Axonal Transport and Motor Proteins

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  1. Why can we have movement in both directions?
    • there are plus and minus end directed motor proteins:
    • kinesin: plus end
    • cytoplasmic dynein: minus end
  2. What does axonal transport allow?
    allows swift exchange of substances between the nerve cell body and the synaptic terminal at which the nerve fiber adjoins its target cell
  3. Vesicles __

    Surplus membrane __

    that will convey NT are manufactured by the Golgi and carried toward the synapse

    at the synaptic terminal is packaged into multivesicular bodies, which return to lysosomes in the cell body for degradation

    move in both directions, catering to the energy demands of the cell
  4. Transport of vesicles is __; that of the mitochondria is __. 

    True or False:
    mitochondria are unidirectional.
    • continuous
    • intermittent
    • False: both directioned
  5. What can be present in axonal transport?
    there can be side arms projecting and ATPase is responsible for energy
  6. On an axon, where is the plus endd?
    going away from the cell body
  7. What do the globular heads of both kinesin and cytoplasmic dynein do?
    hydrolyze atp
  8. What does microtubule binding cause?

    What causes movement?
    ADP to leave and ATP to bind. It is then hydrolyzed

    changes in shape of the head area
  9. What does the tail of both do (intermediate chains of cytosolic dynein and light chain of kinesin)?
    bind to transported vesicles
  10. What were some suggestions about microtubules? (First)
  11. What were some suggestions about microtubules? (Second)
    • kinetochore microtubules were depolymerizing at the centromere and being added to the centromere¬†
    • problem: no driving force
  12. What were some suggestions about microtubules? (third)
    • kinetochore microtubules slide along polar microtubules
    • problem: doesn't account for shortening or lengteniing
  13. What were some suggestions about microtubules? (fourth)
    someone suggested an elastic material int he spindle that shortened and pulled
  14. What were some suggestions about microtubules? (fifth)
    not elastic material but some interaction between actin and MT
  15. What is actually happening?
    • kin MT does get shorter at the kinetochore end, not centrosome end
    • evidence: in newt, movemvent of chromosomes was 50 dimers lost per second

    • -region of force is the kinetochore end
    • -kinetochore microtubule is stationery but is losing dimers
Card Set:
Axonal Transport and Motor Proteins
2013-12-10 22:49:59
Bio Final

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