Mitosis

Question 1

Alpha or Beta Tubilin is the site of growth on a microtubule

Answer 1

Beta

Question 2

How many molecules in a ring on a microtubule

Answer 2

13

Question 3

What is the site of initial nucleation or addition called?

Answer 3

Gamma Tubulin

Question 4

How many centrosomes exist in a normal cell not undergoing mitosis

Answer 4

1. during replication it is duplicated giving rise to the second one

Question 5

Kinesin is a motor protein that moves toward the…

Answer 5

+ end of the microtubule

Question 6

Dyneins is a motor proteins that moves toward the….

Answer 6

• end of the microtubule

Question 7

Catasrophe is…

Answer 7

destruction from the + end towards the minus end

Question 8

Rescue is

Answer 8

Rebuilding after catastrophe towards the + end

Question 9

Loss of what energy molecule causes catastrophe

Answer 9

GTP

Question 10

What role do MAP’s have during catasrophe

Answer 10

MAP’s slow catastrophe allowing GTP an opportunity to rebind to the cap and stabilize the microtubule

Question 11

What is the average half life of normal microtubules in a cell (non mitotic)

Answer 11

15-30 minutes

Question 12

How does nuclear disintegration effect MAP

Answer 12

Something is released upon disintegration of the nucleus that causes all of the MAP’s to fall off reducing the half life of microtubules from 15-30 minutes to 30 seconds

Question 13

What are the three types of microtubules at metaphase

Answer 13

kinetochore MT’s (- end at centriole, + end at chromosome)
Polar MT’s (- end at centriole, + end in middle, binds to ones from the other pole)
Astral MT’s (+ end is distal, searching for missing chromosomes)

Question 14

Key event in Anaphase A

Answer 14

chromosomes move towards the spindle poles

Question 15

Key event that happens in Anaphase B

Answer 15

spindle poles move toward the poles of the cells

Question 16

How does the polar microtubule overlap region stay in contact despite the spindle poles moving away from each other

Answer 16

They continue to grow at the + end

Question 17

Anaphase A movement consists of what kind of movements at either end of the structure

Answer 17

80% of the kinetochore moving down the kinetochore microtubule and 20% of the centriole breaking apart the microtubule reeling the chromosome in

Question 18

Some astral fibers reach the membrane and dynein does what

Answer 18

tries to move towards the - end toward the centriole ultimately pulling the centriole towards the membrane

Question 19

What is the mechanism of action of Taxol and epithilones

Answer 19

Stabalize MT preventing catastrophe, inhibits the MT from searching and attaching to chromosomes

Question 20

What is the mechanism of action for colchicine and vinlastine

Answer 20

cause MT to undergo catastrophe and not able to rebuild

Question 21

Explain the involvement of defective MT in Alzheimer’s

Answer 21

abnormal MAP falls off MT and forms its own filament structure (plaque)

Question 22

What are the MT stabilizing chemotherapy agents?

Answer 22

Taxol and Epithilones

Question 23

What are the MT depolymerizing chemotherapy agents?

Answer 23

Colchincine and vinblastine

Question 24

Phosphorylation has what effect on gamma tubulin?

Answer 24

Allows for it to be nucleated and grow