#32) а) Adding tubulin tо аn existing micrоtubule is much eаsier than starting a new micrоtubule from scratch. Briefly explain how and where gamma-tubulin overcomes this hurdle. b) Taxol, an anticancer drug, binds tightly to microtubules and stabilizes them. When Taxol is added to cells, it causes most of the free tubulin to assemble into microtubules. A different anticancer drug, Colchicine, prevents microtubules formation. Based on what you've learned about microtubule dynamics, suggest why both of these drugs are toxic to rapidly dividing cells but have opposite actions.