Whether a microtubule shrinks or grows is determined by the
A) rate of GTP-bound tubulin addition relative to the rate of tubulin GTP hydrolysis.
B) phosphorylation state of $\beta$-tubulin.
C) rate of ATP hydrolysis relative to the rate of ATP-bound tubulin addition.
D) presence or absence of $\gamma$-tubulin.

Question

Quizplus · Accepted Answer

The rate of GTP-bound tubulin addition relative to the rate of tubulin GTP hydrolysis determines if a microtubule will grow or shrink. If the rate of GTP-tubulin addition is greater than the rate of GTP hydrolysis, the microtubule will grow. If the rate of GTP hydrolysis is greater than the rate of GTP-tubulin addition, the microtubule will shrink. The phosphorylation state of F1F1F1S1F1F1F10-tubulin, the rate of ATP hydrolysis relative to the rate of ATP-bound tubulin addition, and the presence or absence of F1F1F1S1F1F1F10-tubulin do not directly determine microtubule growth or shrinkage.

Whether a Microtubule Shrinks or Grows Is Determined by the β\betaβ

Whether a Microtubule Shrinks or Grows Is Determined by the $\beta$