Cellbio.txt

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marcus.hylen
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158009
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Cellbio.txt
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2012-06-10 02:39:02
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cell biology
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Exam mcq
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    • author "me"
    • tags ""
    • description "Exam"
    • fileName "Cellbio"
    • freezingBlueDBID -1.0
    • ...and... Viewed cells under magnification in the latter half of the seventeeth century
  1. A. Thomas Hunt Morgan
    • B. Antoine van Leeuwenhock
    • C. Robert Hooke
    • D. Matthias Schleiden
    • B. Antoine van Leeuwenhock
    • C. Robert Hooke
  2. Watson and crick showed that the DNA usually is a

    A. Linear polymer
    B. Double helix
    C. Macromolecules
    B. Double helix
    (this multiple choice question has been scrambled)
  3. Three scientists associated with development of the cell theory in the nineteenth century were...

    A. Edward I. Tatum
    B. Matthias Schleiden
    C. Antoine van Leeuwenhock
    D. Rudolf Virchow
    E. Theodor Schwann
    • B. Matthias Schleiden
    • D. Rudolf Virchow
    • E. Theodor Schwann
  4. Cell membranes

    A. Contain lipid molecules that have both a fatty part and water soluble part, are made of RNA
    B. May be associated with proteins or cell wall structure, which add strength and stability to the outer surface of cells
    C. Are ormed of a single layer of fatty molecules called lipids, may contain cholsterol
    B. May be associated with proteins or cell wall structure, which add strength and stability to the outer surface of cells.
    (this multiple choice question has been scrambled)
  5. A prokaryotic cell...

    A. Contains a nucleus
    B. Contains DNA
    C. Has genes
    D. Has organelles
    E. Has a plasma membrane
    • B. Contains DNA
    • C. Has genes
    • D. Has organelles
    • E. Has a plasma membrane
  6. List at least three functions of cell membrane

    A. Cell membranes separate the intracellular contents from the enviroment
    B. Delineate the boundaries of organelles within eukaryotic cell
    C. Control the flow of material into cells by means of transport proteins located in the plasma membrane
    D. Permit cells to respond to specific signals within their enviroment by means of membrane bound receptor proteins
    E. Provide cells with the ability to store energy by limiting diffusion of ions or other molecules from one compartment to another
    • A. Cell membranes separate the intracellular contents from the enviroment
    • B. Delineate the boundaries of organelles within eukaryotic cell
    • C. Control the flow of material into cells by means of transport proteins located in the plasma membrane
    • D. Permit cells to respond to specific signals within their enviroment by means of membrane bound receptor proteins
    • E. Provide cells with the ability to store energy by limiting diffusion of ions or other molecules from one compartment to another
  7. Describe at least three functions of small molecules in cells

    A. Small molecules serve as substrates for making macromolecules
    B. They serve as an energy source for the cell when they are degraded
    C. Some small molecules are used to store cellular energy
    D. Other small molecules are used to send signals within and between cells
    • A. Small molecules serve as substrates for making macromolecules
    • B. They serve as an energy source for the cell when they are degraded
    • D. Other small molecules are used to send signals within and between cells
  8. In most biological membranes, .... Molecules make up the two leaflets of the bilayer into......molecules are embedded

    A. Oligosaccharides
    B. Phospholipids
    C. Galactolipids
    D. Cholesterol
    E. Protein
    • B. Phospholipids
    • E. Protein
  9. The transmembrane domains of most integral membrane proteins have....secondary structure

    A. Extrinsic
    B. Beta sheet
    C. Glycocalyx
    D. Alpha helix
    D. Alpha helix
    (this multiple choice question has been scrambled)
  10. Abundant in the plasma membrane of mammalian cells,.....is an amphiphatic lipid that contains four hydrocarbon rings

    A. Glycophorin
    B. Phosphatidylcholine
    C. Cholesterol
    C. Cholesterol
    (this multiple choice question has been scrambled)
  11. Glycolipids and glycoproteins are located preferentially in the.....face of the.....membrane, or cell surface.

    A. Extrinsic
    B. Exoplasmic
    C. Apical
    D. Basolateral
    E. Plasma
    • B. Exoplasmic
    • E. Plasma
  12. The major integral membrane proteins in mammalian red blood cells are...., whose monometric form spans the lipid bilayer a single time and....., which spans the bilayer at least twelve times.

    A. Glycophorin
    B. Band 3 protein
    C. Cardiolipin
    D. Catalase
    • A. Glycophorin
    • B. Band 3 protein
  13. Membrane proteins that do not interact with the hydrophobic portion of the membrane are called....or.....proteins.

    A. Integral
    B. Peripheral
    C. Extrinsic
    D. Lysosomal
    E. Instrinsic
    • B. Peripheral
    • C. Extrinsic
  14. Carbohydrates containing several sugr units, which are present in many glycolipids and glycoproteins, are called...

    A. Glucocerebrosides
    B. Galactolipids
    C. Phospholipids
    D. Oligosaccharides
    D. Oligosaccharides
    (this multiple choice question has been scrambled)
  15. The concept that integral membrane proteins diffuse in a "sea" of lipid is part of the....model of membrane structure.

    A. Fluid-mosaic
    B. Alpha helical
    C. Sucrase-isomaltase
    A. Fluid-mosaic
    (this multiple choice question has been scrambled)
  16. Common chemical features of all membrane lipids include

    A. A polar portion
    B. A glycerol backbone
    C. Sugar constituents
    D. A hydrophobic domain
    E. A phosphate group
    • A. A polar portion
    • D. A hydrophobic domain
  17. Phospholipids in a fluid, pure phospholipid bilayer frequently undergo

    A. Lateral diffusion
    B. Rotational movement around their long axis
    C. Flip flop from one leaflet to the other
    D. Flexing of acyl chins by movement about the c-c bonds
    E. Movement from the membrane to the aqueous phase
    • A. Lateral diffusion
    • B. Rotational movement around their long axis
    • D. Flexing of acyl chains by movement about the c-c bonds
  18. Which of the following charcteristics generally are correlated with an increase in the fluidity of a lipid bilayer?

    A. An increase in unsaturation of the phospholipid fatty acyl chains
    B. An increase in the length of the fatty acyl chains
    C. More van der waals interactions among the lipid species
    D. An increase in the temperature of the bilayer
    E. Addition of cholesterol to a bilayer whose phospholipids are in the gel state
    • A. An increase in unsaturation of the phospholipid fatty acyl chains
    • D. An increase in the temperature of the bilayer
    • E. Addition of cholesterol to a bilayer whose phospholipids are in the gel state
  19. Integral membrane proteins

    A. Are embedded in the phospholipid bilayer or are covalently attached to a lipid segment that is embedded in the bilayer
    B. Usually can be removed from the membrane by solutions of high ionic strength or chemicals tht bind divalent cations
    C. Usually are soluble in the abscence of detergents
    D. Can be glycoproteins
    E. Are amphiphatic molecules
    • A. Are embedded in the phospholipid bilayer or are covalently attached to a lipid segment that is embedded in the bilayer
    • D. Can be glycoproteins
    • E. Are amphiphatic molecules
  20. Lipid-anchored membrane proteins

    A. Are considered to be peripheral membrane proteins
    B. Are found on both faces of the plasma membrane
    C. Are sometimes covalently attached to glycosylated phospholipids
    D. Include transforming proteins such as v-Src, which is anchored by an amide linkage to myristic aid
    E. Include famesylated proteins
    • B. Are found on both faces of the plasma membrane
    • C. Are sometimes covalently attached to glycosylated phospholipids
    • D. Include transforming proteins such as v-Src, which is anchored by an amide linkage to myristic aid
    • E. Include famesylated proteins
  21. Fluoroscence recovery after photobleaching

    A. Is typically used to measure the rotational motion of membrane lipids and proteins
    B. Is typically used to measure lateral diffusion of membrane lipids and proteins
    C. Involves fluoroscent labeling of cell-surface molecules
    D. Has demonstrated tht lipids diffuse freely over short distances, but generally not over longer distance, in fibroblast membranes
    E. Can be used to determine the fraction of labeled membrane associated molecules that are mobile as well as the rate of lateral motion
    • B. Is typically used to measure lateral diffusion of membrane lipids and proteins
    • C. Involves fluoroscent labeling of cell-surface molecules
    • E. Can be used to determine the fraction of labeled membrane associated molecules that are mobile as well as the rate of lateral motion
  22. Polarized cells in animals

    A. Are general feature of epithelial tissue, which lines body cavities
    B. Include erythrocytes and most other blood cells
    C. Have a plasma membrane divided into specialized regions of different function
    D. Have the same protein molecules exposed on their apical basolateral surfaces
    E. May be sealed together by plasmodesmata to form a barrier to the passage of most small molecules
    • A. Are general feature of epithelial tissue, which lines body cavities
    • C. Have a plasma membrane divided into specialized regions of different function
  23. Tight junctions in epithelial cells

    A. Are sensitive to Ca2+ levels
    B. Can completely inhibit lipid diffusion between the basolateral and apical surfaces
    C. Appear as an interlocking network of ridges in the plasma membrane in freeze-fracture electron micrographs
    D. Are located at the junction of the apical and basolateral surfaces
    E. Permit lipid diffusion between the apical surfaces of adjacent cell-surface
    • A. Are sensitive to Ca2+ levels
    • C. Appear as an interlocking network of ridges in the plasma membrane in freeze-fracture electron micrographs
    • D. Are located at the junction of the apical and basolateral surfaces
  24. Many transformed cells release growth factors that subsequently stimulate the same cells from which they were released. This type of signal pathway is termed:

    A. Endocrine
    B. Mesocrine
    C. Exocrine
    D. Paracrine
    E. Autocrine
    E. Autocrine
    (this multiple choice question has been scrambled)
  25. The process of communication by extracellular signals does not include:

    A. Proteolytic cleavage of a hormone immediately prior to interaction with its receptor
    B. Detection of a hormone by its receptor
    C. Glycosylation of hormone initiated by binding to its receptor
    D. A change in the metabolism of the target cell
    E. Removal of a hormone by its target cell or extracellular degenerative enzyme
    • A. Proteolytic cleavage of a hormone immediately prior to interaction with its receptor
    • C. Glycosylation of hormone initiated by binding to its receptor
  26. Hormones whose receptors are located in the nucleus of the cell include

    A. Progesterone
    B. Nerve growth factor
    C. Thyroxine
    D. Insulin
    E. Follicle-stimulating hormone
    • A. Progesterone
    • C. Thyroxine
  27. Which of the following effects are mediated by acetylcholine?

    A. Contraction of striated muscle
    B. Decrease in the rate of contraction of heart muscle
    C. Release in secretory granules
    D. Initiation of cell division by releasing from DNA synthesis
    E. None of the above
    • A. Contraction of striated muscle
    • C. Release in secretory granules
  28. Which of the following are not considered to be a second messenger

    A. Ca2+
    B. Na2+
    C. GMPPNP
    D. Diacylglycerol
    E. Inositol 1,4,5-trisphosphate
    • B. Na2+
    • C. GMPPNP
  29. Cell-fusion experiments have demonstrated that

    A. Adenylate cyclase can be linked to more than one receptor
    B. Adenylate cyclase can diffuse laterally through the plasma membrane
    C. All G proteins are specific for certain hormone receptors
    D. The G and G proteins are functionally different but biochemically indistinguishable
    E. Epinephrine cannot stimulate the production of cAMP
    • A. Adenylate cyclase can be linked to more than one receptor
    • B. Adenylate cyclase can diffuse laterally through the plasma membrane
  30. Cholera toxin increases cAMP levels by

    A. Binding to adenylate cyclase
    B. Binding Gs protein
    C. Inhibiting cAMP phosphodiesterase
    D. Binding Gi protein
    E. Binding to hormone
    B. Binding Gs protein
    (this multiple choice question has been scrambled)
  31. The enzyme that inactivates cAMP is

    A. A phosphatase
    B. Adenylate cyclase
    C. cAMP-dependent phospholipase
    D. cAMP dependent protein kinase
    E. cAMP phosphodiesterase
    E. cAMP phosphodiesterase
    (this multiple choice question has been scrambled)
  32. The response to Ca2+ ions acting as a second messenger include

    A. Contraction of skeletal muscles
    B. Activation of cAMP dependent phosphodiesterase
    C. Breakdown of glycogen to glucose 1phosphate
    D. Exocytosis of secretory vesicles
    E. Down regulation of LDL receptors
    • A. Contraction of skeletal muscles
    • B. Activation of cAMP dependent phosphodiesterase
    • C. Breakdown of glycogen to glucose 1phosphate
    • D. Exocytosis of secretory vesicles
  33. Insulins ability to enchance glucose transport is primarily due to

    A. An increase in the number of glucose transporters in the plasma membrane
    B. A change in the affinity of the transporters for glucose
    C. A decrease in the activity of the Na K pump
    D. Phosphorylation of glucose
    E. Dephosphorylation of glucose
    D. Phosphorylation of glucose
    (this multiple choice question has been scrambled)
  34. The Na K ATPase

    A. Phosphorylates ADP to ATP
    B. Maintains a resting potential of neurons
    C. Maintains a higher concentration of K+ ions outside the cell than inside the cell
    D. Maintains a higher concentration of K+ ions inside the cell than outside the cell
    E. Is the voltage sensitive channel that initiates an action potential
    B. Maintains a resting potential of neurons
    (this multiple choice question has been scrambled)
  35. Which of the following are criteria used to identify a substance as a neurotransmitter

    A. Introduction of the substance to the synaptic cleft must induce a response similar to than of the presynaptic neuron
    B. The substance must be removed or degraded rapidly
    C. Synaptic vesiclesmust contain the substance
    D. Synaptic vesicles must release the substance when the presynaptic neuron is stimulated
    E. Synaptic vesicles must release a sufficient quantity of the substance to elicit a response
    • B. The substance must be removed or degraded rapidly
    • C. Synaptic vesiclesmust contain the substance
    • D. Synaptic vesicles must release the substance when the presynaptic neuron is stimulate
  36. The postsynaptic membrane can be returned to the depolarized (inactivated) state by

    A. An increase in Ca2+ concentration in the synaptic cleft, which directly inactivates the neurotransmitters
    B. Uptake of neurotransmitters into presynaptic processes
    C. Degradation of neurotransmitters in the synaptic cleft
    D. Diffusion of the neurotransmitters away from the synaptic cleft
    • B. Uptake of neurotransmitters into presynaptic processes
    • C. Degradation of neurotransmitters in the synaptic cleft
  37. Which of the following neurotransmitters are synthesized from tyrosine

    A. Acetylcholine
    B. Epinephrine
    C. Substance p
    D. Dopamin
    E. Norepinephrine
    • B. Epinephrine
    • D. Dopamin
    • E. Norepinephrine
  38. The complete aerobic respiration of glycose produces

    A. Glycerol
    B. Water
    C. Urea
    D. Oxygen
    E. Carbon dioxide
    • B. Water
    • E. Carbon dioxide
  39. ATP is synthesized in

    A. The cytoplasm
    B. Mitochondria
    C. Trans. Golgi-network
    D. Chloroplasts
    E. Lysosomes
    B. Mitochondria
    (this multiple choice question has been scrambled)
  40. Based on the observation that ATP is present in archaebacteria, eubacteria, plants and animals, one can conclude that

    A. The complete hydrolysis of ATP in all organisms will drive gluconeogenesis
    B. ATP was originally an extracellular, secreted product, which was endocytosed and then subsequently used as an energy source
    C. ATP evolved in an early life form
    D. All these life forms have mitochondria where ATP is produced
    E. All these life forms usefructose for their primary energy source
    D. All these life forms have mitochondria where ATP is produced
    (this multiple choice question has been scrambled)
  41. The first step in glycolysis involves

    A. The activation of mitochondrial enzymes
    B. The enzyme hexokinase
    C. Hydrolysis of ATP to ADP
    D. An input of energy
    E. The reduction of molecular oxygen and production of carbon dioxide
    • B. The enzyme hexokinase
    • C. Hydrolysis of ATP to ADP
    • D. An input of energy
  42. The matrix of mitochondria contains

    A. A high concentration of cardiolipin
    B. Dark reaction intermediates
    C. Krebs cycle intermediates
    D. FADH2
    E. Electron transport chain intermediates
    • C. Krebs cycle intermediates
    • D. FADH2
  43. Which of the following parameters has a higher value in metabolically active cells than inactive cells

    A. Surface area of the plasma membrane
    B. Number of mitochondria
    C. Affinity of phosphoenolpyruvate for pyruvate kinase
    D. Glucagon synthase activity
    E. Surface area of mitochondrial cristae
    • B. Number of mitochondria
    • C. Affinity of phosphoenolpyruvate for pyruvate kinase
    • E. Surface area of mitochondrial cristae
  44. Which of the following energy related compounds is not present in both plants and animals

    A. Starch
    B. Glucose
    C. Glycogen
    D. Pyruvate
    E. ATP
    • A. Starch
    • C. Glycogen
  45. The primary source of energy for the transport of proteins through biological membranes is..

    A. Water
    B. ATP
    C. ADP
    B. ATP
    (this multiple choice question has been scrambled)
  46. Most phospholipid biosynthesis occurs in themselves

    A. Cytoplasm
    B. endoplasmic reticulum
    C. Golgi complex
    A. Cytoplasm
    (this multiple choice question has been scrambled)
  47. All newly synthesized phospholipids are located on the side of the endoplasmatic reticulum

    A. Hydrophilic
    B. Cytoplasmic
    C. Lumenal
    B. Cytoplasmic
    (this multiple choice question has been scrambled)
  48. The rough endoplasmic reticulum fraction isolated by centrifugation techniques contains

    A. Bound ribosomes
    B. Cytoplasmic
    C. Golgi complex
    A. Bound ribosomes
    (this multiple choice question has been scrambled)
  49. Protein synthesis is initiated in the

    A. Trans Golgi zone
    B. Cytoplasm
    C. Cis Golgi zone
    B. Cytoplasm
    (this multiple choice question has been scrambled)
  50. Membranes expand by

    A. De novo synthesis
    B. Expansion of existing membranes
    C. Exocytosis of membranes actively transported from outside the cell
    D. Breakdown of endocytotic vesicles
    E. Still unknown mechanisms
    • B. Expansion of existing membranes
    • D. Breakdown of endocytotic vesicles
  51. Which of the following statements are true

    A. All organelles split via fission
    B. Membranes grow by expansion of pre-existing membranes
    C. Endoplasmic reticulum grows by expansion of existing organelles
    D. Plasma membranes are permeable to most proteins
    E. The transport of proteins across membranes requires expenditure of energy
    • B. Membranes grow by expansion of pre-existing membranes
    • E. The transport of proteins across membranes requires expenditure of energy
  52. Once a protein leaves the endoplasmic retinaculum and reaches the Golgi complex, which part of the complex does it enter first?

    A. Trans
    B. cis
    C. trans Golgi retinaculum (TGR)
    D. medial
    E. CURL
    B. cis
    (this multiple choice question has been scrambled)
  53. Regulated secretion is often controlled by the intracellular concentration of

    A. Zinc
    B. Sodium
    C. Manganese
    D. Calcium
    E. Chloride
    D. Calcium
    (this multiple choice question has been scrambled)
  54. During protein maturation in most cells, the sequence of organelles through which proteins move is

    A. Er - Golgi vesicles - trans Golgi reticulum
    B. Not known yet
    C. Golgi vesicles - ER - trans Golgi reticulum
    D. Golgi vesicles - trans Golgi reticulum - ER
    E. trans Golgi reticulum - ER - Golgi vesicles
    A. Er - Golgi vesicles - trans Golgi reticulum
    (this multiple choice question has been scrambled)
  55. Common modifications of proteins in the lumen of the endoplasmic reticulum include

    A. Glycosylation
    B. Formation of disulfide bonds
    C. Conformational folding and formation of quaternary structure
    D. Proteolytic cleavage
    E. Condensation
    • A. Glycosylation
    • B. Formation of disulfide bonds
  56. Misfolded protein can

    A. Be secreted but not retained
    B. Cause protein synthesis to stop
    C. Be retained by the ER
    D. Be digested by ER
    E. Be digested by the trans Golgi complex
    • C. Be retained by the ER
    • D. Be digested by ER
  57. Lysosomal enzymes are activated by which of the following events either in the sorting vesicle of the trans Golgi reticulum (TGR) or in the lysosome

    A. Addition of mannose
    B. Addition of fucose
    C. Decrease in pH
    D. Proteolytic cleavage of the proprotein to the mature enzyme
    E. Addition of phosphate to mannose
    • A. Addition of mannose
    • C. Decrease in pH
    • E. Addition of phosphate to mannose
  58. Most proteins located in mitochondria, chloroplasts and nuclei are synthesized on ribosomes located in the

    A. Cytoplasm
    B. Mitochondria
    C. Nucleus
    A. Cytoplasm
    (this multiple choice question has been scrambled)
  59. Most proteins are translocated to the nucleus via..........in the nuclear envelope

    A. Gaps
    B. Channels
    C. Pores
    C. Pores
    (this multiple choice question has been scrambled)
  60. The nuclear envelope disappears during..............in eukaryotes

    A. Protein synthesis
    B. Mitosis
    C. Phosphorlation
    B. Mitosis
    (this multiple choice question has been scrambled)
  61. The outer membrane of the nuclear envelope is directly continuous with

    A. The ER
    B. Peroxisomes
    C. Lysosomes
    D. The Golgi complex
    E. Receptosomes
    A. The ER
    (this multiple choice question has been scrambled)
  62. The lamins are

    A. Proteins
    B. Filaments
    C. Located in the nucleus
    D. Hydrolytic enzymes
    E. Regulators of nuclear shape
    • A. Proteins
    • B. Filaments
    • C. Located in the nucleus
  63. Which of the following nuclear proteins / complexes are synthesized in the nucleus

    A. DNA polymerase
    B. Histones
    C. RNA polymerase
    D. Lamins
    E. None of the above
    B. Histones
    (this multiple choice question has been scrambled)
  64. Actin and tubulin share in common with each other the property that these individual monomeric units can........ Foing filaments and tubules, respectively.

    A. Degenerate
    B. Be shortened
    C. Polymerize
    C. Polymerize
    (this multiple choice question has been scrambled)
  65. Tubulin is a dimmer containing one.......and one..........subunit and having a total length of 8 nm.

    A. Beta and omega
    B. Alpha and beta
    C. Alpha and gamma
    B. Alpha and beta
    (this multiple choice question has been scrambled)
  66. Microtubules in nondividing cells extend out from the

    A. Minus end
    B. Microtubule-organizing center
    C. Golgi complex
    B. Microtubule-organizing center
    (this multiple choice question has been scrambled)
  67. The spindle apparatus of dividing cells is critical for ensuring that.....are equally spaced and positioned in the cell

    A. Microtubules
    B. Basal bodies
    C. Chromosomes
    C. Chromosomes
    (this multiple choice question has been scrambled)
  68. The plant alkaloid.......inhibits cell division at metaphase due to its ability to bind to tubulin and thus prevent polymerization

    A. Colchicine
    B. Vinblastin
    C. Tyrosine
    C. Tyrosine
    (this multiple choice question has been scrambled)
  69. Proteins that are associated with microtubules in a constant ratio to alpha and beta tubulin and are thought to be responsible for regulating the function of microtubules are collectively called

    A. Isotypes
    B. Gamma-proteins
    C. Microtubule-associated proteins (MAPs)
    C. Microtubule-associated proteins (MAPs)
    (this multiple choice question has been scrambled)
  70. The microtubules in axons and the microtubules emanating from the microtubule-organizing center of most cells radite from structures called

    A. Centriole
    B. Basal bodies
    C. Cilia
    B. Basal bodies
    (this multiple choice question has been scrambled)
  71. The.........ends of spindle microtubules make contact with chromosomes

    A. Plus
    B. Minus
    C. Phase
    A. Plus
    (this multiple choice question has been scrambled)
  72. Newly formed flagella can be synthesized by chlamdomonas experimentally deprived of their flagella in the absence of tubulin..........., indicating that a large pool of free tubulin monomers exists in the cytoplasm

    A. Degradation
    B. Synthesis
    C. Transport
    A. Degradation
    (this multiple choice question has been scrambled)
  73. Centrioles and.........are functionally and structurally similar.

    A. Basalbodies
    B. Microvilli
    C. Filaments
    A. Basalbodies
    (this multiple choice question has been scrambled)
  74. Microtubules regulate.........axonal transport of proteins

    A. Fast
    B. Phase
    C. Tyrosine
    A. Fast
    (this multiple choice question has been scrambled)
  75. The "9+2" array of microtubules is a characteristic structural feature of both.........and.............

    A. Flagella and cilia
    B. Flagella and basal bodies
    C. Flagella and microvilli
    A. Flagella and cilia
    (this multiple choice question has been scrambled)
  76. Kinesin moves proteins from the.......to the.........end of microtubules

    A. Plus, minus
    B. Minus, plus
    C. Central pair, plus
    B. Minus, plus
    (this multiple choice question has been scrambled)
  77. Centrioles and basal bodies consist of nine sets of.............microtubules

    A. Single
    B. Triplet
    B. Triplet
  78. It has been demonstrated through genetic studies that two components of the axoneme, the.............and................, are not necessary for beating

    A. Radial spokes and central pair
    B. Peripheral microtubules and central pair
    C. Radial spokes and dynein arms
    B. Peripheral microtubules and central pair
    (this multiple choice question has been scrambled)
  79. The organization and changes in microtubules during mitosis can be visualized best using the............light microscope, which has the capacity to detect birefringence in paralell, highly ordered structures

    A. Interference
    B. Phase contrast
    C. Polarizing
    B. Phase contrast
    (this multiple choice question has been scrambled)
  80. Microtubules are involved in which of the following processes

    A. Covalent association with actin in muscle cells
    B. Movement of the mitotic spindle
    C. Cell seperation during cytokinesis
    D. Transport of small vesicles within the cytoplasm
    E. Movementnof flagella and cilia
    • B. Movement of the mitotic spindle
    • C. Cell seperation during cytokinesis
    • D. Transport of small vesicles within the cytoplasm
    • E. Movementnof flagella and cilia
  81. Polymerization of alpha-beta-tubulin occurs

    A. At the + end of microtubules
    B. At the - end of microtubules
    C. At kinetochores
    D. In the presence of GTP
    E. In the presence of colchicine
    • A. At the + end of microtubules
    • B. At the - end of microtubules
    • D. In the presence of GTP
  82. Colchicine, vinblastine and vincristine

    A. Inhibit cell division
    B. Bind to actin filaments
    C. Bind to intermediate filaments
    D. Bind to microtubules
    E. Can act as anticancer drugs
    • A. Inhibit cell division
    • D. Bind to microtubules
    • E. Can act as anticancer drugs
  83. MAP1 and MAP2

    A. Can cross-link adjacent microtubules
    B. Inhibit the polymerization of microtubules at the + end but not at the - end
    C. Are microtubule-associated proteins present in many nerve cells
    D. Are nucleoproteins
    E. Initiate the degradation of microtubules in the presence of increased levels of Na+ ions
    C. Are microtubule-associated proteins present in many nerve cells
    (this multiple choice question has been scrambled)
  84. The ATPase activity of cilia and flagella is associated with

    A. Subfiber B
    B. Dynein
    C. Subfiber A
    D. Nexin
    E. The outer sheath
    B. Dynein
    (this multiple choice question has been scrambled)
  85. Centrioles in mammalian cells

    A. Replicate during the G1 phase of cell cycle
    B. Orient themselves perpendicular to each other
    C. Can be synthesized in the absence of a pre-existing centriole
    D. Play important roles in mitosis
    E. Can carry out their own protein synthesis
    • B. Orient themselves perpendicular to each other
    • D. Play important roles in mitosis
  86. .............is the single most abundant protein in most mammalian cells and can exist in a polymeric filamentous form or a monomeric globular form

    A. Tubulin
    B. Actin
    C. Desmin
    D. Vimentin
    B. Actin
    (this multiple choice question has been scrambled)
  87. Myosin varies among species but usually contains of two..........chains and two.........chains

    A. Heavy and light
    B. Beta and gamma
    C. Alpha and beta
    A. Heavy and light
    (this multiple choice question has been scrambled)
  88. Several hundred myosin molecules can assemble into a............., which is the major unit of myosin in muscle cells

    A. Thin filaments
    B. Thick filaments
    B. Thick filaments
  89. Smooth muscle, unlike skeletal muscle, is under.............control

    A. Involuntary
    B. Voluntary
    A. Involuntary
  90. The release of................from the sacroplasmic reticulum triggers the contraction of muscle

    A. Cl- ions
    B. Ca2+ ions
    C. K+ ions
    D. Na+ ions
    B. Ca2+ ions
    (this multiple choice question has been scrambled)
  91. A potent............in the membrane of sacroplasmatic reticulum pumps Ca2+ from the cytosol to the lumen of the SR

    A. Na+ K+ ATPase
    B. Ca2+ ATPase
    B. Ca2+ ATPase
  92. ............is a Ca2+ binding protein associated with the actin filaments of skeletal muscle

    A. Troponin C
    B. Myosin
    C. Trypomyosin
    D. Troponin 1
    A. Troponin C
    (this multiple choice question has been scrambled)
  93. ...............bundles the ends of actin filaments together and is critical for the attachment of these filaments to Z disks in skeletal muscles

    A. Tropomyosin
    B. Myosin
    C. Alpha-actin
    D. Titin
    C. Alpha-actin
    (this multiple choice question has been scrambled)
  94. The thin, actin containing, spikelike projection that emenate from the nerve growth cones are called............

    A. Stress fibres
    B. Microvilli
    C. Filipodia
    C. Filipodia
    (this multiple choice question has been scrambled)
  95. ............are located adjacent to the plasma membrane and contain actin filaments of different polarities. They are comonly found in endothelial cells and are thought to be important in the strength and resiliency of these cells

    A. Microtubules
    B. Stress fibres
    C. Intermediate filaments
    A. Microtubules
    (this multiple choice question has been scrambled)
  96. Intermediate filaments composed of 57-kDa protein............are prevalent in mesenchymal cells. These filaments may help keep the nucleus in a particular position in the cell and form a cage around lipid droplets in adipocytes

    A. Vimentin
    B. Villin
    C. Actin
    A. Vimentin
    (this multiple choice question has been scrambled)
  97. Which of the following comparisons of microtubules and actin filaments are true?

    A. Actin filaments have a smaller diameter than microtubules
    B. Microtubules have associated proteins, whereas actin filaments do not
    C. Microtubules are less stable than actin filaments
    D. The critical concentration for addition of monomers to the polymers is higher in case of actin than tubulin
    E. Actin filaments are more sensitive than microtubules to destabilization by high K+ concentrations
    • A. Actin filaments have a smaller diameter than microtubules
    • C. Microtubules are less stable than actin filaments
    • E. Actin filaments are more sensitive than microtubules to destabilization by high K+ concentrations
  98. Actin filaments in motile animals cells can depolymerize and repolymerize in

    A. 1 week
    B. Days
    C. Minutes
    D. Hours
    E. 1 to 2 milliseconds
    E. 1 to 2 milliseconds
    (this multiple choice question has been scrambled)
  99. Myosin is

    A. A protein with a molecular weight of approximately 10,000
    B. A protein present in both animal and plant cells
    C. A structural protein
    D. A fibrous protein
    E. An assymetric molecule with a globular head at the N-terminal end
    • C. A structural protein
    • D. A fibrous protein
    • E. An assymetric molecule with a globular head at the N-terminal end
  100. The ATPase activity of myosin is enchanced in the presence of

    A. Vimentin
    B. Actin
    C. Cytokeratins
    D. Tubulin
    E. Fodrin
    B. Actin
    (this multiple choice question has been scrambled)
  101. The..........contains many copies of the DNA that codes for ribosomal RNA

    A. Nucleoplasm
    B. Nucleolar organizer
    C. Nucleus
    B. Nucleolar organizer
    (this multiple choice question has been scrambled)
  102. The nuclear DNA of all diploid eukaryotic organisms is divided between two or more..........

    A. Chromosomes
    B. Chloroplasts
    C. Organelles
    A. Chromosomes
    (this multiple choice question has been scrambled)
  103. The............is the only type of membrane found in prokaryotic cells

    A. Brush border
    B. Cristae
    C. Plasma membrane
    C. Plasma membrane
    (this multiple choice question has been scrambled)
  104. The............of a microscope is a measure of its ability to distinguish between two very closely positioned objects

    A. Objective lens
    B. Filter
    C. Resolving power
    C. Resolving power
    (this multiple choice question has been scrambled)
  105. The array of fibrous proteins present in the cytoplasm of most eukaryotic cells is called the...............

    A. Stroma
    B. Microvilli
    C. Cytoskeleton
    C. Cytoskeleton
    (this multiple choice question has been scrambled)
  106. The fusion of an intracellular vesicle with the plasma membrane is called.............

    A. Exocytosis
    B. Endocytosis
    C. Stroma
    D. Photosynthesis
    A. Exocytosis
    (this multiple choice question has been scrambled)
  107. Specimens for visualization in the............microscope must be only 50-100nm in thickness

    A. Transmission electron microscope
    B. Scanning electron microscope
    C. Light microscope
    D. Dark-field microscope
    • A. Transmission electron microscope
    • B. Scanning electron microscope
  108. Compared with prokaryotes, eukaryotes

    A. Usually have more DNA
    B. Usually have less DNA
    C. Have a smaller average cell size
    D. Have organelles
    E. Grow in harsher enviroments
    • A. Usually have more DNA
    • D. Have organelles
  109. Which of the following types of organelles...animal cells

    A. Nucleus
    B. Mitochondria
    C. Endoplasmic reticulum
    D. Chloroplasts
    E. Golgi complex
    • A. Nucleus
    • B. Mitochondria
    • C. Endoplasmic reticulum
    • E. Golgi complex
  110. The conventional light microscope can give detailed high-resolution images of structures such as

    A. Chloroplasts
    B. Nucleoli
    C. Coated vesicles
    D. Mitochondria
    E. Whole cells
    E. Whole cells
    (this multiple choice question has been scrambled)
  111. Elements of the cytoskeleton of eukaryotic cells include

    A. Microfilaments
    B. Mitochondria
    C. Intermediate filaments
    D. Microtubules
    E. Lysosomes
    • A. Microfilaments
    • C. Intermediate filaments
    • D. Microtubules
  112. In order to visualize cell constituents using immunoflourecence microscopy, you would need a

    A. Specific antibody
    B. Scanning electron microscope
    C. Light microscope equipped with specific filters
    D. Flourescent dye
    E. Trsnsmission electron micriscope
    • A. Specific antibody
    • C. Light microscope equipped with specific filters
    • D. Flourescent dye
  113. Functions in the plasma membrane of prokaryotes include

    A. Endocytosis
    B. Carbohydrate transport
    C. Ion transport
    D. Amino acid transport
    E. Photosynthesis
    • B. Carbohydrate transport
    • C. Ion transport
    • E. Photosynthesis
  114. A. Motion of chloroplasts in plant cells - Phase contrast
    B. Viral particles - Transmission Electron Microscope
    C. Motion of bacterial cells - Phase contrast
    D. Cells containing specific protein in a tissue such as the brain - Fluorescence Microscopy
    A. Motion of chloroplasts in plant cells - Phase contrast
  115. A photographic emulsion that is exposed to radioactively labeled cells and developed to reveal the location of the radioactive components is called....

    A. Autoradiography
    B. Chromatography
    C. Photography
    A. Autoradiography
    (this multiple choice question has been scrambled)
  116. Rapid separation of cellular components on the basis of mass or size can be achieved by the technique known as..........centrifugation.

    A. Pool
    B. Pulse-field
    C. Differential
    C. Differential
    (this multiple choice question has been scrambled)
  117. Proteins expose to the detergent called.......can be separated electrophoretically primarily on the basis of their size

    A. Exonuclease
    B. Endonuclease
    C. Sodium Dodecyl Sulfate (SDS)
    C. Sodium Dodecyl Sulfate (SDS)
    (this multiple choice question has been scrambled)
  118. Macromolecules that can be analyzed with the technique known as southern blotting include
    A. DNA
    B. Oligosaccharides
    C. Antibodies
    D. RNA
    E. Proteins
    A. DNA
    (this multiple choice question has been scrambled)
  119. Biological membranes consists of a........bilayer having two........in which...........are embedded

    A. Cholesterol
    B. Phospholipid 1
    C. Alpha helix
    D. Leaflets
    E. Membrane proteins 3
    F. Membrane lipids 2
    • B. Phospholipid 1
    • D. Leaflets
    • E. Membrane proteins 3
  120. Most integral membrane proteins have at least one.........transmembrane domain.

    A. N-linked
    B. Ankyrin
    C. Phospholipid
    D. Alpha-helical
    D. Alpha-helical
    (this multiple choice question has been scrambled)
  121. Glycolipids and glycoproteins are located preferentially in the......of the......, or cell surface.

    A. Exoplasmic face, plasma membrane
    B. Eytoplasmic face, leaflet
    C. Light junctions, plasma membrane
    A. Exoplasmic face, plasma membrane
    (this multiple choice question has been scrambled)
  122. Common chemical features of all membrane lipids include

    A. A polar head group
    B. A glycerol backbone
    C. Sugar constituents
    D. A hydrophobic domain
    E. A phosphate group
    • A. A polar head group
    • D. A hydrophobic domain
  123. Lipid movement in phospholipid bilayers is

    A. Dependent on temperature
    B. Affected by the presence of cholesterol and the length of the fatty acyl chain
    C. Rapid with lateral diffusion rates of about 1 micrometer/s in liposomes
    D. Frequent for flop-flop as well as lateral diffusion
    E. Essentially uniform for the entire population of phospholipids in a biological membrane
    • A. Dependent on temperature
    • B. Affected by the presence of cholesterol and the length of the fatty acyl chain
    • C. Rapid with lateral diffusion rates of about 1 micrometer/s in liposomes
  124. Integral membrane proteins are.

    A. Removed from the membrane by solution of high ionic strength or chemicals that bind divalent cations
    B. Soluble in the absence of detergents
    C. Amphipathic molecules
    D. Extremely rich in hydrophobic amino acids in comparison with other classes of proteins
    E. Abundant and readily purified
    C. Amphipathic molecules
    (this multiple choice question has been scrambled)
  125. Lipid anchored membrane proteins are

    A. An example of one class of peripheral membrane proteins
    B. Restricted to the cell surface
    C. Sometimes covalently attached to complex glycosylated phospholipids
    D. Sometimes transforming proteins such as v-src, which is anchored by an amide likage to myristic acid
    E. Sometimes transforming proteins such as p21-ras, which is anchored by a thioester bond to palmitic acid
    • C. Sometimes covalently attached to complex glycosylated phospholipids
    • D. Sometimes transforming proteins such as v-src, which is anchored by an amide likage to myristic acid
    • E. Sometimes transforming proteins such as p21-ras, which is anchored by a thioester bond to palmitic acid
  126. Typical traits of membrane embedded segments of integral membrane proteins include

    A. An a-helical segment long enough, about 20-25 amino acids, to span the phospholipid bilayer
    B. Exposure of polar C=O and NH groups on the outside
    C. Placement of charged residues on the inteior of the molecule
    D. A highly conserved sequence of hydrophobic amino acids
    E. Associations with membrane lipids that restrict their mobility
    A. An a-helical segment long enough, about 20-25 amino acids, to span the phospholipid bilayer
    (this multiple choice question has been scrambled)
  127. Polarized cells in animals

    A. Are common in free-floating cells of the bloodstream
    B. Are general feature of epithelial tissue, which lines body cavities
    C. Have a plasma membrane divided into specialized regions of different functions
    D. Have different molecules exposed on their apical and basolateral surfaces
    E. May be sealed together by tight junctions to form a barrier to the passage of most small molecules
    • B. Are general feature of epithelial tissue, which lines body cavities
    • C. Have a plasma membrane divided into specialized regions of different functions
    • D. Have different molecules exposed on their apical and basolateral surfaces
    • E. May be sealed together by tight junctions to form a barrier to the passage of most small molecules
  128. The unique properties of different biological membranes are related to

    A. Variations in their phospholipid composition
    B. Qualitative diffeences in their glycolipids
    C. The presence or absence of cardiolipin
    D. The relative abundance of cholesterol
    E. The distinctive properties of their protein species
    • A. Variations in their phospholipid composition
    • B. Qualitative diffeences in their glycolipids
    • D. The relative abundance of cholesterol
    • E. The distinctive properties of their protein species
  129. Vertebrate muscle can classified into the following types

    A. Striated
    B. Multilayered
    C. Smooth
    D. Cardiac
    E. Interdigated
    • A. Striated
    • C. Smooth
    • D. Cardiac
  130. Which of the following sequnces indicates the correct orde from largest to smallest

    A. Muscle - myofibres - myofibril - myosin filament - actin filament
    B. Myofibril - muscle - myofibres - myosin filament - actin filament
    C. Myofibres - myofibril - muscle - myosin filament - actin filament
    D. Myofibres - myofibril - muscle - actin filament - myosin filament
    A. Muscle - myofibres - myofibril - myosin filament - actin filament
    (this multiple choice question has been scrambled)
  131. Which of the following is (are) the major constituent of the (lambda) band in striated muscle

    A. Actin
    B. Myosin
    C. Z disk
    D. Tubulin
    E. Fodrin
    • A. Actin
    • B. Myosin
    • C. Z disk
  132. Which of the following remains constant in length during muscle contraction

    A. I band
    B. A band
    C. Sarcomer length
    D. Myosin thick filaments
    E. Actin thin filaments
    • A. I band
    • B. A band
    • D. Myosin thick filaments
    • E. Actin thin filaments
  133. Actin filaments can be anchored to

    A. Tubulin
    B. Z disks
    C. Interrelated disks
    D. The plasma membrane
    E. Cytoplasmic plaques
    • B. Z disks
    • D. The plasma membrane
  134. The filament network within microvilli and their terminal web include

    A. Actin filaments
    B. Calmodulin
    C. Fimbrin
    D. Fodrin
    E. Villin
    • A. Actin filaments
    • C. Fimbrin
    • E. Villin
  135. In contrast to mictotubules and actin microfilaments, intermediate filaments

    A. Are formed from numerous types of subunit proteins
    B. Do not require energy for assembly
    C. Remain insoluble when extracted from cells
    D. Exhibit no polarity
    E. Exist primarily in the polymerized form and undergo little polymerization-depolymerization cycling within cells
    • A. Are formed from numerous types of subunit proteins
    • D. Exhibit no polarity
  136. Membranes expand by

    A. De novo synthesis
    B. Expansion of existing membranes
    B. Expansion of existing membranes
  137. A
  138. Which of the following posttranslational modification of proteins occur in the lumen of the endoplasmic reticulum

    A. Glyclization
    B. Formation of disulfide bonds
    C. Conformational folding and formation of quaternary structure
    D. Proteolytic cleavage
    • A. Glyclization
    • B. Formation of disulfide bonds
  139. Transport vesicles

    A. Can have a clathrin coat
    B. Contain assembly proteins
    C. Can shuttle proteins from mitochondria to the endoplasmic reticulum
    D. Can fuse with target organelles with the participation of SNAP
    • A. Can have a clathrin coat
    • B. Contain assembly proteins
    • D. Can fuse with target organelles with the participation of SNAP
  140. Secretal proteins

    A. Are all prsent in one type of vesicle
    B. Are often synthesized as a precursor and cleaved before release
    C. May be continuously exocytosed
    D. May require an acidic compartment for maturation
    E. May aggregate within vesicles
    • B. Are often synthesized as a precursor and cleaved before release
    • C. May be continuously exocytosed
    • D. May require an acidic compartment for maturation
  141. Targeting of enzymes to lysosomes involves which of the following steps

    A. Dissociation of ligand from receptor
    B. Binding to a mannose-6-phosphate receptor
    C. Decrease in pH
    D. Fusion with late endosomes
    E. Addition of phosphate to mannose
    • A. Dissociation of ligand from receptor
    • B. Binding to a mannose-6-phosphate receptor
    • C. Decrease in pH
    • E. Addition of phosphate to mannose
  142. Cells that can grow in the presence or absence of oxygen are called.........

    A. Facultative anaerobes
    B. Procaryotes
    C. Eukaryotes
    A. Facultative anaerobes
    (this multiple choice question has been scrambled)
  143. In most mammalian cells, fatty acids are chiefly oxidized in organelles called.......without the production of ATP, however, fatty acid oxidation in.......is the major source of ATP in heart muscle

    A. Lysosomes, endoplasmic reticulum
    B. Cytochromes, microvilli
    C. Peroxisomes, mitochondria
    C. Peroxisomes, mitochondria
    (this multiple choice question has been scrambled)
  144. The mitochondrial........is permeable to most small molecules

    A. Inner membrane
    B. Cristae
    C. Outer membrane
    C. Outer membrane
    (this multiple choice question has been scrambled)
  145. The anaerobic conversion of one glucose molecule to two pyrovate molecules is termed........

    A. Glycolysis
    B. Proteolytic cleavage
    C. Signal transduction
    D. Glycosylation
    A. Glycolysis
    (this multiple choice question has been scrambled)
  146. The highly convoluted infoldings of the mitochondrial inner membrane are called......

    A. Cytochromes
    B. Microvilli
    C. Cristae
    D. Cilia
    C. Cristae
    (this multiple choice question has been scrambled)
  147. Both pyruvate and fatty acyl CoA are converted initially to.......in the matrix of the mitochondrion.

    A. Glucose-6-phosphate
    B. Acetyl CoA
    C. Glucose
    B. Acetyl CoA
    (this multiple choice question has been scrambled)
  148. Which of the following processes are powered directly by a transmembrane proton gradient?

    A. Generation of ATP in mitochondria
    B. Beating of eukaryotic cilia
    C. Formatiom of fructose 1,6-diphosphate by phosphofructokinase-1
    A. Generation of ATP in mitochondria
    (this multiple choice question has been scrambled)
  149. The complete aerobic respiration of glycose produces

    A. Glycerol
    B. Water
    C. Urea
    D. Oxygen
    E. Carbon dioxide
    • B. Water
    • E. Carbon dioxide
  150. ATP is synthesized in

    A. Golgi network
    B. The cytoplasm
    C. Lysosomes
    D. Mitochondria
    D. Mitochondria
    (this multiple choice question has been scrambled)
  151. Which of the following glycolytic enzymes produce ATP during the conversion of glycose to pyrvate

    A. Hexokinase
    B. Pyruvane kinase
    C. Phosphoglycerate mutase
    D. Phosphodifructokinase-(beta)
    B. Pyruvane kinase
    (this multiple choice question has been scrambled)
  152. The matrix of mitochondria contains

    A. A high concentration of glucose
    B. Starch
    C. Citric acid cycle intermediates
    D. FADH
    E. Electron transport chain intemediates
    • C. Citric acid cycle intermediates
    • D. FADH
  153. The first step in glycolysis involves

    A. The activation of mitochondrial enzymes
    B. Hydrolysis of ATP to ADP
    C. An input of energy
    D. The reduction of molecular exygen and production of carbon dioxide
    • B. Hydrolysis of ATP to ADP
    • C. An input of energy
  154. Which of the following features are common to eukaryotes and bacteria

    A. Glycolytic pathway
    B. The malate shuttle
    C. Proton gradients
    D. Cristae
    • A. Glycolytic pathway
    • C. Proton gradients
  155. Most proteins located in mitochondria, chloroplasts and nuclei are synthesized on ribosomes that are located in the.........and are not associated with the.......

    A. Cytoplasm, rough endoplasmic reticulum
    B. Stroma, smooth endoplasmic reticulum
    C. Nucleus, mitochondria
    A. Cytoplasm, rough endoplasmic reticulum
    (this multiple choice question has been scrambled)
  156. Most proteins translocated to the nucleus pass through......in the nuclear envelope.

    A. Pores
    B. Membrane
    C. Chaperone
    D. Contact sites
    A. Pores
    (this multiple choice question has been scrambled)
  157. The nuclear envelope disappears during the........stage of.........in eukaryotes.

    A. Prophase, mitosis
    B. Anaphase, mitosis
    C. Interphase, cell cycle
    A. Prophase, mitosis
    (this multiple choice question has been scrambled)
  158. Among cellular organelles the...........is enclosed by a single membrane, whereas the..........and...........are enclosed by a double membrane

    A. Peroxisome, mitochondria, nucleus
    B. Peroxisome, mitochondrion, golgi complex
    A. Peroxisome, mitochondria, nucleus
  159. The outer membrane of the nuclear envelope is directly continuous with.......

    A. The endoplasmic reticulum
    B. Lysosomes
    C. Chloroplasts
    D. The golgi complex
    E. Peroxisomes
    A. The endoplasmic reticulum
    (this multiple choice question has been scrambled)
  160. Nucleoplasmin has been used intensively to study the mechanism of protein import into the nucleus. Studies within protein

    A. Untilizend electron microscopy of gold-coated nucleoplasmin
    B. Revealed that nucleoplasmin ente the nucleus through pores
    C. Untilizend microinjection techniques
    B. Revealed that nucleoplasmin ente the nucleus through pores
    (this multiple choice question has been scrambled)
  161. The interaction of hormones with receptors on distant target cells is reffered to as............signaling

    A. Autocrine
    B. Paracrine
    C. Endocrine
    C. Endocrine
    (this multiple choice question has been scrambled)
  162. Neurotransmitter stimulation of adjacent neurons is reffered to as...........signaling

    A. Paracrine
    B. Endocrine
    C. Autocrine
    A. Paracrine
    (this multiple choice question has been scrambled)
  163. Receptors for steroid hormones such as estrogens and for................are found in the nucleus and cytoplasm of responsive cell.

    A. Insulin
    B. Thyroid hormones
    C. Peptide hormones
    B. Thyroid hormones
    (this multiple choice question has been scrambled)
  164. A peptide toxin from the bacterium vibrio cholera covalently modifies the G-subunit of certain G protein resulting in persistent activation of...........and invreased production of the second messanger known as...........

    A. Adenylate cyclase, cAMP
    B. Inositol 1,4,5-tris-phosphate;protease
    A. Adenylate cyclase, cAMP
  165. Diabetes can result from a deficiency in the release of the hormone........

    A. Catecholamine
    B. Insulin
    C. Estrogen
    D. Serotonin
    B. Insulin
    (this multiple choice question has been scrambled)
  166. Excessive exposure to hormones may lead to a.................in the number or activity of cell-surface receptors. This phenomenon is referred to as......

    A. Decrease, downregulation
    B. Increase, downregulation
    A. Decrease, downregulation
  167. Many cell-surface hormone receptors are internalized by receptor-mediated endocytosis and subsequently destroyed in........

    A. Lysosomes
    B. ER
    C. Peroxisomes
    A. Lysosomes
    (this multiple choice question has been scrambled)
  168. The second messenger..........plays a crucial role in regulating the synthesis and breakdown of glycogen in liver and muscle cells

    A. cAMP
    B. Inositol 1,4,5-triphosphate
    A. cAMP
  169. Which of the following are not considred to be a second messenger?

    A. Ca2+
    B. Na+
    C. GMPPNP
    D. 1,3 diacylglycerol
    E. Inositol 1,4,5-triphosphate
    • B. Na+
    • C. GMPPNP
  170. Adenylate cycline

    A. Is activated by an increase in intracellular Ca2+ levels
    B. Can diffuse laterally in the plasma membrane
    C. Degrades cAMP to produce AMP
    D. Can be activated by more thathan one receptor
    E. Is activated by binding directly to a hormaone receptor
    D. Can be activated by more thathan one receptor
    (this multiple choice question has been scrambled)
  171. Cholera toxin increases cAMP levels by

    A. Inhibiting cAMP phosphodiestrase
    B. Binding to adenylate cyclase
    C. Modifying G1 protein
    D. Modifying Gs protein
    E. Binding to hormone
    D. Modifying Gs protein
    (this multiple choice question has been scrambled)
  172. Receptor cyrosine kinases

    A. Are often autophosphorylated after addition of hormone
    B. Have been identified as important modulators of cell growth
    C. Are activated by an increase in intracellular Ca2+ levels
    D. Are critical for normal development of some Drosophobia visual cells
    • A. Are often autophosphorylated after addition of hormone
    • B. Have been identified as important modulators of cell growth
    • D. Are critical for normal development of some Drosophobia visual cells
  173. The synthesis of most neuronal proteins occurs in the

    A. Synapses
    B. Cell body
    C. Axon
    D. Axon terminals
    E. Dendrites
    B. Cell body
    (this multiple choice question has been scrambled)
  174. The Na+/K+ ATPase

    A. Phosphorylates ADP to ATP
    B. Maintain a higher concentration of K+ ions outside the cell than inside the cell
    C. Maintain the resting potential of neurons
    D. Maintain a higher concentration of Na+ ions inside the cell than outside the cell
    E. Is the voltage-sensitive channel that initiates an action potential
    C. Maintain the resting potential of neurons
    (this multiple choice question has been scrambled)
  175. Although neurotransmitters have various chemical substances they all

    A. Induce an exitatory response in postsynaptic neurons
    B. Are removed fro or degraded rapidly in the synaptic cleft
    C. Are stored in synaptic vesicles
    D. Are released as a result of the influx of Na+ ions during the action potential
    E. Bind to specific receptors in the postsynaptic membrane
    • B. Are removed fro or degraded rapidly in the synaptic cleft
    • C. Are stored in synaptic vesicles
    • E. Bind to specific receptors in the postsynaptic membrane
  176. The postsynaptic membrane can be returned to the depolarized (inactivated) state by

    A. An increase in Ca2+ concentration in the synaptic cleft, which directly inactivate the neurotransmitter
    B. Uptake of neurotransmitter into presynaptic processes
    C. Degeneration of neurotransmitter in the synaptic cleft
    D. Diffusion of the neurotransmitter away from the synaptic cleft
    • B. Uptake of neurotransmitter into presynaptic processes
    • C. Degeneration of neurotransmitter in the synaptic cleft
  177. Which of the following neurotransmitters are synthesized from tyrosine?

    A. Acetylcholine
    B. Epinephrine
    C. Substance p
    D. Dopamine
    E. Norepinephrine
    • B. Epinephrine
    • D. Dopamine
    • E. Norepinephrine
  178. Insulin ability to enhance hlucose transport is primarily due to

    A. A change in the affinity of the transporter for glucose
    B. A decrease in the activity of the Na+/K+ pump
    C. Dephosphorylation of glucose
    D. An increase in the number of glucose transporter in the plasma membrane
    E. Phosphorylation of glucose
    A. A change in the affinity of the transporter for glucose
    (this multiple choice question has been scrambled)
  179. Which of the following properties are characteristic of paracrine signaling

    A. Occurs when signaling cells respond to molecules that they themselves release
    B. May involve hormones carried in the bloodstream
    C. Can be mediated by peptide hormones
    D. Is important in conduction of nerve impulses
    E. Involves signaling and responding cells that are distant from each other
    D. Is important in conduction of nerve impulses
    (this multiple choice question has been scrambled)
  180. Cyclic AMP

    A. Is found only in eukaryotes
    B. Activates an intracellular protein kinase
    C. Interacts with Gprotein directly
    D. Stimulates sodium channels
    E. Activates an intracellular protein phosphatase
    B. Activates an intracellular protein kinase
    (this multiple choice question has been scrambled)
  181. The various molecules that function as a second messenger

    A. Have related structurs
    B. Bind to cell-surface receptors
    C. Are involved in signal transduction pathways
    D. Are usually rapidly degraded or recycled after release
    E. Often activate enzymes known as kinases
    • C. Are involved in signal transduction pathways
    • E. Often activate enzymes known as kinases
  182. Karykinesis is followed by constrictions of the cell into two separate entities (cytokinesis). Name the events which can be demonstrated during cytokinesis.

    A. Cytokinesis occurs in the plane of the equatorial plate of metaphase
    B. Band of actin filaments become associated with the cleavage furrow
    C. Cleavage furrow depends, and the spindle microtubules become compressed by the advancing furrow
    D. Along metaphase in the cell nucleus disappers nucleolus
    • A. Cytokinesis occurs in the plane of the equatorial plate of metaphase
    • B. Band of actin filaments become associated with the cleavage furrow
  183. Programmed cell death is called

    A. Necrosis
    B. Sporosis
    C. Oncosis
    D. Apoptosis
    D. Apoptosis
    (this multiple choice question has been scrambled)
  184. During apoptosis

    A. Cell die by accident
    B. Cell and nucleus shrink
    C. Chromatin condenses
    D. Nucleus fragments
    • B. Cell and nucleus shrink
    • C. Chromatin condenses
    • D. Nucleus fragments
  185. During necrosis

    A. Cellular debris is generated
    B. An inflammatory responce is elicited
    C. Cell nucleus is undrgoing programmed changes
    • A. Cellular debris is generated
    • B. An inflammatory responce is elicited
  186. The most widely used microsvope is

    A. Dark fkeld microscope
    B. Bright field microscope
    C. Confocal scanning microscope
    D. Electron microscope
    B. Bright field microscope
    (this multiple choice question has been scrambled)
  187. Electron microscopical negative staining is particularly useful for

    A. Illustrating details of small, isolated structures
    B. Recognition of viruses
    C. Study of bacteriophages
    D. Analysis of cell surface
    E. Detection of proteins tagged with flourescent antibodies
    • B. Recognition of viruses
    • C. Study of bacteriophages
  188. Current techniques in cell and molecular biology are

    A. Sodium dodecy sulfate polyacrylamide gel electrophoresis
    B. Immunoblotting
    C. Light microscopy
    • A. Sodium dodecy sulfate polyacrylamide gel electrophoresis
    • B. Immunoblotting
    • C. Light microscopy
  189. Cell plasma membrane studied by use of high-resolution electron microscopy

    A. Contains thick, electron-lucent region
    B. Contains 2 narrow, electron-dense lines
    C. Appears as acidophilic structure
    D. Contains 2 narrow, electron-dense lines separated by an electron-lucent region
    D. Contains 2 narrow, electron-dense lines separated by an electron-lucent region
    (this multiple choice question has been scrambled)
  190. Main membrane proteins are

    A. Receptor proteins
    B. Integral membrane proteins
    C. Ligand molecules
    D. Peripheral proteins
    E. Lipid-anchored proteins
    • B. Integral membrane proteins
    • D. Peripheral proteins
    • E. Lipid-anchored proteins
  191. Plasma membrane mobility is characteristic for

    A. Lipids and many proteins
    B. Some lipids
    C. All proteins
    D. Carbohydrates
    A. Lipids and many proteins
    (this multiple choice question has been scrambled)
  192. Membrane specialization are

    A. Microvilli
    B. Microvilli and glyvocalyx
    C. Cilia
    D. Basal folds
    • A. Microvilli
    • C. Cilia
    • D. Basal folds
  193. The narrow intracellular space between epithelial cells in a sheet is usually about

    A. 30-50nm wide
    B. 1-2nm wide
    C. 20-30nm wide
    D. 50-100nm wide
    B. 1-2nm wide
    (this multiple choice question has been scrambled)
  194. Between the basal plasma membrane folds........are located

    A. Mitochondria
    B. Peroxisomes
    C. Cytoskeleton elements
    D. Lysosomes
    C. Cytoskeleton elements
    (this multiple choice question has been scrambled)
  195. Endocytosis includes

    A. Phagocytosis
    B. Exocytosis
    C. Receptor-mediated endocytosis
    D. Pinocytosis
    • A. Phagocytosis
    • C. Receptor-mediated endocytosis
    • D. Pinocytosis
  196. Principal functions of cell nucleus are

    A. Storing and processing of genetic information
    B. Formation of secretory glands
    C. Replication
    D. Contraction
    E. Transcription
    F. Control of metabolism
    • A. Storing and processing of genetic information
    • C. Replication
    • E. Transcription
    • F. Control of metabolism
  197. Junctional complexes between cells

    A. Seal off intercellular space
    B. Function in cell-cell adhesion
    C. Function in secretion
    D. Function in intercellular communication
    • A. Seal off intercellular space
    • B. Function in cell-cell adhesion
    • D. Function in intercellular communication
  198. Well-known types of chromatin are

    A. Heterochromatin
    B. Intermediate chromatin
    C. Euchromatin
    • A. Heterochromatin
    • C. Euchromatin
  199. In the light and transmission electron microscopy, interphase nuclei show

    A. Filamentous structures known as chromatin
    B. Granular clumps of chromatin
    • A. Filamentous structures known as chromatin
    • B. Granular clumps of chromatin

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