New Jersey Center for Teaching and Learning
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Progressive Science Initiative
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BIOLOGY
Mitosis Lab
Mitosis & Meiosis
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Purpose
Students will observe the events of mitosis in plant and animal
cells and will describe the similarities and differences in the
process in the two types of cells. They will calculate the
relative duration of the cell cycle stages.
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Materials
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Preserved slides of an onion root tip
Preserved slides of whitefish blastula
Compound Microscope
Procedure A:
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Observing Mitosis in Plant and Animal Cells
Step 1 Obtain a microscope from the storage cabinet and place it
on your lab table.
Step 2 Obtain a preserved slide of an onion root tip and one of a
whitefish blastula.
Procedure A:
Observing Mitosis in Plant and Animal Cells
Step 3 Review your smartnotebook regarding the different phases
of mitosis. You may want to use the sketches and the pictures
below as a guide to help you identify the different stages.
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Procedure A:
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Observing Mitosis in Plant and Animal Cells
Step 4 Examine the onion root tip slide first under low power then
switch to high power to study individual cells. Using your Smart
Notebook and the pictures above, locate and sketch one cell in
each phase of mitosis. Label each drawing with the phase, the
type of organism (onion root tip or whitefish blastula), and the
magnification. Repeat this with the slide of the whitefish blastula.
Procedure B:
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Calculating Time for Cell Replication
Note: The length of the cell cycle for cells in actively dividing onion
root tips is approximately 24 hours. You will determine how many
cells are in each phase in your field of view. From this, you can infer
the percentage of time each cell spends in each phase. This part of
the lab is best done with a partner. One partner calls out the phases
the cells are in and the other partner records them.
Step 1 Observe every cell in one high-power field of view and
determine which phase of the cell cycle it is in. When you have
observed and recorded all the cells in one field of view, you should
switch places with your partner. Your partner will now observe cells
in a second field of view and call them out to you and you will record
them. You should count at least two full fields of view and at least
200 cells. If you have not counted at least 200 cells, count a third
field of view. Record your data in Table 1.
Procedure B:
Calculating Time for Cell Replication
Step 2 Calculate the percentage of cells in each phase and record
your results in Table 1. Let’s say that it takes, on average, 24 hours
(1,440 minutes) for onion root tip cells to complete the cell cycle.
Using this information, you can calculate the amount of time spent in
each phase of the cell cycle from the percentage of cells in each
phase. % of cells in stage x 1,440 minutes = minutes of cell cycle
spent in stage.
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Data
Field 1
Field 2
Field 3
# of Cells
# of Cells
# of Cells
Percent of
Total
Time in
Total Cells
Each Stage
# of Cells Counted
Interphase
Prophase
Prometaph
ase
Metaphase
Anaphase
Telophase
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Mitosis Lab Analysis
Grade: «grade»
Subject:«subject»
Date: «date»
1 Describe the main events that occur in each phase of mitosis.
Students type their answers here
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2 What is happening in the cell during interphase?
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Students type their answers here
3 How does mitosis differ in plant and animal cells?
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Students type their answers here
4 Based on your data in Table 1, what can you infer about the
relative length of time an onion root tip cell spends in each stage of
cell division?
Students type their answers here
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