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Mitosis PowerPoint Presentation

Mitosis

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Mitosis

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  1. Mitosis

  2. Why Mitosis? • The purpose of mitosis is to generate two new cells from one cell. • The “daughter cells” generated are exact copies of the “parent cell” • Mitosis is happening in many cells in your body as we speak! • Some cells divide more frequently than others

  3. Mitosis Cytokinesis Interphase Mitosis is part of the Cell Cycle

  4. Interphase Key Events in the Cell Cycle • The cell gets larger • Organelles are made • Genetic information is duplicated • Half of the DNA and organelles go to one end and the other half to the opposite end • The cell is split down the middle to make 2 new cells

  5. G2 Mitosis Cytokinesis G1 S Interphase • Gap1 (G1) • Preparation for growth • Organelles, membranes, and ribosomes made • Synthesis (S) • Chromosomes replicated • Gap2 (G2) • Preparation for division • Mitochondria divide • Remember, mitochondria have their own chromosome! Q4 Part 1

  6. Interphase Mitosis Key Events in the Cell Cycle • The cell gets larger • Organelles are made • Genetic information is duplicated • Half of the DNA and organelles go to one end and the other half to the opposite end • The cell is split down the middle to make 2 new cells Q7

  7. Nucleus of cell after mitosis Chromosomes are not duplicated Nucleus of cell after S phase Chromosomes are duplicated Homologous pair Chromosomes in Somatic Cells Nucleus of cell during G1 Chromosomes not duplicated

  8. Keep in Mind…

  9. Mitosis • Prophase • Metaphase • Anaphase • Telophase P M A T Cytokinesis Interphase

  10. Prophase • Pro =forward, forth • Chromosomes condense • Nuclear envelope breaks down • Membrane surrounding the nucleus • Centrioles move to opposite poles • Spindle fibers grow Q4 Part 2

  11. Metaphase • Meta =after, with • Chromosomes line up at the midline • Spindle attaches to chromosomes at the centromere • The centromere is where the sister chromatids are attached Q4 Part 2

  12. Anaphase • Ana =against • Centromeres split • Sister chromatids are pulled to opposite poles by the shortening of spindle fibers • Once separated, each sister chromatid is now a chromosome (and each is exactly like the chromosome found in the original cell before S of interphase) Q4 Part 2

  13. Telophase • Telo =completion of a goal • Spindle breaks down • Nuclear envelope forms in each of the daughter cells • Chromosomes decondense Q4 Part 2

  14. Interphase Mitosis Cytokinesis Key Events in the Cell Cycle • The cell gets larger • Organelles are made • Genetic information is duplicated • Half of the DNA and organelles go to one end and the other half to the opposite end • The cell is split down the middle to make 2 new cells Q7

  15. Cytokinesis Mitosis Cytokinesis Interphase • “Cell-making” phase • Organelles and cytoplasm are distributed between daughter cells • Microfilament band at equator contracts to pinch apart 2 new daughter cells

  16. Summary of Cell Cycle • Cell grows • DNA replicates • Organelles are made • Chromosomes condense • Chromosomes line up at the equator • Replicated chromosomes are pulled apart to opposite poles • Chromosomes decondense • Two daughter cells are formed G1 S G2 Prophase Metaphase Anaphase Telophase Cytokinesis

  17. IPee on the MAT, See? P M A T C I

  18. G2 Mitosis Cytokinesis G1 S Go • Resting phase • Cell may: • Enter S phase • Die • Cell is damaged • Do nothing • Neuron Go Cell Death Sit tight

  19. G2 Mitosis Cytokinesis G1 S Cell Cycle Checkpoints DNA damage checkpoints Spindle checkpoint

  20. Apoptosis • Programmed cell death • Neat and orderly

  21. Necrosis • Cell explodes • Not so neat and orderly • In response to injury

  22. Telomeres • Consist of a repeated sequence of DNA • Nature’s solution to the end-replication problem • Very tips of chromosomes cannot be replicated • Shortened with each mitotic division • Limits # of possible cell divisions • Cell will not divide after ~50 divisions • Not found in eggs/sperm, bone marrow cells, cancer cells • Shortening is hastened by chronic stress

  23. Cell Differentiation • The process whereby a cell becomes specialized • Every cell contains the exact same genetic information (all 23 chromosome pairs) • One chromosome from mom and one from dad • Not all genetic info is being used by every cell • Different cell types are making different proteins • The proteins being made by a cell give it specialized characteristics (e.g. blood cell vs. brain cell)

  24. Stem Cells • Important for regenerating cells that are lost (e.g. skin cells) and for growth • Stem cells are undifferentiated • Totipotent =able give rise to any cell type • Progenitor cells • Somewhat specialized • Pluripotent =able to produce many different cell types

  25. Pathways to Cell Specialization • Each specialized cell type uses only certain “recipes” from the “cookbook”

  26. Embryonic Stem Cells -IVF • Yields totipotent cells • Uses frozen embryos from in vitro fertilization • in vitro =in a dish • in vivo =in the body

  27. Embryonic Stem Cells –Nuclear Transfection

  28. Cloning

  29. Adult Stem Cells • Pluripotent • Found in bone marrow, umbilical cord blood, certain parts of the brain Even I have stem cells!