Cell Cycle
An Internet Activity
Purpose: In this activity, you will be presented with cells from the tip of an onion root. You will
classify each cell based on what phase it is in.
Procedure:
1. Open Google Chrome. Go to http://www.biology.arizona.edu.
2. Click on the “Cell Biology” link about halfway down the page.
3. Under the “Activities” section in the upper left corner, click on the “On-line Onion Root Tips.”
4. Read the information and watch the animation. Answer the pre-lab questions on the
worksheet. When finished, click “Next” at the bottom.
5. Scan the information about the 5 phases of the cell cycle. For this activity, Interphase will not be
broken down and Cytokinesis will not be considered. Answer the pre-lab questions on the
worksheet. When finished, click “Next.”
6. The table on the next page is the same as the table on the left page of your notebook. Click
“Next.”
7. A cell will be presented to you. As a group, determine which phase you believe this is in. Click
that phase. If you are correct, it will put that cell in the table. If you are not correct, it will
describe the cell to you and tell you why you are wrong. Try again.
8. When you have classified all of the cells, count how many cells are in each phase of the table and
put that number in your table on the left. They should equal 36 total cells.
9. Calculate the percentage of each phase by using the following formula:
Number of Cells
X 100
Total Number of Cells
10. Show your work in the calculations section.
11. Choose one cell from each column and draw it exactly as you see it in the space in the table.
12. Log out and close the computer unless the charge is less than 50%. If the charge is less than
50%, please show it to the instructor.
13. Answer the post-lab questions.
Cell Cycle- Internet Activity Analysis
Pre-Lab Background Information:
a. Why are roots good for studying the cell cycle? _______________________________________________
_______________________________________________________________________________________
b. Although the root captures many cells in different phases of the cell cycle, what must we keep in mind?
_______________________________________________________________________________________
_______________________________________________________________________________________
c. Next to each major event write phase of mitosis in which it occurs. Answers are used more than once.
 ___________________ Spindle fibers align the chromosomes along the middle of the cell nucleus
 ___________________ The DNA duplicates to prepare for mitosis
 ___________________ Cytokinesis may begin during this stage
 ___________________ Chromatin in the nucleus begins to condense
 ___________________ New membranes form around the daughter nuclei
 ___________________ Chromosomes are not clearly discerned in the nucleus
 ___________________ The paired chromosomes separate at the kinetochores and move to opposite
sides of the cell
 ___________________ The nuclear membrane dissolves
 ___________________ The chromosomes disperse and are no longer visible under the light
microscope
Data Table:
Interphase
Number of
Cells
% of Cells
Prophase
Metaphase
Anaphase
Telophase
Total
36
100%
Drawing
Calculations:
Questions:
1) Which phase of the cell cycle did the cell spend the most time in? Why?
______________________________________________________________________________
______________________________________________________________________________
2) Describe what is happening in each phase in your table. ________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________