Cell Division

  1. Requirements for cell division
    • 1. Grow; build new macromolecular structures
    • 2. Duplicate genetic material (DNA replication)
    • 3. Partition/Segregate gentic material (mitosis)
    • 4. Divide content of cytoplams (cytokinesis)
  2. Batterial Cell Divison
    • Simple process produces two cell from one
    • Made easier by single circular chromosome
    • Binary fission
    • Proteins involved similar to eukaryotic proteins
    • Process is distinct and different from mitosis
  3. Key Feature of Bacterial Division
    • Replication and segregation concerted process (simultaneous process)
    • -chromosome is "pushed" to poles during replication
    • -chromosome finish replication at opposite poles
    • Exact mechanism of segregation not known
  4. Eukaryotic Cell Division
    • More complex genome, mutiple chromosomes
    • Genome inside nucleus
    • More complex cytoplasmic contents
  5. How does cell keep track of chromosomes?
    • Keep products of replication together (protein glue)
    • Temporal separation and replication/segregation
  6. Cell Cycle
    Gap 1 prepares for DNA replication
  7. Cell Cycle
    During synthesis DNA is replicated
  8. Cell Cycle
    Gap 2 prepares for mitosis
  9. Cell Cycle
    Mitosis segragate chromosomes
  10. Interphase
    • G1
    • S
    • G2
  11. M Phase
    • Mitosis
    • Cytokinesis
  12. G0
    Cells have left the cycle: noncycling
  13. Eukaryotic Chromosomes
    • Linear structure that contain single DNA molcule
    • DNA molecule is always packaged into chromosomes
    • Amount of dondensation changes during cell cycle
    • Chromosome has visible contriction called centromere
  14. Nucleosomes
    1st DNA wrapped around protein
  15. Centromere
    • Visible contriction
    • -Site where replicated chromosomes held together
    • -Site of kinetochore: functional element of centromere
  16. Phases of Mitosis
    • Divide into 5 phases
    • -Prophase
    • -(Prometaphase)
    • -Metaphase
    • -Anaphase
    • -Telophase
  17. What is the function of mitosis
    • To segregate chromosomes
    • -Each cell gets 1 copy each chromosome
  18. Does cell count or mark chromosomes?
  19. How do we ensure new cells gets entire genome?
    • Keep chromosomes together after replication
    • Align them together in the center of cell
    • Pull apart copies at the same time
    • Completely rearranging microtubles
    • -Construct spindle to separate chromosome
  20. Prophase
    Chromosome condense; nucleus breaks down, spindle forms (microtubles)
  21. Metaphase
    Chromosomes move to center of cell, attached to spindle at equator
  22. Anaphase
    Chromosome are pulled to poles
  23. Telophase
    Reverse of prophase
  24. Cytokinesis
    • Cell is actually divided
    • -Centractile ring of microfilaments
  25. Control of cell cycle
    • Cancer: uncontrolled cell division
    • Irreversible events
    • -DNA replication
    • -Anaphase
    • To insure accuracy cell monitors process
  26. MOC: Positive regulators that drive cell cycle
    • Cyclin proteins are produced in synchrony with cycle
    • Cyclin dependent kinases (cdk) drive cycle
  27. MOC: Checkpoints
    • Are points the cell assess accuracy
    • Allows cell to stop if process is faulty
    • Can even lead to cell death when process goes wrong
  28. CP: G1/s
    • Decision to replicate DNA
    • Check for chromosome integrity
  29. CP: G2/M
    • Is replication complete?
    • Are the chromosomes damaged:
  30. Metaphase/Anaphase
    • Decision to separate chromosomes
    • -All chromosomes align properly
    • -Connected to both poles
Card Set
Cell Division
Cell division flashcards