Name ______________________
LAPTOP ACTIVITY: ONION ROOT TIP MITOSIS
www.msrayspace.wikispaces.com
Go to “Useful Websites” and click on “Onion Root Tip – Mitosis”
Growth in an organism is carefully controlled by regulating the cell cycle. In plants, the roots continue to grow as they
search for water and nutrients. In order to examine cells in the tip of an onion root, a thin slice of the root is placed
onto a microscope slide and stained so the chromosomes will be visible. The cells you'll be looking at in this activity
were photographed with a light microscope and then digitized so you can see them on the computer. Although slicing
the onion root captures many cells in different phases of the cell cycle, keep in mind that the cell cycle is a
continuous process. Scientists have divided the process of cell division into three parts: Interphase, Mitosis, and
Cytokinesis. Mitosis is the divided into four phases; Prophase, Metaphase, Anaphase, and Telophase.
Briefly describe each below:
1. Interphase: _________________________________________________________________
2. Mitosis- Prophase: ____________________________________________________________
3. Mitosis- Metaphase: ___________________________________________________________
4. Mitosis- Anaphase: ____________________________________________________________
5. Mitosis- Telophase: ___________________________________________________________
6. Cytokinesis: _________________________________________________________________
Go to
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
the Onion Root Tip website
Look at the image of the onion root cell. Which phase of the cell cycle do you think the cell is in?
Click on the phase you think the cell is in. If you are wrong, guess again. Use the clues provided!
After you have categorized all the cells, fill in the chart below.
Interphase
Mitosis:
Prophase
Mitosis:
Metaphase
Mitosis:
Anaphase
Mitosis:
Telophase
Total
Number of
Cells:
Number of
Cells
Now, calculate the percent (%) of root tip cells in each phase and fill in the chart. Show your work below.
Use the following equation Number of Cells x 100 = ___%
36
Interphase
Mitosis: Prophase
x 100 = ___%
36
x 100 = ___%
36
Mitosis: Anaphase
x 100 = ___%
36
x 100 = ___%
36
Mitosis: Telophase
x 100 = ___%
36
Mitosis: Metaphase
Onion cells have a 24hr cycle. The percentage you calculated also represents the amount of time onion cells
spend in each phase of the cell cycle.
Make a pie chart showing the amount of time onion root tip cells spend in each. Calculate the number of
hours that an onion root tip goes through each part of the cell cycle. Use the percentage from the front
page to carefully estimate how much space each phase should occupy on the pie chart.
Use color pencils to color in each section of the chart. Fill in the key to the right to show which phase is
indicated by each color.
Fill in the Figure 1. box below by creating a caption for your chart.
Key:
Interphase
Mitosis: Prophase
Mitosis: Metaphase
Mitosis: Anaphase
Mitosis: Telophase
Figure 1:
Question:
What does the data and the chart show about the cell cycle?
(Hint: Which cell cycle lasts the longest? How can you tell?)
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