Mitosis S1M1

  1. Mitosis
    The division of the nucleus in a eukaryotic cell
  2. Interphase consists of what cell phases
    G1 Phase-------S phase-------- G2 Phase
  3. G0 Phase
    A dormant phase when nothing is happening, can stay here for its life (neurons are always here)
  4. What are the two major checkpoints in a cell cycle
    • G1 Checks to make sure the environment is favorable and that the DNA is intact before starting the S phase
    • G2 Checks to see if the DNA intact, and if it is all replicated
  5. Which cell phase is the shortest
    The Mitosis phase
  6. What is the S phase
    It is when the DNA is synthesized and lasts about 8 hrs
  7. List the phases of mitosis in order
    • 1. Preprophase
    • 2. Prophase
    • 3. Metaphase
    • 4. Early Anaphase
    • 5. Late Anaphase
    • 6. Telophase
  8. What happens in Preprophase
    Intranuclear condensation of chromosomes
  9. Prophase
    • 1. Individualization of chromosomes
    • 2. Initiation of mitotic spindle and its completion
    • 3. A disappearance of the nuclear envelope and nucleolus
  10. Metaphase has what characteristics
    Chromosomes are arranged in a center, the spindle is completed, and there is a disappearance of the nuclear envelope and nucleolus
  11. Early Anaphase
    Splitting of chromosomes and migration to poles
  12. Late Anaphase
    • Chromosome at poles
    • Beginning of cell division, and cleavage furrow
  13. Telophase
    • Nuclear completion
    • Nucleolar formation
    • End of cell division
  14. What are the two important proteins for mitosis and their function
    • Cohesins (link sister chromatids)
    • Condensins (link DNA into the condensed coil)
  15. What does a cohesin do and what phase doesn't contain it
    Cross links two adjacent sister chromatids, gluing them together (degraded at the beginning of anaphase allowing the sisters to come apart)
  16. Condensins do what and is active when
    Mediate intramolecular cross linking to coil DNA in the process of chromosome condensation (Active at the beginning of prophase)
  17. MT's are favorite targets for anti cancer drugs why
    They are used to stop the division of cancer cells
  18. Taxol (Paclitaxel)
    • A drug that binds tightly to MT's and stabilizes them
    • (Cells that are effected undergo apoptosis)
    • Chemo!!
  19. Intermediate filaments in mitosis
    Control the breakdown and reformation of the nuclear envelope
  20. What happens to organelles at mitosis
    • ER and Golgi vesiculate and then reform at telophase
    • Nothing happens to the Mitochondria, peroxisomes and Lysosomes
  21. What happens to other functions during mitosis
    They pretty much all just stop
  22. What triggers the disassembly of the nuclear lamina and the nuclear envelope
    Phosphorylation of lamina
  23. Mitosis and Cytokenisis take place during what cell cycle phase
    The M phase
  24. DNA replication happens during what phase
    S Phase
  25. In what order are the cell phases
    G2 - M - G1 - S
  26. What is telophase
    As the nuclear envelope forms around each pair of chromatids, the nucleoli reappear
  27. What is the kinetocore
    It is the binding site of the MT's at the centromere of the chromosome
  28. Anaphase A vs Anaphase B
    • Anaphase A, Chromosomes move to poles
    • Anaphase B, Seperation of the poles themselves
  29. What is the job of the motor proteins
    They move the MT's between each other leading the chromosomes to the cell poles
  30. What two places are the poles located
    On the wall of the cell at the pole ends, and near the center working antiparallel to the MT's next to them
  31. Anaphase A depends on
    Motor proteins at the kinetocore
  32. Anaphase B depends on
    • Motor proteins at the poles that pull them apart from each other
    • On motor proteins in the central spindle
  33. The motor proteins in between the microtubules have what effect
    • They are located at the point where the microtubules overlap and they force them to their respective poles
    • They are (+) end directed motor proteins
  34. The motor proteins at the poles have what effect
    They pull the centrioles towards the poles and away from each other. They are a (-) end directed motor protein
  35. What is the role of actin in mitosis
    Along with myosin 2 they form the contractile ring separating the new cells
Card Set
Mitosis S1M1
Cell Biology