop of 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. Elodea in 5% Salt Solution 1. Remove the slide from the stage of the microscope. 2. Place 2 drops of the 5% salt solution on the slide at the left edge of the cover slip. 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 Figure) 4. Return the slide to the microscope stage and observe the cells at 40X and 100X. 5. Record your observations. Elodea in 10% Salt Solution 1. Repeat the procedure above with 10% salt solution. 2. Observe the cells at 40X and 100X. Record your observations. Flushing Out the Salt Solution 1. Remove the slide from the stage of the microscope. 2. Place 3-5 drops of tap water on the slide at the cover slip. 3. Draw the water through using a small piece of paper towel. 4. Observe the cells at 40x and 100x. Record your observations. 5. Remove the slide from the stage, clean it, and the cover slip, and put it away. Observations Prepare sketches of a group of Elodea cells under each set of conditions (tap water, 5% salt solution, and 10% salt solution). 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. Make your sketches as accurate as possible. Conclusions - Answer the following questions in your lab notebook. 1. What is the shape of a typical Elodea cell? Draw it. Your drawing should include the cell wall, chloroplasts, and central vacuole. Identify the functions for each structure. 2. What happens to the cells as the salt water flows under the cover slip? 3. What happens to the cells when the salt water is flushed out with distilled water? 4. Why did the water in the vacuole pass out of the cell? 5. Why didn’t the outer boundary of the cell collapse?
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