1. What controls cell growth Objective: To study limits on cell growth and why cancer occurs in cells

2. What controls cell growth? Cells will typically divide until they are touching When your skin is torn the cells will divide until they are touching again healing

3. What tells cells to divide Cyclin- protein that regulates timing of cell cycle (in eukaryotes) Internal Regulators- proteins that respond to an event inside the cell

4. What tells cells to divide cont. External Regulators- Proteins that respond to an event outside the cell Growth Factors- important during embryonic development and wound healing Also helps prevent excessive growing

5. Uncontrolled cell growth Uncontrolled cell growth- cancer Cancer cells do not respond to signals that regulate normal cell growth Cancer cell- form tumors- cancer cells break loose from tumor and spread throughout the body

6. Uncontrolled cell growth Some cancers are due to a problem with internal or external regulators Most cancer cells have a defect in the P53 gene Causes cell to lose info needed to respond to signals that would normally control growth.

7. Cancer Stats. Most common cancer in US Skin cancer Cancer that kills most people in US Lung cancer Both are preventable in most cases 1/3 people are likely to get cancer