Quiz 2

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Skitty2004
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295073
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Quiz 2
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2015-02-06 13:09:47
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  1. ATP synthesis in mitochondrion is driven by energy produced in electron
    transport pathway. And this energy is stored in the form of ________. ATP synthesized in this process is called _____ hosphorylation.
    ATP produced in TCA cycle is called ______ phosphorylation.
    • proton gradient
    • oxidative
    • substrate level
  2. Which of the following step does NOT produce NADH?
    Succinate ----> fumarate
  3. All the enzymes in the TCA cycle are water soluble and located in the matrix
    of mitochondrion. True or False.
    False
  4. Pyruvate dehydrogenase is regulated by which covalent modification?
    phosphorylation
  5. The precise mechanism of NADH-UQ reductase is unknown, but the electron
    transport involves...
    FMN
  6. Which complex is not coupled with proton translocation in electron
    transport pathway _______.
    Compex II
  7. The components of electron transport chain include two mobile electron
    carriers, a lipid-soluble molecule _________ and a water-soluble protein __________.
    • UQ
    • Cytochrome c
  8. Which of the following enzyme is not allosterically inhibited by high level of
    NADH?
    Pyruvate carboxylase
  9. Please write down the coenzymes involved in the reaction: pyruvate -------> acetyl-CoA.
    FAD, CoA, Liopic Acid, TPP,NAD+/NADH
  10. The terminal electron acceptor in eukaryotic aerobes is _______.
    O2 (oxygen)
  11. If the F0 unit of ATP synthase has the stoichiometry of a1b2c12, How many
    degrees of rotation of one of the c subunits relative to the a subunit occur
    with each proton transferred to the matrix?
    30
  12. Which enzyme in the citric acid cycle proceeds by a similar mechanism and
    with similar cofactors as pyruvate dehydrogenase?
    α-Ketoglutarate dehydrogenase
  13. Q cycle is a unique redox pathway in ______.
    Cytochrome bc1
  14. Which complex of the electron transport chain does not contain a
    cytochrome?
    NADH-Coenzyme Q reductase
  15. The electron transfer in complex IV is from cytochrome c to _____ to
    heme a, then to ________ and in the end to O2.
    • CuA
    • Heme a3/CuB
  16. The energy-requiring step of ATP synthesis in ATP synthase is the release of ATP. True or False.
    True
  17. Electron transport causes the proton translocation of protons across the
    inner membrane of mitochondria. What compartment has a lower pH?
    intermembrane space
  18. The glycerophsophate shuttle and ________ shuttle feed the electrons from _______ into electron transport in mitochondrion.
    • malate-aspartate
    • NADH produced from glycolysis in cytosol
  19. In your own words, please describe the purpose of TCA cycle in two or three
    sentences. Please be brief and you don’t have to go into details of the
    reactions
    To oxidize Acetyl-CoA into CO2 and release the energy in the form of NADH
  20. Please draw the pathway how the electrons from NADH are transferred to
    O2. Write down the full names of the complexes.
    NADH----> NADH-UQ reductase----> UQ----> UQ-cytochrome c reductase-----> cytochrome c ----> cytochrome c oxidase-----> O2
  21. Please write down the reaction(s) that produces GTP in TCA cycle. Include
    the enzymes (coenzymes) and the structures of the substrates and products.
    And write down an intermediate (structure/name) during catalysis.
  22. For each acetate oxidized, the net outcome of the TCA cycle is...
    two molecules of CO2, one ATP, 3 NADH and one FADH2
  23. Which enzyme in the citric acid cycle catalyzes the reaction that directly produces a high-energy nucleoside triphosphate?
    succinyl-CoA synthetase
  24. Place these substrates in the correct sequence for the TCA cycle.
    a. isocitrate
    b. succinyl-CoA
    c. fumarate
    d. malate
    a, b, c, d
  25. Pyruvate carboxylase catalyzes the most important anaplerotic reaction which is.....
    ATP and biotin-dependent carboxylation of pyruvate to oxaloacetate
  26. Both fumarase and aconitase catalyze the addition of the elements of water across a double bond. This addition is:
    trans
  27. In the isomerization of citrate to isocitrate, the intermediate is:
    cis-aconitate
  28. Which reaction of the TCA cycle catalyzes a substrate-level phosphorylation?
    succinyl-CoA synthetase
  29. Place these enzymes in the correct sequence for the TCA cycle:
    a, c, b, d
  30. The three main regulatory sites in the TCA cycle are:
    citrate synthase, isocitrate dehydrogenase, α-ketoglutarate dehydrogenase
  31. Which of the following is not true concerning citrate synthase?
    the reaction requires an input of energy from ATP
  32. Which enzyme of the TCA cycle is an integral membrane protein?
    succinate dehydrogenase
  33. Pyruvate dehydrogenase (PDH) is regulated by covalent modification. The PDH kinase phosphorylates and inactivates PDH. The PDH kinase is allosterically activated by a low:
    NAD/NADH ratio
  34. Which of the following enzymes catalyzes an anaplerotic reaction for the TCA cycle?
    • pyruvate carboxylase
    • PEP carboxylase
    • malic enzyme
    • (All of the Above)
  35. The oxidative decarboxylation of pyruvate to acetyl-CoA is catalyzed by:
    pyruvate dehydrogenase complex
  36. Which enzyme in the citric acid cycle proceeds by a similar mechanism and with similar cofactors as pyruvate dehydrogenase?
    α-ketoglutarate dehydrogenase
  37. The succinate dehydrogenase reaction is stereospecific. The mechanism involves the removal of:
    the pro-S hydrogen of one carbon and the pro-R hydrogen of the other carbon
  38. The essential feature of thiamine pyrophosphate chemistry is:
    a cationic imine N that acts as an electron sink
  39. The chemiosmotic coupling hypothesis proposed by Peter Mitchell states that:
    electron transport drives protons across the inner mitochondrial membrane from the matrix to the intermembrane space.
  40. The flow of electrons through complex IV is:
    cyto c to CuA to cyto a to cyto a3-CuB to O2
  41. Which of the following electron carriers is the most mobile?
    Ubiquinone
  42. Which of the following is not an inhibitor of complex I, II, or III?
    oligomycin
  43. Which of the following electron carriers participates in both one and two electron transfers?
    coenzyme Q
  44. The malate –aspartate shuttle transfers 2e- from:
    • -mitochondrial NADH to cytosolic NADH
    • -cytosolic NADH to mitochondrial NADH
    • -cytosolic malate to mitochondrial malate
    • (All of the Above)
  45. Which of the following cytochromes of the electron transport chain is NOT tightly bound to an integral membrane protein?
    C
  46. Oligomycin is a macrocyclic antibiotic that inhibits oxidative phosphorylation. It....
    inhibits proton flow by binding to the Fo unit of ATP synthase
  47. Proton transfer through the Fo subunit of ATP synthase causes a:
    T to O conformational change of a β-subunit with release of ATP
  48. Where are most of the processes of electron transport and oxidative phosphorylation localized in eukaryotes?
    inner mitochondrial membrane
  49. In EACH of the two steps of the Q-cycle, when fully reduced coenzyme Q, QH2, is re-oxidized by complex III:
    a. one e- is transferred to cytochrome c1
    b. one e- is transferred to the bL heme
    c. two H+ are released on the cytosolic side of the membrane
    d. one H+ is taken up on the matrix side of the membrane
    e. one e- is transferred from the Qp site on the matrix side to the Qn site on the cytosolic side of the membrane
    a, b, c
  50. If the Fo unit of ATP synthase has the stoichiometry of a1b2c9, how many degrees of rotation of one of the c subunits relative to the α subunit occur with each proton transferred to the matrix?
    40
  51. Which of the following is true about the flavoprotein complexes?
    a. they are all sites where protons are transferred across the inner mitochondrial membrane
    b. they all contain FMN
    c. they all contain FAD
    d. they all contain Fe-S centers
    e. they all transfer electrons to UQ
    d and e only
  52. Which of the following are true?
    a. the glycerophosphate shuttle and the malate-aspartate shuttle yield the same number of ATP's starting from NADH in the cytosol
    b. the glycerophosphate shuttle yields the same number of ATP's per 2 electrons donated as complex II of the electron transport chain
    c. the malate-aspartate shuttle is more energy efficient than the glycerophosphate shuttle
    d. the glycerophosphate shuttle can donate electrons to the electron transport chain even when the cytosolic [NADH] is low
    e. the malate-aspartate shuttle is essentially irreversible
    b, c, and d
  53. The terminal electron acceptor in eukaryotic aerobes is:
    molecular oxygen
  54. Which complex of the electron transport chain does not contain a cytochrome?
    NADH-coenzyme Q reductase
  55. Dinitrophenol, a hydrophobic weak acid with a pKa of 9, is an uncoupler of oxidative phosphorylation. It:
    collapses the proton gradient
  56. Which of the following is a mobile, lipid-soluble electron carrier found in the inner mitochondrial membrane?
    coenzyme Q

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