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Moore, Timothy
Moore, Timothy
Instructor: Mrs. Tammy Moore
Class: VHSG Online Biology
16 December, 2008
MITOSIS RATE
Mitosis of Onion Root Tip
Computing the Average Time Spent in Each Phase of Cell Division
Abstract
By examining the number of cells in each mitotic phase, I computed the average amount of time that
onion root tip cells spend in the phases during cell division.
Introduction
The root tip cells undergo the most rapid cell division of a plant's anatomy during most of its
life span. These cells are easy to observe under a microscope with the stages of cell division easy to
identify from observing the structures of the cell. The number of cells in each stage will be counted and
the results will be used to compute the number of minutes in a day that the cells are in each stage.
Methods and Observations
Materials

Prepared slide of Allium (onion) root tip - or make your own from a thin slice of onion root tip
or use the image at the link listed in the preparing the slide section

Prepared slide of Whitefish blastula

microscope

Slides

Stain
Moore, Timothy
PREPARING THE SLIDE:
[Use this section if you prepared your own slide] The onion root tip was sliced into a very thin
section and stained to make the nucleus visible. This slide was then placed onto the microscope stage.
OBSERVING THE CELLS:
I observed the cells under low power. As I found cells in stages of mitosis, I switched to high
power so that I could observe and draw them. The onion cells in telophase looked different than the
ones in the blastula because plant cells do not constrict or pinch off to separate the two cells. Instead, a
new cell wall is built between them. I counted the number of cells that I could see in each phase so that
I could analyze approximately how much time the cells were in each phase by comparing the
percentages of each stage that I saw.
DATA
[Include images of your cells by either including sketches, photographs, or use the image at
http://www.biology.ualberta.ca/facilities/microscopy/uploads/gallery/Leica_DMRXA/15c_Onion_root_
tip2_63x.jpg. If you use the web image, please note its use and include a citation in the bibliography
section at the end of your report. Include the data of how many cells you saw in each phase.]
CONCLUSION
[Enter your conclusion here about how much time you can estimate the cells are in each phase
as a percent of the total.]
Moore, Timothy
IDENTIFYING AND RECORDING CELL STAGES:
The cells were carefully observed for indications of what stage of cell division it was in. The
chart below was used to count the number of cells in each stage and the was number added to the 'Cell
Count' column.
PHASE
CELL
PERCENT
AMOUNT
Moore, Timothy
COUNT
OF
TIME
Interphase
Prophase
Metaphase
Anaphase
Telophase
Total
100
1440 minutes
I
COMPUTING THE AMOUNT OF TIME IN EACH PHASE:
Next, I computed what percent of the total number of cells where in each phase by adding up
the Cell Count colum and recording the total at the bottom of the column. I divided the number of cells
in each phase by that total to get the percent of cells. That number was added to the 'Percent' column
for each cell stage. That percent was used to compute the percentage of the 1440 minutes that it takes
for an onion cell to complete one full cycle of cell division that it spent in that phase.
Conclusion
Onion cells spend most of the time in the cell division cycle in the [enter which phase your data
supports here] phase. It spends the least amount of time in the [enter which phase your data supports
here]. Other phase take [enter data here].