Which of the following describes the polarity of a microtubule?
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Correct answer: The plus end exposes beta-tubulin; the minus end exposes alpha-tubulin
Microtubules are structurally polar. The faster-growing plus end exposes beta-tubulin subunits, while the slower-growing (or anchored) minus end exposes alpha-tubulin. This polarity dictates the direction of motor protein movement: kinesins move toward the plus end and dyneins toward the minus end.
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