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Mitosis & Cancer: When Making New Cells Goes Terribly Wrong!

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Presentation on theme: "Mitosis & Cancer: When Making New Cells Goes Terribly Wrong!"— Presentation transcript:


2 Mitosis & Cancer: When Making New Cells Goes Terribly Wrong!

3 If we want to cure cancer…  We must understand what causes it. This means understanding the cell cycle.

4 When is mitosis a good thing? 1) When you have to add or replace cells  growth & development  repair  replacement

5 Checkpoints 2) There are strict checkpoints in the cell cycle to ensure that each stage does not start before the last one finished  Checkpoint in Interphase: S phase  to make sure that DNA was replicated correctly

6 When is mitosis a BAD thing 3) When cells reproduce & they are not needed  these cells take over organs, but don’t do the right job  they just keep making copies  cancer  damages organs

7 What is cancer 4) Cancer is a disorder in which some of the body’s own cells lose the ability to control growth  Cancer cells do not respond to the signals that regulate the growth of most cells

8 How do the cells turn bad?  The timing of the cell cycle is regulated by cyclins (proteins)  Cyclins trigger cell division  For example: p53 gene regulates the process that leads the cell into mitosis  Conditions have to be right for the cell to divide 5) Gene proto-oncogenes encourage cell division in normal healthy cells 6) Tumor suppressor genes inhibit cell division

9 Why would cells just make copies? 7) If DNA gets damaged, cells stop listening to correct instructions  mutations  Causes of mutations:  UV radiation  chemical exposure  radiation exposure  heat  cigarette smoke  pollution  age  genetics

10 8) Cells gone bad…  If the proto-oncogene is damaged then cells can either never divide or divide uncontrollably creating a tumor  If the tumor-suppressor gene gets damage it may never tell the cell to stop dividing and the cell will divide and divide creating a tumor

11 Tumors 9) Benign tumor  abnormal cells remain at original site as a lump  most do not cause serious problems & can be removed by surgery

12 Tumors 10) Malignant tumor  cells leave original site  carried by blood system to other tissues  start more tumors  damage functions of organs throughout body

13 Treatments for cancers 11) Treatments kill rapidly dividing cells  chemotherapy  poisonous drugs that kill rapidly dividing cells  radiation  high energy beam kills rapidly dividing cells side effects

14 2009-2010 Any Questions??

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