1. © 2012 Pearson Education, Inc. Lecture by Edward J. Zalisko PowerPoint Lectures for Campbell Biology: Concepts & Connections, Seventh Edition Reece, Taylor, Simon, and Dickey Chapter 8 The Cellular Basis of Reproduction and Inheritance

2. Figure 8.0_2 Chapter 8: Big Ideas Cell Division and Reproduction The Eukaryotic Cell Cycle and Mitosis Meiosis and Crossing Over Alterations of Chromosome Number and Structure

3.  In a healthy body, cell division allows for –growth, –the replacement of damaged cells, and –development from an embryo into an adult. –reproduction (unicellular and multicellular)  Two types of reproduction (involves 2 types of cell division –Mitosis (chromosome #s in parent = same as offspring) –Meiosis.(chromosome #in offspring = ½ of parent) Introduction © 2012 Pearson Education, Inc.

4.  Cancer cells –start out as normal body cells, –undergo genetic mutations, –lose the ability to control the tempo of their own division, and –run amok, causing disease. Introduction © 2012 Pearson Education, Inc.

5. Figure 8.0_3

6. CELL DIVISION AND REPRODUCTION © 2012 Pearson Education, Inc.

7. 8.1 Cell division plays many important roles in the lives of organisms  Living organisms reproduce by two methods. –Asexual reproduction –produces offspring that are identical to the original cell or organism and –involves inheritance of all genes from one parent. –Sexual reproduction –produces offspring that are similar to the parents, but show variations in traits and –involves inheritance of unique sets of genes from two parents. © 2012 Pearson Education, Inc.

8. Figure 8.1A Budding – single parent produces a smaller but identical (clone) offspring. Ex. Yeast, Hydra.

9. Figure 8.1C Vegetative Propagation: Offspring produced from parts other than seeds.

10.  Prokaryotes (bacteria and archaea) reproduce by binary fission or Prokaryotic fission (“dividing in half”).  The chromosome of a prokaryote is –a singular circular DNA molecule associated with proteins and –much smaller than those of eukaryotes. 8.2 Prokaryotes reproduce by binary fission © 2012 Pearson Education, Inc.

11.  Binary fission of a prokaryote occurs in three stages: 1.duplication of the chromosome and separation of the copies, 2.continued elongation of the cell and movement of the copies, and 3.division into two daughter cells. 8.2 Prokaryotes reproduce by binary fission © 2012 Pearson Education, Inc.

12. Figure 8.2A_s1 Plasma membrane Cell wall Duplication of the chromosome and separation of the copies Prokaryotic chromosome 1

13. Figure 8.2A_s2 Plasma membrane Cell wall Duplication of the chromosome and separation of the copies Continued elongation of the cell and movement of the copies Prokaryotic chromosome 1 2

14. Figure 8.2A_s3 Plasma membrane Cell wall Duplication of the chromosome and separation of the copies Continued elongation of the cell and movement of the copies Prokaryotic chromosome 1 2 3 Division into two daughter cells

15. Figure 8.2B Prokaryotic chromosomes

16. THE EUKARYOTIC CELL CYCLE AND MITOSIS © 2012 Pearson Education, Inc.

17.  Eukaryotic cells –are more complex and larger than prokaryotic cells, –have more genes, and –store most of their genes on multiple chromosomes within the nucleus. 8.3 The large, complex chromosomes of eukaryotes duplicate with each cell division © 2012 Pearson Education, Inc.

18.  Eukaryotic chromosomes are composed of chromatin consisting of –one long DNA molecule and –proteins that help maintain the chromosome structure and control the activity of its genes.  To prepare for division, the chromatin becomes –highly compact and –visible with a microscope. 8.3 The large, complex chromosomes of eukaryotes duplicate with each cell division © 2012 Pearson Education, Inc.

19. Figure 8.3A

20. Figure 8.3B Sister chromatids Chromosomes Centromere Chromosome duplication Sister chromatids Chromosome distribution to the daughter cells DNA molecules

21. 8.3 The large, complex chromosomes of eukaryotes duplicate with each cell division © 2012 Pearson Education, Inc.  Before a eukaryotic cell begins to divide, it duplicates all of its chromosomes, resulting in –two copies called sister chromatids –joined together by a narrowed “waist” called the centromere.  When a cell divides, the sister chromatids –separate from each other, now called chromosomes, and –sort into separate daughter cells.

22.  The cell cycle is an ordered sequence of events that extends –from the time a cell is first formed from a dividing parent cell –until its own division. 8.4 The cell cycle multiplies cells © 2012 Pearson Education, Inc.

23.  The cell cycle consists of two stages, characterized as follows: 1.Interphase: growth and duplication of cell contents –G 1 —growth, increase in cytoplasm –S—duplication of chromosomes –G 2 —growth, preparation for division 2.Mitotic phase: chromosome sorting (resulting in cell division) –Mitosis—division of the nucleus –Cytokinesis—division of cytoplasm 8.4 The cell cycle multiplies cells © 2012 Pearson Education, Inc.

24. Figure 8.4 G 1 (first gap) S (DNA synthesis) G 2 (second gap) M Cytokinesis Mitosis I N T E R P H A S E PH A SE T T MI O IC

25.  Mitosis progresses through a series of stages: Mitosis progresses through a series of stages: –prophase, –prometaphase, –metaphase, –anaphase, and –telophase.  Cytokinesis often overlaps telophase. Cell division is a continuum of dynamic changes © 2012 Pearson Education, Inc.

26.  A mitotic spindle is –required to divide the chromosomes, –composed of microtubules, and –produced by centrosomes, structures in the cytoplasm that –organize microtubule arrangement and –contain a pair of centrioles in animal cells. 8.5 Cell division is a continuum of dynamic changes © 2012 Pearson Education, Inc.

27. Figure 8.5_1 INTERPHASE MITOSIS Prophase Prometaphase Centrosome Early mitotic spindle Chromatin Fragments of the nuclear envelope Kinetochore Centrosomes (with centriole pairs) Centrioles Nuclear envelope Plasma membrane Chromosome, consisting of two sister chromatids Centromere Spindle microtubules

28.  Interphase –The cytoplasmic contents double, –two centrosomes form, –chromosomes duplicate in the nucleus during the S phase, and –nucleoli, sites of ribosome assembly, are visible. 8.5 Cell division is a continuum of dynamic changes © 2012 Pearson Education, Inc.

29. Figure 8.5_2 INTERPHASE

30. Figure 8.5_left INTERPHASE MITOSIS ProphasePrometaphase Centrosome Early mitotic spindle Chromatin Fragments of the nuclear envelope Kinetochore Centrosomes (with centriole pairs) Centrioles Nuclear envelope Plasma membrane Chromosome, consisting of two sister chromatids Centromere Spindle microtubules

31.  Prophase –In the cytoplasm microtubules begin to emerge from centrosomes, forming the spindle. –In the nucleus –chromosomes coil and become compact and –nucleoli disappear. 8.5 Cell division is a continuum of dynamic changes © 2012 Pearson Education, Inc.

32. Figure 8.5_3 Prophase

33.  Prometaphase –Spindle microtubules reach chromosomes, where they –attach at kinetochores on the centromeres of sister chromatids and –move chromosomes to the center of the cell through associated protein “motors.” –Other microtubules meet those from the opposite poles. –The nuclear envelope disappears. 8.5 Cell division is a continuum of dynamic changes © 2012 Pearson Education, Inc.

34. Figure 8.5_4 Prophase

35. Figure 8.5_5 MITOSIS Anaphase Metaphase Telophase and Cytokinesis Metaphase plate Cleavage furrow Nuclear envelope forming Daughter chromosomes Mitotic spindle

36. Figure 8.5_right MITOSIS Anaphase Metaphase Telophase and Cytokinesis Metaphase plate Cleavage furrow Nuclear envelope forming Daughter chromosomes Mitotic spindle

37.  Metaphase –The mitotic spindle is fully formed. –Chromosomes align at the cell equator. –Kinetochores of sister chromatids are facing the opposite poles of the spindle. 8.5 Cell division is a continuum of dynamic changes © 2012 Pearson Education, Inc.

38.  Anaphase –Sister chromatids separate at the centromeres. –Daughter chromosomes are moved to opposite poles of the cell as –motor proteins move the chromosomes along the spindle microtubules and –kinetochore microtubules shorten. –The cell elongates due to lengthening of nonkinetochore microtubules. 8.5 Cell division is a continuum of dynamic changes © 2012 Pearson Education, Inc.

39.  Telophase –The cell continues to elongate. –The nuclear envelope forms around chromosomes at each pole, establishing daughter nuclei. –Chromatin uncoils and nucleoli reappear. –The spindle disappears. 8.5 Cell division is a continuum of dynamic changes © 2012 Pearson Education, Inc.

40.  During cytokinesis, the cytoplasm is divided into separate cells.  The process of cytokinesis differs in animal and plant cells. 8.5 Cell division is a continuum of dynamic changes © 2012 Pearson Education, Inc.

41.  In animal cells, cytokinesis occurs as 1.a cleavage furrow forms from a contracting ring of microfilaments, interacting with myosin, and 2.the cleavage furrow deepens to separate the contents into two cells. 8.6 Cytokinesis differs for plant and animal cells © 2012 Pearson Education, Inc.

42. Figure 8.6A Cytokinesis Cleavage furrow Contracting ring of microfilaments Daughter cells Cleavage furrow

43.  In plant cells, cytokinesis occurs as 1.a cell plate forms in the middle, from vesicles containing cell wall material, 2.the cell plate grows outward to reach the edges, dividing the contents into two cells, 3.each cell now possesses a plasma membrane and cell wall. 8.6 Cytokinesis differs for plant and animal cells © 2012 Pearson Education, Inc.

44. Figure 8.6B Cytokinesis Cell wall of the parent cell Daughter nucleus Cell wall Plasma membrane Vesicles containing cell wall material Cell plate forming New cell wall Cell plate Daughter cells

45.  The cells within an organism’s body divide and develop at different rates.  Cell division is controlled by –the presence of essential nutrients, –growth factors, proteins that stimulate division, –density-dependent inhibition, in which crowded cells stop dividing, and –anchorage dependence, the need for cells to be in contact with a solid surface to divide. 8.7 Anchorage, cell density, and chemical growth factors affect cell division © 2012 Pearson Education, Inc.

46. Figure 8.7A Cultured cells suspended in liquid The addition of growth factor

47. Figure 8.7B Anchorage Single layer of cells Removal of cells Restoration of single layer by cell division

48.  The cell cycle control system is a cycling set of molecules in the cell that –triggers and –coordinates key events in the cell cycle.  Checkpoints in the cell cycle can –stop an event or –signal an event to proceed. 8.8 Growth factors signal the cell cycle control system © 2012 Pearson Education, Inc.

49.  There are three major checkpoints in the cell cycle. There are three major checkpoints in the cell cycle. 1.G 1 checkpoint –allows entry into the S phase or –causes the cell to leave the cycle, entering a nondividing G 0 phase. 2.G 2 checkpoint, and 3.M checkpoint.  Research on the control of the cell cycle is one of the hottest areas in biology today. WHY? 8.8 Growth factors signal the cell cycle control system © 2012 Pearson Education, Inc.

50. Figure 8.8A G0G0 G 1 checkpoint G1G1 S M G2G2 Control system M checkpoint G 2 checkpoint

51. Molecular controls of Cell Cycle

52. Figure 8.8B Receptor protein Signal transduction pathway Growth factor Relay proteins Plasma membrane E XTRACELLULAR F LUID C YTOPLASM G 1 checkpoint G1G1 S M G2G2 Control system

53.  Cancer currently claims the lives of 20% of the people in the United States and other industrialized nations.  Cancer cells escape controls on the cell cycle.  Cancer cells –divide rapidly, often in the absence of growth factors, –spread to other tissues through the circulatory system, and –grow without being inhibited by other cells. 8.9 CONNECTION: Growing out of control, cancer cells produce malignant tumors © 2012 Pearson Education, Inc.

54.  A tumor is an abnormally growing mass of body cells. –Benign tumors remain at the original site. –Malignant tumors spread to other locations, called metastasis. 8.9 CONNECTION: Growing out of control, cancer cells produce malignant tumors © 2012 Pearson Education, Inc.

55. Figure 8.9 Tumor Glandular tissue GrowthInvasionMetastasis Lymph vessels Blood vessel Tumor in another part of the body

56.  Cancers are named according to the organ or tissue in which they originate. –Carcinomas arise in external or internal body coverings. –Sarcomas arise in supportive and connective tissue. –Leukemias and lymphomas arise from blood-forming tissues. 8.9 CONNECTION: Growing out of control, cancer cells produce malignant tumors © 2012 Pearson Education, Inc.

57.  Cancer treatments –Localized tumors can be –removed surgically and/or –treated with concentrated beams of high-energy radiation. –Chemotherapy is used for metastatic tumors. 8.9 CONNECTION: Growing out of control, cancer cells produce malignant tumors © 2012 Pearson Education, Inc.

58.  When the cell cycle operates normally, mitosis produces genetically identical cells for –growth, –replacement of damaged and lost cells, and –asexual reproduction. 8.10 Review: Mitosis provides for growth, cell replacement, and asexual reproduction © 2012 Pearson Education, Inc.

59. 1.Compare the parent-offspring relationship in asexual and sexual reproduction. 2.Explain why cell division is essential for prokaryotic and eukaryotic life. 3.Explain how daughter prokaryotic chromosomes are separated from each other during binary fission. 4.Compare the structure of prokaryotic and eukaryotic chromosomes. 5.Describe the stages of the cell cycle. You should now be able to © 2012 Pearson Education, Inc.

60. 6.List the phases of mitosis and describe the events characteristic of each phase. 7.Compare cytokinesis in animal and plant cells. 8.Explain how anchorage, cell density, and chemical growth factors control cell division. 9.Explain how cancerous cells are different from healthy cells. 10.Describe the functions of mitosis. You should now be able to © 2012 Pearson Education, Inc.

61. PH A SE T T MI O IC Figure 8.UN01 Genetically identical daughter cells S G1G1 G2G2 M Mitosis (division of the nucleus) Cytokinesis (division of the cytoplasm) Cytokinesis Mitosis I N T E R P H A S E Ce l l g r o w t h a n d ch r o o m s o e m d u p l i c a t i o n (DNA synthesis)

62. Figure 8.UN04