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Kinesins and Dyneins quiz

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  • What is the main function of motor proteins in cells?
    Motor proteins use energy from ATP to transport molecules across microtubules in a single direction.
  • Which direction do kinesins move cargo along microtubules?
    Kinesins move cargo towards the plus end of microtubules, away from the cell nucleus and towards the plasma membrane.
  • What direction do dyneins transport molecules?
    Dyneins transport molecules towards the minus end of microtubules, directing them towards the cell nucleus.
  • What is the structural composition of motor proteins like kinesins and dyneins?
    Motor proteins are dimers with two heads and a single tail; the heads bind to microtubules and the tail binds to cargo.
  • How do motor proteins move along microtubules?
    They hydrolyze ATP to ADP in their heads, which powers their stepwise movement along microtubules.
  • What is meant by 'processive movement' in motor proteins?
    Processive movement refers to the ability of motor proteins to transport cargo over long distances without detaching from the microtubule.
  • What role do dynactin proteins play in dynein function?
    Dynactin proteins help dyneins stay attached to microtubules and enhance their cargo-carrying capabilities over long distances.
  • How many families of kinesins exist, and which is the most prominent?
    There are 14 families of kinesins, with kinesin 1 being the most prominent and commonly studied.
  • What is the difference between Brownian movement and salutary movement in cells?
    Brownian movement is random thermal motion, while salutary movement is purposeful, directional movement driven by motor proteins.
  • What binds to the cargo in motor proteins?
    The tail of the motor protein binds to the cargo being transported.
  • What do the heads of motor proteins bind to?
    The heads of motor proteins bind to microtubules in a specific orientation, either plus or minus end.
  • What energy source do motor proteins use for movement?
    Motor proteins use ATP as their energy source, hydrolyzing it to ADP during movement.
  • Why do motor proteins need to move cargo over long distances in cells?
    Cells are relatively large compared to proteins, so cargo often needs to travel from the nucleus to the plasma membrane or vice versa.
  • How do motor proteins ensure directional movement?
    Motor proteins move in a single direction along microtubules, determined by their structure and the orientation of their heads.
  • What is the main difference in the directionality of kinesins and dyneins?
    Kinesins move towards the plus end (away from the nucleus), while dyneins move towards the minus end (towards the nucleus).