1. Cell Division

2. Chromosomes  Are made of DNA  Each chromosome consists of sister chromatids attached at a centromere

3. Cell Cycle  During the cell cycle, a cell grows, prepares for division, and divides to form 2 daughter cells, each with each of which then begins the cycle again.  Interphase – time for growth and regular cell activity.  Most of a cells life is spent in Interphase.

4. Interphase

5. Introduction to Cell Division

6. Mitosis  The division of somatic or regular cells.  Its divided into 4 phases.  Remember Interphase is NOT part of Mitosis.

7. Introduction to Mitosis

8. Prophase  First stage of Mitosis  Chromatin condenses into chromosomes  Centrioles separate and a spindle fiber begins to form.  Nuclear membrane breaks down

9. Prophase

10. Metaphase  Second Phase of Mitosis  Chromosomes line up in the middle of the cell.  Each chromosome is connected to a spindle fiber.

11. Metaphase

12. Anaphase  Third Phase of Mitosis  The sister chromatids separate into individual chromosomes and move apart to opposite ends of the cell.

13. Anaphase

14. Telophase  Fourth and Final Stage of Mitosis  Chromosomes gather at opposite ends of the cell and lose their distinct shapes  Two new nuclear membranes have formed.

15. Telophase

16. Cytokinesis  The cytoplasm pinches in half.  Each daughter cell has an identical set of duplicate chromosomes

17. Regulating the Cycle  A protein call cyclin helps regulate the cell cycle in eukaryotic cells.  They respond to internal and external events. These proteins are regulators.

18. When Things Go Wrong  Cancer cells do not respond to the signals that regulate the growth of most cells.  As a result, they form masses of cells called tumors that can damage surrounding tissues.

19. Cancer