Cell Cycle & Cell Division

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Cellular Division : 

1 Cellular Division copyright cmassengale

Cell Division : 

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

Keeping Cells Identical : 

3 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 copyright cmassengale

DNA Replication : 

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

Identical Daughter Cells : 

5 Identical Daughter Cells Parent Cell Two identical daughter cells copyright cmassengale

Chromosomes : 

6 Chromosomes copyright cmassengale

Prokaryotic Chromosome : 

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

Eukaryotic Chromosomes : 

8 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 copyright cmassengale

Eukaryotic Chromosomes : 

9 Eukaryotic Chromosomes 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 copyright cmassengale

Compacting DNA into Chromosomes : 

10 Compacting DNA into Chromosomes DNA is tightly coiled around proteins called histones copyright cmassengale

Chromosomes in Dividing Cells : 

11 Chromosomes in Dividing Cells Duplicated chromosomes are called chromatids & are held together by the centromere Called Sister Chromatids copyright cmassengale

Karyotype : 

12 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 copyright cmassengale

Boy or Girl? : 

13 Boy or Girl? Y - Chromosome X - Chromosome The Y Chromosome Decides copyright cmassengale

Cell Reproduction : 

14 Cell Reproduction copyright cmassengale

Types of Cell Reproduction : 

15 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 copyright cmassengale

Cell Division in Prokaryotes : 

16 Cell Division in Prokaryotes copyright cmassengale

Cell Division in Prokaryotes : 

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

Prokaryotic Cell Undergoing Binary Fission : 

18 Prokaryotic Cell Undergoing Binary Fission copyright cmassengale

Animation of Binary Fission : 

19 Animation of Binary Fission copyright cmassengale

The Cell Cycle : 

20 The Cell Cycle copyright cmassengale

Five Phases of the Cell Cycle : 

21 Five Phases of the Cell Cycle G1 - primary growth phase S – synthesis; DNA replicated G2 - secondary growth phase collectively these 3 stages are called interphase M - mitosis C - cytokinesis copyright cmassengale

Cell Cycle : 

22 Cell Cycle copyright cmassengale

Interphase - G1 Stage : 

23 Interphase - G1 Stage 1st growth stage after cell division Cells mature by making more cytoplasm & organelles Cell carries on its normal metabolic activities copyright cmassengale

Interphase – S Stage : 

24 Interphase – S Stage Synthesis stage DNA is copied or replicated Two identical copies of DNA Original DNA copyright cmassengale

Interphase – G2 Stage : 

25 Interphase – G2 Stage 2nd Growth Stage Occurs after DNA has been copied All cell structures needed for division are made (e.g. centrioles) Both organelles & proteins are synthesized copyright cmassengale

What’s Happening in Interphase? : 

26 What’s Happening in Interphase? What the cell looks like Animal Cell What’s occurring copyright cmassengale

Sketch the Cell Cycle : 

27 Sketch the Cell Cycle Daughter Cells DNA Copied Cells Mature Cells prepare for Division Cell Divides into Identical cells copyright cmassengale

Mitosis : 

28 Mitosis copyright cmassengale

Mitosis : 

29 Mitosis Division of the nucleus Also called karyokinesis Only occurs in eukaryotes Has four stages Doesn’t occur in some cells such as brain cells copyright cmassengale

Four Mitotic Stages : 

30 Four Mitotic Stages Prophase Metaphase Anaphase Telophase copyright cmassengale

Early Prophase : 

31 Early Prophase Chromatin in nucleus condenses to form visible chromosomes Mitotic spindle forms from fibers in cytoskeleton or centrioles (animal) Chromosomes Nucleolus Cytoplasm Nuclear Membrane copyright cmassengale

Late Prophase : 

32 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 copyright cmassengale

Late Prophase : 

33 Late Prophase Nucleus & Nucleolus have disintegrated Chromosomes copyright cmassengale

Spindle Fiber attached to Chromosome : 

34 Spindle Fiber attached to Chromosome Kinetochore Fiber Chromosome copyright cmassengale

Review of Prophase : 

35 Review of Prophase What the cell looks like What’s happening copyright cmassengale

Spindle Fibers : 

36 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 copyright cmassengale

Sketch The Spindle : 

37 Sketch The Spindle copyright cmassengale

Metaphase : 

38 Metaphase Chromosomes, attached to the kinetochore fibers, move to the center of the cell Chromosomes are now lined up at the equator Pole of the Cell Equator of Cell copyright cmassengale

Metaphase : 

39 Metaphase Chromosomes lined at the Equator Asters at the poles Spindle Fibers copyright cmassengale

Metaphase : 

40 Metaphase Aster Chromosomes at Equator copyright cmassengale

Review of Metaphase : 

41 Review of Metaphase What the cell looks like What’s occurring copyright cmassengale

Anaphase : 

42 Anaphase Occurs rapidly Sister chromatids are pulled apart to opposite poles of the cell by kinetochore fibers copyright cmassengale

Anaphase : 

43 Anaphase Sister Chromatids being separated copyright cmassengale

Anaphase Review : 

44 Anaphase Review What the cell looks like What’s occurring copyright cmassengale

Telophase : 

45 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 copyright cmassengale

Comparison of Anaphase & Telophase : 

46 Comparison of Anaphase & Telophase copyright cmassengale

Cytokinesis : 

47 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 copyright cmassengale

Cytokinesis : 

48 Cytokinesis Cleavage furrow in animal cell Cell plate in plant cell copyright cmassengale

Mitotic Stages : 

49 Mitotic Stages copyright cmassengale

Daughter Cells of Mitosis : 

50 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) copyright cmassengale

Identical Daughter Cells : 

51 Identical Daughter Cells Chromosome number the same, but cells smaller than parent cell What is the 2n or diploid number? 2 copyright cmassengale

Review of Mitosis : 

52 Review of Mitosis copyright cmassengale

Draw & Learn these Stages : 

53 Draw & Learn these Stages copyright cmassengale

Draw & Learn these Stages : 

54 Draw & Learn these Stages copyright cmassengale

Name the Mitotic Stages: : 

55 Interphase Prophase Metaphase Anaphase Telophase Name the Mitotic Stages: Name this? Name this? copyright cmassengale

Eukaryotic Cell Division : 

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

Mitosis Animation : 

57 Mitosis Animation Name each stage as you see it occur? copyright cmassengale

Mitosis in Onion Root Tips : 

58 Mitosis in Onion Root Tips Do you see any stages of mitosis? copyright cmassengale

Test Yourself over Mitosis : 

59 Test Yourself over Mitosis copyright cmassengale

Mitosis Quiz : 

60 Mitosis Quiz copyright cmassengale

Mitosis Quiz : 

61 Mitosis Quiz copyright cmassengale

Name the Stages of Mitosis: : 

62 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 copyright cmassengale

Identify the Stages : 

63 Identify the Stages Early, Middle, & Late Prophase Late Prophase Metaphase Anaphase Late Anaphase Telophase Telophase & Cytokinesis ? ? ? ? ? ? ? copyright cmassengale

Locate the Four Mitotic Stages in Plants : 

64 Locate the Four Mitotic Stages in Plants Metaphase Prophase Anaphase Telophase copyright cmassengale

Uncontrolled Mitosis : 

65 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 copyright cmassengale

MeiosisFormation of Gametes (Eggs & Sperm) : 

66 MeiosisFormation of Gametes (Eggs & Sperm) copyright cmassengale

Facts About Meiosis : 

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

Facts About Meiosis : 

68 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) copyright cmassengale

More Meiosis Facts : 

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

Why Do we Need Meiosis? : 

70 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 copyright cmassengale

Fertilization – “Putting it all together” : 

71 Fertilization – “Putting it all together” 1n =3 2n = 6 copyright cmassengale

Replication of Chromosomes : 

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

A Replicated Chromosome : 

73 A Replicated Chromosome Gene X Homologs separate in meiosis I and therefore different alleles separate. copyright cmassengale

Meiosis Forms Haploid Gametes : 

74 Meiosis Forms Haploid Gametes Meiosis must reduce the chromosome number by half Fertilization then restores the 2n number The right number! copyright cmassengale

Meiosis: Two Part Cell Division : 

75 Meiosis: Two Part Cell Division Homologs separate Sister chromatids separate Diploid Diploid Haploid copyright cmassengale

Meiosis I: Reduction Division : 

76 Meiosis I: Reduction Division Early Prophase I (Chromosome number doubled) Late Prophase I Metaphase I Anaphase I Telophase I (diploid) copyright cmassengale

Prophase I : 

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

Tetrads Form in Prophase I : 

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

Crossing-Over : 

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

Homologous Chromosomes During Crossing-Over : 

80 Homologous Chromosomes During Crossing-Over copyright cmassengale

Crossing-Over : 

81 Crossing-over multiplies the already huge number of different gamete types produced by independent assortment Crossing-Over copyright cmassengale

Metaphase I : 

82 Metaphase I Homologous pairs of chromosomes align along the equator of the cell copyright cmassengale

Anaphase I : 

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

Telophase I : 

84 Telophase I Nuclear envelopes reassemble. Spindle disappears. Cytokinesis divides cell into two. copyright cmassengale

Meiosis II : 

85 Meiosis II Only one homolog of each chromosome is present in the cell. Gene X copyright cmassengale

Meiosis II: Reducing Chromosome Number : 

86 Meiosis II: Reducing Chromosome Number Prophase II Metaphase II Anaphase II Telophase II 4 Genetically Different haploid cells copyright cmassengale

Prophase II : 

87 Prophase II Nuclear envelope fragments. Spindle forms. copyright cmassengale

Metaphase II : 

88 Metaphase II Chromosomes align along equator of cell. copyright cmassengale

Anaphase II : 

89 Anaphase II Sister chromatids separate and move to opposite poles. Equator Pole copyright cmassengale

Telophase II : 

90 Telophase II Nuclear envelope assembles. Chromosomes decondense. Spindle disappears. Cytokinesis divides cell into two. copyright cmassengale

Results of Meiosis : 

91 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 copyright cmassengale

Meiosis Animation : 

92 Meiosis Animation copyright cmassengale

Gametogenesis : 

93 Gametogenesis Oogenesis or Spermatogenesis copyright cmassengale

Spermatogenesis : 

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

Spermatogenesis in the Testes : 

95 Spermatogenesis in the Testes Spermatid copyright cmassengale

Spermatogenesis : 

96 Spermatogenesis copyright cmassengale

Oogenesis : 

97 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 copyright cmassengale

Oogenesis in the Ovaries : 

98 Oogenesis in the Ovaries copyright cmassengale

Oogenesis : 

99 Oogenesis copyright cmassengale

Comparing Mitosis and Meiosis : 

100 Comparing Mitosis and Meiosis copyright cmassengale

Comparison of Divisions : 

101 Comparison of Divisions copyright cmassengale

Slide 102: 

102 copyright cmassengale

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