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Cell Microscope Lab Activity Regular

Description
BIO GEN lab activity
Transcript
   Name: _________________________________________________ Date: ________________ Period: ____ Cell Observation Lab Activity 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 Dropper of water Onion skin Scissors Flat toothpicks Cover slips Forceps Prepared cork slides Methylene Blue Microscopes Elodea Prepared blood slides Iodine 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 layer as 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 low power, then medium power, and then high power. 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 the Nucleolus. 1)   Onion cells (and skin cells) are flat and seem to overlap. Explain why this arrangement is beneficial.  _____________________________________________________________________________________________________  _____________________________________________________________________________________________________  _____________________________________________________________________________________________________  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 leaf under low power, then medium power, and then high power using your microscope. Using a  pencil, draw your observations using the 2 powers 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 chloroplast perform? _____________________________________________________________ 3)   Explain why you think it is important to have plants like Elodea in a fish aquarium.  _________________________________________________________________________________________________  _________________________________________________________________________________________________  _________________________________________________________________________________________________ 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?  _________________________________________________________________________________________________  _________________________________________________________________________________________________  _________________________________________________________________________________________________ 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 your cells under low power, then medium power, and then high power using your microscope. Using a pencil, draw your observations using the 2 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?  ___________________________________________________________  ___________________________________________________________  ___________________________________________________________ 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 observe low power, then medium power, and then high power.Draw your observations using the 2 powers 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 (low, medium, 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.  _________________________________________________________________________________________________  _________________________________________________________________________________________________  _________________________________________________________________________________________________  _________________________________________________________________________________________________ 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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