Cytoskeleton

Question 1

What molecule stimulates polymerization of microfilaments?

Answer 1

ATP

Question 2

What protein induces branching of actin filaments?

Answer 2

Arp2/3 (actin-related protein)

Question 3

How does Arp2/3 stimulate new filaments?

Answer 3

It binds a third monomer to the actin filament (compared to the usual two) and that nucleates a branch

Question 4

List four functions of actin.

Answer 4

Epithelial cell polarity; contraction; cell motility; cell division.

Question 5

What are the actin-centered protrusions of cells called?

Answer 5

Microvilli (singular, microvillus)

Question 6

What two drugs interfere with microtubule polymerization at the plus end?

Answer 6

Colchicine and vincristine

Question 7

What drug stabilizes microtubules?

Answer 7

Taxol

Question 8

What protein is responsible for lamellipodia?

Answer 8

Arp2/3 and actin (they form the wide, fan-shaped protrusion of lamellipodiam)

Question 9

______ tubulin hydrolyzes GTP, while ______ does not.

Answer 9

Beta; alpha

Question 10

Microtubules are formed by the polymerization of _____ monomers, a type of G-protein

Answer 10

tubulin

Question 11

_______ is a disease associated with mutations in spastin, a family of cap-severing protein.

Answer 11

Hereditary spastic paraplesia

Question 12

Cellular vesicles are transported toward the plus ends of microtubules with ______.

Answer 12

kinesin

Question 13

Which motor molecule drives the pushing away of mitotic spindles?

Answer 13

Kinesin