CELL DIVISION
CELL DIVISIONWhy do cells need todivide?-To allow an organismto grow.-To pass on geneticmaterial.-To assist an organismssu...
CELL DIVISION              2 types of cell division Mitosis                                  Meiosis-daughter             ...
CELL DIVISION             2 types of cell division         Mitosis                       Meiosis-daughter cells are       ...
CELL DIVISION6 stages ofcell division:1) Interphase2) Prophase          Mitosis3) Metaphase     - The division of         ...
CELL DIVISIONInterphase- Cell is not dividing but  also not dormant- Cell is active,  growing, and  preparing for division...
CELL DIVISION                      G0Interphase:4 stagesGap 0 (G0): - Cell rest cycle - Some cells spend their entire live...
CELL DIVISION                      G0Interphase:4 stagesGap 1 (G1): - Rapid growth (4hrs) - Cell takes in nutrients for en...
CELL DIVISION                          G0Interphase:4 stagesS phase (S):  - ~10 hrs  - DNA synthesis/  replication  - Cell...
CELL DIVISION                        G0Interphase:4 stagesGap 2 phase (G2): - ~4 hrs - Second period of growth in preparat...
CELL DIVISIONS phase (S): Let’s take  a closer look  - The cell duplicates its  DNA.  - What is DNA?- Deoxyribonucleic aci...
CELL DIVISIONDeoxyribonucleic acid2 Strands of attached  nucleotides:
CELL DIVISIONDeoxyribonucleic acid2 Strands of  nucleotides:- Phosphate (PO4)- Nucleobase- Sugar (deoxyribose)
CELL DIVISIONNucleotide bases enable  the coding of genetic      information.   A – Adenine   T – Thymine   G – Guanine   ...
CELL DIVISION- The "coded" information  is the sequence of  nucleotide bases  A – Adenine  T – Thymine  G – Guanine  C – C...
CELL DIVISION- This is the genetic  language.For example,    A CG    makes  Threonine
CELL DIVISIONOn opposing strands:- A attracts only T- G attracts only C  The bases attract  through HYDROGEN  BONDING.  Th...
CELL DIVISION  -adenine
CELL DIVISION- C and G bond together with 3 hydrogen bonds.- A and T bond together with 2 hydrogen bonds.
CELL DIVISION- C and G bond together with 3 hydrogen bonds.- A and T bond together with 2 hydrogen bonds.
CELL DIVISION                      A&T                 C&GWhich ones are A&T?         C&G                                 ...
CELL DIVISION- How does DNA replicate?STEP 1: Separation of the two DNA strandsH-Bonds
CELL DIVISION- How does DNA replicate?STEP 2: Each parent strand attracts  matching nucleotide bases to form  a new chain ...
CELL DIVISIONBut DNA is a very long molecule.Does replication start from one end?  Not usually. It can start at various po...
CELL DIVISIONThere are 3 models of  replication:
CELL DIVISION…Back to interphase where DNA duplication occurs.                     DNA                  Replication     No...
CELL DIVISIONBut wait, how does all of the DNA remain         organized in the nucleus?        Why does it not tangle?
CELL DIVISIONDNA strands are wrapped around histone     proteins which act as “spools”.
CELL DIVISIONHistone proteins that have been wrapped      with DNA form “nucleosomes”.
CELL DIVISIONMoving into mitosis…After interphase, the cellenters mitotic (M) phase: -Cell division occurs through:    A) ...
CELL DIVISIONProphase- Nuclear  membrane and  nucleolus break  down.- Centrosome  divides into 2  centrioles which  begin ...
CELL DIVISIONProphase- Nuclear  membrane and  nucleolus break  down.- Centrosome  divides into 2  centrioles which  begin ...
CELL DIVISIONProphase chromatin  condenses
CELL DIVISIONProphase- Chromosomes  shorten and  thicken into X-  shaped structures  called dyads.
CELL DIVISIONProphase- Remember, every chromosome has been duplicated  during the S phase of interphase.           2 copie...
CELL DIVISIONProphase- A centromere holds two copies of the same  chromosome together.- Each identical chromosome is calle...
CELL DIVISIONMetaphase- Proteins attach to the  centromeres creating  the kinetochores.- Microtubules (spindle  fibres) at...
CELL DIVISIONMetaphase
CELL DIVISIONAnaphase- Paired chromosomes  separate at the  kinetochores and move  to opposite sides of the  cell.- Motion...
CELL DIVISIONTelophase- Chromatids arrive at  opposite poles of cell.- New daughter nuclei  form.- Chromosomes disperse  a...
CELL DIVISIONCytokinesis- Animal cells: the cell membrane pinches (forming a  cleavage furrow) into two daughter cells, ea...
CELL DIVISIONCytokinesis- In plant cells, a cell plate (made of rigid cellulose)  is synthesized between the two daughter ...
CELL DIVISIONMitosis and cytokinesis: Review
CELL DIVISION         Mitosis and cytokinesis: Haploid and DiploidHaploid = 1 set of chromosomes (ex. n=23 chromosomes)Dip...
CELL DIVISION        Karyotype: Photograph of chromosomes taken at the        metaphase stage of mitosis. Homologous pairs...
CELL DIVISION                                       Karyotype: Technique1) Treat the cells with a solution that   will mak...
CELL DIVISIONKaryotype: Technique                        But during mitosis                          (metaphase),         ...
CELL DIVISION  Homologous pairsIdentified by:-chromosome length-centromere position-banding (staining)pattern-satellites (...
CELL DIVISION              Recall: 2 types of cell division Mitosis                                          Meiosis-daugh...
CELL DIVISIONMeiosis: The production of gametes-2 cell divisions (meiosis I and meiosis II)-Daughter cells are genetically...
CELL DIVISIONMeiosis I:Prophase I:-start with 2x the normalamount of chromosomes-chromosomes condense-nuclear membrane and...
CELL DIVISIONMeiosis I:Prophase I:-homologous dyads cometogether, forming tetrads-they overlap in a processcalled synapsis...
CELL DIVISIONMeiosis I:Prophase I:  -dyads come togetherin homologous pairs,forming tetrads -they overlap in aprocess call...
CELL DIVISIONMeiosis I:Prophase I:   Chiasma:     crossover point
CELL DIVISIONMeiosis I:Metaphase I-chromosomesattach themselves   Same as mitosis,to spindle fibres   except the          ...
CELL DIVISIONMeiosis I:Anaphase I                       Same as mitosis,- Homologous pairs     except theseparate and move...
CELL DIVISIONMeiosis I:Telophase I-cleavage furrow forms                         Same as mitosis-nuclear membranesand nucl...
CELL DIVISIONMeiosis II:Second cell division (both Meiosis I daughter cellsperform meiosis II)         Phase              ...
CELL DIVISION
CELL DIVISION
CELL DIVISION
CELL DIVISION           Mitosis                      vs.                   Meiosis                         Diploid (2n)   ...
CELL DIVISION                             Maternal Chromosome A                       Paternal Chromosome A               ...
CELL DIVISIONWhy is meiosis important?1. allows continuity2. ensures genetic diversity   within populationDiversity is gen...
CELL DIVISIONHow does this relate to Mendel?       Monohybrid cross  Before the process of meiosis  was discovered, Mendel...
CELL DIVISIONHow does this relate to Mendel?2)Law of Independent  Assortment:  Alleles from different  chromosomes pass to...
CELL DIVISIONHow does this relate to Mendel?Made possible bythe final division inMeiosis II                               ...
CELL DIVISIONHow does this relate to Mendel?
CELL DIVISION Mistakes during meiosis: Errors during Independent Assortment      Non-disjunction                      Norm...
CELL DIVISIONMistakes during meiosis: Errors during Independent AssortmentAneuploidy: A condition that results when there ...
CELL DIVISION      What are the possible zygotes when a normal gamete is                 joined with a non-disjunct gamete...
CELL DIVISIONMistakes during meiosis: Errors during Independent Assortment Monosomy: A condition in which an individual ha...
CELL DIVISIONMistakes during meiosis: Errors during Independent Assortment    Trisomy: A condition in which an individual ...
CELL DIVISIONMistakes during meiosis: Errors during Independent AssortmentPolysomy: A condition in which an individual has...
CELL DIVISIONMistakes during meiosis: Errors during Independent AssortmentHaploid (n): having one copy of an entire chromo...
CELL DIVISION  Mistakes during meiosis: Errors during Independent AssortmentHow is it possible to get 3 or more    copies ...
CELL DIVISIONCondition   Final # of    Affected     Characteristic            chromosomes   chromosomeDown     47         ...
CELL DIVISIONCondition   Final # of    Affected        Characteristic            chromosomes   chromosomeTurner’s 45      ...
CELL DIVISIONCondition       Final # of    Affected       Characteristic                chromosomes   chromosomeKlinefelte...
CELL DIVISIONCondition   Final # of    Affected      Characteristic            chromosomes   chromosomeJacob’s     47 or m...
CELL DIVISIONCondition   Final # of    Affected       Characteristic            chromosomes   chromosomeSuper       47 or ...
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06 cell division

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  • Hornets kill bees: http://www.youtube.com/watch?v=L54exo8JTUs&feature=fvwrel Hornets from Hell: http://www.youtube.com/watch?v=R5QxUR-mZVM
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  • 06 cell division

    1. 1. CELL DIVISION
    2. 2. CELL DIVISIONWhy do cells need todivide?-To allow an organismto grow.-To pass on geneticmaterial.-To assist an organismssurvival.
    3. 3. CELL DIVISION 2 types of cell division Mitosis Meiosis-daughter -daughter cells are cells aregenetically genetically identical different
    4. 4. CELL DIVISION 2 types of cell division Mitosis Meiosis-daughter cells are -daughter cells aregenetically identical genetically different-performed by somatic - performed to create sexbody cells (ex. bone cells (gametes: spermnerve, or tissues) and egg cells)- parts of the body withhigh rates of attritionmust perform mitosismore often (ex.fingertips vs. liver cells)
    5. 5. CELL DIVISION6 stages ofcell division:1) Interphase2) Prophase Mitosis3) Metaphase - The division of the cells4) Anaphase nucleus and all genetic5) Telophase material.6) Cytokinesis
    6. 6. CELL DIVISIONInterphase- Cell is not dividing but also not dormant- Cell is active, growing, and preparing for division- Chromosomes are not visible (chromatin present).
    7. 7. CELL DIVISION G0Interphase:4 stagesGap 0 (G0): - Cell rest cycle - Some cells spend their entire lives in G0 (they are functional but no new cells are produced (i.e. neuron)
    8. 8. CELL DIVISION G0Interphase:4 stagesGap 1 (G1): - Rapid growth (4hrs) - Cell takes in nutrients for energy, growth, repair - Cells either go into S or G0 after G1
    9. 9. CELL DIVISION G0Interphase:4 stagesS phase (S): - ~10 hrs - DNA synthesis/ replication - Cell duplicates its genetic material to make identical copies of its DNA.
    10. 10. CELL DIVISION G0Interphase:4 stagesGap 2 phase (G2): - ~4 hrs - Second period of growth in preparation for cell division. -Cell grows larger in size.
    11. 11. CELL DIVISIONS phase (S): Let’s take a closer look - The cell duplicates its DNA. - What is DNA?- Deoxyribonucleic acid.- Contains genetic information in coded form.
    12. 12. CELL DIVISIONDeoxyribonucleic acid2 Strands of attached nucleotides:
    13. 13. CELL DIVISIONDeoxyribonucleic acid2 Strands of nucleotides:- Phosphate (PO4)- Nucleobase- Sugar (deoxyribose)
    14. 14. CELL DIVISIONNucleotide bases enable the coding of genetic information. A – Adenine T – Thymine G – Guanine C – Cytosine
    15. 15. CELL DIVISION- The "coded" information is the sequence of nucleotide bases A – Adenine T – Thymine G – Guanine C – Cytosine Every 3 nucleotide bases (called a codon) code for 1 specific amino acid.
    16. 16. CELL DIVISION- This is the genetic language.For example, A CG makes Threonine
    17. 17. CELL DIVISIONOn opposing strands:- A attracts only T- G attracts only C The bases attract through HYDROGEN BONDING. This is called complimentary base pairing.
    18. 18. CELL DIVISION -adenine
    19. 19. CELL DIVISION- C and G bond together with 3 hydrogen bonds.- A and T bond together with 2 hydrogen bonds.
    20. 20. CELL DIVISION- C and G bond together with 3 hydrogen bonds.- A and T bond together with 2 hydrogen bonds.
    21. 21. CELL DIVISION A&T C&GWhich ones are A&T? C&G A&TWhich ones are C&G?
    22. 22. CELL DIVISION- How does DNA replicate?STEP 1: Separation of the two DNA strandsH-Bonds
    23. 23. CELL DIVISION- How does DNA replicate?STEP 2: Each parent strand attracts matching nucleotide bases to form a new chain (enzymes help). New chain Nucleotide bases
    24. 24. CELL DIVISIONBut DNA is a very long molecule.Does replication start from one end? Not usually. It can start at various points in "bubbles".
    25. 25. CELL DIVISIONThere are 3 models of replication:
    26. 26. CELL DIVISION…Back to interphase where DNA duplication occurs. DNA Replication Normally After duplication
    27. 27. CELL DIVISIONBut wait, how does all of the DNA remain organized in the nucleus? Why does it not tangle?
    28. 28. CELL DIVISIONDNA strands are wrapped around histone proteins which act as “spools”.
    29. 29. CELL DIVISIONHistone proteins that have been wrapped with DNA form “nucleosomes”.
    30. 30. CELL DIVISIONMoving into mitosis…After interphase, the cellenters mitotic (M) phase: -Cell division occurs through: A) Mitosis – Process of dividing nuclear material. B) Cytokinesis - Process of separating the cytoplasm and its contents into equal parts. M phase takes ~2 hours in humans.
    31. 31. CELL DIVISIONProphase- Nuclear membrane and nucleolus break down.- Centrosome divides into 2 centrioles which begin forming the spindle fibres.
    32. 32. CELL DIVISIONProphase- Nuclear membrane and nucleolus break down.- Centrosome divides into 2 centrioles which begin forming the spindle fibres.
    33. 33. CELL DIVISIONProphase chromatin condenses
    34. 34. CELL DIVISIONProphase- Chromosomes shorten and thicken into X- shaped structures called dyads.
    35. 35. CELL DIVISIONProphase- Remember, every chromosome has been duplicated during the S phase of interphase. 2 copies of each chromosome:Father’s Mother’s Father’s Mother’sside side side Father’s side Mother’s Mitosis side side *Colors are not accurate
    36. 36. CELL DIVISIONProphase- A centromere holds two copies of the same chromosome together.- Each identical chromosome is called a sister chromatid.
    37. 37. CELL DIVISIONMetaphase- Proteins attach to the centromeres creating the kinetochores.- Microtubules (spindle fibres) attach at the kinetochores and the chromosomes move to the centre (the metaphase plate)
    38. 38. CELL DIVISIONMetaphase
    39. 39. CELL DIVISIONAnaphase- Paired chromosomes separate at the kinetochores and move to opposite sides of the cell.- Motion results from kinetochore movement along the spindle microtubules.
    40. 40. CELL DIVISIONTelophase- Chromatids arrive at opposite poles of cell.- New daughter nuclei form.- Chromosomes disperse and become chromatin.- Spindle fibres disperse.
    41. 41. CELL DIVISIONCytokinesis- Animal cells: the cell membrane pinches (forming a cleavage furrow) into two daughter cells, each with one nucleus
    42. 42. CELL DIVISIONCytokinesis- In plant cells, a cell plate (made of rigid cellulose) is synthesized between the two daughter cells.
    43. 43. CELL DIVISIONMitosis and cytokinesis: Review
    44. 44. CELL DIVISION Mitosis and cytokinesis: Haploid and DiploidHaploid = 1 set of chromosomes (ex. n=23 chromosomes)Diploid = 2 sets of chromosomes (ex. 2n= 46 chromosomes)Tetraploid = 4 sets of chromosomes (ex. 4n = 92 chromosomes) 2n 2n 2n 4n 4n
    45. 45. CELL DIVISION Karyotype: Photograph of chromosomes taken at the metaphase stage of mitosis. Homologous pairs are identified and placed together.daddy mommy Homologous pair
    46. 46. CELL DIVISION Karyotype: Technique1) Treat the cells with a solution that will make them swell-up, which spreads the chromosomes.2) Use a chemical to stop mitosis in metaphase.3) Compress the cells on a slide and take a high resolution photograph.5) Cutting up a photomicrograph and arranging the result into a karyogram.
    47. 47. CELL DIVISIONKaryotype: Technique But during mitosis (metaphase), chromosomes are in duplicated pairs. So each homologous pair consists of 2 dyads. Scientists can cut the photographs so that only one chromatid of every dyad is displayed.
    48. 48. CELL DIVISION Homologous pairsIdentified by:-chromosome length-centromere position-banding (staining)pattern-satellites (tips) andany other physicalcharacteristics
    49. 49. CELL DIVISION Recall: 2 types of cell division Mitosis Meiosis-daughter -daughter cells are cells aregenetically genetically identical different
    50. 50. CELL DIVISIONMeiosis: The production of gametes-2 cell divisions (meiosis I and meiosis II)-Daughter cells are genetically unique-4 daughter cells are produced-Daughter cells are haploid
    51. 51. CELL DIVISIONMeiosis I:Prophase I:-start with 2x the normalamount of chromosomes-chromosomes condense-nuclear membrane and Same as mitosisnucleolus dissolve-centrioles split
    52. 52. CELL DIVISIONMeiosis I:Prophase I:-homologous dyads cometogether, forming tetrads-they overlap in a processcalled synapsis-crossing-over of geneticmaterial, causing exchange ofsegments of DNA, producingrecombinant chromosomes
    53. 53. CELL DIVISIONMeiosis I:Prophase I: -dyads come togetherin homologous pairs,forming tetrads -they overlap in aprocess called synapsis -crossing-over occurs,causing exchange of tetradsegments of DNA
    54. 54. CELL DIVISIONMeiosis I:Prophase I: Chiasma: crossover point
    55. 55. CELL DIVISIONMeiosis I:Metaphase I-chromosomesattach themselves Same as mitosis,to spindle fibres except the chromosomes are no longer identical-chromosomes line (they areup at equatorial recombinant).plate
    56. 56. CELL DIVISIONMeiosis I:Anaphase I Same as mitosis,- Homologous pairs except theseparate and move chromosomes areto opposite poles of no longer identical (they arethe cell recombinant).(tetrads are pulledapart, dyads moveto the poles)
    57. 57. CELL DIVISIONMeiosis I:Telophase I-cleavage furrow forms Same as mitosis-nuclear membranesand nucleoli reform-chromosomes DO NOTun-condense
    58. 58. CELL DIVISIONMeiosis II:Second cell division (both Meiosis I daughter cellsperform meiosis II) Phase Meiosis Prophase II -nuclear membranes and nucleoli dissolve -more spindle fibres form -chromosomes attach to spindle Metaphase II -chromosomes line up at equatorial plate Anaphase II -sister chromatids from each dyad separate and move to opposite poles Telophase II -spindle fibres dissipate -nuclei and nucleoli reform
    59. 59. CELL DIVISION
    60. 60. CELL DIVISION
    61. 61. CELL DIVISION
    62. 62. CELL DIVISION Mitosis vs. Meiosis Diploid (2n) 46 46 Diploid (2n) Diploid (2n) Diploid (2n) 46 46 46 46Diploid (2n) Diploid (2n) 23 23 23 23 Haploid Haploid Haploid Haploid (1n) (1n) (1n) (1n)
    63. 63. CELL DIVISION Maternal Chromosome A Paternal Chromosome A 46 DNA Replication DNA Replication 92 92 Sister chromatids Division #1 (Meiosis I) Synapsis and crossing over Synapsis and crossing over 92 92 Metaphase I, anaphase I, & telophase I Metaphase I, anaphase I, & telophase I 46 46 46 46Division #2 (Meiosis II) Meiosis II 23 23 23 23 23 23 23
    64. 64. CELL DIVISIONWhy is meiosis important?1. allows continuity2. ensures genetic diversity within populationDiversity is generated through…1) crossing-over (makes diverse chromosomes)2) random assortment (each gamete is different)3) random fertilization (random sperm meets with random mature egg)
    65. 65. CELL DIVISIONHow does this relate to Mendel? Monohybrid cross Before the process of meiosis was discovered, Mendel’s observations led him to make 2 conclusions:1)Law of Segregation: 2 alleles for each trait separate during gamete formation (i.e. parents can only pass 1 of their 2 alleles for any trait to their offspring).
    66. 66. CELL DIVISIONHow does this relate to Mendel?2)Law of Independent Assortment: Alleles from different chromosomes pass to gametes randomly – alleles are not connected to or passed on with any other alleles. For example, the allele for pea shape and the allele for pea color are passed onto offspring without relation to one-another.
    67. 67. CELL DIVISIONHow does this relate to Mendel?Made possible bythe final division inMeiosis II Made possible by different chromosomes having different alleles All daughter cells are different
    68. 68. CELL DIVISIONHow does this relate to Mendel?
    69. 69. CELL DIVISION Mistakes during meiosis: Errors during Independent Assortment Non-disjunction Normal Meiosis Non-disjunction: 46 Failure of dyads or 46 tetrads to separate during anaphase I or anaphase II 44 48 46 4622 22 24 24 23 23 23 23
    70. 70. CELL DIVISIONMistakes during meiosis: Errors during Independent AssortmentAneuploidy: A condition that results when there is a missing or extra chromosome, resulting in changes to the normal chromosome number
    71. 71. CELL DIVISION What are the possible zygotes when a normal gamete is joined with a non-disjunct gamete?Non-disjunct egg sperm egg Non-disjunct sperm 22 23 23 24 45 47 Monosomy Trisomy
    72. 72. CELL DIVISIONMistakes during meiosis: Errors during Independent Assortment Monosomy: A condition in which an individual has only one homologue of a specific pair of homologues
    73. 73. CELL DIVISIONMistakes during meiosis: Errors during Independent Assortment Trisomy: A condition in which an individual has three homologues of a specific chromosome.
    74. 74. CELL DIVISIONMistakes during meiosis: Errors during Independent AssortmentPolysomy: A condition in which an individual has more than the normal number of a specific chromosome.
    75. 75. CELL DIVISIONMistakes during meiosis: Errors during Independent AssortmentHaploid (n): having one copy of an entire chromosome set (e.g. sex cells)Diploid (2n): having two copies of an entire chromosome set (e.g. somatic cells)Triploid (3n): having three copies of an entire chromosome setPolyploidy: A condition in which an individual has three or more copies of an entire chromosome set
    76. 76. CELL DIVISION Mistakes during meiosis: Errors during Independent AssortmentHow is it possible to get 3 or more copies of a chromosome?
    77. 77. CELL DIVISIONCondition Final # of Affected Characteristic chromosomes chromosomeDown 47 #21 Broad flat face, slanting eyes,syndrome short, growth failure, mental disabilities, congenital heart disease.
    78. 78. CELL DIVISIONCondition Final # of Affected Characteristic chromosomes chromosomeTurner’s 45 X chromosome Short, facial hair, undevelopedsyndrome (sex breast, degenerate ovaries, chromosome) infertile.
    79. 79. CELL DIVISIONCondition Final # of Affected Characteristic chromosomes chromosomeKlinefelter’s 47 or more X chromosome Tall, longer limbs, poor beardsyndrome growth, feminized physique, loose chest hairs, underdeveloped penis and testes, infertile
    80. 80. CELL DIVISIONCondition Final # of Affected Characteristic chromosomes chromosomeJacob’s 47 or more Y chromosome Normal male, tall, “aggressive”syndrome (often unnoticed, 1/1000 males)
    81. 81. CELL DIVISIONCondition Final # of Affected Characteristic chromosomes chromosomeSuper 47 or more X chromosome Normal female, “aggressive”,female taller, delayed motor skills, often unnoticed, 1/1000 females

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