Question 1

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

Question 2

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

Question 3

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. 
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

Question 4

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

Question 5

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. 
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 6

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

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. 
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

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 
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 9

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

Question 10

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. 
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 11

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

Question 12

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

Question 13

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 
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 14

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

Question 15

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

Accepted Answer

cytoplasmi

Question 16

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

Question 17

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. 
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 18

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 19

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

Question 20

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

Exam 15: Cytoskeletal Systems

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

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

Lamellipodia

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

Elongation of the microtubule occurs by the

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

The microtubule- organizing center (MTOC)

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

Tubulin may assemble and disassemble simultaneously in a process known as

Axonemal microtubules

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

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

Intermediate filaments

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

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

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

Intermediate filaments

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

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

Capping proteins such as CapZ

A Preview of the Cell

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 and Peroxisomes

Signal Transduction Mechanisms: I Electrical and Synaptic Signaling in Neurons

Signal Transduction Mechanisms: Ii Messengers and Receptors

Cellular Movement: Motility and Contractility

Beyond the Cell: Cell Adhesion, Cell Junctions, and Extracellular Structures

The Structural Basis of Cellular Information: DNA, Chromosomes, and the Nucleus

The Cell Cycle, Dna Replication, and Mitosis

Sexual Reproduction, Meiosis, and Genetic Recombination

Gene Expression: I the Genetic Code and Transcription

Gene Expression: II Protein Synthesis and Sorting

The Regulation of Gene Expression

Cancer Cells

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