Cell Growth and Division Inquiry Lab
Introduction: We have been learning about cellular reproduction and cell division in class. Through this
investigation, you will compare and contrast these processes in plant and animal cells. Beginning with
Part I, you will observe the different stages of mitosis and will sketch and describe your observations.
You will then analyze your observations by answering questions. In Part II you will investigate the time
required for each stage of mitosis. Predictions will guide your investigation and data will be collected to
support or reject your initial predictions. Finally, you will analyze your data collection and inquiry.
PART I
Purpose: To observe and identify cells undergoing the process of mitosis. You will compare the stages
of mitosis in plant and animal cells.
Materials: Microscopes, Whitefish cell longitudinal slide (animal), Plant cell longitudinal slide
(Allium/onion)
Procedure:
1. Observe a prepared slide of an onion root tip. Use low power to locate the region of actively
dividing cells near the end of the root. Using high power, examine individual cells in the region.
Find a cell from each stage of mitosis; using your notes, text, or lab manual as an aid.
a. Sketch and label the four phases of mitosis; prophase, metaphase, anaphase, and
telophase.
2. Observe a prepared slide of a whitefish cell. Use low power to locate the region of actively
dividing cells near the end of the root. Using high power, examine individual cells in the region.
Find a cell from each stage of mitosis; using your notes, text, or lab manual as an aid.
a. Describe any differences or similarities you observe between the two slides.
3. Clean up your area and complete the remainder of the lab questions.
Data: (Sketch and label the cells in each of the stages of mitosis for the plant cell). Identify the nucleus,
if present, chromosomes, and cell wall). Write a brief description of what is happening in each of the
cells.
Analysis: (Use complete sentences)
1. Describe differences you observed in the nuclei of the cells during cell division.
2. How does mitosis differ in plant cells and animal cells?
PART II
Purpose: Observe the stages of mitosis in onion root tip cells and determine the length of time it takes
for each phase.
Materials: Compound light microscope, onion root tip slide (l.s)
Procedure:







Predict:
o Which phase of mitosis will take the longest?
o Which phase will you see more of?
Using low power on microscope to bring your slide in focus
Sketch and label the 4 phases of mitosis
Choose a section of 50 cells located at the meristem
Identify the stages of mitosis for each of the cells and record it in your chart
Using the count for each of the phases determine the Relative Length of Each Phase
o Calculate the percentage of all cells found in each phase (write formula)
 Percentage = number of cells in phase X 100%
total number of cells in sample
o Use the percentage for each phase to calculate the duration (write the formula)
 Duration of phase (in minutes) = percentage X 80 minutes
100
Enter data in class chart
Data:
Phase of mitosis
Tally marks
Count
% of all cells
Time (min)
Prophase
Metaphase
Anaphase
Telophase
Analysis: (Use complete sentences)
1. Identify the color the chromosomes are stained.
2. Discuss how you were able to distinguish between early and late anaphase.
3. According to your data table, identify which phase of mitosis lasts the longest. Explain why this
phase might require more time than other phases of mitosis.
4. According to your data table, identify which phase takes the least amount of time?
5. Explain how your results and predictions compare with those of the entire class.
6. Usually, the total time is takes for a phase to complete is equal to the percentage of cells in that
phase. Explain why would this not be true for a small sample of cells?