Virtual Lab: The Cell Cycle and Cancer

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 anaphase
b. Chromatin coils to form visible chromosomes prophase
c. The nuclear membrane disappears prophase
d. Sister chromatids line up in the center of the cell metaphase

2. In which phases of mitosis are sister chromatids visible, and attached to each other at the centromere?

Prophase and metaphase

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? The mitotic index shows that the rate of cell division has incresed in cancerous cells.

4. Which type of cancer is the fastest growing? Explain your answer, using your relevant data. The fastest growing cancer is ovarian cancer. It has the highest Mitiotic index.

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. Yes, cancerous tissue has a higher mitotic index than non cancerous tissue.

b. Could you make a prediction about the average % dividing cells in the cancerous breast tissue? Explain your answer. Based on the other tissue samples I would estimate a mitiotic index between 23 and 40.

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?

The stomach has a high turn over of cells due to food, acid, and churning in the stomach. Ovarian cells are constantly reproducing as part of the menstrual cycle.

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?

The increased rates could be due to exposure to an increased amount of carcinogens like UV Rays and toxins in the environment.