1. 10-3 Regulating the Cell
Cycle
Cyclins are proteins that regulate the cell cycle
– “Tell” cell when to divide, enter cell cycle phases
– Signal spindle formation during Interphase
– In addition to cyclins, other proteins also help regulate cycle
Internal regulators respond to events inside a
cell - check that a cell is prepared for mitosis
– spindle fibers, replicated DNA, etc.
External regulators are outside signals to
speed up/slow down cell division
– ie: contact inhibition,
wound healing

2. Contact Inhibition
Most cells will keep dividing until they
come in contact with other cells

3. What is Cancer?
Result of faulty cell
cycle
– Cells lose ability to control
growth – do not respond to
regulatory signals
– Cells divide out of control – do
not spot dividing when come
in contact with other cells like
normal cells do
– Demonstrate bizarre behavior

5. What is Cancer?
Malignant tumor
– Lump resulting from
division of cancer cell
• Can spread
• Displaces normal tissue
• Can spread into
circulatory system
Metastasis
– Spread of malignant
cells to other tissues
Cancers named for
where they originate
• Non-metastatic,
noninvasive tumors are
called benign

6. What causes Cancer?
Causes of cancer
– Carcinogens – cancer causing
chemicals (tobacco, asbestos)
– Mutations in DNA overproduce
growth factors (cells keep dividing)
OR do not produce suppressors
(cells never stop dividing) - a
defect in p53 gene
– Some viruses
– Heredity - genes
– Radiation

7. Symptoms/Treatments
Symptoms vary
– Unexplained weight change
– Lumps or growths
– Abnormal bleeding
Treatment
– Prevention! (diet, lifestyle, self-examinations)
– Surgery/Radiation/Chemotheraphy

8. Cancer Treatments
GOAL: Stop cells from dividing!
– Surgery – remove the cells/tumor
– Radiation
• High energy radiation disrupts cell division
– Chemotherapy
• Drugs that disrupt cell division
• Anti-mitotic drugs (taxol, vinblastine)