Cell Lab Problem: How do bacterial, animal and plant cells differ? Objective: Create a list of characteristics and criteria to identify bacteria, animal and plant cells. Materials: Light microscope Microviewer image of Bacteria Elodea leaf Iodine Unknown B Glass Slide Methylene blue stain Water Frog/Fish Blood Coverslip Toothpick Onion skin Unknown A Procedure: Pre-Lab: 1. Complete the pre-lab questions #1-4. Part 1: Bacterial Cells 1. Obtain a microviewer and microviewer image of a prepared bacterial slide. 2. A generalized bacterial cell has been drawn for you. 3. Label all of the visible parts of the cell. 4. Fill in the appropriate column in Data Table 1. 5. Return the microviewer and microviewer image of a prepared bacterial slide. Part 2: Human Cheek Cells 1. Obtain supplies 1 microscope, 1 slide, 1 coverslip, 1 toothpick 2. Using the flat end of the toothpick, gently scrape the inside of your cheek. (Gently we want to look at cheek cells, not blood cells). 3. Put the cheek cells from the toothpick onto the center of a slide. 4. Go to the Methylene blue station and add one drop of Methylene blue directly on the cheek cells. 5. Add the coverslip. 6. View the cheek cell under low power. Be sure the sample is centered in the field of view. 7. View the cheek cell under medium power. Be sure the sample is centered in the field of view. 8. View the cheek cell under high power. Be sure the sample is centered in the field of view. 9. On your data sheet draw a single cheek cell as you see it under high power. Be sure to include the magnification in the space provided. 10. Label all of the visible parts of the cell. 11. Fill in the appropriate column in Data Table 1. 12. Clean and dry slide and coverslip (remember to save trees use the smallest piece of paper towels possible). 13. Throw away the toothpick (we won t reuse these). Part 3: Elodea Cells 1. Obtain a leaf of the Elodea plant. 2. Put the leaf on the center of the slide try to get it to be as flat as possible. 3. Go to the DI water station and add 1 drop of water to the slide. 4. Add the coverslip. 5. View the Elodea leaf under low power. Be sure the sample is centered in the field of view. 6. View the Elodea leaf under medium power. Be sure the sample is centered in the field of view. 7. View the Elodea leaf under high power. Be sure the sample is centered in the field of view. 8. On your data sheet draw a single Elodea leaf cell as you see it under high power. Be sure to include the magnification in the space provided. 9. Label all of the visible parts of the cell. 10. Fill in the appropriate column in Data Table 1. 11. Clean and dry slide and coverslip (remember to save trees use the smallest piece of paper towels possible). 12. Throw away the Elodea leaf.
Part 4: Onion Skin Cells 1. Obtain supplies 1 microscope, 1 slide, 1 coverslip, 1 piece of onion 3. Prepare a slide of the onion skin by: a. Peal a thin layer from the inside of a piece of onion. b. Lay the thin layer on the slide. Try to arrange the sample in a single, unwrinkled layer. c. Go to the Iodine station and add one drop of iodine on the onion skin sample. d. Add a cover slip. e. Discard the rest of the sample piece. 4. View the onion under low power. Be sure the sample is centered in the field of view. 6. View the onion under medium power. Be sure the sample is centered in the field of view. 7. View the onion under high power. Be sure the sample is centered in the field of view. 8. On your data sheet draw a single cell of the onion skin sample as you see it under high power. Be sure to include the magnification in the space provided. 9. Label all of the visible parts of the cell. 10. Fill in the appropriate column in Data Table 1. 11. Clean and dry slide and coverslip (remember to save trees use the smallest piece of paper towels possible). 12. Throw away the onion skin. 13. Return the slide and coverslip. Part 5: Frog/Fish Blood 1. Obtain a prepared slide of the blood sample. 2. View the blood under low power. Be sure the sample is centered in the field of view. 6. View the blood under medium power. Be sure the sample is centered in the field of view. 7. View the blood under high power. Be sure the sample is centered in the field of view. 8. On your data sheet draw a single blood cell from the sample as you see it under high power. Be sure to include the magnification in the space provided. 9. Label all of the visible parts of the cell. 10. Fill in the appropriate column in Data Table 1. 11. Return the prepared slide. Application: Part 6: Unknown A 1. Obtain a prepared slide of Unknown A. 2. View Unknown A under low power. Be sure the sample is centered in the field of view. 3. View Unknown A under medium power. Be sure the sample is centered in the field of view. 4. View Unknown A under high power. Be sure the sample is centered in the field of view. 5. On your data sheet draw a single cell of the Unknown A sample as you see it under high power. Be sure to include the magnification in the space provided. 6. Label all of the visible parts of the cell. 7. Fill in the appropriate column in Data Table 1. 8. Return the prepared slide. Part 7: Unknown B 1. Obtain a prepared slide of Unknown B. 2. View Unknown B under low power. Be sure the sample is centered in the field of view. 3. View Unknown B under medium power. Be sure the sample is centered in the field of view. 4. View Unknown B under high power. Be sure the sample is centered in the field of view. 5. On your data sheet draw a single cell of the Unknown B sample as you see it under high power. Be sure to include the magnification in the space provided. 6. Label all of the visible parts of the cell. 7. Fill in the appropriate column in Data Table 1. 8. Return the prepared slide.
Cell Lab Pre-Lab Questions 1. Summarize the steps to create a wet mount slide. Microbiologist: Period Date 2. What objective lens should you start with when you are trying to find your sample? 3. What is the total magnification for the high power objective lens? (Show your work) 4. What was your estimated diameter of the field of view for each power objective lens? Objective Lens Total Magnification Field of View Diameter (mm) Field of View Diameter (µm) Low Medium High Data: 1. Label the cell structures of the bacterium. Bacteria Sample This is a cartoon and not a real image! Magnification: approximately 20000x 2. How do you know the cell in the image above is a bacteria? Use the structures and characteristics to justify your answer.
Data Cheek Cells Elodea Cells Onion Skin Cells Blood Cells
Application Unknown A Unknown B Additional Box (if needed) Additional Box (if needed)
Cell Lab Microbiologist: Period Date Data Table 1 1. Complete the following table based on what you could see in the Cell Lab. (Mark an X if the structure was present and leave it blank if the structure was absent.). 2. Determine if the cell is a Prokaryote or Eukaryote. 3. Estimate the size of a single cell. Cell Part Bacteria Cell Cheek Cell Elodea Cell Onion Cell Blood Cell Unknown A Unknown B Cytoplasm Nucleus Chloroplast Cell wall Cell membrane Estimated size in micrometers 3 µm Prokaryote or Eukaryote Post Lab Questions 1. What structures did you see in all seven samples? 2. a. Which cells were eukaryotes? b. What structures did you see in all the eukaryotic cells? 3. a. Which samples were plant cells? (Use evidence from Data Table 1 to explain your answer!) b. Which samples were animal cells? (Use evidence from Data Table 1 to explain your answer!)
4. Classify each unknown as a plant cell, animal cell, or bacteria cell. Use the characteristics from your drawings/observations and criteria from Data Table 1 as evidence in your explanation. (Identifications without explanations are worth zero points!) Sample Classification Explanation Unknown A Unknown B 5. Is the nucleus always found in the center of the cell? 6. Why did we use stains (methylene blue and iodine) when observing the cells under the microscope? 7. Which organelle was moving in the Elodea cells? WHY? 8. Which plant organelle are the onion cells missing? WHY? This lab sign out must be signed before the end of the lab class. Lab Sign Out task initials task initials task initials Partners Lab station is clean and trash is disposed of All equipment cleaned and accounted for Lab equipment returned to correct location