Biology
Cell Growth and Cycle Virtual Lab:
The Cell Cycle and Cancer
Name: ________________________________
Period: ___________
Date: _____________
Introduction
How is a normal cell transformed into a cancerous cell? The proteins involved in regulating cell division events
no longer appropriately drive progression from one cell cycle stage to the next. Rather than lacking function,
cancer cells reproduce at a rate far beyond the normally tightly regulated boundaries of the cell cycle. Cancer
can be distinguished from many other human diseases because its root cause is not a lack of, or reduction in,
cell function. For example, individuals with diabetes may lack insulin production or the ability to respond to
insulin. With coronary heart disease, poor blood supply to the heart can cause the organ to eventually fail. In
the case of acquired immune deficiency syndrome (AIDS), the immune system loses the cells it needs to fend
off infection. And with many infectious diseases, foreign microorganisms wreak havoc on the host they have
invaded, causing a loss of function within cells, tissues or entire organ systems. Cancers, however, occur due to
an alteration of a normal biological process — cell division.
Cells that progress through the cell cycle unchecked may eventually form malignant tumors, where masses of
cells grow and divide uncontrollably, then develop the ability to spread and migrate throughout the body.
Fortunately, cancer prevention usually occurs through the strict regulation of the cell cycle by groups of
proteins that interact with each other in a very specific sequence of events. It is these events that determine
whether the cell cycle will go forward or remain stalled between stages.
Purpose: The purpose of this virtual lab it to apply our previous knowledge of the cell cycle and use calculate
percentages to determine if cell growth will lead to cancerous cells.
Learning Target: Students will compare and contrast the asexual cell cycles of healthy and cancerous cells
found in the lungs, stomach, and ovaries.
Instructions
1. Go to the following web page,
http://www.mhhe.com/biosci/genbio/virtual_labs_2K8/pages/CellCycle_and_Cancer.html and click on
“Laboratory Exercise” to Open the virtual lab: The Cell Cycle and Cancer
2. The lab simulation will be on the right side of the screen, and the “Question” column will be on the left
side.
3. Read all of the background information and instructions in the “Question” column.
4. Click the “Information” button in the bottom right corner of the lab simulation. Read all of the
background information.
5. Watch the video on Mitosis by clicking on the monitor in the lab simulation.
6. Click on the microscope in the lab simulation to examine the different stages of mitosis as they appear
in different tissue samples. Three types of tissue are available for examination: lung, stomach, and
ovary. Samples of normal tissue and cancerous tissue are included. Examine both normal and
cancerous tissue for each tissue type. Follow the instructions to label each stage of the cell cycle, and
then check your answers by clicking “check”. Record the number of cells in each stage of the cell cycle
in the Data Table. You must examine two different views of each tissue type and condition – click
reset to view alternate samples of each tissue type until you have recorded the number of cells in each
stage of the cell cycle for 2 different samples of each tissue.
7. Calculate the average Mitotic Index (% cells dividing) and average % cells at rest for normal tissues.
Record these numbers in the Data Table.
To calculate the average % cells at rest in normal tissue:
1. (#cells in Interphase in Sample 1 + #cells in Interphase in sample 2)/2 = avg. # cells at rest.
2. (avg. # cells at rest/total #cells) X 100 = average % cells at rest
To calculate the Mitotic Index - average % cells dividing - in normal tissue:
1. (#cells in mitosis in Sample 1 + #cells in mitosis in Sample 2)/2 = avg. #cells dividing
2. (avg. # cells dividing/total # cells) X 100 = average % cells dividing
8.
Do the same calculations for cancerous tissue to complete the Data Table on the worksheet.
9. Answer questions the Quick Review Questions.
Quick Review Questions
1. In which phase of mitosis do each of the following occur:
a. Centromeres split and chromosomes move toward opposite sides of the cell. ______________
b. Chromatin coils to form visible chromosomes. ______________________________
c. The nuclear membrane disappears. ________________________________
d. Sister chromatids line up in the center of the cell. _________________________
2. In which phases of mitosis are sister chromatids visible, and attached to each other at the centromere?
Table 1: Record your data for the number of cells in each stage of the cell cycle observed in normal tissues.
Tissue Type
# Cells in
# Cells in
# Cells in
# Cells in
# Cells in
Interphase
Prophase
Metaphase
Anaphase
Telophase
Lung Tissue
Sample 1
Lung Tissue
Sample 2
Stomach Tissue
Sample 1
Stomach Tissue
Sample 2
Ovarian Tissue
Sample 1
Ovarian Tissue
Sample 2
Table 2: Record your data for the number of cells in each stage of the cell cycle observed in cancerous
tissues.
Tissue Type
# Cells in
# Cells in
# Cells in
# Cells in
# Cells in
Interphase
Prophase
Metaphase
Anaphase
Telophase
Lung Tissue
Sample 1
Lung Tissue
Sample 2
Stomach Tissue
Sample 1
Stomach Tissue
Sample 2
Ovarian Tissue
Sample 1
Ovarian Tissue
Sample 2
Table 3: Use the data in Table 1 to calculate the Mitotic Index (average % cells dividing) for each normal
tissue type.
Tissue Type
Lung - normal
Avg. % cells at rest
Mitotic Index
Stomach - normal
Ovary - normal
Table 4: Use the data in Table 2 to calculate the average % cells dividing and average % cells at rest in each
cancerous tissue type.
Tissue Type
Lung - cancerous
Avg. % cells at rest
Mitotic Index
Stomach - cancerous
Ovary - cancerous
Conclusion Questions: Answer the questions below on notebook paper.
3. What does your data indicate about the rate of cell division in cancerous tissue compared to the rate
of cell division in normal tissue? What data did you use to answer this question?
4. Which type of cancer is the fastest growing? Explain your answer, using your relevant data.
5. With what you have observed in this lab, if you were to compare tissue sample from normal breast
tissue and cancerous breast tissue:
a. Would you expect to see a difference in the rate of cell division in the cancerous breast tissue
compared to the normal breast tissue? Explain your answer.
b. Could you make a prediction about the average % dividing cells in the cancerous breast tissue?
Explain your answer.
6. Consider the % dividing cells in normal lung, normal stomach, and normal ovarian tissue. Why do you
think there are more cells dividing in the stomach and ovary tissue than in the lung tissue?
7. This lab explores three common cancers. An additional form of cancer – Skin Cancer – used to be seen
only in older individuals but is now seen in younger individuals, many in their early 20s. Skin cancer
results from accumulated mutations to the DNA of skin cells, caused primarily by sun exposure. What
factors do you think may be contributing to the increase in skin cancer among young adults?