Ch. 10 Exam Review

Evidence that cytoskeletal elements have ancient origins comes from the: a. All of these choices are correct. b. ability to form functional hybrid microfilaments from actin monomers taken from distantly related organisms. c. observation that both prokaryotes and eukaryotes use cytoskeletal elements to assist cell division. d. sequence similarities of cytoskeletal elements when comparing distantly related organisms. e. presence of cytoskeletal elements in both eukaryotes and prokaryotes.

a

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

a

Where would you predict colchicine to have the greatest effect? a. chromosome segregation b. the shortening of a muscle cell c. Colchicine would likely have no effect on any of these cells or processes. d. fibroblast migration e. sperm cell motility

a

Where would you predict cytochalasins to have the greatest effect? a. fibroblast migration b. chromosome segregation c. Cytochalasins would likely have no effect on any of these cells or processes. d. the shortening of a muscle cell e. sperm cell motility

a

Which is the correct order of cytoskeletal filaments in DECREASING filament diameter? a. microtubules → intermediate filaments → microfilaments b. microtubules → microfilaments → intermediate filaments c. microfilaments → microtubules → intermediate filaments d. intermediate filaments → microfilaments → microtubules

a

Which of the following statements about mammalian skin is INCORRECT? a. A specialized form of extracellular matrix, called the basal lamina, underlies the dermis and separates it from tissues below. b. The epidermis is an outer layer that provides a water-resistant, protective barrier. c. Epithelial cells in the epidermis are primarily composed of keratinocytes that protect underlying tissue. d. Fibroblasts in the dermis produce extracellular matrix proteins to make the dermis strong and flexible. e. The dermis is the layer below the epidermis containing connective tissue, blood vessels, and nerve endings that provides nutrients to the epidermis and a cushion layer for the body.

a

Which one of the following is a characteristic shared by integrins and cadherins? a. The cytoplasmic domains of both proteins are connected to the cytoskeleton. b. Both are peripheral membrane proteins. c. Both are present in adherens junctions, desmosomes, and hemidesmosomes. d. Both facilitate the adhesion of cells to extracellular matrix proteins.

a

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

a

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

a

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

c

The MOST likely reason(s) a metastatic tumor cell might lose its connection to the basal lamina would be: a. a change in the composition of the basal lamina. b. the loss of integrin proteins from the cell's surface, or a change in the type of integrin proteins present on the cell's surface. c. the loss of integrin proteins from the cell's surface. d. a change in the type of integrin proteins present on the cell's surface.

b

The dermis of mammalian skin, including that of humans, contains a large amount of extracellular matrix proteins, including collagen and elastin. As a person ages, the amount of elastin in the dermis declines. Which of the following cell types is likely to be the cause of this change in the dermis of the skin? a. melanocytes b. fibroblasts c. keratinocytes d. epidermal cells

b

Flagella move in a(n): a. whiplike motion by the motor protein kinesin sliding microtubules past each other. b. oarlike motion by the motor protein dynein sliding microtubules past each other. c. whiplike motion by the motor protein dynein sliding microtubules past each other. d. oarlike motion by the motor protein kinesin sliding microtubules past each other. e. whiplike motion by the motor protein dynein sliding microfilaments past each other.

c

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 _____. a. minus end; kinesin b. minus end; dynein c. plus end; kinesin d. plus end; dynein

c

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

c

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

c

Which of the following cytoskeletal elements contribute to the structural integrity and strength of epithelial tissues in animals? a. intermediate filaments and microtubules b. microtubules and microfilaments c. intermediate filaments and microfilaments

c

Which one of the following properly groups a cell junction with a cytoskeletal element and cell adhesion molecule? a. tight junction, cadherin, intermediate filament b. desmosome, microfilament, integrin c. adherens junction, microfilament, cadherin d. desmosome, microtubule, integrin

c

Epithelial tissue is found: a. lining the gastrointestinal tract. b. lining blood vessels. c. on the outer surface of the body. d. All of these choices are correct. lining the lungs.

d

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

d

The cytoskeleton of animal cells includes: a. actin, microfilaments, and intermediate filaments. b. actin, microtubules, and intermediate filaments. c. microtubules and microfilaments. d. microtubules, microfilaments, and intermediate filaments. e. tubulin, microfilaments, and intermediate filaments.

d

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? a. at both ends of the cilia or flagella b. It is not possible to predict from the information provided. c. near the basal body d. near the tip of the cilia or flagella

d

When tumor cells are about to metastasize, which of the following would you expect to happen? a. an increase of cadherin expression and a decrease in integrin expression b. a decrease in cadherin expression and an increase of integrin expression c. an increase in both cadherin and integrin expression d. a decrease in both cadherin and integrin expression

d