Chromosomes morphology and mitosis
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Reproduction of Eukaryotic cell/ Cell division
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Chromosomes morphology and mitosis
- 1. Reproduction of Eukaryotic cell/ Cell division
- 2. 4.1 Chromosome morphology and function 4.2 The cell cycle and mitosis Outline
- 4. 4 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 Eukaryotic Chromosome
- 6. Chromosomes vs. Chromatin Chromosomes • Tightly packaged DNA • Found only during cell division • DNA is not being used for macromolecule synthesis Chromatin • Unwound DNA • Found throughout Interphase • DNA is being used for macromolecule synthesis
- 7. Chromosomes,Eukaryote Though chromosomes are “all about” DNA, in fact much this structure consists of protein Form via replication, not by formed chromatids coming together
- 8. 8 Duplicated chromosomes are called chromatids & are held together by the centromere Called Sister Chromatids Chromosomes in dividing cells
- 9. Chromosome Duplication & Distribution During Cell Division 1. A eukaryotic cell has multiple chromosome, one of which is represented here. Before duplication, each chromosome has a single DNA molecule. 2. Once replicated, a chromosome consists of two sister chromatids connected along their entire lengths by sister chromatidcohesion. Each chromatid contains a copy of the DNA molecule 3. Mechanical processes separate the sister chromatids into two chromosomes and distibute them to two daughter cells. Chromosomes DNA molecules
- 10. How Long is a Chromatid a Chromatid? A chromatid is a chromatid as long as it is held in association with a sister chromatid at the centromere Homologous Chromosome Centromere Sister Chromatid Sister Chromatid When two sister chromatids separate (after metaphase) they go from being a single chromosome to being two different chromosomes
- 11. Chromosomes, Eukaryote Here “chromosome” and “DNA” are not 100% synonymous
- 12. Chromosomes,Eukaryote Genome = DNA Chromosome = DNA + protein (visible light microscope) Chromatin = DNA + protein (but less than for chromosome)DNA
- 13. 13 DNA is tightly coiled around proteins called histones Compacting DNA into chromosomes
- 14. DNA strand tightly coiled around group of small protein
- 15. Forming a series of bead like structures
- 16. The string of nucleosomes compacted by factor of 6, then coiled into an even denser
- 18. 18 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 Karyotype
- 19. 19 Boy or Girl? Y - Chromosome X - Chromosome The Y Chromosome Decides
- 20. 20
- 21. SomeVocabulary Centromere Centrosome Centriole Kinetochore Kinetochore microtubules Mitotic spindle Nonkinetochore microtubles Spindle apparatus Spindle fibers
- 22. SomeVocabulary Centromere Centrosome Centriole Kinetochore Kinetochore microtubules Mitotic spindle Nonkinetochore microtubles Spindle apparatus Spindle fibers Recall that the centrosome is the center of the microtubule array of a cell
- 23. SomeVocabulary Centromere Centrosome Centriole Kinetochore Kinetochore microtubules Mitotic spindle Nonkinetochore microtubles Spindle apparatus Spindle fibers Keep in mind that the term centriole is not an exact synonym of centrosome and that centrosome is not a synonym of the term centromere Recall that these consist of microtubules and that a pair makes up a centrosome
- 24. SomeVocabulary Centromere Centrosome Centriole Kinetochore Kinetochore microtubules Mitotic spindle Nonkinetochore microtubles Spindle apparatus Spindle fibers Responsible for moving chromosomes relative to mitotic spindle
- 25. SomeVocabulary Centromere Centrosome Centriole Kinetochore Kinetochore microtubules Mitotic spindle Nonkinetochore microtubles Spindle apparatus Spindle fibers These are the portion of the mitotic spindle that is connected to chromosomes during mitosis
- 26. SomeVocabulary Centromere Centrosome Centriole Kinetochore Kinetochore microtubules Mitotic spindle Nonkinetochore microtubles Spindle apparatus Spindle fibers These are the microtubles that are responsible for separating chromosomes as well as pushing the centrosomes toward opposite ends of cells
- 27. SomeVocabulary Centromere Centrosome Centriole Kinetochore Kinetochore microtubules Mitotic spindle Nonkinetochore microtubles Spindle apparatus Spindle fibers Microtubules of mitotic spindle that are not connected to the chromosomes but instead responsible for pushing centrosome apart
- 28. SomeVocabulary Centromere Centrosome Centriole Kinetochore Kinetochore microtubules Mitotic spindle Nonkinetochore microtubles Spindle apparatus Spindle fibers The mitotic spindle as visible through a light microscope
- 29. SomeVocabulary Centromere Centrosome Centriole Kinetochore Kinetochore microtubules Mitotic spindle Nonkinetochore microtubles Spindle apparatus Spindle fibers Bundles of microtubles making up the spindle apparatus; it is the bundling that makes them visible through a light microscope
- 31. Eukaryote Cell Cycle Primary growth phase 1st growth stage after cell division Cells mature by making more cytoplasm & organelles Cell carries on its normal metabolic activities
- 32. Eukaryote Cell CycleSynthesis Synthesis stage DNA is copied or replicated
- 34. Eukaryote Cell CycleSecondary growth phase 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
- 35. 35 What the cell looks like Animal Cell What’s occurring Summary - Interphase
- 36. Eukaryote Cell Cycle M phase Division of the nucleus Also called karyokinesis Only occurs in eukaryotes Doesn’t occur in some cells such as brain cells
- 37. Mitosis is conventionally divided into four phases: Prophase Metaphase Anaphase Telophase Cytokinesis is well underway by late telophase MITOSIS
- 38. 38 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 Eukaryotic Cell division
- 40. Mitosis (First half) Nucleus defined, Nucleoli present, Replicated Centrosomes, Asters present, DNA duplicated, DNA still chromatin 1. G2 of Interphase 1.
- 41. Mitosis (First half) Chromatin in nucleus condenses to form visible chromosomes Mitotic spindle forms from fibers in cytoskeleton or centrioles (animal) 2. Early Prophase 2.
- 42. Mitosis (First half) 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 3. Prophase 3.
- 44. 44 What the cell looks like What’s happening Review - Prophase
- 45. 45 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 Mitotic Spindle
- 46. Mitotic Spindle
- 47. Aster(s) Asters are short fibers radiating from centrioles
- 49. Mitosis (Second half) Chromosomes, attached to the kinetochore fibers, move to the center of the cell Chromosomes are now lined up at the equator 4. Metaphase 4.
- 50. 50 What the cell looks like What’s occurring Review - Metaphase
- 51. Mitosis (Second half) Occurs rapidly Sister chromatids are pulled apart to opposite poles of the cell by kinetochore fibers 5. Anaphase 5.
- 52. 52 What the cell looks like What’s occurring Review – Anaphase
- 53. Mitosis (Second half) Sister chromatids at opposite poles Spindle disassembles Nuclear envelope forms around each set of sister chromatids Nucleolus reappears Chromosomes reappear as chromatin 6. Telophase 6.
- 54. 54 Comparison
- 55. 55 Means division of the cytoplasm Division of cell into two, identical halves called daughter cells Cytokinesis
- 56. Cytokinesis,Animals Cytokinesis can occur simultaneous to telophase cleavage furrow forms to split cell
- 57. Cytokinesis,Plants cell plate forms at the equator to divide cell
- 59. 59 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) Daughter cell of mitosis
- 60. 60 Chromosome number the same, but cells smaller than parent cell What is the 2n or diploid number? 2
- 61. 61 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 Uncontolled mitosis
- 62. 62 Draw & Learn these Stages
- 63. 63 Draw & Learn these Stages
- 64. 64 Interphase Prophase Metaphase Anaphase Telophase Name the Mitotic Stages: Name this? Name this?
- 65. 65 Mitosis Animation Name each stage as you see it occur?
- 66. 66 Identify the Stages Early, Middle, & Late Prophase Late Prophase Metaphase Anaphase Late Anaphase Telophase Telophase & Cytokinesis ? ? ? ? ? ? ?
- 67. 67 Mitosis Quiz
- 68. 68 Mitosis Quiz