Lab: Cell Survey dd Lesson Title: Cell Survey Lab Grade/Age Level: Middle school grades 6-8 (age 11-14) Subject Area: Life Science Number of Classes for Lesson Completion: (3) 45-Minute Class Sessions Lesson Description Students will use a compound microscope to examine a variety of cells from the plant, animal, fungi, and bacteria kingdoms Pennsylvania Standards for Science and Technology The following Pennsylvania Standards will be addressed during the lesson 3.1.6.A4 Recognize that all organisms are composed of cells and that many organisms are unicellular and must carry out all life functions in one cell 3.1.6.A6 Identify examples of unicellular and multi-cellular organisms 3.1.7.A5 Explain how the cell is the basic structural and functional unit of living things 3.1.7.A6 Identify the levels of organization from cell to organism Instructional Objectives o To view differences between prokaryotic and eukaryotic cells o To gain experience using the microscope o To view cells from the following kingdoms: Plant, Animal, Bacteria, Fungi Lab: Cell Survey Instructional Procedures o Lesson Set 1. Use the diagram on http://edtech2.boisestate.edu/pattymcginnis/506/Cell_Site/506_cellular_organization. html to demonstrate cellular organization. Explain that they will be looking at different types of cells. 2. Introduce students to the different types of cells by having them access http://edtech2.boisestate.edu/pattymcginnis/506/Cell_Site/506_types_of_cells.html. Ask students to use their textbook to identify several major cell parts. 3. Ask students to answer the following questions. Discuss answers and demonstrate images of cells using interactive white board. What does the cell theory say? Why do you think we should study cells? Define: Prokaryotic Cells Eukaryotic Cells Give an example of a prokaryotic cell. Give two examples of eukaryotic cells. o Techniques and Activities Students will use compound microscope to view a variety of cells; refer to lab sheet following this lesson plan o Lesson Closure Ask students to use what they have learned to compare cells in different kingdoms Adaptations for Learners with Special Needs Have images of the required cells posted into a power point presentation which can be shown on an interactive white board. Allow students to go up to the board to confirm their findings. This accommodation will benefit both learners who have visual impairment and learners who are having difficulty identifying organelles within the cells Extension and Remediation Activities o Extension Have a variety of prepared slides available for students who finish early or would like additional practice with the microscope -2- Lab: Cell Survey o Remediation Reduce the number of required images to accommodate slower students. Partner with a capable student or enlist “student helpers” to check to see if specimens are focused properly Assessment o Lab activity will be collected and assessed for quality and accuracy of work (detailed and labeled drawings) o Lab quiz will be administered in which students will be expected to recognize, describe, and label cells similar to the ones observed in lab Learner Products Learners will complete the following lab activity and submit their drawings for assessment -3- Lab: Cell Survey STUDENT HANDOUT Lab: Cell Survey OBJECTIVES To see the differences between prokaryotic and eukaryotic cells. To gain more experience using the microscope. To view cells from the following kingdoms: Plant, Animal, Bacteria, Fungi Pre Lab Questions: 1. What does the cell theory say? 2. Why do you think we should study cells? 3. Define: a. Prokaryotic Cells b. Eukaryotic Cells 4. Give an example of a prokaryotic cell. 5. Give two examples of eukaryotic cells. PROCEDURE Part A: Observing Bacterial Cells Bacterial cells can be round, spiral shaped, or rod shaped. Draw simple sketches of the bacteria focusing on shape of the cells. Make the sketches in the spaces below. For each, note whether the bacterium is round, rod-shaped, or spiral-shaped. Don’t forget to write in the magnification. 1. Make a wet mount from the dilute yogurt by adding one drop to a slide. -4- Lab: Cell Survey 2. Make a wet mount of the pickle juice by adding one drop to a slide. Yogurt Magnification _____ Shape: ______________ Pickle Juice Magnification _____ Shape: _____________ Part B: Observing Fungi Cells Prelab Questions: 1. What is a spore? 2. What is the purpose of a spore? Procedure Part B: 1. Make a wet mount of the yeast solution by adding one drop to a slide. Add a drop of stain and then cover with a cover slip. Draw in the space below. 2. Take a piece of mushroom gill and tap it onto the slide. Add a drop of water to make a wet mount. Draw it in the space below. Look for the black circles; they are spores. Yeast _____Magnification Mushroom -5- _____ Magnification Lab: Cell Survey Part C: Observing Plant Cells Background: In addition to chloroplasts, some plants have leucoplasts for storing starch (like potatoes) or chromoplasts for additional colors. Note: things that have starch in them turn BLACK when iodine is added. Pre Lab Questions 1. What is a chloroplast? 2. What is the job of a chloroplast? 3. What color are chloroplasts? 4. What is a cell wall? 5. What is the job of the cell wall? Procedure Part C: Elodea Leaf 1. Prepare a wet-mount slide of an Elodea leaf. Find the cell wall, cytoplasm, nucleus, and chloroplasts. 2. Draw and label one cell from the Elodea. Label the cell wall, cytoplasm, nucleus, and chloroplasts. 3. Sketch a representative Elodea cell as observed under high power, and label its parts. Specimen: Elodea Magnification: ______________________ Shape and Description: ________________ _______________________________ -6- Lab: Cell Survey 4. Do the chloroplasts appear to move? Describe their movement. Onion Cells 5. Prepare a wet-mount slide of onion tissue OR use a prepared slide. Onions (Allium) have layers of modified leaves (scales) that can easily be separated from one another. Peel off a portion of one layer and examine the concave side of the piece you have obtained (the side that curves inward). The surface is covered by a thin layer of cells, the epidermis. 6. Remove a small piece of the epidermis by breaking the scale (modified leaf) gently. Peel the epidermis from one of the halves of the scale. Prepare a wet-mount slide of the isolated epidermis. 7. Observe the onion cells using low power (10X objective) and then high power (40X objective). 8. If it is difficult to see the cells, add a drop of iodine. 9. Sketch one of the onion cells under high power, and label the cell wall, nucleus, and cytoplasm. Specimen: Onion Cell Magnification: ______________________ Shape and Description: ________________ _______________________________ 8. Compare the onion cell with the Elodea cell. Since they are both plant cells, they should be similar. You will note that onion cells lack one structure (organelle) that is very conspicuous in Elodea cells. 9. What is this organelle missing in the onion cells? -7- Lab: Cell Survey 10. List the similarities and differences between Elodea cells and onion cells. Similarities Differences Potato Cells 1. Prepare a wet mount slide of a potato. Do this by using a plastic knife to scrape some cells onto a microscope slide. Do not cut the potato! 2. Prepare a wet-mount slide by adding a drop of water and a drop of iodine to your slide. 3. Study the slide at low power (10X objective) and then at high power (40X objective). Specimen: Potato Cells Magnification: ______________________ Shape and Description: ________________ _______________________________ _______________________________ 4. Do you see any chloroplasts? Why or why not? 5. You will probably see some small oval-shaped blue-black structures. These leucoplasts store starch. Why did they turn blue? -8- Lab: Cell Survey Banana Cells 1. If a banana is available, scrape a small amount of tissue from its surface and spread it onto a slide. Add a drop of iodine and a cover slip. Observe the preparation using high power (40X objective). 2. How do these observations compare with what you saw in the potato? Specimen: Banana Cells Magnification: ______________________ Shape and Description: ________________ _______________________________ _______________________________ Carrot Cells 1. Prepare a wet mount slide of carrot or red pepper. Use a plastic knife to scrape some cells onto a slide. Prepare a wet-mount slide using a drop of water. 2. Can you see the chromoplasts? Sketch them. Specimen: Carrot Cells Magnification: ______________________ Shape and Description: ________________ _______________________________ -9- Lab: Cell Survey Procedure Part 4: Examining Animal Cells Animal cells can be studied using the light microscope, but most of the cellular organelles within the cytoplasm are not visible without the use of special staining techniques. You can usually fine the nucleus, the cell membrane, and the cytoplasm. To study the structure of animal cells you will use prepared slides of animal tissues. These are collections of cells that have a similar function. The cells are usually organized into sheets. 1. Obtain a prepared slide of cheek cells. Sketch a few cells, and label the plasma membrane, nucleus, and cytoplasm. Specimen: Cheek Cells Magnification: ______________________ Shape and Description: ________________ _______________________________ _______________________________ 2. Do the cheek cells have a cell wall? 3. Do they have chloroplasts_________ 4. List the similarities and differences between the plant cells and the animal cells you have observed. Similarities Differences - 10 - Lab: Cell Survey REVIEW: For the lab quiz, be able to recognize, describe, and label the different types of cells we have examined today. You should be able to discuss the similarities and differences between the different cell types. - 11 -