Exam 2 - Cytoskeleton

Question 1

What property of the cytoskeletal polymers allows for rapid assembly and disassembly?

Answer 1

Held together by weak noncovalent interactions

Question 2

What cytoskeletal polymer catalyzes the hydrolysis of ATP?

Answer 2

Actin

Question 3

What cytoskeletal polymer catalyzes the hydrolysis of GTP?

Answer 3

Microtubules

Question 4

What cytoskeletal polymer does not catalyze the hydrolysis of a nucleotides?

Answer 4

Intermediate filaments

Question 5

What cytoskeletal polymers are asymmetrical?

Answer 5

Actin and microtubules

Question 6

What cytoskeletal polymer is symmetrical?

Answer 6

Intermediate filaments

Question 7

General term for cytoskeletal filaments. Long linear strings of protein subunits that join end-to-end.

Answer 7

Protofilaments

Question 8

Accessory proteins. Bind to polarized cytoskeletal filaments, use energy from ATP hydrolysis to move along the filament the are associated with.

Answer 8

Motor proteins

Question 9

Initial aggregate of 3 actin monomers. Start of polymerization.

Answer 9

Nucleation

Question 10

The change from growth to rapid shrinkage of a microtubule. Loss of GTP cap at plus end.

Answer 10

Catastrophe

Question 11

The change from rapid shrinkage to growth of microtubule. Regain GTP cap at plus end.

Answer 11

Rescue

Question 12

Phenomenon where the rate at which the subunits at the minus end are being removed is equal to the rate at which the subunits are being added at the plus end therefore maintaining an actin polymer with a constant length.

Answer 12

Treadmilling

Question 13

What is the rate-limiting step in the formaiton of cytoskeletal filament?

Answer 13

Nucleation

Question 14

Nucleoside hydrolysis by actin and tubulin are respnsible for what phenomena?

Answer 14

Treadmilling and dynamic instability

Question 15

True/False: Actin monomers are microtubule subunits.

Answer 15

False, tubulin

Question 16

What are some general functions of the cytoskeleton?

Answer 16

Organize the cell, cellular movement, mechanical strength, etc.

Question 17

How does a hereditary spherocytosis RBC differ than a normal RBC?

Answer 17

Spherical shape, 12 hour half-life, breaks from from shearing force, and can lead to anemia and death

Question 18

What is the monomer of actin?

Answer 18

Actin monomer

Question 19

What cytoskeletal filament functions in cell surface shape, locomotion, secretion, and endocytosis?

Answer 19

Actin

Question 20

What are the monomers of micrutubules?

Answer 20

Tubulin

Question 21

One end of a microtubule is often associated with what structure?

Answer 21

Centrosome

Question 22

What cytoskeletal filament functions in organelle organization, intracellular transport, and centrioles & mitotic spindle?

Answer 22

Microtubules

Question 23

What cytoskeletal filament functions in mechanical strength?

Answer 23

Intermediate filaments

Question 24

How are actin polymers and tubulin polymers similiar?

Answer 24

Both has a plus end/minus end, both have a T form and D form

Question 25

What can actin monomers bind?

Answer 25

ATP or ADP

Question 26

What can tubulin dimers bind?

Answer 26

GTP or GDP

Question 27

Treadmilling predominates in actin/tubulin meanwhile dynamic instability predominates in actin/tubulin.

Answer 27

Actin; Tubulin

Question 28

Keratins are an example of what cytoskeletal filament. Found in hair and nails.

Answer 28

Intermediate filaments