1. Chromosomes & Karyotypes 1

2. CHROMOSOMES

3. DNA - 2 forms Spread out as _____________ in NON-DIVIDING cells Scrunched into ________________ in DIVIDING cells CHROMATIN CHROMOSOMES

4. ________ PROTEINS maintain shape of chromosome Histone

5. CANCER

6. Chromosome structure ____________ 2 identical arms ____________ constricted area holds chromatids together __________________ PAIR__________________ PAIR 2 of each chromosome (one from mom; one from dad) 2 of each chromosome (one from mom; one from dad) CHROMATIDS CENTROMERE HOMOLOGOUS

7. CHROMOSOME NUMBERS Each species has a chromosome number HUMANS have 46 chromosomes (23 pairs )

8. DIPLOID & HAPLOID Cells with 2 copies are _______________ (one from mom; one from dad) All body cells Cells with one copy are ____________________ Sperm and egg 1n + 1n = 2n egg + sperm new organismDIPLOID2n HAPLOID 1n

9. KARYOTYPES ________ = picture of organism’s chromosomes KARYOTYPE

10. Chromosomes that determine sex = _________________________ All others = _________________ Sex chromosomes autosomes Humans have two sex chromosomes X y

11. A KARYOTYPE can tell the sex of an organism In humans XY is a male

12. Chromosome Number All cells in the human body (SOMATIC CELLS) have 46 or 23 pairs of chromosomes Called the DIPLOID or 2n number GAMETES (eggs & sperm) have only 23 chromosomes Called the MONOPLOID or 1n number 12

13. Nondisjunction Chromosomes may fail to separate during meiosis Resulting gametes may have too few or too many chromosomes Disorders: –Down Syndrome – three 21 st chromosomes –Turner Syndrome – single X chromosome –Klinefelter’s Syndrome – XXY chromosomes 13

14. 14 Cellular Division

15. 15 Cell Division All cells are derived from pre- existing cells All cells are derived from pre- existing cells New cells are produced for growth and to replace damaged or old cells New cells are produced for growth and to replace damaged or old cells Differs in prokaryotes (bacteria) and eukaryotes (protists, fungi, plants, & animals) Differs in prokaryotes (bacteria) and eukaryotes (protists, fungi, plants, & animals)

16. 16 Keeping Cells Identical The instructions for making cell parts are encoded in the DNA, so each new cell must get a complete set of the DNA molecules

17. 17 DNA Replication DNA must be copied or replicated before cell division DNA must be copied or replicated before cell division Each new cell will then have an identical copy of the DNA Each new cell will then have an identical copy of the DNA Original DNA strand Two new, identical DNA strands

18. 18 Identical Daughter Cells Parent Cell Two identical daughter cells

19. 19 Chromosomes

20. 20 Prokaryotic Chromosome The DNA of prokaryotes (bacteria) is one, circular chromosome attached to the inside of the cell membrane The DNA of prokaryotes (bacteria) is one, circular chromosome attached to the inside of the cell membrane

21. 21 Eukaryotic Chromosomes All eukaryotic cells store genetic information in chromosomes All eukaryotic cells store genetic information in chromosomes Most eukaryotes have between 10 and 50 chromosomes in their body cells Most eukaryotes have between 10 and 50 chromosomes in their body cells Human body cells have 46 chromosomes or 23 identical pairs Human body cells have 46 chromosomes or 23 identical pairs

22. 22 Eukaryotic Chromosomes Each chromosome is composed of a single, tightly coiled DNA molecule Each chromosome is composed of a single, tightly coiled DNA molecule Chromosomes can’t be seen when cells aren’t dividing and are called chromatin Chromosomes can’t be seen when cells aren’t dividing and are called chromatin

23. 23 Compacting DNA into Chromosomes DNA is tightly coiled around proteins called histones

24. 24 Chromosomes in Dividing Cells Duplicated chromosomes are called chromatids & are held together by the centromere Called Sister Chromatids

25. 25 Karyotype A picture of the chromosomes from a human cell arranged in pairs by size A picture of the chromosomes from a human cell arranged in pairs by size First 22 pairs are called autosomes First 22 pairs are called autosomes Last pair are the sex chromosomes Last pair are the sex chromosomes XX female or XY male XX female or XY male

26. 26 Boy or Girl? Y - Chromosome X - Chromosome The Y Chromosome Decides

27. 27 Cell Reproduction

28. 28 Types of Cell Reproduction Asexual reproduction involves a single cell dividing to make 2 new, identical daughter cells Asexual reproduction involves a single cell dividing to make 2 new, identical daughter cells Mitosis & binary fission are examples of asexual reproduction Mitosis & binary fission are examples of asexual reproduction Sexual reproduction involves two cells (egg & sperm) joining to make a new cell (zygote) that is NOT identical to the original cells Sexual reproduction involves two cells (egg & sperm) joining to make a new cell (zygote) that is NOT identical to the original cells Meiosis is an example Meiosis is an example

29. 29 Cell Division in Prokaryotes

30. 30 Cell Division in Prokaryotes Prokaryotes such as bacteria divide into 2 identical cells by the process of binary fission Prokaryotes such as bacteria divide into 2 identical cells by the process of binary fission Single chromosome makes a copy of itself Single chromosome makes a copy of itself Cell wall forms between the chromosomes dividing the cell Cell wall forms between the chromosomes dividing the cell Parent cell 2 identical daughter cells Chromosome replicates Cell splits

31. 31 Prokaryotic Cell Undergoing Binary Fission

32. 32 Animation of Binary Fission

33. 33 The Cell Cycle

34. 34 Five Phases of the Cell Cycle G 1 - primary growth phase G 1 - primary growth phase S – synthesis; DNA replicated S – synthesis; DNA replicated G 2 - secondary growth phase G 2 - secondary growth phase collectively these 3 stages are called interphase M - mitosis M - mitosis C - cytokinesis C - cytokinesis

35. 35 Cell Cycle

36. 36 Interphase - G 1 Stage 1 st growth stage 1 st growth stage make more cytoplasm & organelles make more cytoplasm & organelles normal metabolic activities normal metabolic activities

37. 37 Interphase – S Stage Synthesis stage Synthesis stage DNA replicated DNA replicated Two identical copies of DNA Original DNA

38. 38 Interphase – G 2 Stage 2 nd Growth Stage 2 nd Growth Stage cell structures needed for division are made cell structures needed for division are made organelles & proteins are made organelles & proteins are made

39. 39 What’s Happening in Interphase? What the cell looks like Animal Cell What’s occurring

40. 40 Sketch the Cell Cycle Daughter Cells DNA Copied Cells Mature Cells prepare for Division Cell Divides into Identical cells

41. 41 Mitosis

42. 42 Mitosis Division of the nucleus Division of the nucleus Has four stages Has four stages Doesn’t occur in brain cells Doesn’t occur in brain cells

43. 43 Four Mitotic Stages Prophase Prophase Metaphase Metaphase Anaphase Anaphase Telophase Telophase

44. 44 Early Prophase Chromatin condenses to chromosomes Chromatin condenses to chromosomes Mitotic spindle forms from cytoskeleton or centrioles (animal) Mitotic spindle forms from cytoskeleton or centrioles (animal) Chromosomes Nucleolus Cytoplasm Nuclear Membrane

45. 45 Late Prophase Nuclear membrane broken down Nuclear membrane broken down Chromosomes condense Chromosomes condense Spindle fibers attach to the centromeres Spindle fibers attach to the centromeres

46. 46 Late Prophase Nucleus & Nucleolus have disintegrated Chromosomes

47. 47 Spindle Fiber attached to Chromosome Kinetochore Fiber Chromosome

48. 48 Review of Prophase What the cell looks like What’s happening

49. 49 Sketch The Spindle

50. 50 Metaphase Chromosomesmove to the center of the cell Chromosomesmove to the center of the cell Chromosomes line up at the equator Chromosomes line up at the equator Pole of the Cell Equator of Cell

51. 51 Metaphase Chromosomes lined at the Equator Asters at the poles Spindle Fibers

52. 52 Metaphase Aster Chromosomes at Equator

53. 53 Review of Metaphase What the cell looks like What’s occurring

54. 54 Anaphase Sister chromatids are pulled apart to opposite poles Sister chromatids are pulled apart to opposite poles

55. 55 Anaphase Sister Chromatids being separated

56. 56 Anaphase Review What the cell looks like What’s occurring

57. 57 Telophase Sister chromatids at opposite poles Sister chromatids at opposite poles Spindle disassembles Spindle disassembles Nuclear envelope forms Nucleolus reappears Nuclear envelope forms Nucleolus reappears CYTOKINESIS occurs CYTOKINESIS occurs Chromosomes reappear as chromatin Chromosomes reappear as chromatin

58. 58 Comparison of Anaphase & Telophase

59. 59 Cytokinesis Means division of the cytoplasm Means division of the cytoplasm In plant cells, cell plate forms to divide cell In plant cells, cell plate forms to divide cell

60. 60 Cytokinesis animal cell Cell plate in plant cell

61. 61 Mitotic Stages

62. 62 Daughter Cells of Mitosis same number of chromosomes same number of chromosomes Identical to each other, but smaller Identical to each other, but smaller

63. 63 Review of Mitosis

64. 64 Draw & Learn these Stages

65. 65 Draw & Learn these Stages

66. 66 Interphase Prophase Metaphase Anaphase Telophase Name the Mitotic Stages: Name this?

67. 67 Eukaryotic Cell Division Used for growth and repair Used for growth and repair Produce two new cells identical to the original cell Produce two new cells identical to the original cell Cells are diploid (2n) Cells are diploid (2n) Chromosomes during Metaphase of mitosis ProphaseMetaphase Anaphase Telophase Cytokinesis

68. 68 Mitosis Animation Name each stage as you see it occur?

69. 69 Mitosis in Onion Root Tips Do you see any stages of mitosis?

70. 70 Test Yourself over Mitosis

71. 71 Mitosis Quiz

72. 72 Mitosis Quiz

73. 73 Name the Stages of Mitosis: Interphase Early prophase Mid-Prophase Late Prophase Metaphase Late Anaphase Early Anaphase Early Telophase, Begin cytokinesis Late telophase, Advanced cytokinesis

74. 74 Identify the Stages Early, Middle, & Late Prophase Late Prophase MetaphaseAnaphase Late Anaphase Telophase Telophase & Cytokinesis ? ? ?? ? ??

75. 75 Locate the Four Mitotic Stages in Plants Metaphase Prophase Anaphase Telophase

76. 76 Uncontrolled Mitosis If mitosis is not controlled, unlimited cell division occurs causing cancerous tumors If mitosis is not controlled, unlimited cell division occurs causing cancerous tumors Cancer cells

77. 77 Meiosis Formation of Gametes (Eggs & Sperm)

78. 78 Facts About Meiosis Preceded by interphase which includes chromosome replication Preceded by interphase which includes chromosome replication Two meiotic divisions --- Meiosis I and Meiosis II Two meiotic divisions --- Meiosis I and Meiosis II Called Reduction- division Called Reduction- division Original cell is diploid (2n) Original cell is diploid (2n) Four daughter cells produced that are monoploid (1n) Four daughter cells produced that are monoploid (1n)

79. 79 Facts About Meiosis Daughter cells contain half the number of chromosomes as the original cell Daughter cells contain half the number of chromosomes as the original cell Produces gametes (eggs & sperm) Produces gametes (eggs & sperm) Occurs in the testes in males (Spermatogenesis) Occurs in the testes in males (Spermatogenesis) Occurs in the ovaries in females (Oogenesis) Occurs in the ovaries in females (Oogenesis)

80. 80 Start with 46 double stranded chromosomes (2n) Start with 46 double stranded chromosomes (2n) After 1 division - 23 double stranded chromosomes (n) After 1 division - 23 double stranded chromosomes (n) After 2nd division - 23 single stranded chromosomes (n) After 2nd division - 23 single stranded chromosomes (n) Occurs in our germ cells that produce gametes Occurs in our germ cells that produce gametes More Meiosis Facts

81. 81 Why Do we Need Meiosis? It is the fundamental basis of sexual reproduction It is the fundamental basis of sexual reproduction Two haploid (1n) gametes are brought together through fertilization to form a diploid (2n) zygote Two haploid (1n) gametes are brought together through fertilization to form a diploid (2n) zygote

82. 82 Fertilization – “Putting it all together” 1n =3 2n = 6

83. 83 Replication of Chromosomes Replication is the process of duplicating a chromosome Replication is the process of duplicating a chromosome Occurs prior to division Occurs prior to division Replicated copies are called sister chromatids Replicated copies are called sister chromatids Held together at centromere Held together at centromere Occurs in Interphase

84. 84 A Replicated Chromosome Homologs Homologs (same genes, different alleles) (same genes, different alleles) Sister Chromatids (same genes, same alleles) Gene X Homologs separate in meiosis I and therefore different alleles separate.

85. 85 Meiosis Forms Haploid Gametes Meiosis must reduce the chromosome number by half Meiosis must reduce the chromosome number by half Fertilization then restores the 2n number Fertilization then restores the 2n number from momfrom dadchild meiosis reduces genetic content too much! The right number!

86. 86 Meiosis: Two Part Cell Division Homologsseparate Sisterchromatidsseparate Diploid Meiosis I Meiosis II Diploid Haploid

87. 87 Meiosis I: Reduction Division Nucleus Spindlefibers Nuclearenvelope Early Prophase I (Chromosome number doubled) Late Prophase I Metaphase I Anaphase I Telophase I (diploid)

88. 88 Prophase I Early prophase Homologs pair. Homologs pair. Crossing over occurs Crossing over occurs. Late prophase Chromosomes condense. Chromosomes condense. Spindle forms. Spindle forms. Nuclear envelope fragments. Nuclear envelope fragments.

89. 89 Tetrads Form in Prophase I Homologous chromosomes (each with sister chromatids) Homologous chromosomes (each with sister chromatids) Join to form a TETRAD Called Synapsis

90. 90 Crossing-Over Homologous chromosomes in a tetrad cross over each other Homologous chromosomes in a tetrad cross over each other Pieces of chromosomes or genes are exchanged Pieces of chromosomes or genes are exchanged Produces Genetic recombination in the offspring Produces Genetic recombination in the offspring

91. 91 Homologous Chromosomes During Crossing-Over

92. 92 Crossing-over multiplies the already huge number of different gamete types produced by independent assortment Crossing-Over

93. 93 Metaphase I Homologous pairs of chromosomes align along the equator of the cell

94. 94 Anaphase I Homologs separate and move to opposite poles. Sister chromatids remain attached at their centromeres attached at their centromeres.

95. 95 Telophase I Nuclear envelopes reassemble. Spindle disappears. Cytokinesis divides cell into two.

96. 96 Meiosis II Only one homolog of each chromosome is present in the cell Only one homolog of each chromosome is present in the cell. Meiosis II produces gametes with one copy of each chromosome and thus one copy of each gene. Sister chromatids carry identical genetic information. Gene X

97. 97 Meiosis II: Reducing Chromosome Number Prophase II Metaphase II Anaphase II Telophase II 4 Identical haploid cells

98. 98 Prophase II Nuclear envelope fragments. Spindle forms.

99. 99 Metaphase II Chromosomes align along equator of cell.

100. 100 Anaphase II Sister chromatids separate and move to opposite poles Sister chromatids separate and move to opposite poles. Equator Pole

101. 101 Telophase II Nuclear envelope assembles. Chromosomes decondense. Spindle disappears. Cytokinesis divides cell into two.

102. 102 Results of Meiosis Gametes (egg & sperm) form Four haploid cells with one copy of each chromosome One allele of each gene Different combinations of alleles for different genes along the chromosome

103. 103 Meiosis Animation

104. 104 Gametogenesis Oogenesis or Spermatogenesis

105. 105 Spermatogenesis Occurs in the testes Occurs in the testes Two divisions produce 4 spermatids Two divisions produce 4 spermatids Spermatids mature into sperm Spermatids mature into sperm Men produce about 250,000,000 sperm per day Men produce about 250,000,000 sperm per day

106. 106 Spermatogenesis in the Testes Spermatid

107. 107Spermatogenesis

108. 108 Oogenesis Occurs in the ovaries Occurs in the ovaries Two divisions produce 3 polar bodies that die and 1 egg Two divisions produce 3 polar bodies that die and 1 egg Polar bodies die because of unequal division of cytoplasm Polar bodies die because of unequal division of cytoplasm Immature egg called oocyte Immature egg called oocyte Starting at puberty, one oocyte matures into an ovum (egg) every 28 days Starting at puberty, one oocyte matures into an ovum (egg) every 28 days

109. 109 Oogenesis in the Ovaries

110. 110 Oogenesis Oogonium(diploid) Mitosis Primaryoocyte(diploid) Meiosis I Secondaryoocyte(haploid) Meiosis II (if fertilization occurs) First polar body may divide (haploid)Polarbodiesdie Ovum (egg) Second polar body (haploid) a A X X a X A X a X a X Matureegg A X A X

111. 111 Comparing Mitosis and Meiosis

112. 112 MitosisMeiosis Number of divisions 12 Number of daughter cells 24 Genetically identical? YesNo Chromosome # Same as parent Half of parent Where Somatic cells Germ cells When Throughout life At sexual maturity Role Growth and repair Sexual reproduction Comparison of Divisions

113. 113