Multiple Choice
Treadmilling is when a microtubule end switches from polarization to depolarization.
15. Cytoskeleton and Cell Movement
Microtubules
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Under which condition is a GTP cap formed during microtubule formation?
A
If the microtubule end is hydrolyzed slowly
B
If the microtubule end is hydrolyzed quickly
Verified step by step guidance1
Understand that microtubules are dynamic structures composed of tubulin dimers, which consist of alpha-tubulin and beta-tubulin subunits.
Recognize that GTP (guanosine triphosphate) binds to the beta-tubulin subunit of the tubulin dimer. This GTP is crucial for the stability and growth of microtubules.
Learn that during microtubule polymerization, tubulin dimers add to the growing end of the microtubule, and the GTP bound to beta-tubulin is eventually hydrolyzed to GDP (guanosine diphosphate).
A GTP cap is formed when the addition of GTP-bound tubulin dimers to the microtubule end occurs faster than the hydrolysis of GTP to GDP. This cap stabilizes the microtubule and promotes further growth.
If the hydrolysis of GTP is slow compared to the addition of new GTP-bound dimers, a GTP cap is maintained, preventing depolymerization and allowing the microtubule to continue growing.
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