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122 Cards in this Set
- Front
- Back
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What limits the resolving power of a light microscope?
a. the type of lens used to magnify the object under study b. the shortest wavelength of light used to illuminate the specimen c. the type of lens that focuses a beam of electrons through the specimen d. the type of heavy metal or dye that is used to stain the specimen e. the ratio of an object's image to its real size |
B. the shortest wavelength of light used to illuminate the specimen
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When biologists wish to study the internal ultrastructure of cells, they most likely would use
a. a light microscope. b. a scanning electron microscope. c. a transmission electronic microscope. d. A and C only e. A, B, and C |
C. a transmission electronic microscope
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The advantage of light microscopy over electron microscopy is that
a. light microscopy provides for higher magnification than electron microscopy. b. light microscopy provides for higher resolving power than electron microscopy. c. light microscopy allows one to view dynamic processes in living cells. d. both A and B e. both B and C |
C. light microscopy allows one to view dynamic processes in living cells.
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A primary objective of cell fractionation is to
a. view the structure of cell membranes. b. identify the enzymes outside the organelles. c. determine the size of various organelles. d. separate the major organelles so their particular functions can be determined. e. crack the cell wall so the cytoplasmic contents can be released. |
D. separate the major organelles so their particular functions can be determined
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In the fractionation of homogenized cells using centrifugation, the primary factor that determines whether a specific cellular component ends up in the supernatant or the pellet is
a. the relative solubility of the component. b. the size and weight of the component. c. the percentage of carbohydrates in the component. d. the number of enzymes in the fraction. e. the presence or absence of lipids in the component. |
B. the size and weight of the component
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Which of the following correctly lists the order in which cellular components will be found in the pellet when homogenized cells are treated with increasingly rapid spins in a centrifuge?
a. ribosomes, nucleus, mitochondria b. chloroplasts, ribosomes, vacuoles c. nucleus, ribosomes, chloroplasts d. vacuoles, ribosomes, nucleus e. nucleus, mitochondria, ribosomes |
E. nucleus, mitochondria, ribosomes
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Quantum dots are small (15-30 nm diameter), bright particles visible using light microscopy. If the dots can be specifically bound to individual proteins on a plasma membrane of a cell, which of the following correctly describes the advantage of using quantum dots in examining proteins?
a. The dots permit the position of the proteins to be determined more precisely. b. The dots permit the average distance between the proteins to be determined more precisely. c. The dots permit the size of the proteins to be determined more precisely. d. The dots permit the motion of the proteins to be determined more precisely. e. All of the above are correct. |
D. The dots permit the motion of the proteins to be determined more precisely
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Which of the following are prokaryotic cells?
a. plants b. fungi c. bacteria d. animals e. B and C only |
C. bacteria
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All of the following are part of a prokaryotic cell except
a. DNA. b. a cell wall. c. a plasma membrane. d. ribosomes. e. an endoplasmic reticulum. |
E. an endoplasmic reticulum
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The volume enclosed by the plasma membrane of plant cells is often much larger than the corresponding volume in animal cells. The most reasonable explanation for this observation is that
a. plant cells are capable of having a much higher surface-to-volume ratio than animal cells. b. plant cells have a much more highly convoluted (folded) plasma membrane than animal cells. c. plant cells contain a large vacuole that reduces the volume of the cytoplasm. d. animal cells are more spherical, while plant cells are elongated. e. the basic functions of plant cells are very different from those of animal cells. |
C. plant cells contain a large vacuole that reduces the volume of the cytoplasm
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Which of the following comparisons between prokaryotic and eukaryotic cells is incorrect?
a. The lack of organelles in prokaryotes means that they are structurally less complex than eukaryotes. b. The lack of internal membranes means that prokaryotes cannot compartmentalize function to the same extent as eukaryotes. c. All membrane function in prokaryotes is accomplished in the plasma membrane, while in eukaryotes, these functions are more distributed among the organelles. d. The specialization of function in organelles suggests that eukaryotes will contain a wider variety of phospholipids than prokaryotes. e. The lack of organelles in prokaryotes means that the basic cellular functions are different in prokaryotes than in eukaryotes. |
E. The lack of organelles in prokaryotes means that the basic cellular functions are different in prokaryotes than in eukaryotes
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Match the structure to its proper cell type:
A. a feature of all cells B. found in prokaryotic cells only C. found in eukaryotic cells only D. found in plant cells only E. found in animal cells only PLASMA MEMBRANE |
A. a feature of all cells
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Match the structure to its proper cell type:
A. a feature of all cells B. found in prokaryotic cells only C. found in eukaryotic cells only D. found in plant cells only E. found in animal cells only TONOPLAST |
D. found in plant cells only
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Match the structure to its proper cell type:
A. a feature of all cells B. found in prokaryotic cells only C. found in eukaryotic cells only D. found in plant cells only E. found in animal cells only NUCLEOID |
B. found in prokaryotic cells only
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Which of the following does not contain functional ribosomes?
a. a prokaryotic cell b. a plant mitochondrion c. a chloroplast d. an animal mitochondrion e. a nucleolus |
E. a nucleolus
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Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?
a. lipids b. starches c. proteins d. steroids e. glucose |
C. proteins
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Which of the following compounds require the presence of the nuclear pores to move between the cytoplasm and the interior of the nucleus?
a. ribosomal RNA b. messenger RNA c. proteins synthesized in the cytoplasm that are part of ribosomes d. A and B only e. A, B, and C |
E. ribosomal RNA, messenger RNA, and proteins
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Which of the following organelles is not a common destination for small vesicles that bud off the Golgi apparatus?
a. plasma membrane b. lysosomes c. vacuole d. endoplasmic reticulum e. all of the above |
D. endoplasmic reticulum
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Which of the following incorrectly matches the type of cell, type of protein, and site of the protein's synthesis?
a. prokaryote, cytoplasmic protein, free cytoplasmic ribosome b. eukaryote, plasma membrane protein, rough ER c. prokaryote, plasma membrane protein, ribosome bound to plasma membrane d. eukaryote, cytoplasmic protein, free cytoplasmic ribosome e. prokaryote, secreted protein, free cytoplasmic ribosome |
E. prokaryote, secreted protein, free cytoplasmic ribosome
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Under which of the following conditions would you expect to find a cell with a predominance of free ribosomes?
a. a cell that is secreting proteins b. a cell that is producing cytoplasmic enzymes c. a cell that is constructing its cell wall or extracellular matrix d. a cell that is digesting food particles e. a cell that is enlarging its vacuole |
B. a cell that is producing cytoplasmic enzymes
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Which type of organelle is primarily involved in the synthesis of oils, phospholipids, and steroids?
a. ribosome b. lysosome c. smooth endoplasmic reticulum d. mitochondrion e. contractile vacuole |
C. smooth endoplasmic reticulum
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Which structure is the site of the synthesis of proteins that may be exported from the cell?
a. rough ER b. lysosomes c. plasmodesmata d. Golgi vesicles e. tight junctions |
A. rough ER
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Which of the following structures is most directly associated with the secretion of compounds that will become part of the plant cell wall?
a. smooth ER b. rough ER c. plasmodesmata d. Golgi-derived vesicles e. Golgi apparatus |
D. Golgi-derived vesicles
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The Golgi apparatus has a polarity or sidedness to its structure and function. Which of the following statements correctly describes this polarity?
a. Transport vesicles fuse with one side of the Golgi and leave from the opposite side. b. Proteins in the membrane of the Golgi may be sorted and modified as they move from one side of the Golgi to the other. c. Lipids in the membrane of the Golgi may be sorted and modified as they move from one side of the Golgi to the other. d. Soluble proteins in the cisternae (interior) of the Golgi may be sorted and modified as they move from one side of the Golgi to the other. e. All of the above correctly describe polar characteristics of the Golgi function. |
E. All of the above correctly describe polar characteristics of the Golgi function
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Of the following, which is probably the most common route for membrane flow in the endomembrane system?
a. Golgi -> lysosome -> ER _> plasma membrane b. tonoplast -> plasma membrane -> nuclear envelope -> smooth ER c. nuclear envelope -> lysosome -> Golgi -> plasma membrane d. rough ER -> vesicles -> Golgi -> plasma membrane e. ER -> chloroplasts -> mitochondrion -> cell membrane |
D. rough ER -> vesicles -> Golgi -> plasma membrane
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Which of the following cell components is not directly involved in synthesis or secretion?
a. ribosome b. rough endoplasmic reticulum c. Golgi body d. smooth endoplasmic reticulum e. lysosome |
E. lysosome
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The fact that the outer membrane of the nuclear envelope has bound ribosomes allows one to most reliably conclude that
a. at least some of the proteins that function in the nuclear envelope are made by the ribosomes on the nuclear envelope. b. the nuclear envelope is not part of the endomembrane system. c. the nuclear envelope is physically continuous with the endoplasmic reticulum. d. small vesicles from the Golgi fuse with the nuclear envelope. e. nuclear pore complexes contain proteins. |
A. at least some of the proteins that function in the nuclear envelope are made by the ribosomes on the nuclear envelope
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The difference in lipid and protein composition between the membranes of the endomembrane system is largely determined by
a. the physical separation of most membranes from each other. b. the transportation of membrane among the endomembrane system by small membrane vesicles. c. the function of the Golgi apparatus in sorting membrane components. d. the modification of the membrane components once they reach their final destination. e. the synthesis of lipids and proteins in each of the organelles of the endomembrane system. |
C. the function of the Golgi apparatus in sorting membrane components
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In animal cells, hydrolytic enzymes are packaged to prevent general destruction of cellular components. Which of the following organelles functions in this compartmentalization?
a. chloroplast b. lysosome c. central vacuole d. peroxisome e. glyoxysome |
B. lysosome
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Which of the following statements correctly describes some aspect of protein excretion in prokaryotic cells?
a. Prokaryotes are unlikely to be able to excrete proteins because they lack an endomembrane system. b. The mechanism of protein excretion in prokaryotes is probably the same as that in eukaryotes. c. Proteins that are excreted by prokaryotes are synthesized on ribosomes that are bound to the cytoplasmic surface of the plasma membrane. d. In prokaryotes, the ribosomes that are used for the synthesis of secreted proteins are located outside of the cell. e. Prokaryotes contain large pores in their plasma membrane that permit the movement of proteins out of the cell. |
C. Proteins that are excreted by prokaryotes are synthesized on ribosomes that are bound to the cytoplasmic surface of the plasma membrane
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produces and modifies polysaccharides that will be secreted
A. lysosome B. vacuole C. mitochondrion D. Golgi apparatus E. peroxisome |
D. Golgi Apparatus
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contains hydrolytic enzymes
A. lysosome B. vacuole C. mitochondrion D. Golgi apparatus E. peroxisome |
A. lysosome
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helps to recycle the cell's organic material
A. lysosome B. vacuole C. mitochondrion D. Golgi apparatus E. peroxisome |
A. lysosome
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one of the main energy transformers of cells
A. lysosome B. vacuole C. mitochondrion D. Golgi apparatus E. peroxisome |
C. mitochondrion
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contains its own DNA and ribosomes
A. lysosome B. vacuole C. mitochondrion D. Golgi apparatus E. peroxisome |
C. mitochondrion
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a compartment that often takes up much of the volume of a plant cell
A. lysosome B. vacuole C. mitochondrion D. Golgi apparatus E. peroxisome |
B. vacuole
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contains enzymes that transfer hydrogen from various substrates to oxygen, producing H2O2
A. lysosome B. vacuole C. mitochondrion D. Golgi apparatus E. peroxisome |
E. peroxisome
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a versatile plant compartment that may hold reserves of organic compounds or inorganic ions
A. lysosome B. vacuole C. mitochondrion D. Golgi apparatus E. peroxisome |
B. vacuole
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Of the following, what do both mitochondria and chloroplasts have in common?
a. ATP is produced. b. DNA is present. c. Ribosomes are present. d. B and C only e. A, B, and C are correct. |
E. ATP is produced, DNA is present, Ribosomes are present
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Grana, thylakoids, and stroma are all components found in
a. vacuoles. b. chloroplasts. c. mitochondria. d. lysosomes. e. nuclei. |
B. choloplasts
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Organelles other than the nucleus that contain DNA include
a. ribosomes. b. mitochondria. c. chloroplasts. d. B and C only e. A, B, and C |
D. mitochondria and chloroplasts
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Which of the following statements incorrectly describes common structural features of an animal secretory cell and a photosynthetic plant cell?
a. Both cells have Golgi apparatus. b. Both cells have mitochondria. c. Both cells have chloroplasts. d. Both cells have a plasma membrane. e. Both cells have a nucleus. |
C. Both cells have chloroplasts.
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The chemical reactions involved in respiration are virtually identical between prokaryotic and eukaryotic cells. In eukaryotic cells, ATP is synthesized primarily on the inner membrane of the mitochondria. Where are the corresponding reactions likely to occur in prokaryotic respiration?
a. in the cytoplasm b. on the inner mitochondrial membrane c. on the endoplasmic reticulum d. on the plasma membrane e. on the nuclear envelope |
D. on the plasma membrane
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A biologist ground up some plant leaf cells and then centrifuged the mixture to fractionate the organelles. Organelles in one of the heavier fractions could produce ATP in the light, while organelles in the lighter fraction could produce ATP in the dark. The heavier and lighter fractions are most likely to contain, respectively,
a. mitochondria and chloroplasts. b. chloroplasts and peroxisomes. c. peroxisomes and chloroplasts. d. chloroplasts and mitochondria. e. mitochondria and peroxisomes. |
D.chloroplasts and mitochondria.
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Which of the following is a place where both DNA and ribosomes are unlikely to be found in any type of cell?
a. stroma of chloroplasts b. mitochondrial matrix c. nucleus d. cytoplasm e. Golgi apparatus |
E. Golgi Apparatus
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All of the following are correct matches of the location of a protein and the location of its synthesis except
a. plasma membrane protein-rough ER. b. mitochondrial membrane protein-free cytoplasmic ribosomes. c. cytoplasmic proteins-free cytoplasmic ribosomes. d. chloroplast stromal protein-chloroplast ribosomes. e. mitochondrial matrix protein-rough ER. |
E. mitochondrial matrix protein-rough ER.
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Which of the following are capable of converting light energy to chemical energy?
a. chloroplasts b. mitochondria c. leucoplasts d. peroxisomes e. Golgi bodies |
A. chloroplasts
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A cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. It could be a cell from
a. a bacterium. b. an animal, but not a plant. c. a plant, but not an animal. d. a plant or an animal. e. any kind of organism. |
D. a plant or an animal
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Which of the following is not a known function of the cytoskeleton?
a. to maintain a critical limit on cell size b. to provide mechanical support to the cell c. to maintain the characteristic shape of the cell d. to hold mitochondria and other organelles in place within the cytosol e. to assist in cell motility by interacting with specialized motor proteins |
A. to maintain a critical limit on cell size
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Motor proteins provide for molecular motion in cells by interacting with what types of cellular structures?
a. sites of energy production in cellular respiration b. membrane proteins c. ribosomes d. cytoskeletons e. cellulose fibers in the cell wall |
D. cytoskeletons
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Cells can be described as having a cytoskeleton of internal structures that contribute to the shape, organization, and movement of the cell. All of the following are part of the cytoskeleton except
a. the nuclear envelope. b. microtubules. c. microfilaments. d. intermediate filaments. e. actin. |
A. the nuclear envelope.
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Which of the following pairs is mismatched?
a. nucleolus-ribosomal RNA b. nucleus-DNA replication c. lysosome-protein synthesis d. cell membrane-lipid bilayer e. cytoskeleton-microtubules |
C. lysosome-protein synthesis
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Of the following, which cell structure would most likely be visible with a light microscope that has been manufactured to the maximum resolving power possible?
a. mitochondrion b. microtubule c. ribosome d. largest microfilament e. nuclear pore |
A. mitochondrion
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Which of the following contain the 9 + 2 arrangement of microtubules?
a. cilia b. centrioles c. flagella d. A and C only e. A, B, and C |
D. cilia and flagella
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Cells would be unable to form cilia or flagella if they did not have
a. centrosomes. b. ribosomes. c. actin. d. A and B only e. A, B, and C |
D. centrosomes and actin
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Which of the following possesses a microtubular structure similar to a basal body?
a. centriole b. lysosome c. nucleolus d. peroxisome e. ribosome |
A. centriole
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Microfilaments are well known for their role in which of the following?
a. ameboid movement b. formation of cleavage furrows c. contracting of muscle cells d. A and B only e. A, B, and C |
E. amoeboid movement, formation of cleavage furrows, contracting of muscle cells
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Which of the following statements about the cytoskeleton is incorrect?
a. The dynamic aspect of cytoskeletal function is made possible by the assembly and disassembly of a few simple types of proteins into large aggregates. b. Microfilaments are structurally rigid and resist compression, while microtubules resist tension (stretching). c. Movement of cilia and flagella is the result of motor proteins causing microtubules to move relative to each other. d. Chemicals that block the assembly of the cytoskeleton would prevent many different processes in cells. e. Transport vesicles among the membranes of the endomembrane system depend on the function of the cytoskeleton. |
B. Microfilaments are structurally rigid and resist compression, while microtubules resist tension (stretching).
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All of the following structures and proteins are directly associated with movement in cells or by cells except
a. cilia. b. dynein. c. actin. d. flagella. e. centrosomes. |
E. centrosomes
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All of the following serve an important role in determining or maintaining the structure of plant cells. Which of the following are distinct from the others in terms of composition?
a. microtubules b. microfilaments c. plant cell walls d. intermediate filaments e. nuclear lamina |
C. plant cell walls
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Which of the following relationships between cell structures and their respective functions is not correct?
a. cell wall: support, protection b. chloroplasts: chief sites of cellular respiration c. chromosomes: genetic control information d. ribosomes: site of protein synthesis e. mitochondria: formation of ATP |
B. chloroplasts: chief sites of cellular respiration
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The cell walls of bacteria, fungi, and plant cells and the extracellular matrix of animal cells are all external to the plasma membrane. Which of the following is not a characteristic of all of these extracellular structures?
a. They must be highly permeable to water and small molecules in order to allow cells to exchange matter and energy with their environment. b. They must permit information transfer between the cell's external environment and the cytoplasm. c. They must provide a rigid structure that maintains an appropriate ratio of cell surface area to volume. d. They are constructed of materials that are largely synthesized in the cytoplasm and then transported out of the cell. e. They are composed of a mixture of proteins and carbohydrates. |
C. They must provide a rigid structure that maintains an appropriate ratio of cell surface area to volume
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When a potassium ion ( ) moves from the soil into the vacuole of a cell on the surface of a root, it must pass through several cellular structures. Which of the following correctly describes the order in which these structures will be encountered by the ion?
a. plasma membrane primary cell wall cytoplasm tonoplast b. secondary cell wall plasma membrane primary cell wall cytoplasm tonoplast c. primary cell wall plasma membrane cytoplasm tonoplast d. primary cell wall plasma membrane tonoplast cytoplasm vacuole e. tonoplast primary cell wall plasma membrane cytoplasm |
C. primary cell wall plasma membrane cytoplasm tonoplast
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A cell lacking the ability to make and secrete glycoproteins would most likely be deficient in its
a. nuclear DNA. b. extracellular matrix. c. Golgi apparatus. d. B and C only e. A, B, and C |
D. extracellular matrix and Golgi apparatus
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The extracellular matrix is thought to participate in the regulation of animal cell behavior by communicating information from the outside to the inside of the cell via
a. gap junctions. b. the nucleus. c. DNA and RNA. d. integrins. e. plasmodesmata. |
D. integrins
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Plasmodesmata in plant cells are most similar in function to which of the following structures in animal cells?
a. peroxisomes b. desmosomes c. gap junctions d. extracellular matrix e. tight junctions |
C. gap junctions
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Ions can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through
a. plasmodesmata. b. intermediate filaments. c. tight junctions. d. desmosomes. e. gap junctions. |
E. gap junctions
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The first to propose that cell membranes are phospholipid bilayers.
A. H. Davson and J. Danielli B. I. Langmuir C. C. Overton D. S. Singer and G. Nicolson E. E. Gorter and F. Grendel |
E. Gorter and Grendel
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Membranes are a phospholipid bilayer between two layers of hydrophilic proteins.
A. H. Davson and J. Danielli B. I. Langmuir C. C. Overton D. S. Singer and G. Nicolson E. E. Gorter and F. Grendel |
A. Davson and Danielli
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The membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids.
A. H. Davson and J. Danielli B. I. Langmuir C. C. Overton D. S. Singer and G. Nicolson E. E. Gorter and F. Grendel |
D. Singer and Nicholson
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Which of the following types of molecules are the major structural components of the cell membrane?
a. phospholipids and cellulose b. nucleic acids and proteins c. phospholipids and proteins d. proteins and cellulose e. glycoproteins and cholesterol |
C. phospholipids and proteins
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When biological membranes are frozen and then fractured, they tend to break along the middle of the bilayer. The best explanation for this is that
a. the integral membrane proteins are not strong enough to hold the bilayer together. b. water that is present in the middle of the bilayer freezes and is easily fractured. c. hydrophilic interactions between the opposite membrane surfaces are destroyed on freezing. d. the carbon-carbon bonds of the phospholipid tails are easily broken. e. the hydrophobic interactions that hold the membrane together are weakest at this point. |
E. the hydrophobic interactions that hold the membrane together are weakest at this point
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All of the following molecules are part of the cell membrane except
a. lipids. b. nucleic acids. c. proteins. d. phosphate groups. e. steroids. |
B. nucleic acids
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The original model for the bilayer structure of cell membranes, which was prepared in the 1920s, was based on which of the following?
a. detailed electron micrographs of freeze-fractured membranes b. the presence of proteins as a functional component of biological membranes c. the observation that all membranes contain phospholipids and proteins d. the understanding that phospholipids are amphipathic molecules e. A and B only |
D. the understanding that phospholipids are amphipathic molecules
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The presence of cholesterol in the plasma membranes of some animals
a. enables the membrane to stay fluid more easily when cell temperature drops. b. enables the animal to remove hydrogen atoms from saturated phospholipids. c. enables the animal to add hydrogen atoms to unsaturated phospholipids. d. makes the membrane less flexible, allowing it to sustain greater pressure from within the cell. e. makes the animal more susceptible to circulatory disorders. |
A. enables the membrane to stay fluid more easily when cell temperature drops.
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According to the fluid mosaic model of cell membranes, which of the following is a true statement about membrane phospholipids?
a. They can move laterally along the plane of the membrane. b. They frequently flip-flop from one side of the membrane to the other. c. They occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane. d. They are free to depart from the membrane and dissolve in the surrounding solution. e. They have hydrophilic tails in the interior of the membrane. |
A. They can move laterally along the plane of the membrane
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The lateral mobility (fluidity) of lipids and proteins in membranes is a consequence of
a. lack of covalent bonds between the lipid and protein components of the membrane. b. weak hydrophobic interactions among the components in the interior of the membrane. c. the presence of liquid water in the interior of the membrane. d. A and B only e. A, B, and C |
D. lack of covalent bonds between the lipid and protein components of the membrane, and weak hydrophobic interactions among the components in the interior of the membrane.
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What is one of the ways that the membranes of winter wheat are able to remain fluid when it is extremely cold?
a. by increasing the percentage of unsaturated phospholipids in the membrane b. by increasing the percentage of cholesterol molecules in the membrane c. by decreasing the number of hydrophobic proteins in the membrane d. A and B only |
A. by increasing the percentage of unsaturated phospholipids in the membrane
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The surface of an integral membrane protein would be best described as
a. hydrophilic. b. hydrophobic. c. amphipathic. d. completely covered with phospholipids. e. exposed on only one surface of the membrane. |
C. amphipathic
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When a membrane is freeze-fractured, the bilayer splits down the middle between the two layers of phospholipids. In an electron micrograph of a freeze-fractured membrane, the bumps seen on the fractured surface of the membrane are
a. peripheral proteins. b. phospholipids. c. carbohydrates. d. integral proteins. e. cholesterol molecules. |
D. integral proteins
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All of the following are functions of integral membrane proteins except
a. protein synthesis. b. active transport. c. hormone reception. d. cell adhesion. e. cytoskeleton attachment. |
A. protein synthesis
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Which of the following is a reasonable explanation for why unsaturated fatty acids help keep any membrane more fluid at lower temperatures?
a. The double bonds form a kink in the fatty acid tail, forcing adjacent lipids to be further apart. b. Unsaturated fatty acids have a higher cholesterol content. c. Unsaturated fatty acids permit more water in the interior of the membrane. d. The double bonds block interaction among the hydrophilic head groups of the lipids. e. The double bonds result in a shorter fatty acid tail. |
A. The double bonds form a kink in the fatty acid tail, forcing adjacent lipids to be further apart.
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Which of the following is correct about integral membrane proteins?
a. They lack tertiary structure. b. They are loosely bound to the surface of the bilayer. c. They are usually transmembrane proteins. d. They are not mobile within the bilayer. e. They serve only a structural role in membranes. |
C. They are usually transmembrane proteins
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Of the following functions, which is most important for the glycoproteins and glycolipids of animal cell membranes?
a. facilitated diffusion of molecules down their concentration gradients b. active transport of molecules against their concentration gradients c. maintaining the integrity of a fluid mosaic membrane d. maintaining membrane fluidity at low temperatures e. a cell's ability to distinguish one type of neighboring cell from another |
E. a cell's ability to distinguish one type of neighboring cell from another
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What is one of the functions of cholesterol in animal cell membranes?
a. facilitates transport of ions b. stores energy c. maintains membrane fluidity d. speeds diffusion e. phosphorylates ADP |
C. maintains membrane fluidity
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What membrane-surface molecules are thought to be most important as cells recognize each other?
a. phospholipids b. integral proteins c. peripheral proteins d. cholesterol e. glycoproteins |
E. glycoproteins
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An animal cell lacking oligosaccharides on the external surface of its plasma membrane would likely be impaired in which function?
a. transporting ions against an electrochemical gradient b. cell-cell recognition c. maintaining fluidity of the phospholipid bilayer d. attaching to the cytoskeleton e. establishing the diffusion barrier to charged molecules |
B. cell-cell recognition
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Which of the following adheres to the extracellular surface of animal cell plasma membranes?
a. fibers of the extracellular matrix b. fibers of the cytoskeleton c. the phospholipid bilayer d. cholesterol e. carrier proteins |
A. fibers of the extracellular matrix
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What kinds of molecules pass through a cell membrane most easily?
a. large and hydrophobic b. small and hydrophobic c. large polar d. ionic e. monosaccharides such as glucose |
B. small and hydrophobic
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Which of the following is a characteristic feature of a carrier protein in a plasma membrane?
a. It is a peripheral membrane protein. b. It exhibits a specificity for a particular type of molecule. c. It requires the expenditure of cellular energy to function. d. It works against diffusion. e. It has few, if any, hydrophobic amino acids. |
B. It exhibits a specificity for a particular type of molecule
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After a membrane freezes and then thaws, it often becomes leaky to solutes. The most reasonable explanation for this is that
a. transport proteins become nonfunctional during freezing. b. the lipid bilayer loses its fluidity when it freezes. c. aquaporins can no longer function after freezing. d. the integrity of the lipid bilayer is broken when the membrane freezes. e. the solubility of most solutes in the cytoplasm decreases on freezing. |
D. the integrity of the lipid bilayer is broken when the membrane freezes
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Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly?
a. CO2 b. an amino acid c. glucose d. K+ e. starch |
A. CO2
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The selective permeability of biological membranes is dependent on which of the following?
a. the type of transport proteins that are present in the membrane b. the lipid bilayer being permeable to primarily small, nonpolar molecules c. the types of carbohydrates on the surface of the membrane d. A and B only e. A, B, and C |
D. the type of transport proteins that are present in the membrane and the lipid bilayer being permeable to primarily small, nonpolar molecules
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Which of the following statements is correct about diffusion?
a. It is very rapid over long distances. b. It requires an expenditure of energy by the cell. c. It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration. d. It is an active process in which molecules move from a region of lower concentration to one of higher concentration. e. It requires integral proteins in the cell membrane. |
C. It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.
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Water passes quickly through cell membranes because
a. the bilayer is hydrophilic. b. it moves through hydrophobic channels. c. water movement is tied to ATP hydrolysis. d. it is a small, polar, charged molecule. e. it moves through aquaporins in the membrane. |
E. it moves through aquaporins in the membrane.
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A patient has had a serious accident and lost a lot of blood. In an attempt to replenish body fluids, distilled water, equal to the volume of blood lost, is transferred directly into one of his veins. What will be the most probable result of this transfusion?
a. It will have no unfavorable effect as long as the water is free of viruses and bacteria. b. The patient's red blood cells will shrivel up because the blood fluid is hypotonic compared to the cells. c. The patient's red blood cells will swell because the blood fluid is hypotonic compared to the cells. d. The patient's red blood cells will shrivel up because the blood fluid is hypertonic compared to the cells. e. The patient's red blood cells will burst because the blood fluid is hypertonic compared to the cells. |
C. The patient's red blood cells will swell because the blood fluid is hypotonic compared to the cells
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Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a salt solution become limp and soft. From this we can deduce that the cells of the celery stalks are
a. hypotonic to both fresh water and the salt solution. b. hypertonic to both fresh water and the salt solution. c. hypertonic to fresh water but hypotonic to the salt solution. d. hypotonic to fresh water but hypertonic to the salt solution. e. isotonic with fresh water but hypotonic to the salt solution. |
C. hypertonic to fresh water but hypotonic to the salt solution.
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A cell whose cytoplasm has a concentration of 0.02 molar glucose is placed in a test tube of water containing 0.02 molar glucose. Assuming that glucose is not actively transported into the cell, which of the following terms describes the tonicity of the external solution relative to the cytoplasm of the cell?
a. isotonic b. hypertonic c. hypotonic d. flaccid e. turgid |
A. isotonic
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69. The difference between pinocytosis and receptor-mediated endocytosis is that
a. pinocytosis brings only water into the cell, but receptor-mediated endocytosis brings in other molecules as well. b. pinocytosis increases the surface area of the plasma membrane whereas receptor-mediated endocytosis decreases the plasma membrane surface area. c. pinocytosis is nonselective in the molecules it brings into the cell, whereas receptor-mediated endocytosis offers more selectivity. d. pinocytosis requires cellular energy, but receptor-mediated endocytosis does not. e. pinocytosis can concentrate substances from the extracellular fluid, but receptor-mediated endocytosis cannot. |
a. pinocytosis brings only water into the cell, but receptor-mediated endocytosis brings in other molecules as well.
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68. In addition to exporting materials from the cytoplasm of the cell, the process of exocytosis is also important in
a. the production of cell walls by plant cells. b. the increase in the size of cells. c. maintaining the osmotic balance between the cytoplasm and the cell exterior. d. A and B only e. A, B, and C |
a. the production of cell walls by plant cells.
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67. What is the cause of familial hypercholesterolemia?
a. defective LDL receptors on the cell membranes b. poor attachment of the cholesterol to the extracellular matrix of cells c. a poorly formed lipid bilayer that cannot incorporate cholesterol into cell membranes d. inhibition of the cholesterol active transport system in red blood cells e. a general lack of glycolipids in the blood cell membranes |
a. defective LDL receptors on the cell membranes
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66. White blood cells engulf bacteria through what process?
a. exocytosis b. phagocytosis c. pinocytosis d. osmosis e. receptor-mediated exocytosis |
b. phagocytosis
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65. The membrane activity most nearly opposite to exocytosis is
a. plasmolysis. b. osmosis. c. facilitated diffusion. d. phagocytosis. e. active transport. |
d. phagocytosis.
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64. An organism with a cell wall would have the most difficulty doing which process?
a. diffusion b. osmosis c. active transport d. phagocytosis e. exocytosis |
d. phagocytosis
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63. All of the following processes take material into cells except
a. pinocytosis. b. endocytosis. c. exocytosis. d. active transport. e. carrier-facilitated diffusion. |
c. exocytosis.
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62. Which of the following statements about membrane structure and function is false?
a. Diffusion of gases is faster in air than across membranes. b. Diffusion, osmosis, and facilitated diffusion do not require any direct energy input from the cell. c. The types of proteins that are exposed on one side of a membrane are nearly identical to those exposed on the other side of the membrane. d. Voltage across the membrane depends on an unequal distribution of ions across the plasma membrane. e. Special membrane proteins can cotransport two solutes by coupling diffusion down a concentration gradient to transport against the concentration gradient. |
c. The types of proteins that are exposed on one side of a membrane are nearly identical to those exposed on the other side of the membrane.
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61. The sodium-potassium pump in animal cells requires cytoplasmic ATP to pump ions across the plasma membrane. When the proteins of the pump are first synthesized in the rough ER, what side of the ER membrane will the ATP binding site be on?
a. It will be on the cytoplasmic side of the ER. b. It will be on the side facing the interior of the ER. c. It could be facing in either direction because the orientation of proteins is scrambled in the Golgi apparatus. d. It doesn't matter, because the pump is not active in the ER. e. Not enough information is provided to answer this question. |
a. It will be on the cytoplasmic side of the ER.
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60. What mechanisms do plants use to load sucrose produced by photosynthesis into specialized cells in the veins of leaves?
a. an electrogenic pump b. a proton pump c. a contransport protein d. A and C only e. A, B, and C |
e. A, B, and C
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59. Which of the following characterizes the sodium-potassium pump?
a. Sodium ions are pumped out of a cell against their gradient. b. Potassium ions are pumped into a cell against their gradient. c. The pump protein undergoes a conformational change. d. Only A and B are correct. e. A, B, and C are all correct. |
e. A, B, and C are all correct.
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58. Ions diffuse across membranes down their
a. chemical gradients. b. concentration gradients. c. electrical gradients. d. electrochemical gradients. e. A and B are correct. |
d. electrochemical gradients.
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57. The movement of potassium into an animal cell requires
a. low cellular concentrations of sodium. b. high cellular concentrations of potassium. c. an energy source such as ATP or a proton gradient. d. a cotransport protein. e. a gradient of protons across the plasma membrane. |
c. an energy source such as ATP or a proton gradient.
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56. If a membrane protein in an animal cell is involved in the cotransport of glucose and sodium ions into the cell, which of the following is most likely not true?
a. The sodium ions are moving down their electrochemical gradient. b. Glucose is entering the cell against its concentration gradient. c. Sodium ions can move down their electrochemical gradient through the cotransporter whether or not glucose is present outside the cell. d. The higher sodium ion concentration outside the cell is the result of an electrogenic pump. e. A substance that blocked sodium ions from binding to the cotransport protein would also block the transport of glucose. |
c. Sodium ions can move down their electrochemical gradient through the cotransporter whether or not glucose is present outside the cell.
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55. The sodium-potassium pump is called an electrogenic pump because it
a. pumps equal quantities of Na+ and K+ across the membrane. b. pumps hydrogen ions out of the cell. c. contributes to the membrane potential. d. ionizes sodium and potassium atoms. e. is used to drive the transport of other molecules against a concentration gradient. |
c. contributes to the membrane potential.
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54. In most cells, there are electrochemical gradients of many ions across the plasma membrane even though there are usually only one or two electrogenic pumps present in the membrane. The gradients of the other ions are most likely accounted for by
a. cotransport proteins. b. ion channels. c. carrier proteins. d. B and C only e. A, B, and C |
a. cotransport proteins.
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53. What is the voltage across a membrane called?
a. water potential b. chemical gradient c. membrane potential d. osmotic potential e. electrochemical gradient |
c. membrane potential
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52. The main difference(s) between facilitated diffusion and active transport is (are)
a. facilitated diffusion moves substances down their concentration gradient and active transport moves them against their gradient. b. facilitated diffusion does not rely on cellular energy and active transport does. c. facilitated diffusion uses channel or carrier proteins and active transport does not. d. A and B only e. A, B, and C |
e. A, B, and C
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51. Glucose diffuses slowly through artificial phospholipid bilayers. The cells lining the small intestine, however, rapidly move large quantities of glucose from the glucose-rich food into their glucose-poor cytoplasm. Using this information, which transport mechanism is most probably functioning in the intestinal cells?
a. simple diffusion b. phagocytosis c. active transport pumps d. exocytosis e. facilitated diffusion |
e. facilitated diffusion
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50. Carrier molecules in the membrane and metabolic energy are required for
a. osmosis. b. facilitated diffusion. c. active transport. d. B and C only e. A, B, and C |
c. active transport.
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49. The movement of a substance across a biological membrane against its concentration gradient with the help of energy input is
a. diffusion. b. active transport. c. osmosis. d. facilitated diffusion. e. exocytosis. |
b. active transport.
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48. What are the membrane structures that function in active transport?
a. peripheral proteins b. carbohydrates c. cholesterol d. cytoskeleton filaments e. integral proteins |
e. integral proteins
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47. All of the following membrane activities require energy from ATP hydrolysis except
a. facilitated diffusion. b. active transport. c. Na+ ions moving out of the cell. d. proton pumps. e. translocation of potassium into a cell. |
a. facilitated diffusion.
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46. You are working on a team that is designing a new drug. In order for this drug to work, it must enter the cytoplasm of specific target cells. Which of the following would not be a factor that determines whether the molecule enters the cell?
a. size of the drug molecule b. polarity of the drug molecule c. charge on the drug molecule d. similarity of the drug molecule to other molecules transported by the target cells e. lipid composition of the target cells' plasma membrane |
e. lipid composition of the target cells' plasma membrane
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