Cell Structure and Function
1
Lab #4H: Characteristics of Prokaryotic and Eukaryotic Cells
Pre$Lab$Discussion:$
Cells are the basic units of structure and function of all living things. There are two major divisions into
which all cells fall – prokaryotic and eukaryotic.
Prokaryotic cells are cells that lack a nucleus and membrane-bound organelles. Bacteria and related
microorganisms are prokaryotes. Eukaryotic cells are cells that contain a nucleus and membrane-bound
organelles. Organisms such as animals, plants, fungi, and protists are all eukaryotes.
In this investigation, you will observe several prepared slides to examine he differences between
prokaryotic and eukaryotic cells. You will also use these differences to classify an unknown specimen.
Problem$
What are the differences between prokaryotic and eukaryotic cells?
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Materials$(per$group)$
Microscope
Lens paper
Prepared slides of prokaryotic and eukaryotic cells
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Safety
Always handle the microscope with extreme care. You are responsible for its proper care and use. Use caution when
handling glass slides as they can break easily and cut you. Note all safety alert symbols next to the steps in the procedure
and review the meaning of each symbol
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Procedure$
1. Take a microscope from te storage area and place it about 10 centimeters from the edge of the
laboratory table.
2. Carefully clean the eyepiece and objective lens with lens paper.
3. Place your first prepared slide on the microscope stage so that it is centered over the stage
opening. Hold the slide in position with the stage clips.
4. Using the low-power objective lens, locate the cell(s) under the microscope. Turn the coarse
adjustment knob until the cell comes into focus.
5. In the Data Table, write the name of the type of cell that you examined. Describe the general
shape of the cell in the space provided. Estimate the length of the cell and record this figure.
Refer to laboratory Investigation 4 if you need to review how to estimate the size of objects
under the microscope. Put a check mark next to the cell structures you are able to observe under
low power.
6. Switch to medium-power objective lens, focus, and then switch to the high-power objective
lens. CAUTION: when turning to the high-power objective lens, you should always look at the
objective from the side of your microscope so that the objective lens does not hit or damage the
slide. Look for cell structures unobservable under low power. Put a check next to these
structures in the Data Table. Based on your observations, decide if the cell is prokaryotic or
eukaryotic and record this in the Data Table.
7. In the appropriate place in Observations, draw and label what you see using the high-power
objective lens. Record the magnification of the microscope.
8. Repeat steps 1 through 7 using other prepared slides provided by your teacher.
9. Repeat steps 1 through 7 using a unidentified prepared slide provided by your teacher.
10. When you have finished examining all of the prepared slides, return the microscope to the
storage area.
