Cell cycle control
Bio1400 Chapter 10 Openstax Biology
1. Draw a simple diagram of the cell cycle and place on it the three checkpoints
for cell cycle regulation. Indicate the function of each checkpoint.
2. Distinguish between karyokinesis and cytokinesis in cell division.
Positive Cell Cycle Regulation
3. Describe the association of cyclins and cyclin-dependent kinases (Cdks).
4. What evidence supports the claim that cyclins are involved with the three
checkpoints in regulating cell cycle?
5. Once again we see the action of a kinase (Cdks). What do kinases do?
6. What is the role of the Cdk inhibitors?
Negative Cell Cycle Regulation
7. Name the three regulatory molecules and explain the function of each.
8. Describe how the positive and negative controls differ.
9. Rb and other proteins that negatively regulate the cell cycle are sometimes
call tumor suppressors. Why do you think the name tumor suppressor might
be appropriate for these proteins?
Roles of Proto-oncogenes and Tumor Suppressor Genes
10. Human papillomavirus can cause cervical cancer. The virus encodes E6, a
protein that binds p53. Based on this fact and what you know about p53,
what effect do you think E6 binding has on p53 activity?
a. E6 activates p53
b. E6 inactivates p53
c. E6 mutates p53
d. E6 binding marks p53 for degradation
11. Describe what is meant by a tumor and metastasis.
12. Do you think plants get cancer? If they did, how might the cancer process in
plants differ from that of animals?
13. Normally we think a mutated gene produces a non-functional protein and
with this protein a biological process does not then occur. How is it then that
a mutated gene product can cause cancer which is active cell division?