Download Cell Observation Lab Activity

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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
Cover slips
Microscopes
Droppers
Forceps
Elodea leaf
Onion skin
Methylene blue dye
Various prepared slides (blood, cork)
Toothpick
Procedures: Making a Wet Mount Using Water
Specimen #1: Prepare a wet mount of onion cells.
A. Obtain a clean slide and place a drop of iodine in the middle of the slide. If
needed, rinse your slide with water and wipe dry to clean.
B. Peel a thin layer of onion skin as seen in the picture to the right.
C. Place the onion peel in the drop of iodine and then add a cover slip.
D. Examine the onion under your microscope. Using a pencil, draw your
observations below.
E. Label the Cell wall, Nucleus, Cytoplasm. If you’re lucky, you can find the Nucleolus.
Onion Analysis: Best Writing Skills
1. Onion cells (and skin cells) are flat and seem to overlap. Explain why this arrangement is beneficial.
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Specimen #2: Prepare a wet mount of Elodea cells.
A.
B.
C.
D.
E.
Obtain a clean slide and place a drop of water in the middle of the slide.
Pluck a leaf from the Elodea plant and place the leaf in the drop of water. Make sure the leaf is flat.
Add a cover slip over your elodea cell.
Examine the elodea under your microscope and using a pencil, draw your observations below.
Be sure to find and label the Cell wall, Chloroplast, and the Cytoplasm.
Elodea Analysis: Best Writing Skills
2. Which process do the chloroplasts perform? _____________________________________________
3. Using the fine adjustment with high power, focus up and down on one particular cell. As you focus,
some of the chloroplasts go out of view and others come into view. How can you explain this?
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4. Why do you think it is important to have plants like Elodea in a balanced aquarium?
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5. Review your drawing of an elodea and onion cell. 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)
B)
C)
D)
E)
Obtain a clean slide and add a drop of methylene blue in the middle of the slide.
GENTLY rub the flat end of the toothpick against the inside of your cheek to obtain cells.
Rub the used toothpick in the drop of methylene blue to transfer your cheek cells.
Add a coverslip and observe under with your microscope.
Draw a picture of your cheek cells and label the parts you can see.
Specimens 4 and 5: Examine prepared slides of cork and blood.
A. Obtain a prepared slide of cork and blood from your teacher.
B. Place the slides under the microscope and observe. Draw the power that best shows the cells.
C. Draw and label the parts you can see below. Once circle for cork…one for blood.
Cork Analysis: Best Writing Skills
6. Knowing that cork is the remains of dead plant cells, which part (or parts) were you able to see?
What is the function of this (these) part(s)?
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Blood Analysis: Best Writing Skills
7. What is the function of red blood cells? How does their shape allow them to do their job?
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General Analysis: Best Writing Skills
8. When first viewing an object under the microscope, explain why you should always find it under the
lowest power available.
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9. Why do cells have different shapes?
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