Quiz 11

The extracellular matrix is particularly important for which type of tissue? -nervous -epithelial -muscle -connective

connective

Cancer can be characterized by: -All of these choices are correct. -cells with an enhanced ability to adhere to proteins in the basal lamina. -a mass of rapidly dividing cells called a tumor. -metastasized tumor cells that leave the tumor and invade distant parts of the body.

All of these choices are correct.

Intermediate filaments: -play an important role in preventing skin from tearing by shear stress. -undergo little change in length in comparison to microtubules and microfilaments. -All of these choices are correct. -have a diameter that is larger than a microfilament, but smaller than a microtubule. -play an important role in maintaining cell shape.

All of these choices are correct.

Microtubules increase in length: -All of these choices are correct. -more quickly at one end than the other. -by growing outward from the centrosome. -if free tubulin dimers are available. -in cycles, following rapid depolymerization.

All of these choices are correct.

What is the advantage of forcing materials to travel through cells instead of between cells? -Exposure to toxins is limited. -Cells can control which materials are transported. -Exposure to bacteria or viruses is limited. -All of these choices are correct.

All of these choices are correct.

Why are the ends of microfilaments and microtubules called "plus ends" and "minus ends"? -Because the actin and tubulin monomers that make up microfilaments and microtubules have evolved more rapidly than most other proteins. -Because monomers can be added to one end only (the "plus end"), and can only be removed from the other end (the "minus end"). -Because monomers are added more quickly to one end (the "plus end") than they are to the other end (the "minus end"). -Because polymerization occurs at one end (the "plus end") and depolymerization occurs at the other end (the "minus end").

Because monomers are added more quickly to one end (the "plus end") than they are to the other end (the "minus end").

What would happen in a cell if its α-tubulin was mutated and unable to bind to its β tubulin? -The cell would have no microtubules. -The cell would have no microfilaments. -The cell would be unaffected. -The cell would have no intermediate filaments.

The cell would have no microtubules.

Which of the following statements about intracellular transport is TRUE? -Myosin and kinesin move substances toward the "plus end" of microtubules and microfilaments, respectively. -Kinesin and myosin move substances toward the "minus end" of microtubules and microfilaments, respectively. -Myosin and kinesin move substances toward the "minus end" of microtubules and microfilaments, respectively. -Kinesin and myosin move substances toward the "plus end" of microtubules and microfilaments, respectively.

Kinesin and myosin move substances toward the "plus end" of microtubules and microfilaments, respectively.

Which one of the following statements about intracellular transport is TRUE? -Microtubules and microfilaments facilitate cellular movement, but intermediate filaments do not. -Microtubules and intermediate filaments facilitate cellular movement, but microfilaments do not. -Intermediate filaments and microfilaments facilitate cellular movement, but microtubules do not. -Intermediate filaments, microfilaments, and microtubules all facilitate cellular movement of one kind or another.

Microtubules and microfilaments facilitate cellular movement, but intermediate filaments do not.

Which one of the following statements about intracellular transport is TRUE? -Myosin moves substances along microfilaments. -Kinesin and myosin move substances along microtubules. -Myosin and dynein move substances along microfilaments. -Kinesin and dynein move substances along microfilaments.

Myosin moves substances along microfilaments.

The extracellular matrix is composed of: (1) proteins; (2) polysaccharides; (3) nucleic acids. -Statement (1) is correct. -Statement (3) is correct. -Statement (2) is correct. -Statements (1) and (2) are correct. -All of these statements are correct.

Statements (1) and (2) are correct.

Epidermolysis bullosa is a set of rare genetic disorders that is caused by: -an intermediate filament gene that disrupts hemidesmosomes, weakening epidermal cell connections. -a keratin gene that disrupts microfilaments, weakening epidermal cell connections. -a microfilament gene that disrupts desmosomes, weakening epidermal cell connections. -a keratin gene that disrupts intermediate filaments, weakening epidermal cell connections. -All of these choices are correct.

a keratin gene that disrupts intermediate filaments, weakening epidermal cell connections.

Which of the following is associated with microfilaments? -cilia and flagella -desmosomes -adherens junction

adherens junction

Cilia and flagella: -are specialized organelles that move by rotary motion. -are specialized cells that move by rotary motion. -contain microfilaments arranged in nine pairs around the periphery and two microfilaments in the center. -contain microtubules arranged in nine pairs around the periphery and two microfilaments in the center. -are specialized organelles that propel some algae, plant, and animal cells.

are specialized organelles that propel some algae, plant, and animal cells.

Some cytoskeletal elements are more permanent than others. Which components of the cytoskeleton are dynamic structures? -intermediate filaments -microfilaments -microtubules -both microtubules and microfilaments -both microtubules and intermediate filaments

both microtubules and microfilaments

Which of the following cytoskeletal elements is capable of assembling and disassembling in the cell? -intermediate filaments -microfilaments -both microtubules and microfilaments -microtubules

both microtubules and microfilaments

Which of the following is associated with microtubules? -desmosomes -adherens junction -cilia and flagella

cilia and flagella

Myosin motor proteins use ATP to: -carry vesicles along a microfilament within a cell in a minus-to-plus direction. -slide along intermediate filaments to contract muscle cells. -carry vesicles along a microfilament within a cell in a plus-to-minus direction. -carry vesicles along a microtubule within a cell in a minus-to-plus direction. -carry vesicles along a microtubule within a cell in a plus-to-minus direction.

carry vesicles along a microfilament within a cell in a minus-to-plus direction.

Kinesin motor proteins use ATP to: -carry vesicles along a microtubule within a cell in a minus-to-plus direction. -slide along microfilaments to contract muscle cells. -carry vesicles along a microfilament within a cell in a minus-to-plus direction. -carry vesicles along a microtubule within a cell in a plus-to-minus direction. -carry vesicles along a microfilament within a cell in a plus-to-minus direction.

carry vesicles along a microtubule within a cell in a minus-to-plus direction.

Dynein motor proteins use ATP to: -carry vesicles along a microfilament within a cell in a plus-to-minus direction. -carry vesicles along a microfilament within a cell in a minus-to-plus direction. -carry vesicles along a microtubule within a cell in a minus-to-plus direction. -slide along microfilaments to contract muscle cells. -carry vesicles along a microtubule within a cell in a plus-to-minus direction.

carry vesicles along a microtubule within a cell in a plus-to-minus direction.

Cadherin is an example of a(n): -motor protein. -extracellular matrix protein. -intermediate filament protein. -cell adhesion molecule.

cell adhesion molecule.

Which of the following is associated with intermediate filaments? -desmosomes -cilia and flagella -adherens junction

desmosomes

Which motor protein(s) would you find in a flagellum? -kinesin -myosin -dynein -both myosin and dynein

dynein

Where would you find a cell adhesion molecule? -in the microvilli -near the centrosome -in a cell junction -in a cilium

in a cell junction

Zebrafish embryos change the color of the melanophore cells in their skin to a darker shade by: -kinesin motor proteins moving pigment granules outward from the center of the cell. -dynein motor proteins moving pigment granules inward toward the plus end of microtubules. -kinesin motor proteins moving pigment granules inward toward the center of the cell. -dynein motor proteins moving pigment granules outward from the center of the cell. -dynein motor proteins moving pigment granules inward toward the center of the cell.

kinesin motor proteins moving pigment granules outward from the center of the cell.

Microtubules and microfilaments are said to be "dynamic" elements of the cytoskeleton. In this case, "dynamic" means that: they are constantly changing and are never in the same place for very long. microtubules and microfilaments are assembled and disassembled and then reassembled again in a regulated manner. once individual microfilaments and microtubules have formed, they can change shape and move around inside the cell.

microtubules and microfilaments are assembled and disassembled and then reassembled again in a regulated manner.

The cytoskeleton of plant cells includes: -microtubules, microfilaments, and intermediate filaments. -actin, microtubules, and intermediate filaments. -actin, microfilaments, and intermediate filaments. -tubulin, microfilaments, and intermediate filaments. -microtubules and microfilaments.

microtubules and microfilaments.

Which is the correct order of cytoskeletal filaments in DECREASING filament diameter? -intermediate filaments → microfilaments → microtubules -microtubules → intermediate filaments → microfilaments -microfilaments → microtubules → intermediate filaments -microtubules → microfilaments → intermediate filaments

microtubules → intermediate filaments → microfilaments

Dynein is a motor protein found attached to: -lamin. -microtubules. -intermediate filaments. -microfilaments.

microtubules.

Kinesin is a motor protein found attached to: -tubulin. -microfilaments. -intermediate filaments. -microtubules.

microtubules.

Microfilaments increase in length: -by assembling outward from the centrosome. -more quickly at one end than the other. -All of these choices are correct. -in cycles, following rapid depolymerization. -if free tubulin dimers are available.

more quickly at one end than the other.

Which one of the following is NOT a cellular function associated with microtubules? -organization of organelles -chromosome segregation -muscle contraction -movement of cilia and flagella

muscle contraction

The internal cytoskeletal structure of cilia and flagella grows out from a structure called a basal body located near the cell surface. Based on this information, where would you predict the plus end of the microtubules to be located? -at both ends of the cilia or flagella -near the tip of the cilia or flagella -near the basal body -It is not possible to predict from the information provided.

near the tip of the cilia or flagella

The property of dynamic instability implies that the individual protein subunits of microtubules are held together by: -noncovalent interactions. -All of these choices are correct. -covalent bonds. -disulfide bonds.

noncovalent interactions.

In nerve cells, the centrosome is located near the nucleus. Vesicles move from near the nucleus to the end of long extensions (axons) along microtubules. Based on these two facts, it is possible to conclude that these vesicles are moving in the _____ direction on the microtubule using the motor protein _____. -plus end; dynein -plus end; kinesin -minus end; dynein -minus end; kinesin

plus end; kinesin