Lab 9: Mitosis
Student Name:
Course ID/Section: Date:
Answer the questions and report your data in this fillable PDF using the observations and results
you recorded in your lab manual while performing the experiments. Save the completed PDF file
with your last name and lab number and submit the report as directed by your instructor. (For
example: jones_lab9.pdf)
Consider the Concepts
1. Cell division in prokaryotes is a fairly simple process that occurs rapidly. Describe two reasons
that cell division in eukaryotes is more complicated.
Part 1: Interphase
2. Complete the following table with the data you collected during the lab activity counting interphase
and mitosis cells in the onion root tip microscope image.
# of cells in interphase
# of cells in mitosis
total # of cells counted
percentage of time cells spend in interphase
hours per day cells spend in interphase
3. If you looked at a region of cells in the body of the onion rather than in the onion's root tip, how
would your results differ?
Part 2: Identifying Phases of the Cell Cycle
4. Looking at the onion root tip and whitefish blastula cells, describe one or more distinguishing
visible features at each stage of mitosis.
6. Consider the appearance of the chromosomes and cell structures in the microscope images
containing cells in metaphase. Describe two visible differences between the appearance of
metaphase in onion root tip cells and whitefish blastula cells.
5. Consider the visible appearance of each cell you sorted into distinct mitotic phases. Because
mitosis is a continuous process, many cells are photographed as they transition between the
"phases." Did you encounter any cells that appeared to be in transition between phases? If so,
describe the physical appearance of the cell and the identify the transition in progress.
Part 3: Cell Cycle Regulation and Cancer
7. What is melanoma? How can excessive exposure to sunlight create abnormalities within a cell
that can cause melanoma?
8. The risk for developing melanoma increases with excessive exposure to sunlight, an
environmental carcinogen. Describe a different carcinogen and list one or more cancer types
linked to its exposure.
9. What is “mitotic rate” and how is it used to determine prognosis (chance of recovery)?
10. What are “mitotic inhibitors” and how do they stop the spread of cancerous cells?
11. How does radiation therapy stop the spread of cancerous cells?
© 2012 Dallas County Community College District