1. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero Chapter 12 The Cell Cycle

2. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Key Roles of Cell Division Unicellular organisms – Reproduce by cell division 100 µm Figure 12.2 A

3. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Key Roles of Cell Division Multicellular organisms – Development from a fertilized cell – Growth – Repair 20 µm200 µm (b) Growth and development. (c) Tissue renewal. Bone marrow cells Figure 12.2 B, C

4. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Concept 12.1 How does Cell division results in genetically identical daughter cells?

5. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Concept 12.1 How does Cell division results in genetically identical daughter cells? – Cells duplicate their genetic material before they divide

6. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings A cell’s DNA = Genome Genome Chromosomes DNA molecule and proteins (Chromatin) Genes 50 µm

7. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings – Cell not dividing = Chromosomes thin, loosely packed fibers called chromatin

8. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings – Cell not dividing = Chromosomes thin, loosely packed fibers called chromatin – Cell dividing = Individual Chromosomes visible

9. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings – Before a cell divides chromosomes replicate = sister chromatids joined together at the centromere Figure 8.4B

10. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings – Before a cell divides chromosomes replicate = sister chromatids joined together at the centromere Figure 8.4B

11. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings – Before a cell divides chromosomes replicate = sister chromatids joined together at the centromere Figure 8.4B

12. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings – During Cell division sister chromatids separate 2 daughter cells each contain a complete, identical set of chromosomes Figure 8.4C

13. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The cell cycle 2 major phases- Interphase and Mitotic Figure 8.5

14. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Interphase- 3 subphases – G 1 phase – S phase – G 2 phase Figure 8.5

15. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings – Interphase Cell parts are made (G1, G2 phase) Chromosomes duplicate (S phase) – Mitotic phase Duplicated chromosomes separate Separated chromosomes are distributed into two daughter cells What Happens During Each Phase?

16. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Interphase + Mitotic Phase = Cell cycle: 1.Interphase 2.Prophase 3.Metaphase 4.Anaphase 5.Telophase 6.Cytokinesis

17. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings – The 5 stages of cell division Figure 8.6 (Part 1) Interphase: - Cell growth - Chromosomes condense - Chromosomes duplicate - Nuclear envelope begins to breakdown

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19. – The stages of cell division Figure 8.6 (Part 1) Prophase: -Duplicated Chromosomes appear as 2 sister chromatids connected at the centromere - Mitotic spindle forms in cytoplasm from centrosomes

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21. – The stages of cell division Figure 8.6 (Part 1) Metaphase: -Mitotic spindle fully formed -Duplicated Chromosomes line up on metaphase plate located in middle of the cell -Each sister chromatid is attached to a spindle fiber

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23. – The stages of cell division Figure 8.6 (Part 1) Anaphase: -Sister chromatids are pulled apart and taken to opposite poles of the cell by the spindle fibers -Cell elongates

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25. – The stages of cell division Telophase: Roughly opposite prophase: -Nuclear envelopes begin to reform around chromosomes -Chromosomes begin to uncoil -Mitotic spindle disappears -Mitosis complete!

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27. – The stages of cell division Cytokinesis: -Division of the cytoplasm -Animals = cleavage furrow

28. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Cytokinesis differs for plant and animal cells – Animals Cytokinesis occurs by a constriction of the cell (cleavage) Figure 8.7A

29. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings – Plants membranous cell plate (golgi vesicles) forms and splits the cell in two Figure 8.7B

30. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings What Phase of Mitosis?

31. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings What Phase of Mitosis?

32. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 8.11 Review: stages of mitosis Figure 8.11A

33. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings A group of cells is assayed for DNA content immediately following mitosis and is found to have an average of 8 picograms of DNA per nucleus. Those cells would have __________ picograms at the end of the S phase and __________ picograms at the end of G 2. A8... 8 B8... 16 C16... 8 D16... 16 E12... 16

34. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Mitotic Spindle: A Closer Look The mitotic spindle – Is an apparatus of microtubules that controls chromosome movement during mitosis

35. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Spindle Centrosomes Spindle microtubules Asters

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37. How are chromosomes pulled to poles? 1 1

38. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings How are chromosomes pulled to poles?

39. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings How are chromosomes pulled to poles?

40. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings How are chromosomes pulled to poles?

41. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings ? Cytokinesis usually, but not always, follows mitosis. If a cell completed mitosis but not cytokinesis, what would be the result? Aa cell with a single large nucleus Ba cell with high concentrations of actin and myosin Ca cell with two abnormally small nuclei Da cell with two nuclei Ea cell with two nuclei but with half the amount of DNA

42. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Binary Fission: Prokaryotes (bacteria) 1.Origin of replication = duplicated

43. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Binary Fission Prokaryotes (bacteria) 1.Origin of replication = duplicated 2.One copy of origin moves to opposite end

44. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Binary Fission Prokaryotes (bacteria) 1.Origin of replication = duplicated 2.One copy of origin moves to opposite end 3.Replication continues; cell elongates

45. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Review Interphase + Mitotic phase = Cell division in Eukaryotes Binary Fission- Cell division in Prokaryotes – Similarities and Differences? Mitotic Spindle- How do sisters move to poles?

46. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings How are chromosomes pulled to poles? 1 1

47. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings How are chromosomes pulled to poles?

48. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings How are chromosomes pulled to poles?

49. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings How are chromosomes pulled to poles?

50. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Concept 12.3 How is cell cycle is regulated ? = Molecular control system - Controls frequency of cell division - Ex: Skin vs. muscle cells

51. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Cell Cycle Control System 3 checkpoints of the cell cycle

52. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Cell Cycle Control System 3 checkpoints of the cell cycle

53. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Cell cycle stops (G 0 ) until a go-ahead signal is received

54. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Cell Cycle Control System G2 Checkpoint

55. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings What are the “go-ahead” signal molecules? 2 types of regulatory proteins: 1. Cyclins 2. Cyclin-dependent kinases* (Cdks) *activate/inactivate proteins by phosphorylation

56. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings What are the “go-ahead” signal molecules? 2 types of regulatory proteins: 1. Cyclins 2. Cyclin-dependent kinases* (Cdks) *activate/inactivate proteins by phosphorylation G2 checkpoint “go- ahead” molecule

57. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The activity of cyclins and Cdks for G2 checkpoint

58. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The activity of cyclins and Cdks

59. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Internal and external signals Cell cycle checkpoint is control by: Internal signals – Ex: MPF External signals – Ex: PDGF

60. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings External factors for cell cycle control Growth factors- Stimulate cells to divide PDGF – platelet-derived growth factor Fibroblast cell

61. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings External factors for cell cycle control Growth factors- Stimulate cells to divide PDGF – platelet-derived growth factor Fibroblast cell PDGF required for Fibroblast cell division

62. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings External factors for cell cycle control Growth factors- Stimulate cells to divide PDGF – platelet-derived growth factor Fibroblast cell PDGF required for Fibroblast cell division

63. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PDGF Experiment

64. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PGDF Experiment Results

65. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings External factors for cell cycle control 1. Anchorage dependence 2. Density-dependent inhibition

66. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Cancer cells – Exhibit neither density-dependent inhibition nor anchorage dependence

67. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Loss of Cell Cycle Controls in Cancer Cells Cancer cells – Do not respond normally to the body’s control mechanisms – Form tumors: Benign, malignant, metastatic

68. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Benign, Malignant and Metastatic tumors malignant 2 4 malignant  metastatic 3 Benign 1 Tumor Glandular tissue Cancer cell Blood vessel Lymph vessel Metastatic Tumor Figure 12.19

69. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings ??????????????????????????????????????????? List differences between: Mitosis (eukaryotic cells) Binary Fission (prokaryotic cells)

70. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings ? Differences between mitosis in eukaryotic cells and binary fission in prokaryotic cells: Nuclear envelope Spindle Several chromosomes vs. one

71. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Review Cell division- Reproduction (unicellular) Cell division- Development, Growth, Repair Genetic material duplicated and divides BEFORE cell divides. WHY? Chromosome Sister Chromatids 2 Chromosomes

72. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Review Interphase + Mitotic phase = Cell division in Eukaryotes Binary Fission- Cell division in Prokaryotes – Similarities and Differences? Mitotic Spindle- How do sisters move to poles?

73. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Review! Ch. 12: Cell Cycle Control – Molecular signals Internal – G2 = MPF (cyclin +CdK) External Cancer