RR Final 8 Mitosis Prometaphase- Metaphase

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RR Final 8 Mitosis Prometaphase- Metaphase
2013-11-23 11:52:18
Cell Bio

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  1. Start of prometaphase
                                                                  i.      Dissolution of nuclear envelope is the start and mitotic assembly is completed; chromosomes are moved into position at the center of the cell
  2.                                                               i.      Beginning: __ are scattered around space that was the __
    1.       __ of the microtubules __ and __, in search for chromosomes
    2.       The microtubules that contact a __are __ and __
    a.       Attaches at __
    • compacted chromosomes
    • nuclear region
    • Free ends
    • grow and shrink
    • kinetochore 
    • captured and stabilized
    • sidwall
  3.                                                               i.      Once contact made, some chromosomes __ along the wall fo the microtubule, powered by __ located in the kinetochore
    1.       Soon, the __becomes stably associated with __ of one or more __
    a.       A chromosome that is attached to microtubules from only one spindle pole represents an __
    • move actively
    • motor proteins
    • kinetochore 
    • plus end
    • spindle microtubules
    • unstable intermediate stage
  4.                                                               i.      Eventually, the unattached kinetochore on the sister chromatid does what?
    1.       These mcirotubules grow out from chromosome by __ and, ocne assembled, become incorporated into __
    • capturesits own microtubules from opposite pole
    • incoroporateion of tubulin subunits at the kinetochore
    • mitotic spindle
  5.                                                               i.      Not directly in center yet, but move back and forth
    1.       Chromosomes at this time are moved by __ toward the center of the __, midway between the poles
    a.       The forces required for chromosome movements during prometaphase are generated by __ associated with both the __and __
    • congression
    • mitotic spindle
    • motor prtoteins
    • kinetochores 
    • arms of the chromosomes
  6.                                                               i.      Microtubule dynamics also play a key role in facilitating __ during __
    1.       As the chromosomes __toward center of mitotic spindle, the longer microtubules attached to one kinetochore are __, while the shorter microtubules attached to the sister kinetochore are __
    • chromosome movements during prometaphase
    • congress 
    • shortened
    • elongated
  7. a.       These changes in microtubule length are thought to be governed by differences in __ on the two sister kinetochores
                                                                                                                                          i.      __ and __ of microtubules occur by __ and __ of __ at the __ of the microtubule
    1.       This occurs while the __ of each microtubule is attached to kinetochore
    • pulling force (tension)
    • Shortening and elongation
    • loss or gain of subunits
    • plus end
    • plus end
  8. Eventually, the chromosome moves toward centerà __
  9. Metaphase:

                                                                  i.      Aligned on __—with one chromatid of each chromosome connected by its __ to microtubules from one pole and its sister chromatid connected by its __ to microtubules from the opposite pole—the cell has reached the stage of metaphase
    • spindle equator
    • kinetochore
    • kinetochore
  10. 1.       Plane of alignment of the chromosomes at metaphase is referred to as the __

    a.       The mitotic spindle of the metaphase cell contains a highly organized array of microtubules that is ideally suited for the task of __ positioned at the center of the cell
    • metaphase plate
    • separating the duplicated chromatids
  11.                                                               i.      The microtubules of metaphase spindle are of three groups. What are they?
    • astral
    • chromosomal (or kinetochore)
    • polar
  12. Astral microtubules
    - structure
    radiate outward from centrosome into region outside the body of the spindle; they help position the spindle apparatus in the cell and determine the plane of cytokinesis
  13. Chromosomal (or kinetochore) kicrotubules
    - structure

    a.       In mammalian cells, each kinetochore is attached to a bundle of __, which forms a __
    b.      During metaphase, the chromosomal microtubules do what?
    • extend between the centrosome and the kinetochores of the chromosomes
    • 20-30 microtubules
    • spindle fiber
    • exert a pulling force on the kinetochores
  14.    i.      As a result, the chromosomes are maintained in the __ by a “__” between balanced __ fibers from opposite poles
    1.       these __ generated __within the kinetochore and cause __of the chromosomes situated at the __
    • equatorial plane
    • tug-of-war
    • pulling forces exerted by chromosomal spindle
    • pulling forces
    • deformations 
    • oscillations 
    • metaphase plate
  15. a.       during anaphase, chromosomal microtubules are required for what?
    the movement of the chromosomes toward the poles
  16. Polar microtubules
    Structure: 1.       extend from the centrosome past the chromosomes;    polar microtubules from one centrosome overlap with their counterparts from the opposite centrosome

    Function:  form a structural basket that maintains the mechanical integrity of the spindle