Cellular          Division             Unicellular: for reproductionMulticellular: growth/repair of damaged body parts    ...
Words to know• DNA/RNA• Chromosomes - organized structure of DNA and  protein• Chromatins - mass of genetic material compo...
Cell DivisionAll cells are derived from pre- existing cellsNew cells are produced for growth and to replace damaged or o...
Keeping Cells IdenticalThe instructions for making cell parts are encoded in the DNA, so each new cell must get a complete...
DNA ReplicationDNA must be copied or         Original DNA                       strand replicated before cell division   ...
Identical Daughter Cells                       Two                     identical                     daughter             ...
Chromosomesstructure within the cell  that bears the genetic      or as a circularmaterial as a threadlike    strand of DN...
Prokaryotic ChromosomeThe DNA of prokaryotes (bacteria) is one, circular chromosome attached to the inside of the cell me...
Eukaryotic ChromosomesAll eukaryotic cells store genetic information in chromosomesMost eukaryotes have between 10 and 5...
Eukaryotic ChromosomesEach chromosome is composed of a single, tightly coiled DNA moleculeChromosomes can’t be seen (wit...
Compacting DNA into        ChromosomesDNA is tightly coiled around proteins called histones                           11
Chromosomes in Dividing CellsDuplicated chromosomes are called chromatids & are held together by the centromere          ...
KaryotypeA picture of the chromosomes from a human cell arranged in pairs by sizeFirst 22 pairs are called autosomesLas...
Boy or Girl?The Y Chromosome Decides                    Y - Chromosome   X - Chromosome                                   ...
Cell Reproduction                    15
Types of Cell ReproductionAsexual reproduction involves a single cell dividing to make 2 new, identical daughter cellsMi...
Division Mechanisms  Prokaryotic organisms        – Binary fission  Eukaryotic organisms             – Mitosis   • Karyoki...
Cell Division in Prokaryotes                   18
Cell Division in Prokaryotes Prokaryotes such as                            Parent  bacteria divide into 2               ...
Prokaryotic CellUndergoing Binary Fission                            20
Animation of Binary Fission                              21
The Cell Cycle           22
Five Phases of the Cell CycleG1 - primary growth/gap phaseS – synthesis; DNA replicatedG2 - secondary growth/gap phase ...
Cell Cycle             24
Interphase - G1 Stage1st growth/gap stage after cell divisionCells mature by making more cytoplasm & organellesCell car...
Interphase – S StageSynthesis stageDNA is copied or replicated                                  Two                     ...
Interphase – G2 Stage2nd Growth/Gap StageOccurs after DNA has been copie; also in preparation for M phaseAll cell struc...
What’s Happening in Interphase?What the cell looks like      Animal CellWhat’s occurring                             28
Sketch the Cell Cycle                    DNA Copied                                 Cells prepare for            Cells    ...
Mitosis          30
MitosisDivision of the nucleus (karyokinesis)Division of the cytoplasm (cytokinesis)Only occurs in eukaryotesHas four ...
Four Mitotic StagesProphaseMetaphaseAnaphaseTelophase                          32
Early ProphaseChromatin in nucleus condenses to form visible chromosomesMitotic spindle forms from fibers in cytoskeleto...
Late ProphaseNuclear membrane & nucleolus are broken downChromosomes continue condensing & are clearly visibleSpindle f...
Late ProphaseChromosomes       Nucleus & Nucleolus have disintegrated                                                35
Spindle Fiber attached to         ChromosomeKinetochore Fiber Chromosome                              36
Review of ProphaseWhat the cell looks like                What’s happening   37
Spindle FibersThe mitotic spindle form from the microtubules in plants and centrioles in animal cellsPolar fibers extend...
Sketch The Spindle                     39
Metaphase  Chromosomes, attached to the   kinetochore fibers, move to the center   of the cell  Chromosomes are now line...
MetaphaseAsters atthe polesSpindle      ChromosomesFibers       lined at the             Equator                          ...
MetaphaseAster        Chromosomes at Equator                                 42
Review of MetaphaseWhat the cell looks       like  What’s occurring                             43
AnaphaseOccurs rapidlySister chromatids are pulled apart to opposite poles of the cell by kinetochore fibers            ...
Anaphase  SisterChromatids   beingseparated                        45
Anaphase ReviewWhat thecell looks   like What’soccurring                               46
TelophaseSister chromatids at opposite polesSpindle disassemblesNuclear envelope forms around each set of sister chroma...
Comparison of Anaphase & Telophase                                 48
CytokinesisMeans division of the cytoplasmDivision of cell into two, identical halves called daughter cellsIn plant cel...
CytokinesisCleavage furrow    Cell plate in  in animal cell    animal cell                                   50
Mitotic Stages                 51
Daughter Cells of MitosisHave the same number of chromosomes as each other and as the parent cell from which they were fo...
Identical Daughter Cells                                 What is                                  the 2n                  ...
Review  ofMitosis          54
Draw & Learn these Stages                            55
Draw & Learn these Stages                            56
Name the Mitotic Stages:            Interphase            Name this?                                         ProphaseTelop...
Eukaryotic Cell Division Used for growth and  repair Produce two new cells  identical to the original  cell             ...
Mitosis AnimationName each stage as you see it occur?                                       59
Mitosis in Onion Root Tips  Do you see any stages of mitosis?                                      60
Test Yourself over Mitosis                61
Mitosis Quiz               62
Mitosis Quiz               63
Name the Stages of Mitosis:                    Early prophase Early Anaphase                      Metaphase             In...
Identify the Stages                    ?          Early, Middle, & Late Prophase            ?                       ?   ? ...
Locate the Four Mitotic       Stages in Plants                   Anaphase                              Telophase          ...
Uncontrolled Mitosis If mitosis is not  controlled, unlimited  cell division occurs  causing cancerous  tumors Oncogenes...
MeiosisFormation of Gametes   (Eggs & Sperm)                       68
Words to knowGametes - reproductive cells that unite during sexual  reproduction to form a new cell called a zygote (male ...
Facts About MeiosisPreceded by interphase which includes chromosome replicationTwo meiotic divisions: Meiosis I and Meio...
Facts About MeiosisDaughter cells contain half the number of chromosomes as the original cellProduces gametes (eggs & sp...
More Meiosis Facts Start   with 46 double strandedchromosomes (2n)After 1 division - 23 doublestranded chromosomes (n)A...
Why Do we Need Meiosis?It is the fundamental basis of sexual reproductionTwo haploid (1n) gametes are brought together t...
Fertilization – “Putting it       all together”                     2n = 6 1n =3                              74
Replication of ChromosomesReplication is the process of duplicating a         Occurs in chromosome           InterphaseO...
A Replicated Chromosome              Gene X  Homologues                          Sister   (same genes,                    ...
Meiosis Forms Haploid Gametes Meiosis must reduce the chromosome number  by half Fertilization then restores the 2n numb...
Meiosis: Two Part Cell            Division                                 Sister                                 chromati...
Meiosis I: Reduction Division   Nucleus             Spindle                       fibers            Nuclear    Early      ...
Prophase IEarly prophase   Late prophaseHomologues      Chromosomes condense.pair.            Spindle forms.Crossing o...
Tetrads Form in Prophase I  Homologous chromosomes         Join to form a(each with sister chromatids)       TETRAD       ...
Crossing-Over  Homologous   chromosomes in a   tetrad cross over   each other  Pieces of   chromosomes or   genes are   ...
Homologous Chromosomes During Crossing-Over                         83
Crossing-OverCrossing-over multiplies the already huge   number of different gamete types  produced by independent assortm...
Metaphase I     Homologous pairs     of chromosomes      align along the      equator of the            cell              ...
Anaphase IHomologues separate andmove to opposite poles.Sister chromatids remainattached at theircentromeres.             ...
Telophase I Nuclear envelopes reassemble. Spindle disappears. Cytokinesis divides cell into two.                          ...
Meiosis II         Only one homologue of eachGene X          chromosome is present in          the cell.               cel...
Meiosis II: Reducing      Chromosome NumberProphase Metaphase   II                      Telophase            II           ...
Prophase II   Nuclear envelope   fragments.   Spindle forms.                      90
Metaphase II    Chromosomes align    along equator of cell.                         91
Anaphase IIEquator          Pole          Sister chromatids          separate and          move to opposite          poles...
Telophase II     Nuclear envelope     assembles.     Chromosomes     decondense.     Spindle disappears.     Cytokinesis d...
Results of Meiosis       Gametes (egg & sperm)       form       Four haploid cells with       one copy of each       chrom...
Gametogenesis  Oogenesis      orSpermatogenesis                  95
SpermatogenesisOccurs in the testesTwo divisions produce 4 spermatidsSpermatids mature into spermMen produce about 250...
Spermatogenesis in the       Testes         Spermatid                         97
Spermatogenesis                  98
OogenesisOccurs in the ovariesTwo divisions produce 3 polar bodies that die and 1 eggPolar bodies die because of unequa...
Oogenesis in the Ovaries                           100
Oogenesis                               First polar body                               may divide          a              ...
ComparingMitosis and Meiosis              102
Comparison of Divisions                   Mitosis             Meiosis   Number of                               2         ...
Meiosis                               Mitosis                                   A type of cellular reproduction in    A pr...
Quiz #11. The stage of the cell cycle where each   chromosome is composed of 2 chromatids in   preparation for mitosis.a. ...
3. Which sequence of the cell cycle is  common to eukaryotes?  a. G1, G2, S, M, cytokinesis  b. G1, M, G2, S, cytokinesis ...
5. If given the allele brown, which among the  genes below is it NOT an alternative form  of?a. Hair color                ...
7. Which of the following cells undergo  meiosis?a. Sperm cells           c. Brain cellsb. Kidney cells          d. All of...
9. How many chromosomes are there in a  mature human cell?  a. No chromosomes  b. 26 pairs of chromosomes  c. 44 chromosom...
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  • Replication is the process of duplicating chromosome. The new copy of a chromosome is formed by DNA synthesis during S-phase. The chromosome copies are called sister chromatids. Sister chromatids are held together at the centromere.
  • Cell cycle & cell division.htm

    1. 1. Cellular Division Unicellular: for reproductionMulticellular: growth/repair of damaged body parts Renewal/repair of worn out cells 1
    2. 2. Words to know• DNA/RNA• Chromosomes - organized structure of DNA and protein• Chromatins - mass of genetic material composed of DNA and proteins that condense to form chromosomes during eukaryotic cell division• Chromatids - each of the two threadlike strands into which a chromosome divides longitudinally during cell division. Each contains a double helix of DNA. 2
    3. 3. Cell DivisionAll cells are derived from pre- existing cellsNew cells are produced for growth and to replace damaged or old cellsAllows the cell to pass DNA copy to daughter cellsDiffers in prokaryotes (bacteria) and eukaryotes (protists, fungi, plants, & animals) 3
    4. 4. Keeping Cells IdenticalThe instructions for making cell parts are encoded in the DNA, so each new cell must get a complete set of the DNA molecules 4
    5. 5. DNA ReplicationDNA must be copied or Original DNA strand replicated before cell division Two new, identical DNAEach new cell strands will then have an identical copy of the DNA 5
    6. 6. Identical Daughter Cells Two identical daughter cells Parent Cell 6
    7. 7. Chromosomesstructure within the cell that bears the genetic or as a circularmaterial as a threadlike strand of DNA (or linear strand of DNA RNA in some bonded to various viruses) in the proteins in the nucleus cytoplasm of of eukaryotic cells prokaryotes 7
    8. 8. Prokaryotic ChromosomeThe DNA of prokaryotes (bacteria) is one, circular chromosome attached to the inside of the cell membrane 8
    9. 9. Eukaryotic ChromosomesAll eukaryotic cells store genetic information in chromosomesMost eukaryotes have between 10 and 50 chromosomes in their body cellsHuman body cells have 46 chromosomes or 23 identical pairs 9
    10. 10. Eukaryotic ChromosomesEach chromosome is composed of a single, tightly coiled DNA moleculeChromosomes can’t be seen (with a microscope) when cells aren’t dividing and are called chromatin 10
    11. 11. Compacting DNA into ChromosomesDNA is tightly coiled around proteins called histones 11
    12. 12. Chromosomes in Dividing CellsDuplicated chromosomes are called chromatids & are held together by the centromere Called Sister Chromatids 12
    13. 13. KaryotypeA picture of the chromosomes from a human cell arranged in pairs by sizeFirst 22 pairs are called autosomesLast pair are the sex chromosomesXX female or XY male 13
    14. 14. Boy or Girl?The Y Chromosome Decides Y - Chromosome X - Chromosome 14
    15. 15. Cell Reproduction 15
    16. 16. Types of Cell ReproductionAsexual reproduction involves a single cell dividing to make 2 new, identical daughter cells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 Meiosis is an example 16
    17. 17. Division Mechanisms Prokaryotic organisms – Binary fission Eukaryotic organisms – Mitosis • Karyokinesis (division of nucleus) • Cytokinesis (division of cytoplasm) – Meiosis
    18. 18. Cell Division in Prokaryotes 18
    19. 19. Cell Division in Prokaryotes Prokaryotes such as Parent bacteria divide into 2 cell identical cells by the process of binary fission Chromosome Single chromosome doubles makes a copy of itself Cell splits Cell wall forms between the chromosomes dividing the cell 2 identical daughter cells 19
    20. 20. Prokaryotic CellUndergoing Binary Fission 20
    21. 21. Animation of Binary Fission 21
    22. 22. The Cell Cycle 22
    23. 23. Five Phases of the Cell CycleG1 - primary growth/gap phaseS – synthesis; DNA replicatedG2 - secondary growth/gap phase collectively these 3 stages are called interphaseM - mitosisC - cytokinesis 23
    24. 24. Cell Cycle 24
    25. 25. Interphase - G1 Stage1st growth/gap stage after cell divisionCells mature by making more cytoplasm & organellesCell carries on its normal metabolic activities i.e. respiration, digestion etc. 25
    26. 26. Interphase – S StageSynthesis stageDNA is copied or replicated Two identical copies of DNA Original DNA 26
    27. 27. Interphase – G2 Stage2nd Growth/Gap StageOccurs after DNA has been copie; also in preparation for M phaseAll cell structures needed for division are made (e.g. centrioles)Both organelles & proteins are synthesized 27
    28. 28. What’s Happening in Interphase?What the cell looks like Animal CellWhat’s occurring 28
    29. 29. Sketch the Cell Cycle DNA Copied Cells prepare for Cells Division MatureDaughter Cells Cell Divides into Identical cells 29
    30. 30. Mitosis 30
    31. 31. MitosisDivision of the nucleus (karyokinesis)Division of the cytoplasm (cytokinesis)Only occurs in eukaryotesHas four stagesDoesn’t occur in some cells such as brain cells 31
    32. 32. Four Mitotic StagesProphaseMetaphaseAnaphaseTelophase 32
    33. 33. Early ProphaseChromatin in nucleus condenses to form visible chromosomesMitotic spindle forms from fibers in cytoskeleton or centrioles (animal) Nucleolus Cytoplasm Nuclear MembraneChromosomes 33
    34. 34. Late ProphaseNuclear membrane & nucleolus are broken downChromosomes continue condensing & are clearly visibleSpindle fibers called kinetochores attach to the centromere of each chromosomeSpindle finishes forming between the poles of the cell 34
    35. 35. Late ProphaseChromosomes Nucleus & Nucleolus have disintegrated 35
    36. 36. Spindle Fiber attached to ChromosomeKinetochore Fiber Chromosome 36
    37. 37. Review of ProphaseWhat the cell looks like What’s happening 37
    38. 38. Spindle FibersThe mitotic spindle form from the microtubules in plants and centrioles in animal cellsPolar fibers extend from one pole of the cell to the opposite poleKinetochore fibers extend from the pole to the centromere of the chromosome to which they attachAsters are short fibers radiating from centrioles 38
    39. 39. Sketch The Spindle 39
    40. 40. Metaphase Chromosomes, attached to the kinetochore fibers, move to the center of the cell Chromosomes are now lined up at the equator Equator of CellPole ofthe Cell 40
    41. 41. MetaphaseAsters atthe polesSpindle ChromosomesFibers lined at the Equator 41
    42. 42. MetaphaseAster Chromosomes at Equator 42
    43. 43. Review of MetaphaseWhat the cell looks like What’s occurring 43
    44. 44. AnaphaseOccurs rapidlySister chromatids are pulled apart to opposite poles of the cell by kinetochore fibers 44
    45. 45. Anaphase SisterChromatids beingseparated 45
    46. 46. Anaphase ReviewWhat thecell looks like What’soccurring 46
    47. 47. TelophaseSister chromatids at opposite polesSpindle disassemblesNuclear envelope forms around each set of sister chromatidsNucleolus reappearsCYTOKINESIS occursChromosomes reappear as chromatin 47
    48. 48. Comparison of Anaphase & Telophase 48
    49. 49. CytokinesisMeans division of the cytoplasmDivision of cell into two, identical halves called daughter cellsIn plant cells, cell plate forms at the equator to divide cellIn animal cells, cleavage furrow forms to split cell 49
    50. 50. CytokinesisCleavage furrow Cell plate in in animal cell animal cell 50
    51. 51. Mitotic Stages 51
    52. 52. Daughter Cells of MitosisHave the same number of chromosomes as each other and as the parent cell from which they were formedIdentical to each other, but smaller than parent cellMust grow in size to become mature cells (G1 of Interphase) 52
    53. 53. Identical Daughter Cells What is the 2n or diploid number? 2Chromosome number the same, but cells smaller than parent cell 53
    54. 54. Review ofMitosis 54
    55. 55. Draw & Learn these Stages 55
    56. 56. Draw & Learn these Stages 56
    57. 57. Name the Mitotic Stages: Interphase Name this? ProphaseTelophase Name this? Metaphase Anaphase 57
    58. 58. Eukaryotic Cell Division Used for growth and repair Produce two new cells identical to the original cell Chromosomes during Metaphase of mitosis Cells are diploid (2n) Prophase Metaphase Anaphase Telophase Cytokinesis 58
    59. 59. Mitosis AnimationName each stage as you see it occur? 59
    60. 60. Mitosis in Onion Root Tips Do you see any stages of mitosis? 60
    61. 61. Test Yourself over Mitosis 61
    62. 62. Mitosis Quiz 62
    63. 63. Mitosis Quiz 63
    64. 64. Name the Stages of Mitosis: Early prophase Early Anaphase Metaphase Interphase Early Telophase, Begin cytokinesis Late Late telophase, Prophase Advanced Mid-Prophase Late cytokinesis Anaphase 64
    65. 65. Identify the Stages ? Early, Middle, & Late Prophase ? ? ? Metaphase AnaphaseLate Prophase ? ? ?Late Anaphase Telophase Telophase & Cytokinesis 65
    66. 66. Locate the Four Mitotic Stages in Plants Anaphase Telophase MetaphaseProphase 66
    67. 67. Uncontrolled Mitosis If mitosis is not controlled, unlimited cell division occurs causing cancerous tumors Oncogenes are special proteins that increase the chance that a normal cell develops into a tumor cell Cancer cells 67
    68. 68. MeiosisFormation of Gametes (Eggs & Sperm) 68
    69. 69. Words to knowGametes - reproductive cells that unite during sexual reproduction to form a new cell called a zygote (male = sperm, female = egg cell)Germ cells – sperm or egg cellsSomatic cells - any cell other than the reproductive cellsDiploid - a cell that contains two sets of chromosomes (2n), as normally found in somatic cellsHaploid - have one set of chromosomes (n=1) as in germ cells, or half as many as a somatic cellHomologous – chromosomes that are alike in structure and genesAlleles – different forms of a gene ex. if talking about hair color as the gene, different alleles would be different colors like red, blonde, black etc. 69
    70. 70. Facts About MeiosisPreceded by interphase which includes chromosome replicationTwo meiotic divisions: Meiosis I and Meiosis IIAka reduction-divisionOriginal cell is diploid (2n)Four daughter cells produced that are haploid (n) 70
    71. 71. Facts About MeiosisDaughter cells contain half the number of chromosomes as the original cellProduces gametes (eggs & sperm)Occurs in the testes in males (Spermatogenesis)Occurs in the ovaries in females (Oogenesis)Human diploid cells have 46 chromosomes (2n=46)Human sperm and egg cells have 23 chromosomes (n=23) each 71
    72. 72. More Meiosis Facts Start with 46 double strandedchromosomes (2n)After 1 division - 23 doublestranded chromosomes (n)After 2nd division - 23 singlestranded chromosomes (n) Occurs in our germ cells 72
    73. 73. Why Do we Need Meiosis?It is the fundamental basis of sexual reproductionTwo haploid (1n) gametes are brought together through fertilization to form a diploid (2n) zygote 73
    74. 74. Fertilization – “Putting it all together” 2n = 6 1n =3 74
    75. 75. Replication of ChromosomesReplication is the process of duplicating a Occurs in chromosome InterphaseOccurs prior to divisionReplicated copies are called sister chromatidsHeld together at centromere 75
    76. 76. A Replicated Chromosome Gene X Homologues Sister (same genes, Chromatidsdifferent alleles) (same genes, same alleles) Homologues separate in meiosis I and therefore different alleles separate. 76
    77. 77. Meiosis Forms Haploid Gametes Meiosis must reduce the chromosome number by half Fertilization then restores the 2n number from mom from dad child too much! meiosis reduces genetic content The right number! 77
    78. 78. Meiosis: Two Part Cell Division Sister chromatids Homologues separate separate Meiosis Meiosis I IIDiploid Diploid Haploid 78
    79. 79. Meiosis I: Reduction Division Nucleus Spindle fibers Nuclear Early envelope Prophase I Late Metaphase(Chromosome Prophase I Anaphase Telophase I number I I (diploid) doubled) 79
    80. 80. Prophase IEarly prophase Late prophaseHomologues Chromosomes condense.pair. Spindle forms.Crossing over Nuclear envelopeoccurs. fragments. 80
    81. 81. Tetrads Form in Prophase I Homologous chromosomes Join to form a(each with sister chromatids) TETRAD Called Synapsis 81
    82. 82. Crossing-Over  Homologous chromosomes in a tetrad cross over each other  Pieces of chromosomes or genes are •Occurs in nonsister chromatids exchanged •Increases genetic variability  Produces Genetic recombination in the offspring Genetic recombination inwhich a strand of the geneticmaterial (DNA/RNA)is brokenand then joined to the end of a different DNA molecule. 82
    83. 83. Homologous Chromosomes During Crossing-Over 83
    84. 84. Crossing-OverCrossing-over multiplies the already huge number of different gamete types produced by independent assortment 84
    85. 85. Metaphase I Homologous pairs of chromosomes align along the equator of the cell 85
    86. 86. Anaphase IHomologues separate andmove to opposite poles.Sister chromatids remainattached at theircentromeres. 86
    87. 87. Telophase I Nuclear envelopes reassemble. Spindle disappears. Cytokinesis divides cell into two. 87
    88. 88. Meiosis II Only one homologue of eachGene X chromosome is present in the cell. cell Sister chromatids carry identical genetic information.Meiosis II produces gametes withone copy of each chromosome andthus one copy of each gene. 88
    89. 89. Meiosis II: Reducing Chromosome NumberProphase Metaphase II Telophase II Anaphase II 4 Identical II haploid cells 89
    90. 90. Prophase II Nuclear envelope fragments. Spindle forms. 90
    91. 91. Metaphase II Chromosomes align along equator of cell. 91
    92. 92. Anaphase IIEquator Pole Sister chromatids separate and move to opposite poles. 92
    93. 93. Telophase II Nuclear envelope assembles. Chromosomes decondense. Spindle disappears. Cytokinesis divides cell into two. 93
    94. 94. 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 94
    95. 95. Gametogenesis Oogenesis orSpermatogenesis 95
    96. 96. SpermatogenesisOccurs in the testesTwo divisions produce 4 spermatidsSpermatids mature into spermMen produce about 250,000,000 sperm per day 96
    97. 97. Spermatogenesis in the Testes Spermatid 97
    98. 98. Spermatogenesis 98
    99. 99. OogenesisOccurs in the ovariesTwo divisions produce 3 polar bodies that die and 1 eggPolar bodies die because of unequal division of cytoplasmImmature egg called oocyteStarting at puberty, one oocyte matures into an ovum (egg) every 28 days 99
    100. 100. Oogenesis in the Ovaries 100
    101. 101. Oogenesis First polar body may divide a (haploid) X a Polar bodies a X die a X X Mitosis Meiosis I Meiosis II A X (if fertilizationOogonium occurs) A(diploid) Primary X oocyte (diploid) A X Ovum (egg) Mature Secondary A egg oocyte X (haploid) Second polar body (haploid) 101
    102. 102. ComparingMitosis and Meiosis 102
    103. 103. Comparison of Divisions Mitosis Meiosis Number of 2 1 divisions Number of 2 4daughter cells Genetically Yes No identical?Chromosome # Same as parent Half of parent Where Somatic cells Reproductive cells When Throughout life At sexual maturity Growth and Role Sexual reproduction repair 103
    104. 104. Meiosis Mitosis A type of cellular reproduction in A process of asexual reproduction which the number of chromosomes in which the cell divides in twoDefinition: are reduced by half through the producing a replica, with an equal separation of homologous number of chromosomes in haploid chromosomes in a diploid cell. cell Cellular Reproduction & generalFunction: sexual reproduction growth and repair of the bodyType of Reproduction: Sexual AsexualOccurs in: Humans, animals, plants, fungi all organismsGenetically: different identical Yes, mixing of chromosomes canCrossing Over: No, crossing over cannot occur. occur.Pairing of Homologues: Yes NoNumber of Divisions: 2 1Number of Haploid Daughter Cells 4 2produced:Chromosome Number: Reduced by half Remains the same The steps of meiosis are The steps of mitosis are Interphase, Prophase I, Metaphase Interphase, Prophase, Metaphase,Steps: I, Anaphase I, Telophase I, Anaphase, Telophase and Prophase II, Metaphase II, Cytokinesis Anaphase II and Telophase II.Karyokenesis: Occurs in Interphase I Occurs in Interphase Occurs in Telophase I & TelohpaseCytokenesis: Occurs in Telophase II The centromeres do not separate The centromeres split duringCentromeres Split: during anaphase I, but during Anaphase anaphase II Sex cells only: Female egg cells or Makes everything other than sexCreates: 104
    105. 105. Quiz #11. The stage of the cell cycle where each chromosome is composed of 2 chromatids in preparation for mitosis.a. G1 c. Mb. S d. G22. Which of the following distinguishes prophase I of meiosis from prophase of mitosis?a. Homologue chromosomes pair upb. Spindle formsc. nuclear membrane breaks downd. chromosomes become visible 105
    106. 106. 3. Which sequence of the cell cycle is common to eukaryotes? a. G1, G2, S, M, cytokinesis b. G1, M, G2, S, cytokinesis c. G1, S, M, G2, cytokinesis d. G1, S, G2, M, cytokinesis4. A cell with forty two chromosomes divides mitotically. How many chromosomes will each gamete have?a. 21 c. 84b. 42 d. 168 106
    107. 107. 5. If given the allele brown, which among the genes below is it NOT an alternative form of?a. Hair color c. Nail colorb. Skin color d. Eye color6. Meiosis results in:a. 2 haploid daughter cellsb. 4 haploid daughter cellsc. 2 diploid daughter cellsd. 4 diploid daughter cells 107
    108. 108. 7. Which of the following cells undergo meiosis?a. Sperm cells c. Brain cellsb. Kidney cells d. All of the above8. Which refers to the region of attachment for two sister chromatids? a. Centriole c. Microtubule b. Cenromere d. Spindle fiber 108
    109. 109. 9. How many chromosomes are there in a mature human cell? a. No chromosomes b. 26 pairs of chromosomes c. 44 chromosomes and X and Y chromosomes d. 50 chromosomes10. Cytokinesis occurs during which phase of meiosis? a. Telophase c. Prophase b. Anaphase d. Metaphase 109
    110. 110. 110
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