1. Cell Division

2.  Some cells divide constantly: cells in the embryo, skin cells, gut lining cells, etc. Epithelial Cell Intestinal Cell 7 week old embryo

3. Cell Division  Other cells divide rarely or never. Brain Cell – Nerve cell Spinal Cord Cell- Nerve cell Cardiac Cell (Heart Muscle)

4. Cell Division Vocabulary  somatic cell – a body cell; a cell whose genes will not be passed on to future generations.  sex or germ cell - a cell that is destined to become a gamete (egg or sperm); a cell whose genes can be passed on to future generations.

5. Cell Division  2 kinds of cell division:  1. Mitosis: division of somatic cells  2. Meiosis: creation of new sex cells Sperm cellsHuman egg cell Pancreatic cells

6. Cell Cycle  A typical cell goes through a process of growth, development, and reproduction called the cell cycle.  Most of the cycle is called interphase. INTERPHASE

7. Cell Cycle  The longest phase in the cell cycle is interphase.  The 3 stages of interphase are called G 1, S, and G 2.

8. Cell Cycle  Cells spend most of their time in G 1 : it is the time when the cell grows.  Control of cell division occurs in G 1 : a cell that isn’t destined to divide goes into G 0.

9. Cell Cycle  The S phase (“Synthesis”) is the time when the DNA is doubled. Parent strands Daughter strands

10. Cell Cycle  In G2 DNA replication is checked and the cell is getting ready to divide.

12. Cell Division  All living cells come from other living cells.  During mitosis, the nucleus of the cell divides, forming two nuclei with identical genetic information.

13. Mitosis  Mitosis produces two genetically identical cells.  Mitosis is referred to in the following stages: prophase, metaphase, anaphase, and telophase.

14. Prophase  In prophase, the cell begins the process of division.  The chromosomes condense.

15. chromatin duplicated chromosome

16. Prophase  Nuclear envelope disappears.

17. Prophase  Centrioles migrate to opposite ends of the cell.  Spindle fibers form. Aster and the mitotic apparatus in an animal cell

18. Draw Prophase

19. Prophase Sister chromatids Centromere Centriole Spindle fibers

20. Metaphase  The chromosomes line up at the middle of the cell, with the centrioles at opposite ends and the spindle fibers attached to the centromeres. Centriole Spindle fibers Metaphase plate

22. Draw Metaphase

23. Anaphase  In anaphase, the chromosomes divide.  At this point, each chromosome goes from having 2 sister chromatids to being 2 separate chromosomes

24. Anaphase  The spindle fibers shrink and the chromosomes are pulled to opposite ends.

25. Draw Anaphase

26. Telophase  In telophase the nucleus actually divides.  The chromosomes are at the edges of the cell.  The nuclear envelope re- forms around the two sets of chromosomes.

27. Draw Telophase

28. Cytokinesis  The division of the cytoplasm.  In animal cells, a Cleavage Furrow forms and separates Daughter Cells Cleavage furrow in a dividing frog cell.

29. Cytokinesis  In plant cells, a Cell Plate forms and separates Daughter Cells. Cell Plate forming

30. ANIMAL VS. PLANT MITOSIS  ANIMAL CELL  Centriole present  Daughter cells separated by cleavage furrow  PLANT CELL  No visible centriole  Daughter cells separated by cell plate

31. Mitosis: Can you name the stages? 1 2 3 4 5

32. Prophase 2 3 4 5

33. Mitosis: Can you name the stages? Prophase Metaphase 3 4 5

34. Mitosis: Can you name the stages? Prophase Metaphase Anaphase 4 5

35. Mitosis: Can you name the stages? Prophase Metaphase Anaphase Telophase 5

36. Mitosis: Can you name the stages? Prophase Metaphase Anaphase Telophase Cytokinesis

37.  Phases of mitosis - IPMATC Interphase Cytokinesis

38.  Phases of mitosis - IPMATC I mportant P eople M ust A nalyze T asks C orrectly I mpatient P eople M ay A ttack T eachers C onstantly