1. Cell Cycle and Mitosis

2. Cell cycle – steps that a cell goes through to grow and divide – 3 stages: Interphase – cell growth Mitosis – nuclear division Cytokinesis – cytoplasm division http://www.cellsalive.com/cell_cycle.htm

3. Interphase “resting” phase cell spends majority of time in interphase – 3 parts: G1 – cell growth/metabolism S – DNA is copied G2 – chromosomes start to coil up

4. Mitosis # of Cells# of chromosomes per cell Before Mitosis After Mitosis

5. Phases of Mitosis 1.PROPHASE -nucleus disappears -chromosomes coil and are visible

6. Phases of Mitosis 2.METAPHASE -chromosomes line up in the middle of the cell along the equator

7. Phases of Mitosis 3.ANAPHASE -chromosomes split and are pulled to the opposite ends of cell

8. Phases of Mitosis 4.TELOPHASE -nuclei reappear -chromosomes uncoil -cell starts to pinch into 2 cells

9. Cytokinesis

10. Mitosis Revisited # of Cells# of chromosomes per cell Before Mitosis14 After Mitosis In mitosis, one parent cell becomes two daughter cells with the same number of chromosomes as the parent cell. http://www.cellsalive.com/mitosis.htm

11. In humans …

12. Why mitosis? 1.Asexual reproduction -many unicellular organisms use mitosis to make more of themselves

13. Why Mitosis? 2.To make more body cells in multicellular organisms -cells cannot get too big (nutrient demand)

14. Why Mitosis -From one cell to adult

15. Why Mitosis -To replace dead cells (ex. skin cells, blood cells, cheek cells) -To replace damaged cells (ex. a cut healing) http://www.schremppstudio.com/cutfinger.html

16. Onion Mitosis

17. Whitefish Mitosis

18. When Mitosis Goes Wrong Cell cycle is controlled by enzymes. When enzymes malfunction, there is uncontrolled mitosis. This can lead to cancer. prostate cancer cells cancer cells