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Onion Root Tip Mitosis Lab Name Date Section Onion Root Tip Mitosis Lab

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Onion Root Tip Mitosis Lab Name Date Section Onion Root Tip Mitosis Lab Powered By Docstoc
					Name:
Date:
Section:

Onion Root Tip Mitosis Lab

Objectives:
   - Students will be able to…
         o Work in small groups to prepare an onion root tip squash and view it
            under the microscope.
         o Identify the phases of mitosis under the microscope
         o Identify the stage of mitosis that requires the most time
         o Apply knowledge of Mitosis by identifying mitosis stages in a teacher
            prepared onion root tip slide.

Hypothesis:
 If
_________________________________________________________________________________________________
Then
_________________________________________________________________________________________________

Materials
Onions in water for 3 days
Stain
Slides
Cover Slips
Microscopes
Computer Access
Forceps (aka Tweezers)
HCl (Hydrochloric Acid)
Carnoy (mixture of vinegar and alcohol)
Toluidine Blue (Blue dye)
Water
Dropper for water
Paper Towel

Methods:
    1. Use tweezers to transfer an onion root tip into a cup of HCl.
       *This allows the cell wall to start to dissolve, so we can see inside the cell.
2. After 4 minutes, transfer the root into the Carnoy fluid for 4 minutes.
3. Place the root onto a slide.
4. Cover the root tip with one drop of Toluidine Blue (Blue dye) for 1 minute.
5. After 1 minute blot away the stain.
*Be extremely careful!!! Not to touch the root tip!! This will ruin your slide!!!
6. When the stain is blotted away carefully, cover the root tip with 1 to 2 drops of
water.
*You may need to repeat this process several times until your blue dye is gone.
7. Gently lower a cover slip over the root tip.
8. Cover the slide with a paper towel and firmly press on the cover slip. Do not
twist the cover slip at all. This will press the root into a single cellular level. Use a
pencil tip to press down on top of the paper towel to make sure you have as thin as a
layer as possible.
9. Observe your preparation under the low power of a microscope.
10. Search your slide and try to find various stages of mitosis occurring!

Example of Cells in each stage of Cell Division.
Results
Please include the following questions and drawings with your lab writeup.

Questions:
   1. When viewing your group slide under the microscope were you able to see
      individual cells?
   2. Were you able to see/identify various stages of mitosis? If so, which ones and
      how many of each?
   3. What is a distinguishing visible feature of each stage of mitosis?

Prophase:

Metaphase:

Anaphase:

Telophase:




 Interphase    Prophase      Metaphase     Anaphase      Telophase     Cytokinesis
 # of cells    # of cells    # of cells    # of cells    # of cells    # of cells


Drawings      Drawings       Drawings       Drawings       Drawings       Drawings
Online Lab Results

http://www.biology.arizona.edu/cell_bio/activities/cell_cycle/cel
l_cycle.html

Interphas    Prophase     Metaphase     Anaphase     Telophase   Cytokinesi
e            #_______     #________     #________    #________   s
#________    _            _             _            _           #_________
%________    %_______     %________     %________    %________   _
             _            _             _            _           %_________
                                                                 _
                        # of cells and quick sketch




   1. Based on your data, how many cells were in each phase?
      Interphase-_______
      Prophase-________
      Metaphase-_______
      Anaphase-_________
      Telophase-_________
      Cytokinesis-________

   2. What phase had the most cells?


   3. What phase had the least cells?
Discussion
*Don’t forget to answer all usual questions on your lab packet as well as the
following.

1. Why do you think that most of the cells were located in the phase that they
    were?
2. What happens in this phase that requires them to spend so much time there?
3. In comparing your own prepared slide with the online tutorial, did you have
similar results? If so, what do you think enabled you to receive these results?
If not, what do you think went wrong?

Works Cited
Carolina Biological Supply Company.
The Biology Project: The University of Arizona
Pictures from:

				
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posted:8/10/2011
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