Question 1

Axonemal microtubules are

Accepted Answer

A) dynamically unstable. 
B) anchored on basal bodies. 
C) randomly oriented in the axoneme. 
D) required to maintain axons. 
E) involved in intracellular organelle transport. 
A) dynamically unstable. 
B) anchored on basal bodies. 
C) randomly oriented in the axoneme. 
D) required to maintain axons. 
E) involved in intracellular organelle transport.

Question 2

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

Accepted Answer

A) keratin - epithelial cells 
B) desmin - smooth muscle cells 
C) vimentin - mesenchymal cells 
D) nestin - connective tissue cells 
E) GFA protein - glial cells 
A) keratin - epithelial cells 
B) desmin - smooth muscle cells 
C) vimentin - mesenchymal cells 
D) nestin - connective tissue cells 
E) GFA protein - glial cells

Question 3

Which of the following cytoskeletal proteins is found in prokaryotes?

Accepted Answer

A) keratin 
B) tubulin 
C) crescentin 
D) vimentin 
E) actin 
A) keratin 
B) tubulin 
C) crescentin 
D) vimentin 
E) actin

Question 4

Microfilaments

Accepted Answer

A) are composed of eight protofilaments joined end to end with staggered overlaps. 
B) are composed of two helical strands of actin monomers oriented in the same direction. 
C) are composed of two helical antiparallel strands of actin monomers. 
D) are composed of α- and β-actin dimers. 
E) polymerize at the same rate from both ends of the filament. 
A) are composed of eight protofilaments joined end to end with staggered overlaps. 
B) are composed of two helical strands of actin monomers oriented in the same direction. 
C) are composed of two helical antiparallel strands of actin monomers. 
D) are composed of α- and β-actin dimers. 
E) polymerize at the same rate from both ends of the filament.

Question 5

Which of the following is not known to be involved in associating actin microfilaments with plasma membranes?

Accepted Answer

A) PIP2 
B) spectrin 
C) ankyrin 
D) band 4.1 
E) A,B,C,and D are involved in associating actin microfilaments with plasma membranes. 
A) PIP2 
B) spectrin 
C) ankyrin 
D) band 4.1 
E) A,B,C,and D are involved in associating actin microfilaments with plasma membranes.

Question 6

In the table below,list the classes of IF,the IF protein subunits,and the tissue (or cells)in which they are found.
 $$\begin{array} { | l | l | l | } 
\hline \text { Class } & \text { IF Protein } & \text { Tissue/Cells } \
\hline & & \
\hline & & \
\hline & & \
\hline & & \
\hline & & \
\hline & & \
\hline
\end{array}$$

Accepted Answer

See both Table 13-4 and the table below.

Question 7

γ-TuRCs contain ________-tubulin and nucleate microtubule growth from MTOCs known as ________.

Accepted Answer

The answer of γ-TuRCs contain ________-tubulin and nucleate microtubule growth...

Question 8

Actin bundles give shape and support to ________ found in intestinal mucosal cells.

Accepted Answer

A) cilia 
B) flagella 
C) microvilli 
D) nuclei 
E) lamellipodia 
A) cilia 
B) flagella 
C) microvilli 
D) nuclei 
E) lamellipodia

Question 9

Dynamic assembly and disassembly of a cytoplasmic microtubule in a cell occurs primarily at its plus end,because its minus end is usually anchored to

Accepted Answer

A) a basal body. 
B) a centromere. 
C) a microtubule organizing center. 
D) a mitochondrial outer membrane. 
E) the plasma membrane. 
A) a basal body. 
B) a centromere. 
C) a microtubule organizing center. 
D) a mitochondrial outer membrane. 
E) the plasma membrane.

Question 10

________ causes microtubules to form tight bundles in nerve cell axons.

Accepted Answer

A) MAP2 
B) EB1 
C) Tau 
D) FtsZ 
E) Desmin 
A) MAP2 
B) EB1 
C) Tau 
D) FtsZ 
E) Desmin

Question 11

Rho Family GTPases (Rho,Rac,Cdc42)stimulate cytoskeletal microfilament assembly for all of the following except

Accepted Answer

A) stress fiber formation. 
B) lamellipodia formation. 
C) nuclear envelope breakdown for mitosis. 
D) cytokinetic furrow formation. 
E) filopodia formation. 
A) stress fiber formation. 
B) lamellipodia formation. 
C) nuclear envelope breakdown for mitosis. 
D) cytokinetic furrow formation. 
E) filopodia formation.

Question 12

Cytoskeletal elements are found in

Accepted Answer

A) bacteria. 
B) archaea. 
C) eukaryotes. 
D) B and C only. 
E) A,B,and C. 
A) bacteria. 
B) archaea. 
C) eukaryotes. 
D) B and C only. 
E) A,B,and C.

Question 13

Mutations of keratins in the ________ that resist tensile forces in the skin cause the blistering disease known as epidermolysis bullosa simplex.

Accepted Answer

A) intermediate filaments 
B) microtubules 
C) microfilaments 
D) actin filaments 
E) crescentin filaments 
A) intermediate filaments 
B) microtubules 
C) microfilaments 
D) actin filaments 
E) crescentin filaments

Question 14

Which of the following is false about dynamic instability of a microtubule end?

Accepted Answer

A) During a growth phase,assembly of GTP-tubulin is faster than incorporated GTP is hydrolyzed,forming a GTP-cap. 
B) During a catastrophe phase,hydrolysis of incorporated GTP is faster than GTP-tubulin addition,forming a GDP-cap. 
C) During rescue,GTP-tubulin assembles fast enough to reestablish a GTP cap. 
D) Each end of a microtubule can undergo dynamic instability independently. 
E) A,B,C,and D are true. 
A) During a growth phase,assembly of GTP-tubulin is faster than incorporated GTP is hydrolyzed,forming a GTP-cap. 
B) During a catastrophe phase,hydrolysis of incorporated GTP is faster than GTP-tubulin addition,forming a GDP-cap. 
C) During rescue,GTP-tubulin assembles fast enough to reestablish a GTP cap. 
D) Each end of a microtubule can undergo dynamic instability independently. 
E) A,B,C,and D are true.

Question 15

Which of the following is not associated with the bundle of microfilaments supporting each microvillus in small intestine mucosal cells?

Accepted Answer

A) fimbrin 
B) villin 
C) fascin 
D) myosin I 
E) All are associated with the microvillus microfilament bundle. 
A) fimbrin 
B) villin 
C) fascin 
D) myosin I 
E) All are associated with the microvillus microfilament bundle.

Question 16

According to your text,how many classes of IFs exist?

Accepted Answer

The answer of According to your text,how many classes of...

Question 17

What are some of the drugs used to study microfilaments?

Accepted Answer

cytochalas

Question 18

Centrosome ring-shaped complexes contain ________ and ________.

Accepted Answer

A) α-tubulin; β-tubulin 
B) γ-tubulin; MCAK 
C) γ -tubulin; MAP2 
D) γ-tubulin; GRiPs 
E) γ-tubulin; crescentin 
A) α-tubulin; β-tubulin 
B) γ-tubulin; MCAK 
C) γ -tubulin; MAP2 
D) γ-tubulin; GRiPs 
E) γ-tubulin; crescentin

Question 19

Microtubules contribute to each of the following except

Accepted Answer

A) intracellular transport. 
B) the human red blood cell disklike shape. 
C) orientation of plant cellulose microfibrils. 
D) filopodial structure. 
E) mitotic spindles. 
A) intracellular transport. 
B) the human red blood cell disklike shape. 
C) orientation of plant cellulose microfibrils. 
D) filopodial structure. 
E) mitotic spindles.

Question 20

Microtubules have an outer diameter of

Accepted Answer

A) 7 nm. 
B) 8-12 nm. 
C) 25 nm. 
D) 7 mm. 
E) 25 mm. 
A) 7 nm. 
B) 8-12 nm. 
C) 25 nm. 
D) 7 mm. 
E) 25 mm.

Exam 13: Cytoskeletal Systems

Axonemal microtubules are

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

Which of the following cytoskeletal proteins is found in prokaryotes?

Microfilaments

Which of the following is not known to be involved in associating actin microfilaments with plasma membranes?

In the table below,list the classes of IF,the IF protein subunits,and the tissue (or cells)in which they are found. Class IF Protein Tissue/Cells

γ-TuRCs contain ________-tubulin and nucleate microtubule growth from MTOCs known as ________.

Actin bundles give shape and support to ________ found in intestinal mucosal cells.

Dynamic assembly and disassembly of a cytoplasmic microtubule in a cell occurs primarily at its plus end,because its minus end is usually anchored to

________ causes microtubules to form tight bundles in nerve cell axons.

Rho Family GTPases (Rho,Rac,Cdc42)stimulate cytoskeletal microfilament assembly for all of the following except

Cytoskeletal elements are found in

Mutations of keratins in the ________ that resist tensile forces in the skin cause the blistering disease known as epidermolysis bullosa simplex.

Which of the following is false about dynamic instability of a microtubule end?

Which of the following is not associated with the bundle of microfilaments supporting each microvillus in small intestine mucosal cells?

According to your text,how many classes of IFs exist?

What are some of the drugs used to study microfilaments?

Centrosome ring-shaped complexes contain ________ and ________.

Microtubules contribute to each of the following except

Microtubules have an outer diameter of

A Preview of Cell Biology

The Chemistry of the Cell

The Macromolecules of the Cell

Cells and Organelles

Bioenergetics: the Flow of Energy in the Cell

Enzymes: the Catalysts of Life

Membranes: Their Structure,function,and Chemistry

Transport Across Membranes: Overcoming the Permeability Barrier

Chemotrophic Energy Metabolism: Glycolysis and Fermentation

Chemotrophic Energy Metabolism: Aerobic Respiration

Phototrophic Energy Metabolism: Photosynthesis

The Endomembrane System

Cellular Movement: Motility and Contractility

Beyond the Cell: Cell Adhesions, cell Junctions, and Extracellular Structures

The Structural Basis of Cellular Information: Dna, chromosomes, and the Nucleus

DNA Replication, repair, and Recombination

Gene Expression: Ithe Genetic Code and Transcription

Gene Expression: Iiprotein Synthesis and Sorting

The Regulation of Gene Expression

Molecular Biology Techniques for Cell Biology

Signal Transduction Mechanisms: Ielectrical and Synaptic Signaling in Neurons

Signal Transduction Mechanisms: Iimessengers and Receptors

The Cell Cycle and Mitosis

Sexual Reproduction,meiosis,and Genetic Recombination

Filters

γ-TuRCs contain -tubulin and nucleate microtubule growth from MTOCs known as .

Centrosome ring-shaped complexes contain and .