Download Animal Mitosis under the Microscope

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Activity 2.2: Animal Mitosis under the Microscope
In this activity you will have an opportunity to view animal cells during mitosis.
You will examine a prepared slide of the whitefish embryo to identify cells that are
dividing. Because prepared slides are used, these cell divisions have been “frozen in
time.” You will not be able to watch a single cell divide from prophase to telophase.
Materials
•
microscope
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lens paper
•
prepared microscope slide of a whitefish embryo
•
paper, coloured pencils
Instructions
1. Obtain a whitefish embryo slide and place it on the stage of your microscope.
2. View the slide under low-power magnification. Focus using the coarse
adjustment knob.
3. Rotate the nosepiece to the medium power objective lens. Focus the image
using the fine adjustment knob only. Identify a few dividing cells.
4. Rotate the nosepiece to the high power objective lens. Use only the fine
adjustment knob to focus the image. Locate and observe cells in each phase of
mitosis. Don’t worry if what you see does not look exactly like those in your
notes.
5. Draw and title each of the phases that you see (minimum of 5 diagrams). Label
chromosomes if they are visible. It is important to draw and label only the
structures that you see under the microscope. Do not forget the guidelines that
were taken in class.
6. Return your microscope to the low power objective lens and remove the slide .
Observations
1. Observe the slide under low power and then medium power. How can you tell the
cells are dividing?
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2. Observe the slide under high power. Locate and observe cells in each of the phases
of mitosis.
a) Draw a cell in each of the four phases of mitosis (prophase, metaphase,
anaphase, and telophase). Create a diagram of each phase of mitosis using
your word processor or other software. A number of options are available for
submitting your file. Ask your teacher if s/he can read the file format you want to
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use to create the file. If you do not have software for creating the drawing, you
may hand draw it. Enlarge your drawing and draw what you see. You will submit
a photograph or a scan of your drawings.
b) Label the chromosomes, nuclear membrane, nucleolus, spindle fibres, and cell
membrane if they are visible.
c) Write a brief description for each of the phases. Refer to the images you have
seen on mitosis and the resource section of this assignment for assistance.
prophase
description:_________________________
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metaphase
description:_________________________
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anaphase
description:_________________________
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telophase
description:_________________________
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3. While observing the slide under high power, count the number of cells seen in
interphase and each of the phases of mitosis.
interphase
prophase
metaphase anaphase
telophase
Tally
Total
number of
cells
Analysis:
1. Why is the whitefish blastula used for viewing mitosis?
2. Explain why the cells you observed are not dividing at this time?
3. Calculate the percentage of cells that are in each of the phases: interphase,
prophase, metaphase, anaphase, and telophase. Use the data you collected on
the total number of cells in each phase. Show all calculations.
Example Interphase:
You counted 30 cells in total the field of the microscope.
10 out of the 30 cells counted were in interphase.
Per cent = 10/30 X 100
= 33 %
4. The percentage of cells in each phase represents the time spent in each of these
phases. Which phase has the highest percentage of cells and therefore
represents the longest time the cell spends in this stage?