Question

Choose the phrase that best completes this sentence: Microtubules ____________ and are required to pull duplicated chromosomes to opposite poles of dividing cells.

(a) generate contractile forces
(b) are intermediate in thickness
(c) can rapidly reorganize
(d) are found in especially large numbers in muscle cells

Answer 1

Microtubules can rapidly reorganize and are essential for pulling duplicated chromosomes to opposite poles during cell division. They serve as tracks for motor proteins and help ensure proper chromosome segregation.

Step-by-step explanation:

The correct phrase that completes the sentence 'Microtubules ____________ and are required to pull duplicated chromosomes to opposite poles of dividing cells' is (c) can rapidly reorganize. This is because microtubules are dynamic structures within the cell that can assemble and disassemble quickly, allowing them to change length and move cellular components, such as chromosomes during cell division.

Microtubules function as the tracks along which kinetic motor proteins, like dynein, move to segregate chromosomes during mitosis. They extend from the centrosomes at opposite ends of the cell, and as they grow and shrink, they exert forces that pull the duplicated chromosomes apart to ensure each new daughter cell gets an identical set of chromosomes after cell division.