1. Control of the Cell Cycle Ch. 9.4

2. Ways to control the cell cycle 1. Enzymes (ex. p53) Are series of specialized proteins that control a cell as it goes through the cell cycle Are series of specialized proteins that control a cell as it goes through the cell cycle Some trigger the progression of the next phase Some trigger the progression of the next phase Some stop the progression of the next phase Some stop the progression of the next phase

3. Ways to control the cell cycle 2. Chemical signals A type of cell-to-cell communication A type of cell-to-cell communication Cells tell each other when to divide, die, and perform other functions Cells tell each other when to divide, die, and perform other functions

4. Ways to control the cell cycle 3. Contact Inhibition When cells touch one another, that signals stop dividing When cells touch one another, that signals stop dividing When cells die they leave an opening, signaling to the other cells to divide to replace the lost ones When cells die they leave an opening, signaling to the other cells to divide to replace the lost ones

6. Cell Death/Abnormal Growth caused by: Failure to produce enzymes or signals Failure to produce enzymes or signals Overproduction of enzymes or signals Overproduction of enzymes or signals Production of enzymes at the wrong time Production of enzymes at the wrong time Enzyme production is controlled by genes Enzyme production is controlled by genes G1 (Interphase) is a key control period (production of proteins) G1 (Interphase) is a key control period (production of proteins)

7. Cancer Cancer is a product of out-of-control cell reproduction that results in a tumor Cancer is a product of out-of-control cell reproduction that results in a tumor 2 types of tumors: 2 types of tumors: Benign tumor – an abnormal mass of normal cells Benign tumor – an abnormal mass of normal cells Usually harmless and removed by surgery Usually harmless and removed by surgery Remain at original site Remain at original site Malignant tumor – an abnormal mass of cancerous cells Malignant tumor – an abnormal mass of cancerous cells

8. Cancer cells Cancer is caused by severe disruptions of the proteins that control the cell cycle Cancer is caused by severe disruptions of the proteins that control the cell cycle The disruptions leads to uncontrolled cell division The disruptions leads to uncontrolled cell division Cancer cells have the ability to: Cancer cells have the ability to: Spread quickly to other cells Spread quickly to other cells Starve other “normal” cells around them Starve other “normal” cells around them Metastasis (spread from original site) Metastasis (spread from original site)

9. Metastasis

10. Cancer Treatments Cancer can be a result of different causes (genetic, environmental, life choices), so there is no one single “cure” Cancer can be a result of different causes (genetic, environmental, life choices), so there is no one single “cure” …or is there? Meet John Kanizus a former Trinity HS graduate and brother to Mrs. Shamitko, one of our physics teachers! …or is there? Meet John Kanizus a former Trinity HS graduate and brother to Mrs. Shamitko, one of our physics teachers!or is thereor is there

11. Treatments con’t Treatment programs usually include multiple approaches that are taken to try to control or halt the cancer Treatment programs usually include multiple approaches that are taken to try to control or halt the cancer Surgery to remove malignant tumors Surgery to remove malignant tumors Radiation therapy Radiation therapy Chemotherapy Chemotherapy

12. Radiation vs. Chemotherapy Radiation Radiation Cancerous cells are exposed to high- energy radiation Cancerous cells are exposed to high- energy radiation Radiation disrupts cell division Radiation disrupts cell division Since cancer cells divide more often, they’re more likely to be destroyed Since cancer cells divide more often, they’re more likely to be destroyed Minimal damage to normal cells Minimal damage to normal cells Can cause sterility Can cause sterility

13. Radiation vs. Chemotherapy Chemotherapy Chemotherapy Treatment with drugs that disrupt the cell cycle Treatment with drugs that disrupt the cell cycle Works by preventing or freezing the spindle fibers during mitosis Works by preventing or freezing the spindle fibers during mitosis Can affect intestinal cells (nausea) and hair follicles (hair loss) Can affect intestinal cells (nausea) and hair follicles (hair loss)