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Online Onion Root Tips Activity at the University of Arizona's Biology Project.

  1. Read the first three pages of this web area on the Biology Project, Onion Root Tip Activity. The first two pages of this exercise explains mitosis and its stages.  Print page 3.  At the end of the exercise, you will fill out the chart on time spent in each stage.

  2. The actual exercise starts on page 4.   In the upper right corner of the screen, you will see a photomicrograph of an onion root cell in either interphase or one of the stages of mitosis.  Under the photo are the terms interphase, prophase, metaphase, anaphase, and telophase.  Look at the photo and determine which stage you think describes the cell. Click on that term.  If you are correct, the cell will be placed under the term, you will be informed that you are correct, and a new cell will appear for you to classify.  If you are not correct, you will be asked to try again.

  3. You will repeat this process for a total of 36 cells.  After you have completed classifying all the cells, print this cell classification sheet.  Now complete the chart on page three that you previously printed.  For example if, at the end of this exercise, you find that 9 of the 36 cells were in interphase, write 9 in the square for number of cells in interphase and 25% in the square for percent of cells. Hint - this is NOT correct

  Interphase Prophase Metaphase Anaphase Telophase  


number of cells
percent of cells


  1. Complete exercises II through IV of Lab 7 (pages Lab7-2 through Lab 7-5) in the .SG/LM. Fill out the answer sheets on pages Lab 7-6 through Lab 7-8 as you work the exercises.
  1. Mail or e-mail Lab 7

    cell classification sheet and the chart on time spent in each stage from the Onion Root Tip Activity.

    Answer sheets on pages Lab 7-6 to 7-8.

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Emma Erdahl, Associate Professor of Biology
Northern Virginia Community College
Last revised: 12/03/2002