Question 1

Activation of which of the following is associated with the formation of focal adhesions and stress fibers?

Accepted Answer

A)  intermediate filaments
B)  y- tubulin
C)  Rho
D)  Ras
E)  Cdk- 42

Question 2

Ring- shaped complexes in the centrosome contain _ in combination with _ .

Accepted Answer

A)  gamma tubulin; tubulin GTP
B)  alpha tubulin; gamma tubulin
C)  gamma tubulin; pericentrin
D)  beta tubulin; tubulin GTP
E)  alpha tubulin; cilium

Question 3

resist tensile forces and contain keratin to form the protective barrier of the skin.

Accepted Answer

A)  Actin filaments
B)  Intermediate filaments
C)  Microtubules
D)  Microfilaments
E)  Keratin- associated filaments

Question 4

Axonemal microtubules

Accepted Answer

A)  are highly disorganized, but very stable.
B)  are required to maintain axons.
C)  are organized around a central shaft or axoneme.
D)  may be loosely associated with basal bodies.
E)  did not become clearly recognized until better fixation techniques became available in the 1960s.

Question 5

The model was proposed by Mitchison and Kirschner to explain how polymerization and depolymerization of microtubules occur simultaneously.

Accepted Answer

The answer of The model was proposed by Mitchison and...

Question 6

Intermediate filaments

Accepted Answer

A)  are grouped into five classes based on the cell types in which they are found.
B)  are smooth and sticky.
C)  have molecular masses averaging 500 kDa.
D)  were first discovered in muscle cells.
E)  assemble from nonfibrous filaments.

Question 7

The microtubule- organizing center (MTOC)

Accepted Answer

A)  acts as an anchor for both ends of the microtubule.
B)  is associated with two centrioles in plant cells.
C)  is positioned near the cell membrane.
D)  is called a centrosome during interphase.
E)  serves as a site for microtubule and microfilament assembly.

Question 8

Intermediate filaments

Accepted Answer

A)  are 70 nm in diameter.
B)  can be composed of the protein vimentin.
C)  are solely responsible for animal cell shape.
D)  are composed of alpha and beta tubulin.
E)  both A and D

Question 9

Which of the following is NOT a function of the cytoskeleton?

Accepted Answer

A)  cell movement
B)  positioning of enzymes
C)  moving of organelles
D)  passive transport
E)  cell division

Question 10

The two main types of eukaryotic microtubules are the _ and _ microtubules.

Accepted Answer

cytoplasmi...

Question 11

All of the following are components associated with the bacterial cytoskeleton EXCEPT

Accepted Answer

A)  MreB.
B)  plaktin.
C)  crescentin.
D)  FtsZ.
E)  both B and C B

Question 12

Tubulin may assemble and disassemble simultaneously in a process known as

Accepted Answer

A)  MAP motoring.
B)  treadmilling.
C)  actin- regulated assembly.
D)  microtubule organizing.
E)  dynamic instability.

Question 13

Which stage of microtubule assembly is the stage in which nucleation occurs?

Accepted Answer

A)  elongation
B)  sheets of protofilaments
C)  dimers
D)  closing of microtubules
E)  oligomers

Question 14

One of the following drugs blocks cell division because it stabilizes the microtubules. What is this drug, and for what is it used?

Accepted Answer

A)  benzimidazole; colchicine
B)  vincristine; bacterial infections
C)  vinblastine; antimitotic therapy
D)  nocodazole; allergies
E)  taxol; breast cancer

Question 15

Capping proteins such as CapZ

Accepted Answer

A)  cause microtubules branching.
B)  stabilize microtubules.
C)  destabilize microtubules.
D)  connect microtubules to microfilaments.
E)  cause microtubules to lengthen.

Question 16

Microtubules have an inner diameter of and an outer diameter of .

Accepted Answer

A)  25 nm; 30 nm
B)  8 nm; 12 nm
C)  15 nm; 25 nm
D)  7 mm; 14 mm
E)  15 mm; 25 mm

Question 17

Elongation of the microtubule occurs by the

Accepted Answer

A)  addition of G- actin subunits to the (+) end.
B)  addition of tubulin subunits to the (+) end.
C)  addition of tubulin subunits to each end.
D)  deletion of G- actin subunits from the (+) end.
E)  addition of the tubulin subunits to the (+) end, but removal from the (- ) end.

Question 18

A variety of proteins link actin to membranes. A protein is used to link actin to the membrane.

Accepted Answer

A)  spectrin; ER
B)  linker; plasma
C)  band 4.1; mucous
D)  band 4.1; basal
E)  ankyrin; lysosome B

Question 19

Which of the following intermediate filament proteins is incorrectly matched with the tissue in which it is found?

Accepted Answer

A)  cytokeratins- epithelial
B)  GFA protein- nervous
C)  nestin- connective
D)  vimentin- mesenchymal
E)  desmin- smooth muscle

Question 20

Lamellipodia

Accepted Answer

A)  contain microtubules.
B)  do not involve actin or tubulin.
C)  add structural rigidity to cells.
D)  are found in the basal lamina.
E)  are thin sheets of cytoplasm use for cell movement. E

Exam 15: Cytoskeletal Systems

Activation of which of the following is associated with the formation of focal adhesions and stress fibers?

Correct AnswerverifiedShow Answer

Ring- shaped complexes in the centrosome contain _ in combination with _ .

Correct AnswerverifiedShow Answer

resist tensile forces and contain keratin to form the protective barrier of the skin.

Correct AnswerverifiedShow Answer

Axonemal microtubules

Correct AnswerverifiedShow Answer

The model was proposed by Mitchison and Kirschner to explain how polymerization and depolymerization of microtubules occur simultaneously.

Correct AnswerverifiedShow Answer

Intermediate filaments

Correct AnswerverifiedShow Answer

The microtubule- organizing center (MTOC)

Correct AnswerverifiedShow Answer

Intermediate filaments

Correct AnswerverifiedShow Answer

Which of the following is NOT a function of the cytoskeleton?

Correct AnswerverifiedShow Answer

The two main types of eukaryotic microtubules are the _ and _ microtubules.

Correct Answerverifiedcytoplasmi...View AnswerShow Answer

All of the following are components associated with the bacterial cytoskeleton EXCEPT

Correct AnswerverifiedB

Tubulin may assemble and disassemble simultaneously in a process known as

Correct AnswerverifiedShow Answer

Which stage of microtubule assembly is the stage in which nucleation occurs?

Correct AnswerverifiedShow Answer

One of the following drugs blocks cell division because it stabilizes the microtubules. What is this drug, and for what is it used?

Correct AnswerverifiedShow Answer

Capping proteins such as CapZ

Correct AnswerverifiedShow Answer

Microtubules have an inner diameter of and an outer diameter of .

Correct AnswerverifiedShow Answer

Elongation of the microtubule occurs by the

Correct AnswerverifiedShow Answer

A variety of proteins link actin to membranes. A protein is used to link actin to the membrane.

Correct AnswerverifiedB

Which of the following intermediate filament proteins is incorrectly matched with the tissue in which it is found?

Correct AnswerverifiedShow Answer

Lamellipodia

Correct AnswerverifiedE

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cytoplasmi...
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B

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B

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E