1. Ch.10-3 Regulating the Cell Cycle
CELL DIVISION

2. POINT > Identify 3 reasons cells divide
POINT > Describe the role of cyclins in cell division
POINT > Identify other factors that affect cell division
POINT > Define apoptosis
POINT > Discuss causes and treatments of cancer

4. POINT > Identify 3 reasons cells divide
1. Growth & Development

5. POINT > Identify 3 reasons cells divide
1. Growth & Development
2. Repair & Healing

6. POINT > Identify 3 reasons cells divide
1. Growth & Development
2. Repair & Healing
3. Reproduction (in asexual organisms)

7. POINT > Describe the role of cyclins in cell division
Cyclins are a family of proteins that regulate the timing of the cell cycle
Cyclins “tell” the cell when to:
Replicate chromosomes
Divide
Enter another phase of the cell cycle

8. POINT > Describe the role of cyclins in cell division
Directions (5 min total)
Open textbook to p.288 Answer questions 1-3 with partner
Cyclin production during interphase signals cell to enter mitosis
Cyclin destruction during mitosis signals cell to stop dividing and enter interphase

9. WB CHECK:
When during the cell cycle does cyclin production occur?
Cyclin production causes the cell to
a) enter interphase
b) prepare for mitosis
c) end mitosis
d) increase active transport

10. WB CHECK:
When during the cell cycle does cyclin destruction occur?
Cyclin destruction causes the cell to
a) enter interphase
b) prepare for mitosis
c) undergo cytokinesis
d) increase active transport

11. POINT > Identify other factors that affect cell division
Many other factors help regulate the cell cycle: Internal regulators respond to events inside the cell (attachment of spindle fibers, DNA replication, etc) Internal regulators allow the cell cycle to proceed only when certain events (like DNA replication) have been completed

12. POINT > Identify other factors that affect cell division
External regulators respond to events outside the cell (growth factors, cell surface proteins, etc) These regulators can direct cells to speed up or slow down the cell cycle

13. WB CHECK:
What is one event an internal cell cycle regulator might detect or respond to?
An example of an external cell cycle regulator would be
a) DNA polymerase
b) Cyclins
c) Spindle fiber proteins
d) Growth factors

14. POINT > Define apoptosis
Apoptosis is “programmed cell death” through a series of controlled steps Cells commit “suicide” as part of normal growth and development

15. POINT > Define apoptosis
Apoptosis is essential to shaping structures of tissues and organs in plants and animals
Cells with mutations or problems with DNA replication also undergo apoptosis
Mouse Embryo Paw

16. WB CHECK:
Apoptosis is important for a) ensuring mitosis occurs normally b) proper development of organs and body structures c) preventing mutated cells from growing d) a-c e) b-c f) a and c

17. POINT > Discuss causes and treatments of cancer
Melanoma
POINT > Discuss causes and treatments of cancer
Cancer is a group of disorders characterized by uncontrolled cell division
Uncontrolled cell division creates tumors (masses of cancer cells)
Benign tumors do not spread and are usually treatable
Malignant tumors do spread, invading and damaging other tissues

18. POINT > Discuss causes and treatments of cancer
Cancer is usually caused by mutations to a cell’s regulatory genes
(causes of mutations include tobacco, radiation, natural mutations, and viral infections)
As a result, control over the cell cycle breaks down:
1. Cells don’t respond to external growth factors
2. Cells fail to produce internal regulators
3. Mutated cells fail to undergo apoptosis

19. POINT > Discuss causes and treatments of cancer
Cancer is usually treated through:
Surgery
Radiation
Chemotherapy
Targeted therapy: Newer methods - may use specific antibodies of immune system to destroy cells
Classic treatment options

20. Homework: Read 286-290 Assess #1-3 page 290 Workbook pages 111-112