Download Cell Division Discussion Sheet #2 for PPT #2

Cell Division PPT #2 Discussion Sheet – Regulation of Cell Division
1. In general, what conditions, situations and needs of the cell drive cell division?
2. Cell division is a controlled activity. There are two points where cell division is irreversible within
the cycle. Describe them and how they are controlled.
3. NAME the three checkpoints in the cycle and where they are located. Make a sketch to show
where.
4. Why is G1/S Checkpoint the most critical? What happens if the cell does not receive a signal
from this checkpoint to proceed with cell division?
5. How does a cell know when to divide?
6. There are generally two kinds of signals that give the ‘go-ahead’ and promote cell division and
growth. Describe them. How are they regulated or controlled?
7.
What are three specific types of controls?
8. The checkpoints – (see handout)
9. Because the factors that control cell division are so important, the genes that control these
activities are HIGHLY conserved. What does this mean?
10. Growth factors are external signals that help coordinate cell division. Describe their role in both
density-dependent inhibition and anchorage dependence.
11. Describe how proto-oncogenes and tumor suppressor genes can work as ‘growth factors’ to
create cancer in the body:
12. Because cancer is essentially uncontrolled cell division, describe the kind of controls that are lost
with a specific focus the gene p53.
13. In order for cancer to occur, approximately 6 key mutations must occur within the cell’s
genome. Describe them.
14. What are the causes of the ‘hits’ described in #13?
15. What are the two different kinds of tumors and what is the difference between them?
16. What is the difference between high –energy radiation and chemotherapy?