1. Cell Reproduction  Chromosomes  Cell Division  Meiotic Cell Cycle

2. Mitosis Introduction Mitosis Introduction To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once ASX Video plays about 14-1/4 minASX Video plays about 14-1/4 min A Video Quiz is included in the presentationA Video Quiz is included in the presentation

3. Chromosomes ChromosomeChromosome Structure Numbers  Sex  Sex Chromosomes & Autosomes  Diploid  Diploid & Haploid Cells  Karyotyping

4. Learning Objectives TSW …TSW … 1.Describe the structure of a chromosome 2.Compare prokaryotic chromosomes w/ eukaryotic chromosomes 3.Explain the difference btw/ sex chromosomes & autosomes 4.Give examples of haploid & diploid cells

5. Chromosomes Chromosome StructureChromosome Structure  DNA – deoxyribonucleic acid  Proteins  Histones Serve as “spools” for long DNA moleculeServe as “spools” for long DNA molecule Maintain chromosome shapeMaintain chromosome shape  Nonhistone proteins Control regional activity of DNAControl regional activity of DNA Chromosome FunctionChromosome Function  Genetic Code – hereditary material When NOT involved in cell division, chromosomes exist as chromatin – a mixture of DNA & proteins w/in the nucleus

6. Chromosome Condensation coiling around histones coiling around histones coiling into supercoils coiling into supercoils further coiling into visible structures (light microscope) further coiling into visible structures (light microscope) histones

7. Chromosome & Sister Chromatids Terminology: Terminology:  centromere  constricted region of chromosome  sister chromatids are joined here  kinetochore – structure w/in centromere where spindle microtubules attach to sister chromatids  1 kinetochore for each chromatid

8. Chromosome Numbers Chromosome NumberChromosome Number  Characteristic for each species  2 different species may have the same chromosome number Chimpanzees & gorillas w/ 48 – both apes; closely related Chimpanzees & gorillas w/ 48 – both apes; closely related Potatoes & gorillas w/ 48 – not closely related Potatoes & gorillas w/ 48 – not closely related

9. Types of Animal Chromosomes Sex Chromosomes (1 pair = 2 in humans)Sex Chromosomes (1 pair = 2 in humans)  Chromosomes that carry genes for sexual expression  Determine the sex of an organism  May carry genes for other characters  Human Sex Chromosomes – “X” & “Y”  XX = female  XY = male Autosomes (22 pairs = 44 in humans)Autosomes (22 pairs = 44 in humans)  Carry genes for most characters

10. Homologous Chromosomes Karyotype – displays homologuesKaryotype – displays homologues Homologous ChromosomesHomologous Chromosomes  chromosome pairs of the same length, centromere position, and staining pattern that posses genes for the same characters  one homologue is inherited from the organism’s father  one homologue is inherited from the organism’s mother

11. Homologous Chromosomes

12. Chromosome Sets Haploid CellsHaploid Cells  1 set of chromosomes  Symbol = n  In humans, n = 23  In fruit fly, n = 4 Diploid CellsDiploid Cells  2 sets of chromosomes  Symbol = 2n  In humans, 2n = 46  In fruit fly, 2n = 8

13. Karyotype Homologous Chromosomes (a.k.a., homologues)Homologous Chromosomes (a.k.a., homologues)  Same size & shape  Centromere in same position  Same staining characteristics  Carry genes for same characteristics KaryotypeKaryotype  Photomicrograph of the chromosomes from a dividing cell  Can be used to determine genetic defects or sex of organism Sex Chromosomes Q: Is this a karyotype of a male or a female?

14. Karyotyping To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once ASF Video plays about 3 minASF Video plays about 3 min

15. Cell Division Cell Division in ProkaryotesCell Division in Prokaryotes Cell Division in EukaryotesCell Division in Eukaryotes  The Cell Cycle  Interphase  Mitosis  Cytokinesis

16. Learning Objectives TSW …TSW … 1.Describe the events of binary fission 2.Describe each phase of the cell cycle 3.Summarize the phases of mitosis 4.Compare cytokinesis in plant & animal cells

17. Binary Fission Note: no nucleus; no mitosis 12 3

18. Binary Fission & Asexual Reproduction Binary Fission & Asexual Reproduction To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once ASX Video plays about 1 minASX Video plays about 1 min

19. Eukaryotic Cell Division Mitotic Cell DivisionMitotic Cell Division  One diploid (2n) parent cell  two diploid (2n) daughter cells  Genetic material in daughter cells is identical  Occurs in asexual reproduction of unicellular eukaryotes & addition of new cells to tissues/organs

20. Eukaryotic Cell Division Meiotic Cell DivisionMeiotic Cell Division  One diploid (2n) parent cell  four diploid (2n) daughter cells  Genetic material in daughter cells is NOT identical  Occurs in sexual reproduction of multicellular eukaryotes

21. Mitotic Cell Cycle: Overview Major Stages of Mitotic Cell Division:Major Stages of Mitotic Cell Division: ―Interphase  Divided into 3 phases ―Cell Division  Mitosis (M phase)  Division of nucleus  Divided into 4-5 main phases  Cytokinesis  Division of cytoplasm “mitotic phase” = division of the cell: mitosiscytokinesis

22. The Cell Cycle Movie The Cell Cycle Movie To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once MOV Video plays about 1 minMOV Video plays about 1 min

23. Interphase: Phases of Interphase Preparatory Stage:Preparatory Stage:  G 1 phase  cell growth; organelles duplicate; mitochondria & chloroplasts self- replicate  S phase  DNA replication  G 2 phase  enzymes & other materials necessary for division synthesized; cell growth continues  G 0 phase  Cell exists the cell cycle; organelles duplicate EX: mature nerve cells of CNS

24. DNA Replication

25. Interphase

26. Interphase To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once MOV Video plays about 25 secMOV Video plays about 25 sec

27. Mitosis: Phases of Mitosis ProphaseProphase MetaphaseMetaphase AnaphaseAnaphase TelophaseTelophase “Philadelphia”“Philadelphia” or whoever! MadeMade A TouchdownTouchdown APneumonic Aide! Aide!

28. Mitosis: Prophase Division of the Nucleus:Division of the Nucleus:  Early Prophase  chromosomes condense as sister chromatids  nucleoli dissolve  spindle apparatus begins to form from centrosomes (MTOC)

29. Cytoskeletal Elements of Division Terminology:Terminology:  Centrosome  microtubule organizing center (MTOC)  synthesizes mitotic spindle  Centrioles  animal cells only  2/centrosome  9 sets of triplet microtubules arranged in ring

30. Chromosome & Sister Chromatids

31. Mitosis: Early Prophase Mitosis: Early Prophase To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once MOV Video plays about 20 secMOV Video plays about 20 sec

32. Mitosis: Late Prophase Division of the Nucleus:Division of the Nucleus:  Late Prophase (Prometaphase)  nuclear envelope fragments  spindle stretches across cell  spindle microtubules: Kinetochore fibers – some attach to chromosomes at kinetochoresKinetochore fibers – some attach to chromosomes at kinetochores Polar fibers – other microtubules stretch toward polesPolar fibers – other microtubules stretch toward poles

33. Mitosis: Late Prophase (Prometaphase) Mitosis: Late Prophase (Prometaphase) To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once MOV Video plays about 20 secMOV Video plays about 20 sec

34. Mitosis: Metaphase Division of the Nucleus: (cont)Division of the Nucleus: (cont)  Metaphase  spindle across cell w/ centrosomes at opposite poles  chromosomes line up across metaphase plate [cell equator] attached to “kinetochore fibers” spindle microtubulesattached to “kinetochore fibers” spindle microtubules “polar” microtubules span cell from equator to each pole“polar” microtubules span cell from equator to each pole

35. Spindle Apparatus

36. Centrosomes centrosome

37. Kinetochore Structure

38. Mitosis: Metaphase Mitosis: Metaphase To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once MOV Video plays about 12 secMOV Video plays about 12 sec

39. Mitosis: Anaphase Division of the Nucleus: (cont)Division of the Nucleus: (cont)  Anaphase  centromeres separate  sister chromatids move to opposite cell poles as kinetochore fibers shorten  Polar fibers lengthen

40. Kinetochore Function

41. Mitosis: Anaphase Mitosis: Anaphase To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once MOV Video plays about 22 secMOV Video plays about 22 sec

42. Mitosis: Anaphase Time Lapse Mitosis: Anaphase Time Lapse To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once MOV Video plays about 9 secMOV Video plays about 9 sec

43. Mitosis: Early Telophase Division of the Nucleus: (cont)Division of the Nucleus: (cont)  Early Telophase  polar fibers lengthen stretching cell  chromosomes (formerly sister chromatids) reach opposite poles of cell

44. Mitosis: Late Telophase Division of the Nucleus: (cont)Division of the Nucleus: (cont)  Late Telophase  daughter nuclear envelopes reform  daughter nucleoli reform  chromosomes decondense to chromatin

45. Mitosis: Telophase Mitosis: Telophase To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once MOV Video plays about 20 secMOV Video plays about 20 sec

46. Cytokinesis Division of the Cytoplasm:Division of the Cytoplasm:  Begins during late anaphase to early telophase  Finishes immediately after telophase  Daughter cells separated by different mechanisms in plants & animals

47. Cytokinesis

48. Cytokinesis Cleavage furrow formation: animal cellsCleavage furrow formation: animal cells  microfilaments attached to cell membrane & shorten to pinch cell in two: separating daughter nuclei Cell plate formation:Cell plate formation: plant cells  vesicles produced from Golgi apparatus form and fuse btw/ daughter nuclei

49. Animal Cell Cytokinesis Cleavage Furrow Formation

50. Plant Cell Cytokinesis Cell Plate Formation

51. Cytokinesis To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once MOV Video plays about 41 secMOV Video plays about 41 sec

52. Review of Mitosis & Cytokinesis Review of Mitosis & Cytokinesis To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once MOV Video plays about 30 secMOV Video plays about 30 sec

53. Mitotic Cell Division: Time Lapse Mitotic Cell Division: Time Lapse To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once ASF Video plays about 52 secASF Video plays about 52 sec

54. Roles of Cell Division Asexual ReproductionAsexual Reproduction  prokaryotes  protistans  fungi Growth & DevelopmentGrowth & Development  multicellular organisms Repair & RegenerationRepair & Regeneration  multicellular organisms  plants  primitive animals

55. Asexual Reproduction Prokaryotes Prokaryotes Protistans Protistans Plants Plants Fungi Fungi Lower Animals Lower Animals amoeba dividing

56. Asexual Reproduction clone

57. Growth & Development Multicellular Organisms Fertilized egg Ist division Early embryo Late embryo Fetus Toddler Young child Young adult

58. Differentiation

59. Tissue Renewal Multicellular Organisms bone marrow stem cells

60. Preservation of the Genome

61. The Role of Mitosis in Organisms The Role of Mitosis in Organisms To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once MOV Video plays about 30 secMOV Video plays about 30 sec

62. Meiotic Cell Division Stages of MeiosisStages of Meiosis  Meiosis I  Meiosis II Formation of GametesFormation of Gametes  Spermatogenesis  Oogenesis Asexual & Sexual ReproductionAsexual & Sexual Reproduction

63. Learning Objectives TSW …TSW … 1.List & describe the phases of meiosis 2.Compare the end products of mitosis with those of meiosis 3.Explain crossing over & discuss how it contributes to the production of a unique individual 4.Summarize the major characteristics of spermatogenesis & oogenesis

64. Human Karyotype Note: Note: 23 pairs of chromosomes = 2 sets

65. General Cell Types Germ CellsGerm Cells  diploid (2n)  produced during growth & development by mitosis  undergo meiotic cell division to produce gametes Somatic CellsSomatic Cells  diploid (2n)  produced during growth & development by mitosis  all cells of the body except for germ cells

66. Overview of Meiotic Cell Division

67. Meiotic Cell Division Meiosis I Interphase – preparatory stageInterphase – preparatory stage Meiosis I – 1 st nuclear division: halving of the chromosome numberMeiosis I – 1 st nuclear division: halving of the chromosome number 1 st Cytokinesis – division of the cytoplasm: 2 daughter cells formed1 st Cytokinesis – division of the cytoplasm: 2 daughter cells formed

68. Meiotic Cell Division: Meiosis II (Interkinesis) – in some kinds of organisms(Interkinesis) – in some kinds of organisms Meiosis II – 2 nd nuclear division in both cells from meiosis I: separation of the sister chromatidsMeiosis II – 2 nd nuclear division in both cells from meiosis I: separation of the sister chromatids 2 nd Cytokinesis – division of the cytoplasm in both cells from meiosis I: 4 daughter cells formed2 nd Cytokinesis – division of the cytoplasm in both cells from meiosis I: 4 daughter cells formed

69. Meiosis & Chromosome Reduction Meiosis & Chromosome Reduction To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once MOV Video plays about 55 secMOV Video plays about 55 sec

70. Interphase: Phases of Interphase Preparatory Stage:Preparatory Stage:  G 1 phase  cell growth; organelles duplicate; mitochondria & chloroplasts self- replicate  S phase  DNA replication  G 2 phase  enzymes & other materials necessary for division produced; cell growth continues

71. Meiotic Interphase Meiotic Interphase To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once MOV Video plays about 20 secMOV Video plays about 20 sec

72. Meiosis I: Reduction Division Prophase I (includes Prometaphase)Prophase I (includes Prometaphase)  similar to mitosis except: homologous chromosomes pair in synapsis to form tetrads Metaphase IMetaphase I  similar to mitosis except: homologs line up across the metaphase plate Anaphase IAnaphase I  similar to mitosis except: homologs are separated to opposite poles of the cell Telophase ITelophase I  similar to mitosis except: nuclei may or may not reform completely

73. Meiosis I: Prophase Meiosis I: Prophase To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once MOV Video plays about 55 secMOV Video plays about 55 sec

74.  Homologous chromosomes pair up at prophase  Each homologue has two sister chromatids: tetrad  The sister chromatids from different homologues become tangled: cross-over Synapsis

75. Tetrads & Cross Over occurs during prophase I

76. Meiosis & Crossover Meiosis & Crossover To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once MOV Video plays about 1 minMOV Video plays about 1 min

77. Meiosis I: Metaphase Meiosis I: Metaphase To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once MOV Video plays about 27 secMOV Video plays about 27 sec

78. Independent Assortment  Homologous chromosomes line up independently from one another across the cell equator during metaphase

79. Results of Cross Over

80. Meiosis I: Anaphase Meiosis I: Anaphase To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once MOV Video plays about 16 secMOV Video plays about 16 sec

81. Meiosis I: Telophase & 1st Cytokinesis Meiosis I: Telophase & 1st Cytokinesis To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once MOV Video plays about 25 secMOV Video plays about 25 sec

82. 1st Cytokinesis Occurs concurrently with telophase IOccurs concurrently with telophase I Results in 2 daughter cellsResults in 2 daughter cells Daughter cells contain ½ of original chromosomesDaughter cells contain ½ of original chromosomes

83. Interkinesis Occurs in some species Occurs in some species after telophase I & 1 st cytokinesis Nuclei of daughter cells completely reform Nuclei of daughter cells completely reform Chromosomes –still as joined as sister chromatids – decondense Chromosomes –still as joined as sister chromatids – decondense G phases may occur; NO S phase G phases may occur; NO S phase

84. Meiosis II: Equational Division Prophase II (includes Prometaphase)Prophase II (includes Prometaphase) Metaphase IIMetaphase II Anaphase IIAnaphase II Telophase IITelophase II  same processes as mitosis for all phases

85. Meiosis II & 2 nd Cytokinesis Meiosis II & 2 nd Cytokinesis To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once MOV Video plays about 42 secMOV Video plays about 42 sec

86. 2nd Cytokinesis Occurs concurrently with telophase IIOccurs concurrently with telophase II Results in 4 daughter cellsResults in 4 daughter cells Daughter cells contain ½ of original chromosomesDaughter cells contain ½ of original chromosomes

87. DNA Content of Cells Original amount of DNA = XOriginal amount of DNA = X After interphase, amnt DNA = 2XAfter interphase, amnt DNA = 2X After meiosis I, amnt DNA = XAfter meiosis I, amnt DNA = X After meiosis II, amnt DNA = ½ XAfter meiosis II, amnt DNA = ½ X

88. Formation of Gametes SpermatogenesisSpermatogenesis  Occurs in male germ cells  Produces sperm OogenesisOogenesis  Occurs in female germ cells  Produces ova (eggs)

89. Spermatogenesis

90. Oogenesis

91. Mitosis -v- Meiosis Prophase & Prophase Prophase I  Synapsis Synapsis of homologs homologs & chiasmata of non-sister chromatids in tetrad Metaphase & Metaphase Metaphase I  Homologs Homologs align at and span metaphase plate Anaphase & Anaphase Anaphase I Homologs separate; separate; sister chromatids do not

92. Comparison of Mitosis & Meiosis Comparison of Mitosis & Meiosis To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once ASX Video plays about 30 minASX Video plays about 30 min

93. Random Fertilization With 23 chromosomes, each gamete has 8 million possible chromosome combinationsWith 23 chromosomes, each gamete has 8 million possible chromosome combinations A zygote can have 8 million (for egg) X 8 million (for sperm) possible diploid combinations which equals 64 trillion different kinds of individuals resulting from one possible matingA zygote can have 8 million (for egg) X 8 million (for sperm) possible diploid combinations which equals 64 trillion different kinds of individuals resulting from one possible mating This does not take into account variation due to cross over!This does not take into account variation due to cross over!

94. Sexual Life Cycles & Genetic Variation Sources of Genetic Variation via Sexual ReproductionSources of Genetic Variation via Sexual Reproduction  Independent assortment of chromosomes at metaphase I  Cross over  Random fertilization

95. The Role of Meiosis Alternation of Fertilization & Meiosis:Alternation of Fertilization & Meiosis:  The Human Life Cycle  The Variety of Sexual Life Cycles Sexual ReproductionSexual Reproduction

96. Modes of Reproduction Asexual ReproductionAsexual Reproduction  A single individual is the sole parent & passes copies of all of its genes to its offspring  Clones Sexual ReproductionSexual Reproduction  Two parents give rise to offspring that have unique combinations of genes inherited from both parents

97. Asexual Reproduction clone

98. Asexual Life Cycle Asexual Life Cycle To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once MOV Video plays about 46 secMOV Video plays about 46 sec

99. Sexual Reproduction In Animals

100. Life Cycles & Gametes Life CycleLife Cycle  the generation-to-generation sequence of stages in the reproductive history of an organism from conception to production of its own offspring GametesGametes  reproductive cells  eggs – from the female  sperm – from the male  haploid cells – 1 set of chromosomes; ½ chromosome number of adults (23 in humans)

101. Sexual Reproduction & Differentiation Sexual Reproduction & Differentiation To View Video:To View Video: –Move mouse cursor over slide title- link –When hand appears, click once ASF Video plays about 3-3/4 minASF Video plays about 3-3/4 min

102. Typical Eukaryotic Life Cycles alternation of generations

103. Fertilization & Meiosis Meiotic Cell DivisionMeiotic Cell Division  the production of gametes  reduces the number of chromosomes to ½ that of the adult organism  haploid cells – 1 set of chromosomes (23 in humans)

104. Fertilization & Meiosis FertilizationFertilization  the union of gametes  results in a diploid zygote (fertilized egg) that grows and develops via mitosis into an adult organism  diploid cells – 2 sets of chromosomes (46 in humans)