Practical 5: Observing stages of mitosis Flashcards

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1
Q

Observing stages of mitosis

A
  1. Cut a 5mm sample of the root tip using a scalpel.
  2. Transfer root tip to sample tubes containing HCl and leave for 5 minutes.
  3. Transfer to watch glass containing cold distilled water. Leave for 5 minutes.
  4. Dry root tips on filter paper.
  5. Place tip on a microscope slide. Macerate with a needle to spread the cells out.
    This makes the chromosomes visible and will therefore show which cells are
    undergoing mitosis.
  6. Add a drop of toluidine blue to the slide and leave to stain for 2 minutes.
  7. Lower the cover slip down carefully onto the slide. Make sure there are no air
    bubbles in the slide which may distort the image, and that the coverslip doesn’t
    slide sideways which could damage the chromosomes.
  8. Wrap in a paper towel and gently ‘squash’ the slide.
  9. Place under a microscope and set the objective lens on the lowest
    magnification, then use the coarse adjustment knob to move the lens down to
    just above the slide.
    10.Use the fine adjustment knob to carefully re-adjust the focus until the image is
    clear (can use a higher magnification if needed).
    11.To calculate mitotic index, cells undergoing mitosis must be counted (cells
    with chromosomes visible), as well as the total number of cells.

risks- broken glass, hydrochloric acid

variables-
control = size of root tips
independent = N/A
dependent = N/A

plot data by drawing an image observed

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