Standard Biology Chapter 22 Cellular Reproduction

1. Standard BiologyChapter 22Cellular Reproduction Section 22:1 Mitosis

2. Mitosis • One cell divides and divides to form 3 trillion cells (you) • Process of cell reproduction by which 2 new identical cells are formed from one parent cell

3. Mitosis • Needed for growth, repair, and replacement of body parts • Growth: new muscle • Repair: broken bone need new bone cells • Replacement: new blood cells when have loss of blood

4. Mitosis • All body cells are formed by mitosis (body cells are all cells that are not sex cells)

5. Cell Type Brain Cell Red Blood Cell Platelets Stomach Lining Liver Cells Intestine Lining Skin Life Span 30-50 years 120 days 10 days 2 days 200 days 3 days 20 days Different Cells Have Different Life Span

6. Mitosis • Mitosis continues your entire life • Cells go through mitosis at different rates, some are slow and some are fast

7. Cell Cycle • Most of the time cells are not dividing, they are just growing and doing their job • Interphase: time between mitosis when cells grow, do their job and get ready for mitosis by: • Doubling chromosomes get sister chromatids • Making more cell parts (mitochondria…)

8. Steps of Mitosis Prophase • Sister chromatids thicken so can be seen • Nuclear membrane disappears • Centrioles (animals only) move away from each other • Spindle fibers form between centrioles

9. Prophase • Chromosome (two sister chromatids) • Centriole • Spindle fiber • Nuclear membrane (disintegrating)

10. Prophase

11. Steps of Mitosis Metaphase • Sister chromatids are hooked to spindle fiber • Sister chromatids are in center of cell

12. Metaphase

13. Metaphase

14. Steps of Mitosis Anaphase • Sister chromatids are pulled apart

15. Anaphase

16. Anaphase PLANT ANIMAL

17. Steps of Mitosis Telophase • Each chromatid forms a nucleus • Nuclear membrane forms around the 2 new nuclei • Spindle fibers disappear • Chromatids thin and can’t be seen • Cell cytoplasm usually divides (cytokinesis)

18. Telophase

19. Telophase • After Telophase the 2 new cells are in interphase • Cytokinesis is the division of the cell contents forming two new cells

20. Results of Mitosis • Results of mitosis: get 2 new cells that are genetically identical (same chromosome) but smaller in size

21. Differences between mitosis in plants and animals 1. Plants don’t have centrioles, animals cells do; both have spindle fibers Centrioles

22. Differences between mitosis in plants and animals 2. Plants have cell wall so must add more cell wall between new cells not just pinch in cytoplasm to divide it

24. Standard BiologyChapter 22Cellular Reproduction Section 22:2 Meiosis

25. Meiosis • Sex cells (eggs and sperm) are produced by a process different from mitosis • Meiosis: cell divides twice to form 4 new cells each with ½ the number of chromosomes • Start with one body cell end with 4 sex cells

26. Meiosis • Interphase happens just like mitosis, chromosomes are doubled

27. Steps of Meiosis:Meiosis I Prophase I • Sister chromatids shorten and thicken • Nuclear membrane disappears • Centrioles move to opposite ends of cell • Spindle fibers form • Two pair of sister chromatids (matching chromosomes) come together; get tetrads; exchange genetic material

28. Steps of Meiosis:Meiosis I Prophase I Homologous Chromosomes (tetrads)

29. Steps of Meiosis:Meiosis I Metaphase I • Tetrads in center of cell • Spindle fibers attached to chromosomes

30. Steps of Meiosis:Meiosis I Metaphase I Tetrads

31. Steps of Meiosis:Meiosis I Anaphase I • A pair of sister chromatids gets pulled away from the other pair of sister chromatids

32. Steps of Meiosis:Meiosis I Telophase I • Cell divides • Nuclear membrane DOES NOT REFORM

33. Steps of Meiosis:Meiosis II Prophase II and Metaphase II • Spindle fibers attach to sister chromatids • Sister chromatids are in middle of cell Metaphase II Prophase II

34. Steps of Meiosis:Meiosis II Anaphase II and Telophase II • Sister chromatids are pulled apart • Nuclear membrane reforms Anaphase II Telophase II

35. Result of Meiosis • Results of Meiosis: end with 4 sex cells that have ½ of the chromosomes as parent cell

36. How Alike sex cells formed by meiosis ½ number of chromosomes humans develop at puberty How Different egg larger than sperm sperm has tail, can move sperm form in male testes eggs form in female ovary only get 1 egg in meiosis get 4 sperm in meiosis Sperm, Egg, and FertilizationComparison of Sperm and Egg

37. Sperm, Egg, and Fertilization Formation of Polar Bodies • Happens in meiosis to produce eggs • Cell division is not equal, most of cytoplasm goes to one cell • Polar body is the cell formed with little cytoplasm • Polar bodies do not form eggs, they die

38. Sperm, Egg, and Fertilization Formation of Polar Bodies

39. Sperm, Egg, and Fertilization Fertilization • Joining of sperm and egg • Chromosomes come together and pair up forming a new organism with the correct number of chromosomes • New organism has ½ chromosomes form mother and ½ chromosomes from father

40. Sperm, Egg, and Fertilization

41. Standard BiologyChapter 22Cellular Reproduction Section 22:3 Changes in the Rate of Mitosis

42. Changes that Occur in the Human Body with Age

43. Changes that Occur in the Human Body with Age

44. Aging • Becoming older • All living things age • Loss of hair • Wrinkled skin • Bone calcium loss • Cells wear out faster than they are replaced or are not replaced (mitosis slows down) • Muscle cells (including heart) are not replaced, each cell can get bigger but no new cells

45. Aging

46. Cancer • Healthy cells: regular rate of mitosis • Cancer: too fast rate of mitosis • Shape of cell and nuclei change • Abnormal cells crowd out normal cells • Fig 22-11 p. 478

49. Causes of Cancer Environmental factors • Chemicals: chewing tobacco (mouth) • Smoking tobacco (lung)

50. Causes of Cancer Environmental factors • Radiation: UV light (skin) • Viruses: (warts and cervical cancer) • Diet