Topic 7: Microtubules and Motors

Question 1

What are the general functions of mcirotublues?

Answer 1

determine cell shape, involved in cell movement, transport within the cell, separation of chromosomes Durning mitosis

Question 2

How do microtubules grow?

Answer 2

Tubulin subunits are the building blocks of microtubules. Composed of tubulin dimers. GTP is bound, tubulin dimers have a high affinity for each other, so polymerization occurs. When GDP is bound tubulin dimers have a lower affinity for each other disassembly occurs.

Question 3

What does it mean microtubules are polar

Answer 3

A fast growing + end and slow growing - end.

Question 4

What is dynamic instability?

Answer 4

Transitioning of microtublule at random from extended periods of slow growth and brief periods of rapid shortening

Question 5

How does a centrosome influence microtubule growth and stability?

Answer 5

It is the organizing center. Anchors the - end and initiates microtubule growth. + end extends towards the periphery.

Question 6

What protein is associated with the pericentriolar region and what does it do for microtubules?

Answer 6

y tubulin, acts as a seed for rapid microtubule growth

Question 7

What are two microtubule motor proteins?

Answer 7

Dynein: Moves toward the - end
Kinesin: Moves towards the + end

Question 8

How can microtubule motors cause cilia movement?

Answer 8

Nexin links 9 microtubule doublets to each other. Because nexin links the doublets together the microtubules bends and then the cilia moves

Question 9

astral microtubules

Answer 9

radiate toward periphery, anchored close to the membrane

Question 10

interpolar microtubules

Answer 10

towards the center

Question 11

kinetochore microtubules

Answer 11

attached to the centromere of the chromosome

Question 12

How does astral microtubules and motor proteins aid in the separation of chromosomes in mitosis?

Answer 12

Astral microtubules push the spindles poles apart. Dynein is anchored at periphery of cell on astral microtubules when moves pulls the spindle pols towards it.

Question 13

How do interpolar microtubules and motor proteins aid in the separation of chromosomes in mitosis?

Answer 13

Interpolar microtubules push spindle poles apart. Kinesin moves to result in interpolar microtubules sliding against each other to push the poles apart.