1. Cell Control System

2. Checkpoints Cell Cycle is very tightly controlled
“Cyclin” (Protein) stop cells at specific Checkpoints during the cycle (G1, G2, M)
Everything ok  cell cycle continues

3. Apoptosis – Cell Suicide
If something is wrong, the cycle does not continue until the error is fixed.
If the error cannot be fixed, the cell will undergo apoptosis

5. Why are checkpoints necessary?
No good reason to make a copy of a bad cell
Cancer Prevention
A “cancerous” cell is one that multiplies out of control. The checkpoints are ignored.

6. Cancer

7. What is Cancer?
Loss of CELL CYCLE CONTROLS  the controls are no longer functioning properly (cdk and cyclin)
 cancer is the condition resulting from: excess cell division or deficient apoptosis (Cell death)

8. Contact Inhibition
contact inhibition = cells can tell if they are being “crowded” by other cells and will stop dividing.
Cancer cells do not respond to this stop signal.
Keep dividing and piling up  Tumor mass

9. Treatment Radiation – mutation of DNA
Chemotherapy – attacks spindle fibers
Issues with treatment – why do ppl get so sick during treatment??
Attacks ALL mitotic cells
Adult – skin/hair, blood, digestive lining, eggs/sperm
Children – still growing all over