Structures known as microvilli are associated with:
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increased surface area for nutrient absorption.
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What is the best characterization of the minus end of a dynamic filament?
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It is slow growing.
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Cadherin is an example of:
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A cell adhesion molecule
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Which of the following is a component of the extracellular matrix produced by an animal cell?
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Collagen
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Which one of the following is not a cellular function associated with microtubules?
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Muscle contraction
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Cadherins bind to which type of cytoskeletal element(s)?
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Both intermediate filaments and microfilaments
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Which of the following is a component of the extracellular matrix made by a plant cell?
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Cellulose
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The basal lamina is:
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a specialized form of the extracellular matrix found beneath all epithelial tissues.
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Myosin is a motor protein that associates with:
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Microfilaments
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Where would you find a cell adhesion molecule?
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In a cell junction
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Within the plant cell wall, the primary cell wall contains ______, and the secondary cell wall is composed of ______.
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both pectin and cellulose; both lignin and cellulose
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An epithelial tissue is defined as:
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A collection of cells that lines cavities or outside surfaces
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Which motor protein(s) would you find in a flagellum?
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Dynein
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The extracellular matrix is particularly important for which type of tissue?
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Connective
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The area where the epidermis and the dermis meet is highly folded so that the epidermis "fits" into the dermis. What do you think is the function of this highly folded area?
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The epidermis is the outer layer and is under constant physical stress. This highly folded area between the epidermis and the dermis gives the epidermis additional support and protection against abrasive stress.
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Dynamic instability is the rapid assembly and disassembly of:
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Microtubules
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A cadherin protein can only bind to:
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The extracellular domain of the same type of cadherin
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Many scientists use a specific type of mouse cell to coat the surface of petri dishes. These cells form a layer on which other kinds of cells, often of different species, can adhere and grow. The mouse cells used to coat petri dishes are likely:
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Fibroblasts
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Many scientists are working to generate organs in vitro. In some cases, cells are seeded onto a "scaffold" shaped like the desired target organ. Such scaffolds are likely composed of extracellular matrix proteins.
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True
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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 _____.
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plus end; kinesin
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How do cells connect to the extracellular matrix?
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through integrins
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Which type of cellular junction(s) allow(s) for the movement of proteins and transfer RNA molecules?
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Plasmodesmata
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A researcher is assessing the expression of a certain protein in cells. This protein appears as a "web" in the cytoplasm of cells. The protein is likely:
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A component of the cytoskeleton
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Whats the epidermis and the dermis made up of?
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The epidermis is made up of epithelial tissue whereas the dermis is made up primarily of connective tissue.
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The epidermis contains several layers and receives its nutrients from the dermis by diffusion. Which of the following explains why the outermost layers of the epidermis consist of dead cells?
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One of the major functions of the epidermis is forming a waterproof barrier. Once that barrier is formed, nutrients cannot pass through it and the cells beyond that layer die.
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Macrophage cells undergo a process called phagocytosis in which material is brought into a cell in the form of membrane vesicles and then transported along microtubules toward the cell center. Assuming that the centrosome is near the cell center, you can predict that these vesicles are moving to the _____ end of microtubules using the motor protein _____.
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minus end; dynein
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The classic experiment using isolated cells from two species of sponges provided evidence that:
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Cell adhesion molecules are species specific
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Could an isolated melanin granule move along an actin microfilament?
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No, motor proteins are specific for the type of filament they bind.
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The most likely reason(s) a metastatic tumor cell might lose its connection to the basal lamina would be:
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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.
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If intermediate filaments were capable of dynamic instability, which of the following outcomes would be most likely?
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cell adhesion would be affected
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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?
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near the tip of the cilia or flagella
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Red blood cells are characterized as having an actin cytoskeleton associated with their plasma membrane. The presence of the membrane cytoskeleton most likely accounts for:
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the shape of the cell, enhanced gas exchange, and the ability of these cells to fit through narrow capillaries
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A researcher is studying a population of cells that are shaped normally, but appear to slide past one another. This is likely the result of mutations in genes encoding:
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Components of cell junctions
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Which one of the following is not a cellular function of microfilaments?
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Flagellar movement
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Predict what would happen if an embryonic epidermal cell switched from expressing E-cadherin to N-cadherin.
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The cell would leave the epidermis and join the neural cells.
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Motor proteins cause movement by:
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(1) undergoing a conformational change, (2) harnessing energy from ATP, (3) binding to the cytoskeleton.
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Imagine that you are examining a mouse that does not produce basal lamina in the skin. How will this mouse be different from a normal, wild-type mouse?
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The epidermis will not be connected to the dermis.
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The natural loss of dead cells from the surface of your skin is a result of:
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both the loss of adherens junctions between epithelial cells, and the breakdown of desmosomes.
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What is the advantage of forcing materials to travel through cells instead of between cells?
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Cells can control which materials are transported, exposure to bacteria/viruses is limited, and exposure to toxins is limited.
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Microfilaments are composed of ____________ in ____________arrangement.
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repeating actin subunits; a thin double-helix
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Microfilaments help a cell ____________________
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Maintain its size and shape
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Cell movement can be facilitated by microfilaments in what way?
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By dynamic growing and shrinking at the ends.
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Which of the following would be more likely to cause development of a microvillus on an intestinal epithelial cell?
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plus (+) end growth of microfilaments at the tip of the microvillus but no shrinkage at the minus (−) end
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Which of the following best describes a role that microfilaments play in the structure and function of red blood cells?
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They maintain the biconcave shape to maximize gas exchange.
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Microtubules form from dimers of _____and ______subunits that polymerize into a ____________
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Alpha-tubulin; Beta-tubulin; hollow tube
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Microtubules are __________ because they __________ and depolymerize at their ends.
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Dynamic; polymerize
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The ability of microtubules to undergo rapid ___________ and slower ____________ is associated with the ability of the ______________ to explore the cell and locate chromosomes.
