Has anyone seen/done this lab before??
Lab 2 Worksheet: The Cell Cycle and Cancer
Student instructions: Follow the step-by-step instructions for this exercise found on the worksheet below and in the virtual lab and record your answers in the spaces below. Submit this completed document by the assignment due date found in the Syllabus.
Please make sure that your answers are typed in RED.
Please type your Name and Student ID Number here:
Directions
1. Open the virtual lab titled “The Cell Cycle and Cancer”.
2. Click on the monitor to watch the video on the cell cycle.
Video Script
The cell cycle is a complex series of continuous events consisting of Interphase and mitosis. During Interphase, the nucleus and the darker stained nucleolus can be clearly seen. The DNA is copied. The chromosomes can not yet be seen because they are still in the form of uncoiled chromatin. In animal cells the centrioles duplicate themselves.
In prophase the chromatin coils to form visible chromosomes. The nuclear envelope and nucleolus disappear and a spindle forms between the pairs of centrioles, which have moved to opposite ends of the cell.
In metaphase, the chromosomes move to the equator of the spindle. With each chromotid attached to a separate spindle fiber by its centromere.
During anaphase, the centromeres split and the sister chromatids are pulled apart to opposite poles of the cell. Each chromatid is now a separate chromosome.
Telophase is the final phase of mitosis. In Telophase two daughter cells are formed with a complete set of chromosomes at each end of the cell. The cytoplasm divides the nucleolus and nuclear envelope reappear and the chromosomes begin to uncoil. When the new cells are separated they enter Interphase and a new cycle begins.
3. Next, click on the “Information” button to learn more about cancer.
4. If you come upon terms that are unfamiliar to you, please refer to your textbook for further explanation or search the word here:
http://encarta.msn.com/encnet/features/dictionary/dictionaryhome.aspx5. Click on the microscope to begin learning about the phases of mitosis; click on the picture of each phase of mitosis to study each phase separately.
6. Click and drag the labels to the corresponding cells under the microscope and then click “Check”.
7. Use Table 1 below to record the number of cells in each phase of mitosis in the tissue sample.
8. When you have counted all the cells in a particular sample, click the “Tissue Slides” box and select a new sample. You will choose from all six normal or cancerous tissues.
9. Once you have gone through each of the 6 slides and recorded your cell counts for each of the six tissues (three normal and three cancerous), click “Reset” to get the box of slides containing the second samples of each of those six tissues (three normal and three cancerous). Repeat steps 6-7 for the second set of slides.
10. Use the data collected from Tables 1 and 2 to calculate the Average Number of Cells at Rest and the Mitotic Indices for both normal and cancerous tissue types. Record your calculations in Tables 3 and 4, respectively, and use the following equation to calculate your percentages:
Average % of Cells at Rest = (# cells in Interphase from Tissue Sample 1 + # cells in Interphase from Tissue Sample 2) / (total # cells in Sample 1 + total number of cells in Sample 2)
X 100%
Mitotic Index = (# cells dividing in Tissue Sample 1 + # cells dividing in Tissue Sample 2) / (total # cells in Sample 1 + total number of cells in Sample 2)
X 100%
*Round percentages to the nearest WHOLE number.
11. Respond to the Lab Questions below.
Table 1: Record your data for the number of cells in each stage of the cell cycle observed in normal tissues.
Answers will vary depending on the slides the computer selects.
Tissue Type # Cells in Interphase # Cells in Prophase # Cells inMetaphase # Cells in Anaphase # Cells inTelophase
Lung TissueSample 1
Lung TissueSample 2
Stomach TissueSample 1
Stomach TissueSample 2
Ovarian TissueSample 1
Ovarian TissueSample 2
Table 2: Record your data for the number of cells in each stage of the cell cycle observed in cancerous tissues.
Answers will vary depending on the slides the computer selects.
Tissue Type # Cells in Interphase # Cells in Prophase # Cells inMetaphase # Cells in Anaphase # Cells inTelophase
Lung TissueSample 1
Lung TissueSample 2
Stomach TissueSample 1
Stomach TissueSample 2
Ovarian TissueSample 1
Ovarian TissueSample 2
Table 3: Use the data in Table 1 to calculate the Mitotic Index (Average % Cells Dividing) and Average % Cells at Rest for each normal tissue type.
Tissue Type Avg. % Cells at Rest Mitotic Index
Lung - normal
Stomach - normal
Ovary - normal
Table 4: Use the data in Table 2 to calculate the Mitotic Index (Average % Cells Dividing) and Average % Cells at Rest for each cancerous tissue type.
Tissue Type Avg. % Cells at Rest Mitotic Index
Lung - cancerous
Stomach - cancerous
Ovary - cancerous
Lab 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?
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?
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