Download Worksheet

Name: ________________________________
Biology, Mr. Lo
Period: _______
Date: _____________
Mitosis Lab
Purpose
1. Locate cells in prepared onion root slides that are in the process of mitosis.
2. Using your class diagrams, identify and draw cells that are indifferent stages of mitosis.
Materials: microscope, prepared slides of onion root tip
Procedure and Questions
1. Under low power, locate with a microscope the region of rapidly dividing cells on the prepared slide of
onion root tip as shown in the picture below. After locating the cells, switch to high power.
2. Locate cells that appear to be in various stages of mitosis. Use the figure below as a guide of what you
should see.
3. Using the figure below, label one clear example of each stage of mitosis: interphase, prophase,
metaphase, anaphase, and telophase/cytokinesis.
1
Name: ________________________________
Period: _______
Date: _____________
Biology, Mr. Lo
4. Each microscope has been setup so that you can see as many stages of mitosis in one view. Using a
pencil, draw 4 cells undergoing different stages of mitosis. Next, write the stage of mitosis the cell is
going through as well as a short description explaining your answer.
Stage: _______________________________
Stage: _______________________________
Stage: _______________________________
Stage: _______________________________
2
Name: ________________________________
Biology, Mr. Lo
Period: _______
Date: _____________
Post-Lab Questions
1. Why do you think we look at the onion root cell for examples of cells going through the different stages
of mitosis?
2. Why does a cell undergo mitosis?
3. When a cell is in interphase…
a. Is the DNA in the form of chromatin or chromosomes?
b. Is the nuclear membrane present?
c. In what sub-stage is the DNA replicated?
4. At the end of prophase…
a. Is the DNA in the form of chromatin or chromosomes?
b. Is the nuclear membrane present?
5. At the end of metaphase…
a. Where is the DNA located in the cell?
b. What brought the DNA to this location?
c. Where do these objects attach to the DNA?
6. When a cell is in anaphase…
a. What happens to the DNA?
7. At the end of telophase…
a. Is the nuclear membrane present?
b. Is the DNA in the form of chromatin or chromosomes?
8. When a cell finished cytokinesis…
a. Is the nuclear membrane present?
b. Is the DNA in the form of chromatin or chromosomes?
c. How many cells are present?
3
Name: ________________________________
Biology, Mr. Lo
Period: _______
Date: _____________
Cell Cycle Activity
In this online activity, you will look at 36 pictures of actual onion root cells in various stages of the cell cycle.
You and a partner will classify each cell based on its stage of mitosis. Based on the number of cells found in
each phase, you can approximate the amount of time cells spends in each stage.
Procedure
1. Go to http://www.biology.arizona.edu/cell_bio/activities/cell_cycle/cell_cycle.html.
2. Click on “Next” and review the information and provided diagrams.
3. Click on “Next” through the next two sections.
4. Identify the stages of mitosis for each cell.
5. Count the number of cells in each stage of mitosis and complete the following chart.
Interphase
Prophase
Metaphase
Anaphase
Telophase
Total
# of Cells
36
% of Cells
100%
Amount of
Time in
Each Stage
24 hours
6. To calculate the percentage of cells in each stage, divide the # of cells in each stage by 36 and multiply
by 100%. Your answer should be accurate to 1 decimal place.
% of Cells 
# of cells
5
X 100% 
X 100%  13.9%
Total # of cells
36
7. To calculate the amount of time spent in each stage…
a. Convert the % of cells into a decimal (13.9% = .139).
b. Multiply this percentage by 24. This will give you the amount of hours spent in each stage.
Answers should be accurate to 1 decimal place.
.139 X 24 hours  3.3 hours
Post-Lab Questions
1. In which stage do cells spend the…
a. longest amount of time?
b. least amount of time?
2. Explain these differences.
4