Chp. 11 - Cell Cycle

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Chp. 11 - Cell Cycle
2010-04-17 18:36:56

Cell Cycle
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  1. uncontrolled cell growth leads to?
  2. 2 types of cell division
    mitosis and meiosis
  3. What does meiosis do?
    produces gametes

    Produces haploid daughter cells

    Basis of sexual reproduction
  4. What does mitosis do?
    Produces daughter cells that are identical to parent cells

    Produces Somatic cells (Body Cells)
  5. What is cytokinesis?
    the division of the cytoplasm into two daughter cells
  6. What is mitosis reponsible for?

    Wound Repair

    Cellular Respiration
  7. Chromosomes contain what?
  8. DNA contains what?
    Genetic Information
  9. Growing cells cycle between which two phases?
    Mitotic phase and Interphase
  10. Mitotic phase is the
    Dividing phase
  11. Interphase is the
    Non-dividing phase
  12. 2 key events of cell cycle
    -replication - chromosomes are copied

    -splitting copied chromosomes into daughter cells
  13. In what stage does DNA replication occur
    Synthesis phase
  14. What is the S phase?
    The stage where DNA replication occurs
  15. Interpahse has how many gap phases
    2 phases where no DNA synthesis occurs
  16. What happens during gap phase?
    Organelles replicate and additional cytoplasm is made
  17. What are the 4 phases of the cell cycle?
    G1 phase

    S phase

    G2 phase

  18. what is a chromatid?
    each of two replicated strands
  19. What happens before mitosis?
  20. What happens in interphase?
    Chromosomes replicate and are now composed of 2 sister chromatids
  21. what happens in prophase?
    chromosomes condense

    mitotic spindles begin to form from microtubule organizing center
  22. what happens in prometaphase?
    nuclear envelope breaks down

    spindle fibers attach to chromosomes at kinteochore
  23. what happens in metaphase?
    chromosomes are lined up in the middle of the cell
  24. What happens in anaphase?
    Sister Chromatids seperate and are pulled to opposite poles
  25. What happens in telophase?
    nuclear envelope reforms

    spindle apparatus is disintegrates

    chromosomes begin to decondense
  26. What happens during cytokinesis in animals?
    Actin-Myosin ring causes plasma membrane to pinch in a cleavage furrow forming 2 daughter cells
  27. what happens during cytokinesis in plants?
    vesicles are transported from golgi apparatus to middle of dividing cell to form cell plate.
  28. How do chromosomes move during mitosis?
    deattach-move-attach cycle of motor proteins allow chromosomes to walk
  29. Why can't chromosomes walk on their own?
    Tubulin subunits within the kinetochore are lost therefore shorteining microtubules
  30. what is the Go phase
    when non-dividing cells get stuck in G1 phase.
  31. G1 pahse can be eliminated in what type of cells?
    rapidly dividing cells
  32. What induces mitosis?
    Mitosis promoting factor (MPF)
  33. Where is MPF found
    Cytoplasm of M phase cells
  34. what are the 2 subunits of MPF
    Cyclin and protein kinases
  35. what is Cyclin?
    regulatory protein
  36. what do protein kinases do?
    catalyze the transfer of phosphate from ATP to protein
  37. What can activated MPF do?
    phosphorylate chromosomal proteins, start M phase

    phosphorylate nuclear lamins, start nuclear envelope breakdown

    phosphorylate microtubule associated proteins, activate mitotic spindle

    phosphorylate enzymes that degrades cyclin, cyclin concentration declines
  38. What is a cell-cycle checkpoint?
    Point in cell-cycle where regulatory molecules determine if a cell proceeds with cell division
  39. What are the 3 checkpoints?


  40. What is the purpose of the G1 checkpoint?
    Determines whether cells continue to divide or enter G0 phase
  41. 4 factors that determine whether cell passes G1 checkpoint
    -cell size - cell must be large enough to split

    -nutrient condition - cell must have enough food to grow

    -cell must be able to receive social signals from other cells

    -action of tumor suppressors - regulatory proteins that can stop cell cycle
  42. What is the first and most important checkpoint?
    G1 checkpoint
  43. What is the purpose of the G2 checkpoint
    to stop cells from growing if their DNA is damaged or chromosome replication is not working properly
  44. what is the purpose of the M phase checkpoint?
    To stop cell growth if chromosomes are not properly attached to mitotic spindle
  45. What does the M phase checkpoint prevent?
    incorrect chromosome seperation that could give daughter cells the wrong number of chromosomes
  46. What is the purpose of cell checkpoints?
    To prevent the division of cells that are damaged or have other problems.
  47. What is cancer?
    uncontrollable cell growth that invades nearby cell tissues and spreads to other sites in the body
  48. What are the two defects found in cancerous cells?
    -proteins required for cell growth are always active

    -tumore supressor genes are prevented from shutting down the cell cycle
  49. how does a tumor form?
    when one or more cells in an organism divide uncontrollably
  50. what are benign tumors?
    noninvasive and noncancerous tumors
  51. what are malignant tumors?
    invasive tumors that can spread throughout the body and initiate secondary tumors
  52. what is metastasis?
    when cancer cells detach from the original tumor and invade other tissues
  53. Cancer cells are thought to come from cells with defects in what checkpoint?
    G1 checkpoint
  54. How does social control play a role in cell division?
    cells respond to signals of other cells so they only divide when their growth benefits the whole organism
  55. What are growth factors?
    Polypeptides or small portiens that signal other cells to grow
  56. How are cancer cells no longer subject to social control at the G1 checkpoint?
    Cancer cells divide without Growth Factors
  57. How do growth factors initiate cell division?
    they trigger cyclin synthesis which activates cyclin-Cdk complexes, leading to activation of S-phase proteins
  58. Most cancers arise from defects in what?
    cell-cycle regulation