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Exam 3 Quiz

44 Questions
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This is to prpare for exam 3

Questions and Answers
  • 1. 
    • A. 

      Closer to the synthesis site

    • B. 

      Farther from the nucleus

    • C. 

      Farther from the synthesis site

    • D. 

      Closer to the nucleus

  • 2. 
    You incubate liposomes with a series of purified proteins nomrally found in the coats of cell transport vesicles. after adding one of them to the liposome mixture, budding of vesicles fromt he liposomes began. what does this mean?
    • A. 

      Liposomes cause the protein to denature

    • B. 

      The protein is involved in the intiation of vesicle formation

    • C. 

      The protein is involved in liposome denaturation

    • D. 

      The protein triggers protein synthesis

    • E. 

      The protein causes the entry of water into the liposomes

  • 3. 
    What determines the sequence of sugar addition to glycoprteins traveling through the gogli complex?
    • A. 

      Nothing- the sequence is random.

    • B. 

      The spatial arrangement of specific glycosyltransferases that contact proteins as they pass through the Golgi complex

    • C. 

      The concentration of sugars in the Golgi complex

    • D. 

      The sequence of sugars in the Gogli complex

  • 4. 
    How and where is the asymmetry of the phospholipid bilayers initially established?
    • A. 

      It is initially established in the Golgi complex during lipid and protein modification

    • B. 

      It is initially established in the ER during lipid and protein synthesis

    • C. 

      It is initially established in the secretory vesicles during lipid and protein modification

    • D. 

      It is initially established in the in the mitochodnria by random insertion into the membranes.

    • E. 

      All of the above

  • 5. 
    The building blocks of a nucleoside are _____
    • A. 

      A pentose sugar and a phosphate group

    • B. 

      A pentose sugar and a nitrogenous base

    • C. 

      A phosphate group and a nitrogenous base

    • D. 

      A pentose sugar, a phosphate group and a nitrogenous base

    • E. 

      A pentose sugar, a phosphate gruop and an amino acid

  • 6. 
    The __-carbon of the sugar of a nucleotide participates in the formation of the phosphodiester bond?
    • A. 

      1

    • B. 

      2

    • C. 

      3

    • D. 

      5

    • E. 

      C and d

  • 7. 
    To what site does Sar1 bind after it binds to GTP?
    • A. 

      The luminal leaflet of the ER membrane

    • B. 

      The cytosolic leaflet of the Golgi membrane

    • C. 

      The luminal leaflet of the Gogle membrane

    • D. 

      The cytosolic leaflet of the ER membrane

  • 8. 
    Which of the models below suggests that the Golgi cisternae are transient structures that form at the cis face of the stack by fusion of membranous carriers from the ER and ERGIC and that each cisterna travels through the Golgi complex from the cis to the trans end of the stack, changing in composition as it progresses?
    • A. 

      The cisternal maturation model

    • B. 

      The cargo carrying model

    • C. 

      The vesicular transport model

    • D. 

      The secretory transport model

    • E. 

      The chemiosmotic model

  • 9. 
    In general, how are proteins targeted to specific destinations?
    • A. 

      Sorting signals is located on the gene

    • B. 

      Sorting signals is located on the proteins

    • C. 

      Receptors in trasport vesicle walls that recognize them

    • D. 

      Sorting signals is located on the cellular compartments

    • E. 

      B and c

  • 10. 
    Why is the Er so well-suited and ideally constructed for its role as a port of entry for secretory proteins?
    • A. 

      It has a large surface area allowing the attachment of many ribosoems

    • B. 

      The ER cisternae lumen favors the folding and disassembly of proteins

    • C. 

      The RER segregates secreotry, lysosomal and plant-cell vacuclar proteins from toher newly made proteins, allowing their modication, and sends them to their destination

    • D. 

      A and c

    • E. 

      A, b and c

  • 11. 
    How are proteins normally resident in the ER retrieved when they escape the ER?
    • A. 

      Proteins that normally reside int he ER lumen have short amino acid sequences at their C-terminus that serve as retrieval sequences.

    • B. 

      Proteins that normally reside int he ER lumen have short amino acid sequences at their N-terminus that serve as retrieval sequences.

    • C. 

      Proteins that normally reside int he ER membrane have short amino acid sequences at their C-terminus that serve as retrieval sequences.

    • D. 

      Proteins that normally reside int he ER membrane have short amino acid sequences at their N-terminus that serve as retrieval sequences.

    • E. 

      A and c

  • 12. 
    Which type of cytoskeletal element is characterized as a hollow, rigid cylindrical tube with walls coposed of tubulin subunits
    • A. 

      Microfilaments

    • B. 

      Microtubules

    • C. 

      Intermediate filaments

    • D. 

      All of the above

  • 13. 
    Which of the following is (are) made on free ribosomes?
    • A. 

      Proteins that are to remain in the cytosol

    • B. 

      Peripheral proteins of the inner cell membrane surface

    • C. 

      Peripheral proteins of the outer cell membrane surface

    • D. 

      Proteins to be transported to the nuclelus

    • E. 

      A, b and d

  • 14. 
    Which molecule below is a GTP-binding protein that is requred for the release of a clatherin-coated vesicle from the membrane on which it was formed?
    • A. 

      AP2

    • B. 

      GGA

    • C. 

      Clathrin

    • D. 

      Dynamin

    • E. 

      Opscrin

  • 15. 
    What endosome serves as a sorting station that directs different types of receptors and ligands along diferent pathways?
    • A. 

      Medial endosomes

    • B. 

      Late endosomes

    • C. 

      Early lysosomes

    • D. 

      Medial lysomes

    • E. 

      Early endosomes

  • 16. 
    Which of the following are components of Chargaff's rules of bases?
    • A. 

      Amount of G= Amount of C

    • B. 

      Amount of purines= Amount of pyrimidines

    • C. 

      %C+T=%A+G

    • D. 

      Amount of A= Amount of T

    • E. 

      All of the above

  • 17. 
    Most vesicles budding from the Golgi body have a fuzzy, electron-dense coat on their ______ surface. The coat appears to be made of _______.
    • A. 

      Luminal, lipid

    • B. 

      Cytosolic, lipid

    • C. 

      Cytosolic, carbohydrate

    • D. 

      Luminal, protein

    • E. 

      Cytosolic, protein

  • 18. 
    All of the following statements about cellular trafficking are true EXCEPT
    • A. 

      COPI-coated vesicles move materials from Gogli to the secretory vesicle

    • B. 

      Tethering proteins mediate docking between target and vesicle

    • C. 

      COPII-coated vesicles move materials from ER to Golgi

    • D. 

      Movement may be mediated by microtubules

  • 19. 
    The heads of kinesin like proteins have farily closely related amino acid sequences but diverse tail sequences. what ist he explation for this seeming contradiction?
    • A. 

      The similarity of kinesin like protein heads and the variation in their tails are purely random

    • B. 

      The similarity of the heads is explained by their similar roles in interacting with microtubules; the variation in the tails reflects the variation of cargoes to which they bind

    • C. 

      The similarity of the heads is explained by their different roles in interacting with microtubules; the variation in the tails reflects the similar cargoes to which they bind.

    • D. 

      The similarity of the heads is explained by their similar roles in interacting with microtubules; the variation in the tails reflects the similar of cargoes to which they bind

    • E. 

      The similarity of the heads is explained by their different roles in interacting with microtubules; the variation in the tails reflects the variety of cargoes to which they bind.

  • 20. 
    • A. 

      A R straight and mix it with S cells

    • B. 

      A S strain and mix it with R cells

    • C. 

      A S strain and mix it with heat-killed S cells

    • D. 

      None of the above

  • 21. 
    Which protein below is often a component of intermediate filaments?
    • A. 

      Keratin

    • B. 

      Lubulin

    • C. 

      Actin

    • D. 

      Primentin

    • E. 

      A and d

  • 22. 
    • A. 

      In a retrograde direction

    • B. 

      Toward the plus-end of the microtubule

    • C. 

      In an anterograde direction

    • D. 

      Towards the fastest growing end of the microtubule

    • E. 

      C and d

  • 23. 
    The uptake (both specific and nonspecific) of fluid, dissolved solutes and suspended macromolecules is called ____
    • A. 

      Endocytosis

    • B. 

      Phagoctyosis

    • C. 

      Autophagy

    • D. 

      Exoctyosis

    • E. 

      Pinocytosis

  • 24. 
    The vesicle is targeted to the appropriate compartment by
    • A. 

      Endocytosis

    • B. 

      Rabs

    • C. 

      GTP binding proteins

    • D. 

      T-snares

  • 25. 
    What recognizes the signal sequence as it exits the ribosomes and of what is it made?
    • A. 

      Signal recognition particle, DNA and protein

    • B. 

      Signal recognition particle, carbohydrate and protein

    • C. 

      SRP and its components, RNA and protein

    • D. 

      Signal recognition protein, carbohydrate and lipid

  • 26. 
    Which coated vesicles move materials in a retrograde direction from the ERGIC and Golgi stack toward the ER?
    • A. 

      Cadmium-coated vesicles

    • B. 

      COPI-coated vesicles

    • C. 

      Clathrin-coated vesicles

    • D. 

      COPII-coated vesicles

  • 27. 
    In addition to microtubule motor proteins ____ are also involved in vesicular transport.
    • A. 

      Actin

    • B. 

      Non-muscle myosins

    • C. 

      Tubulin

    • D. 

      Dynein

    • E. 

      Kinesin-like proteins

  • 28. 
    The accumulation of misfolded proteins in the ER is a potentially lethal situation and thus causes the triggering of what process?
    • A. 

      The polysomal response

    • B. 

      The posttranscriptional resopnse

    • C. 

      The unfolded protein response (UPR)

    • D. 

      The proleasomal response

  • 29. 
    Ring-shaped complexes in the centrosome contain ______ in combination with _____
    • A. 

      Gamma tubulin; tubulin GTP

    • B. 

      Gamma tubulin; tubulin ATP

    • C. 

      Beta tubulin, tubulin GTP

    • D. 

      Gamma tubulin, myosin I ATP

    • E. 

      None of the above

  • 30. 
    The current model for the nucleation of microtubules is that a helical array of y-tubulin subunit forms an open, nng-shaped template on which the first row of alphabeta-tubulin dimers assembles. how does this model account for the polarity of microtubules?
    • A. 

      Only the alpha-tubulin of a heterodimner can bind to the ring of y-subunits

    • B. 

      Only the beta-tubulin of a heterodimner can bind to the ring of y-subunits

    • C. 

      The ring structure straightens out the microtuble

    • D. 

      The ring structure interacts with a homodimer instead of a heterdimer

  • 31. 
    Which end of a microtubule is the slow growing end
    • A. 

      The minus end

    • B. 

      The end with beta-tubulin at the tip

    • C. 

      The end with alpha-tubulin at the tip

    • D. 

      A and c

    • E. 

  • 32. 
    What GTP-binding protein plays a regulatory role in the formation and disassembly of the COPII coat?
    • A. 

      Sar1

    • B. 

      Gar1

    • C. 

      ARF1

    • D. 

      Ras

    • E. 

      Src

  • 33. 
    ____ refers to the fact that the sequence of one DNA strand specifies the sequence of the other strand in the double helix?
    • A. 

      Indirectionality

    • B. 

      Complexity

    • C. 

      Complementary

    • D. 

      Similarity

    • E. 

      Compulsivity

  • 34. 
    How do protein coats select the contents of vesicles they help to form?
    • A. 

      They electromagnetically attract the correct cargo proteins

    • B. 

      The coats have a specific affinity for the cytosolic tails of integral membrane receptors for cargo proteins that reside in the donor membrane

    • C. 

      The coats have a specific affinity for the luminal tails of integral membrane

    • D. 

      Receptors for cargo proteins that reside in the donor membrane

    • E. 

      The coat proteins directly attach to the cargo proteins in the lumen of the forming vesicles

  • 35. 
    What circumstantial evidence supports the proposed role of the Rabs-in recruiting cytosolic tethering proteins to specific membrane surfaces?
    • A. 

      With over 60 Rab genes identified in humans, Rabs constitute the most diverse group of proteins involved in membrane trafficking

    • B. 

      Rabs have the potential of giving each cell compartment a unique surface identity

    • C. 

      Different Rabs have been found to be associated with different membrane compartments

    • D. 

      The preferential localization of Rabs would allow them to recruit the various proteins involved in targeting specificity

    • E. 

      All others are correct

  • 36. 
    What is the supposed function of the small subfamily of kinesins that is incapable of movement
    • A. 

      They stabilize microtubules

    • B. 

      They encouraging depolymerization

    • C. 

      They cause polymerization

    • D. 

      They block other kinesins from moving along microtubules

    • E. 

      They add phosphate groups to tubulin

  • 37. 
    • A. 

      The plus end

    • B. 

      The minus end

    • C. 

      The end with beta-tubulin at the tip

    • D. 

      The end with alpha-tubulin at the tip

    • E. 

      A and d

  • 38. 
    When the rate of loss of actin subunits from the pointed end of an actin filament is balanced by the rate of their addition to the barbed end, __________
    • A. 

      The filaments are said to be steady state

    • B. 

      The length of the filaments remains the same

    • C. 

      Treadmilling occrus

    • D. 

      A, b and c

  • 39. 
    What led Avery, MacLead and McCarty to conclude that DNA was the transformation principle reported by Griffith and others?
    • A. 

      The transformation principle exhibited a host of chemical properties shared by DNA and protein

    • B. 

      When exposed to various enzymes, the transforming principle was only inactivated by DNAse

    • C. 

      When exposed to various enzymes, the transforming principle was inactivated by all enzymes except DNAse

    • D. 

      When exposed to various enzymes, the transofrming principle was only inactivated by protease

    • E. 

      B and c

  • 40. 
    Which type of cytoskeletal element is described as a solid, thinner structure, often organized into a branching network, and composed of actin subunits?
    • A. 

      Microfilaments

    • B. 

      microtubules

    • C. 

      Intermediate filaments

    • D. 

      All of the above

    • E. 

      Macrofilaments

  • 41. 
    Kinesin movement along a microtubule is said to be ______ meaning that it can move long distances along an individual microtubule without falling off
    • A. 

      Excessive

    • B. 

      Progressive

    • C. 

      Excessive

    • D. 

      Processive

    • E. 

      Aggresive

  • 42. 
    Typically, receptors for hormones or growth factors are destroyed during endocytosis, leading to a reduction in the cell sensitivity to further stimulation by that particular hormone or growth factor. this is a mechanism by which cells regulate their ability to respond to extracellular messengers. what is it called?
    • A. 

      Receptor up-regulation

    • B. 

      Receptor annihilation

    • C. 

      Endocytic assignation

    • D. 

      Receptor down-regulation

    • E. 

      Super signaling

  • 43. 
    Hich of the proteins below is (are) not made on the membrane-bound ribosomes of the RER?
    • A. 

      Inner peripheral membrane proteins

    • B. 

      Soluble lysosomal proteins

    • C. 

      Vacuolar enzymes

    • D. 

      Proteins of the extracellular matrix

    • E. 

      All of the above

  • 44. 
    Which of the following are pathways of vesicle trafficking through the cytoplasm that have been discovered?
    • A. 

      Biosynthetic pathway

    • B. 

      Secretory pathway

    • C. 

      Endocytic pathway

    • D. 

      Hydrolytic pathway

    • E. 

      A, b and c

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