Online Onion Root Lab
Objectives:
 Examine cells in the various stages of the cell cycle
 Identify which stage of the cell cycle certain cells are in
 Draw cells in each stage of the cell cycle
 Calculate percentage of time spent in each stage of the cell cycle
 Differentiate between mitosis in plant and animal cells
Procedure:
A. Go to the website, www.biology.arizona.edu
B. On the left of the screen click on “Onion Root Tips”
C. Read through the information and answer the following questions before
you classify any of the cells
1. Why are onion root tip cells ideal for studying the cell cycle?
2. How are onion cells prepared in order to view them?
3. What happens during interphase?
4. What is the main event that occurs during metaphase?
5. What is the main event that occurs during telophase?
D. Continue to click next. Eventually a picture of an onion cell will appear. You need to click on the phase that
you think the cell is in. You will be told if you are correct. If you are incorrect a clue will be given to help
you determine the right answer. Do this for all 36 cells.
E. After classifying all 36 cells according to the phase they are in, transfer the data onto the table below.
Calculate the percentages for how long each cell spends in each phase using 36 as your sample size.
Interphase
Prophase
Metaphase
Anaphase
Telophase
Total
number of cells
36
percent of cells
100%
ACTIVITY 2
Procedure:
A. Go to the website, http://bio.rutgers.edu/~gb101/virtuallabs_101.html
B. Choose Lab 2: Cell Reproduction. Read the introduction on the left and answer the following questions.
1. What type of onion is being used in this activity?
2. Explain the difference between mitosis and cytokinesis
3. Besides the reasons you already listed above, name another reason onion root tips are a good choice to
study.
C. After answering the questions click on “click to begin”. On the left, choose Part 3 and again “click to
begin”.
D. Click where it says “root tip” and use the following directions
 Click on the image to magnify the root tip.
 Use the scroll bars to move around the root tip.
 Identify at least one cell in each of the stages of division summarized in the review.
 Place the cursor over a dividing cell and click once. Identify the stage of division.
 When you have identified at least one cell in each stage, proceed to the next section.
E. When finished click on “Mitosis in an animal cell” under Part 4 and then “click here to begin.
4. What type of animal is being used to study mitosis in animal cells?
F. Sketch each phase at least once. You only need to draw in 5 boxes!!! Different students will be drawing in
different boxes. You still need to identify the phase for every box and write the name of each phase in every
box.
5. Describe two differences you noticed between mitosis in animal cells and mitosis in plant cells.
6. Which stage or stages were the hardest to identify? Explain.
7. Which stage or stages were the easiest to identify? Explain.
Taken from* hempfieldarea.k12.pa.us/.../Cell Reprod/Online Onion Root Lab.d