Decide whether each of the following statements are true or false and explain why.

A. The structural polarity of all microtubules is such that α-tubulin is exposed at one end and β-tubulin is exposed at the opposite end.

B. The role of ATP hydrolysis in actin polymerization is similar to the role of GTP hydrolysis in tubulin polymerization: both serve to weaken bonds in the polymer and thereby promote depolymerization.

C. All microtubule organizing centers contain centrioles that help nucleate microtubule polymerization.

D. All proteins that bind to the ends of microtubules or actin filaments cap the ends to prevent futher polymerization.

E. In most animal cells, minus end-directed microtubule motors deliver their cargo to the periphery of the cell, whereas plus end-directed microtubule motors deliver their cargo to the interior of the cell.

F. Cadherins promote cell-cell interactions by binding to cadherin molecules of the same or closely related subtype on adjacent cells.