Problem:

Question 1: Explain LIFO and FIFO.

Question 2: Which of the following statements about microtubules is true?

A) Motor proteins move in a directional fashion along microtubules by using the inherent structural polarity of a protofilament.

B) The centromere nucleates the microtubules of the mitotic spindle.

C) Because microtubules are subject to dynamic instability, they are used only for transient structures in a cell.

D) ATP hydrolysis by a tubulin heterodimer is important for controlling the growth of a microtubule.

Give reasoning with your answer.