Online Onion Root Tip Investigation
Objective: Determining the amount of time spent in different phases of the cell cycle.
In this activity you will be presented with cells from the tip on an onion root. You will classify each cell based
on what phase it is in. At the end you will count up the cells found in each phase and use those numbers to
predict how much time a diving cell spends in each phase.
Materials:
Phone
Pencil
Ruler
Procedure:
1. Open a new Internet page and enter the website for the Onion Root Tip Lab. The website is:
www.biology.arizona.edu/cell_bio/activities/cell_cycle/cell_cycle.html
2. Read the two introductory pages of the onion root tip. Click on next.
3. Follow the directions online to complete the assignment. Use the table in your results section to
record the total number of cells in each column. (There should be 36 total cells. Each time you guess a
phase correctly, you will receive a picture of a new cell.) Calculate the row in your table for %.
4. Click on the cell biology tab. Select cell cycle and mitosis. Click on test yourself. Answer the
following questions provided: 1, 3, 4, 6, 7, 8, & 11. Answer the two additional analysis questions below.
5. Turn this paper in for a lab grade.
Results:
Number of Cells in Each Phase of the Cell Cycle
Interphase
Prophase
Metaphase Anaphase Telophase
# of Cells
% of
Cells
Total
36
100%
Online Questions:
1.
3.
4.
6.
7.
8.
11.
Analysis Questions (1&2): Answer in complete sentences!!!
1. According to your calculations, what phase does the cell stay the longest in? Why would you think that
to be true?
2. How much TOTAL time does the cell spend in the 4 phases of mitosis? Is it more or less time than the
cell spends in interphase? Why might this be true?