Question 1

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

Accepted Answer

A)  α-tubulin; cilium
B)  α-tubulin; γ-tubulin
C)  β-tubulin; tubulin GTP
D)  γ-tubulin; pericentrin
E)  γ-tubulin; tubulin GTP

Question 2

Axonemal microtubules

Accepted Answer

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

Question 3

F-actin filaments

Accepted Answer

A)  are composed of four linear strands.
B)  are composed of polymerized G-actin monomers wound around each other in a helix.
C)  are oriented similar to DNA, with strands helical and antiparallel to one another.
D)  are composed of G-actin dimers.
E)  polymerize at the same rate in both directions from both ends of the filament. B

Question 4

Of the following microtubule-interacting proteins,which might you potentially investigate as a mechanism for disrupting cell division in actively replicating tumor cells?

Accepted Answer

A)  Tau
B)  +-TIP proteins
C)  catastrophins
D)  G-actin
E)  FtsZ

Question 5

Choose the item that best matches the other items.
-microvilli

Accepted Answer

A)  breaking and capping actin
B)  increase cellular surface area
C)  assembly and disassembly
D)  terminal web
E)  control microtubule organizationF) plectinG) central shaftH) nucleating actin branchesI) bind to profilin and CapZJ) oligomer formationK) nucleating tubulin branchesL) hemidesmosomeM) decorate the actin microfilamentN) dyneinO) prevents loss of subunitsP) desmosome  Q) nuclear lamina  R) account for 10-15% of microtubules  S) inhibits microtubule assembly  T) two identical polypeptides joined end-to-end  U) found in cilia and flagella

Question 6

Choose the item that best matches the other items.
-motor MAPs

Accepted Answer

A)  breaking and capping actin
B)  increase cellular surface area
C)  assembly and disassembly
D)  terminal web
E)  control microtubule organizationF) plectinG) central shaftH) nucleating actin branchesI) bind to profilin and CapZJ) oligomer formationK) nucleating tubulin branchesL) hemidesmosomeM) decorate the actin microfilamentN) dyneinO) prevents loss of subunitsP) desmosome  Q) nuclear lamina  R) account for 10-15% of microtubules  S) inhibits microtubule assembly  T) two identical polypeptides joined end-to-end  U) found in cilia and flagella

Question 7

Rho GTPases have the all of the following effects on cytoskeletal actin except

Accepted Answer

A)  stress fiber formation.
B)  formation of pseudopodia.
C)  stabilization of neurons.
D)  assembly of the cytokinetic furrow.
E)  regulation of endocytosis and exocytosis. C

Question 8

The structure,function,and assembly of microtubules are regulated by ________ proteins (MAPs).

Accepted Answer

microtubul...

Question 9

The microtubule-organizing center (MTOC)

Accepted Answer

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

Question 10

Based on composition similarities,actin can be divided into two major groups: the muscle-specific actins (________-actin)and nonmuscle actins (________- and ________-actin).

Accepted Answer

The answer of Based on composition similarities,actin can be divided...

Question 11

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

Accepted Answer

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

Question 12

Lamellipodia

Accepted Answer

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

Question 13

Microtubules and microfilaments differ with respect to each of the following except

Accepted Answer

A)  size.
B)  occurrence.
C)  associated motor proteins.
D)  a state of dynamic instability.
E)  subunits. D

Question 14

Intermediate filaments

Accepted Answer

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

Question 15

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

Accepted Answer

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

Question 16

Choose the item that best matches the other items.
-nucleation

Accepted Answer

A)  breaking and capping actin
B)  increase cellular surface area
C)  assembly and disassembly
D)  terminal web
E)  control microtubule organizationF) plectinG) central shaftH) nucleating actin branchesI) bind to profilin and CapZJ) oligomer formationK) nucleating tubulin branchesL) hemidesmosomeM) decorate the actin microfilamentN) dyneinO) prevents loss of subunitsP) desmosome  Q) nuclear lamina  R) account for 10-15% of microtubules  S) inhibits microtubule assembly  T) two identical polypeptides joined end-to-end  U) found in cilia and flagella

Question 17

What is the importance of proteins that precisely control when and where cytoskeletal elements form and depolymerize? Make sure to give examples in your explanations.

Accepted Answer

They allow for precise control,orientati...

Question 18

Tubulin may assemble and disassemble simultaneously in a process known as

Accepted Answer

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

Question 19

The ________ is a dense network of microfilaments just beneath the plasma membrane.

Accepted Answer

The answer of The ________ is a dense network of...

Question 20

Of the following proteins,which would be a good target for drug therapy if one needed to interfere with breaking down the microfilament network?

Accepted Answer

A)  profilin
B)  CapZ
C)  gelsolin
D)  tropomodulin
E)  calmodulin

Exam 15: Cytoskeletal Systems

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

Correct AnswerverifiedShow Answer

Axonemal microtubules

Correct AnswerverifiedShow Answer

F-actin filaments

Correct AnswerverifiedB

Of the following microtubule-interacting proteins,which might you potentially investigate as a mechanism for disrupting cell division in actively replicating tumor cells?

Correct AnswerverifiedShow Answer

Choose the item that best matches the other items. -microvilli

Correct AnswerverifiedShow Answer

Choose the item that best matches the other items. -motor MAPs

Correct AnswerverifiedShow Answer

Rho GTPases have the all of the following effects on cytoskeletal actin except

Correct AnswerverifiedC

The structure,function,and assembly of microtubules are regulated by ________ proteins (MAPs).

Correct Answerverifiedmicrotubul...View AnswerShow Answer

The microtubule-organizing center (MTOC)

Correct AnswerverifiedShow Answer

Based on composition similarities,actin can be divided into two major groups: the muscle-specific actins (________-actin)and nonmuscle actins (________- and ________-actin).

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Lamellipodia

Correct AnswerverifiedShow Answer

Microtubules and microfilaments differ with respect to each of the following except

Correct AnswerverifiedD

Intermediate filaments

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Choose the item that best matches the other items. -nucleation

Correct AnswerverifiedShow Answer

What is the importance of proteins that precisely control when and where cytoskeletal elements form and depolymerize? Make sure to give examples in your explanations.

Correct AnswerverifiedThey allow for precise control,orientati...View AnswerShow Answer

Tubulin may assemble and disassemble simultaneously in a process known as

Correct AnswerverifiedShow Answer

The ________ is a dense network of microfilaments just beneath the plasma membrane.

Correct AnswerverifiedShow Answer

Of the following proteins,which would be a good target for drug therapy if one needed to interfere with breaking down the microfilament network?

Correct AnswerverifiedShow Answer

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

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B

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C

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microtubul...
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Based on composition similarities,actin can be divided into two major groups: the muscle-specific actins (-actin)and nonmuscle actins (- and -actin).

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D

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

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They allow for precise control,orientati...
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