Stages of Mitosis Lab
Introduction
Mitosis is division of the nucleus and its chromosomes. It is followed by division of the
cytoplasm known as cytokinesis. Both mitosis and cytokinesis are parts of the life of a cell
called the Cell Cycle. Most of the life of a cell is spent in a non-dividing phase called
Interphase. Interphase includes G1 stage in which the newly divided cells grow in size, S
stage in which the numbers of chromosomes are doubled and appear as chromatin, and G2
stage where the cell makes the enzymes & other cellular materials needed for mitosis.
Mitosis has 4 major stages --- Prophase, Metaphase, Anaphase, and Telophase. When a living
organism needs new cells to repair damage, grow, or just maintain its condition, cells undergo
mitosis.
Problem Statement:
What percentage of time do cells spend dividing?
Materials:
Microscope, prepared slide onion root tip
Procedure:
1.
2.
3.
4.
Set up a compound light microscope and turn on the light.
Place a slide containing a stained preparation of the onion root tip.
Locate the growth zone, which is just above the root cap at the very end of the tip.
Focus in on low power, and then switch to medium or high power.
5. Now count the number of cells found in each stage of mitosis and place the data in the
chart below.
6. Determine the percentage of time each cell will spend in each stage of mitosis. Divide
the number of each cell by the total number of cells and multiply by 100 to determine
the percentage. Place these values in the chart below.
Percent of time in each stage =
Stage of Mitosis
Number of Cells
# of cells in stage
Total # of Cell
X 100%
Prophase
Metaphase
Anaphase
Telophase
Interphase
(Not a Mitotic Stage)
Total # cells
Time Spent in Cellular Phases
Percent of Time
70
60
50
Interphase
40
Prophase
30
Metaphase
20
Anaphase
Telophase
10
0
Interphase
Prophase
Metaphase
Anaphase
Telophase
Conclusion:
The amount of time a cell spends in different cell cycle stages was
investigated. As we identified the stages, we found that most of the
cells were in Interphase. About 30% of the time the cells were in
Prophase, 8% in Metaphase, 6% in Anaphase and 3% in Telophase.
This means that most of the time, the cells should not be dividing.
Telophase seems to be the shortest phase because we didn’t catch very
many of them in this stage. All the other groups also found most of
their cells in Interphase. Cells divide to grow, repair and replace so
you should NOT find them dividing all the time, only SOME of the
time. An improvement to this lab would be to use different type of cell
samples. Learning about cell division is important because…….
Questions to help you with #3 on your template:
1. Of the four stages of mitosis, which one takes the most time to complete?
2. Which is the shortest stage in duration?
3. What would happen if the process of mitosis skipped metaphase? telophase?