Name: ____________________________________________________________________
The Basic Unit of Life
Your mission: to observe a variety of living things and once living things under the microscope and
to identify specific organelles (cell wall, cell membrane and cytoplasm)
Materials
Microscope
Microscope slides
Water
Cork
Cover slips
Iodine Stain
Eye dropper
Blood
Toothpicks
Procedure – The Cell Wall
Cork cells are excellent for studying a cell part common to all plant cells. This part is the cell wall.
In a cork cell, the cell wall is easily visible. The cork is no longer living. The cell wall remains as the
only evidence of once living materials.
1.
Prepare a wet mount of your cork slice
2. Examine the cork under low power and then high power of your microscope. Use the fine
adjustment to obtain a 3 dimensional view of the cells.
3. Use the space below to draw several cork cells as they appear under high magnification.
Label the cell wall.
Analysis
1.
Describe the appearance of the cork cells. ________________________________________
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2. Are cork cells alive?_______ How do you know? ___________________________________
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3. Are the cork cells filled with living material or are they empty? _______________________
4. What specific organelle is all that remains of the cell? ________________________________
5. In 1665, Robert Hooke, an English scientist, reported an interesting observation while
looking through his microscope at cork. “I took a good clear piece of cork, and with a
penknife sharpened as keen as a razor, I cut a piece of it off, then examining it with a
microscope, me thought I could perceive it to appear a little porous, much like a honeycomb,
but that the pores were not regular”
a. What were the honeycomb units at which Hooke was looking? ___________________
6. Are cork cells part of a producer or a consumer? ________________ How do you know this?
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Procedure – Cell Membrane & Cytoplasm
Human cheek cells are excellent for examining cell membranes and cytoplasm.
1. Place a drop of iodine solution and a strand of hair on to the slide.
2. Gently scrape the inside of your cheek with the end of the toothpick. You will not be able to
see anything on the toothpick when you remove it from your mouth.
3. Dip the toothpick into the iodine on the slide and mix once or twice.
4. Examine under low and high power of your microscope. The hair will help you in locating
the proper depth.
5. Locate and examine the cells that are separated from each other rather than those in
clumps.
6. Use the space below to draw several cheek cells as they appear under high magnification.
Label the cell membrane and cytoplasm.