Adjacent microtubule doublets in cilia and flagella produce a bending movement because
a. tubulin is contracting on one side of the microtubules.
b. dynein is contracting on one side of the microtubules.
c. kinesin is contracting on one side of the microtubules.
d. nexin links between microtubule doublets convert a sliding movement into a bending movement.
e. dynein heads move in a plus-end direction.
Ans: d. nexin links between microtubule doublets convert a sliding movement into a bending movement.
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