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Observing Mitosis Lab – Part 1: Plant Cells
Background:
In a growing plant root, the cells at the tip of the root are constantly dividing to allow the root to grow. Because each
cell divides independently of the others, a root tip contains cells at different stages of the cell cycle. This makes a root
tip an excellent tissue to study the stages of cell division.
Materials:
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Microscope
Prepared slides of onion (Allium) root tips
Procedure:
1. Get a microscope and bring it to your lab bench. Make sure that the low power objective is in
position.
2. Obtain a prepared slide of an onion root tip (there will likely be more than one root tip on a slide).
Hold the slide up to the light to see the pointed ends of the root sections. This is the root tip, where
the cells were actively dividing. (The root tips were freshly sliced into thin sections, then preserved
when the slide was prepared).
3. Place the slide on the microscope stage with the root tips pointing away from you. Using the low
power objective to find a root tip, and focus it with the coarse adjustment knob until it is clearly
visible. Just above the root “cap” is a region that contains many new small cells. The larger cells of
this region were in the process of dividing when the slide was made. These are the cells that you will
be observing. Focus and centre the image then switch to medium power. Focus and centre the image
and then switch to high power.
4. Observe the box-like cells that are arranged in rows. The chromosomes of the cells have been stained
to make them easily visible. Select one cell whose chromosomes are clearly visible. (If you need to
change the focus when using the high power objective, remember to only use the fine adjustment
knob).
5. Look for cells in each of the phases: interphase, prophase, metaphase, anaphase, and telophase. Draw
a labelled sketch of each of these cells (not a scientific diagram).
6. Draw a proper scientific diagram of a cell in prophase, and a cell in anaphase.
7. Make up a data table to record the number of cells that you see in each of the stages of mitosis. The
easiest way to do this is for you to look through the microscope, going along each row of cells. For
each cell indicate on a scrap piece of paper what stage the cell appears to be in. Tally the marks when
you are finished and record the totals in your data table.
Observing Mitosis Lab – Part 1: Plant Cells
1. Labelled sketches of each phase (not Biological diagrams):
Interphase
Prophase
Anaphase
Biological diagram of Prophase:
Biological diagram of Anaphase:
Metaphase
Telophase
Analysis and Conclusions:
1. Data table:
2. What stage were the majority of cells in?
3. What percentage of the cells were in each stage?
Interphase
Prohase
Metaphase
Anaphase
Telophase
4. The onion plant began as a single cell with 16 chromosomes. How many chromosomes are in each
cell that you observed? How do you know?
Observing Mitosis Lab – Part 2: Animal Cells
Instructions:
1. Obtain a microslide viewer booklet on animal mitosis.
2. Answer the questions using the information found in the booklet and by observing the slides of
mitosis through the microslide viewer.
3. Answers do NOT need to be in proper sentence format.
Introduction Questions:
1. What type of organism is an Ascaris?
2. How many chromosomes does Ascaris have?
3. Where is the equatorial plate?
Slide #1 The Zygote:
4. What is a zygote?
5. Where did the 2 masses of chromatin come from?
Slide #2 Pro-metaphase:
6. How many chromosomes came from each parent to form the zygote?
Slide #3 Metaphase:
7. What observation confirms that this stage is metaphase?
8. Describe how the centrioles appear.
9. Draw a Biological diagram of this slide (Label the structures identified in the booklet):
10. Describe what is happening during this stage of mitosis.
Slide #5 Early Anaphase:
11. How many chromosomes are there in total?
12. How many chromosomes will there be in each new cell?
Slide #7 Telophase:
13. Draw a Biological diagram of this slide (Label only what you can see!)
Slide #8 Late Telophase:
14. How many cells are present in this final stage?
15. How many chromosomes are present in each cell?
16. How many chromosomes in a human cell?
Analysis and Conclusions:
1. After observing both plant and animal cells during cell division, describe the differences you
observed between plant and animal cell mitosis.
2. Which phases of mitosis were the most difficult to distinguish between? Why?