Download Lab: Cell Microscope Observation Activity

Your Name: ________________________________________________ Date: ________________ Period: ______ Lab: Cell Microscope Observation Activity Partner Name: ______________________________________________
Introduction: Living things are made of cells. All cells have parts that do certain jobs. Cells have an outer covering called the cell (plasma) membrane. The cell membrane controls what enter/exits a cell. The clear jellylike material inside the cell is the cytoplasm. The nucleus is the control center of the cell. Plant cells have a thick outer covering called the cell wall. It is found on the outside of the cell membrane. Cell parts can be studied by making wet mounts slides. A wet mount slide is a temporary slide. It is not made to last a long time. You can make wet mount slides of living and once living materials to study cell parts. Materials: Glass slides Cover slips Microscopes Dropper of water Forceps Elodea Onion skin Preparedcork slides Prepared blood slides Scissors Methylene Blue Iodine Flat toothpicks Specimen #1: Prepare a wet mount of onion cells. A. Obtain a clean slide; if the microscope slide needs to be cleaned, rinse with water and wipe or pat dry. Place a drop of iodine in the middle of a clean microscope slide. B. Peel a layer of onion skin as seen in the picture to the right, then using your forceps, peel a single thin layeras seen in second picture to the right and place it in the drop of iodine. Be sure the onion skin is flat. C. Place a coverslip on top of the onion skin. This prevents the microscope lens from being damaged. D. Examine the onion with the scanning objective lens, then low power, and then high power using your microscope. Using a pencil, draw your observations using the two powers that it appears best. E. Using a pencil, draw and label the Cell wall, Nucleus, and the Cytoplasm in your onion drawing. If you’re lucky, you can even find theNucleolus. 1) Onion cells (and skin cells) are flat and seem to overlap. Explain why this arrangement is
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_________________________________________________________________________________________ Specimen #2: Prepare a wet mount of Elodea cells. A. Place a drop of water in the middle of a clean microscope slide.If the microscope slide needs to be cleaned, rinse it with water and wipe dry. B. Pluck a leaf from the Elodea plant and place the leaf into the drop of water. Make sure the leaf is flat. C. Add a cover slip over your elodea leaf; this prevents the microscope lens from being damaged. D. Examine the Elodea cells with the scanning objective lens, then low power, and then high power using your microscope. Using a pencil, draw your observations using the twopowers that it appears best. Take your time. If you are patient and observant, you might see the green chloroplasts floating in the cytoplasm interior of the cell. E. Using a pencil, draw and label the Cell wall, Chloroplast, and the Cytoplasm in your elodea drawing. 2) Which process does the chloroplastperform? _____________________________________________________________ 3) Explain why you think it is important to have plants like Elodea in a fish aquarium. ______________________________________________________________________________________
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______________________________________________________________________________________ 4) Review your drawing of elodea cells and onion cells. Both samples are plants but only elodea has chloroplasts. Where do onions grow and can you explain why they do not have any chloroplasts? ______________________________________________________________________________________
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______________________________________________________________________________________ Specimen #3: Prepare a wet mount of your cheek cells. A. Obtain a clean slide; if needed, rinse your slide with water and wipe dry to clean. Add a drop of methylene blue in the middle of the slide. B. GENTLY swab your cheek using the FLAT end of your toothpick. Again, be gentle…even the tiniest touch will produce cells. C. Rub the used toothpick in the drop of methylene blue to transfer your cheek cells. Add a coverslip. D. Examine the cheek cells with the scanning objective lens, then low power, and then high power using your microscope. Using a pencil, draw your observations using the two powers that it appears best. Take your time. Be sure to label the cell membrane, cytoplasm, and nucleus. You may even be able to see the nucleolus. 5) Review your drawing of an elodea cell and compare it to your cheek cell. What differences do you notice between an animal cell and a plant cell? _________________________________________________________________________________________
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_________________________________________________________________________________________ Specimen #4: Prepared slide of cork. A. Obtain a prepared slide of cork from your teacher. B. Place the cork slide under the microscope and examine the cork with the scanning objective lens, then low power, and then high power using your microscope. Draw your observations using the twopowers that it appears best. C. Using a pencil, draw and label the cell wall in your cork drawing. 6) Who first observed cork? ____________________________________ When did this happen? _____________________ 7) Cork cells are dead. In the sample you witnessed, you can only see the cell wall. All the other parts have decomposed. What is the cell wall made from that has allowed it to remain even after the cells are dead? ______________________________ 8) What type of molecule is the answer to #7? ____________________________________________________________________
General Analysis Questions 9) Which magnification (scanning objective lens, low power, or high power) allows you to see less detail, but more of the overall specimen?____________________________________ 10) When first viewing an object under the microscope, explain why you should always find it using the lowest power available. Be sure to say more than “it’s easier”. Explain why it is easier. ______________________________________________________________________________________
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_____________________________________________________________________________________ 11) The shape of a cell helps the cell better perform its function. Give and explain an example of this statement. ______________________________________________________________________________________
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