Biochemistry Final

47 Questions

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Biochemistry Quizzes & Trivia

Review for final


Questions and Answers
  • 1. 
    In mitochondria, ATP is made by a proton gradient passing through ATP synthase from one compartment to another. If pressure and volume are constant and no heat is exchanged in the process, what type of energy was used to drive the reaction?
    • A. 

      Enthalpy

    • B. 

      Entropy

    • C. 

      Free energy

    • D. 

      Internal energy

  • 2. 
    During muscular exercise the intracellular pH may decrease by one pH unit. As a result of this change the phosphoryl group transfer potential of ATP will:
    • A. 

      Increase

    • B. 

      Decrease

    • C. 

      Remain unchanged due to H+ binding

    • D. 

      Remain unchanged due to Mg++ binding

  • 3. 
    For a reaction at equlibrium the following is true:
    • A. 

      H=TS

    • B. 

      H>TS

    • C. 

      H

    • D. 

      S=0

    • E. 

      All of the above

  • 4. 
    The fact that all cells have the same 10 steps of glycolysis, but with different enzymatic rates suggests that glycolysis
    • A. 

      Has adapted to different conditions

    • B. 

      Is not as important as it used to be

    • C. 

      Is being replaced by aerobic respiration

    • D. 

      None of the above

  • 5. 
    Organisms that acquire energy from redox reactions and carbon form organic compounds are
    • A. 

      Photoautotrophs

    • B. 

      Chemoautotrophs

    • C. 

      Photoheterotrophs

    • D. 

      Chemoheterotrophs

  • 6. 
    In general, metabolic pathways that are non central for life are
    • A. 

      Diverse

    • B. 

      Aerobic

    • C. 

      Conserved

    • D. 

      Anaerobic

  • 7. 
    The substrates for anabolism are?
    • A. 

      ADP and ATP

    • B. 

      ATP and NADPH

    • C. 

      NAD+ and NADP+

    • D. 

      ATP and NADH

  • 8. 
    The products of catabolism are?
    • A. 

      CO2 plus H2O

    • B. 

      Aminoacids, monosaccharides, fatty acid

    • C. 

      CO2, NH3 and H2O

    • D. 

      Light, CO2 and water

  • 9. 
    Which vitamin is the active component of FAD?
    • A. 

      Thiamine

    • B. 

      Riboflavin

    • C. 

      Panthotenic acid

    • D. 

      Lipoic acid

  • 10. 
    In the first phase of glycolysis, each glucose that enters is broken down to:
    • A. 

      Two molecules of dihydroxyacetone phosphate

    • B. 

      Two molecules of glycerate-3-phosphate

    • C. 

      Two molecules of fructose-1,6-bisphos- phate.

    • D. 

      Dihydroxyacetone phosphate and glycer- aldehyde-3-phosphate

  • 11. 
    The decarboxylation of of pyruvate followed by NADH reduction of the product produces?
    • A. 

      Lactate

    • B. 

      AcCpa

    • C. 

      PEP

    • D. 

      Ethanol

  • 12. 
    Your mM concentration of glucose assuming that you have 5L of blood? MM glucose = 180g/mol If you had an hypoglycemia episode and your blood glucose drops to 50mg/dL, what is
    • A. 

      .55

    • B. 

      2.77

    • C. 

      4

    • D. 

      3

  • 13. 
    One of these is a specific effector of phosphofructokinase
    • A. 

      Citrate

    • B. 

      ATP

    • C. 

      F-2,6-biphosphate

    • D. 

      F-6-phosphate

  • 14. 
    Which enzyme catalyzes substrate-level phosphorylation?
    • A. 

      Phosphofructokinase

    • B. 

      Phosphoglycerate kinase

    • C. 

      Glyceraldehyde

    • D. 

      Phosphoglycerate mutase

  • 15. 
    Glycolysis in eukarytes occurs in the 
    • A. 

      Cytosol

    • B. 

      Mitochondrial

    • C. 

      Cell membrane

    • D. 

      Glyoxysome

  • 16. 
    The final reaction of in glycolysis under anaerobic conditions produces
    • A. 

      Lactate

    • B. 

      Pyruvate

    • C. 

      Acetyl CoA

    • D. 

      Asparate

  • 17. 
    The product of the pyruvate dehydrogenase enzyme is
    • A. 

      Pyruvate

    • B. 

      Phosphoenolpyruvate

    • C. 

      AcetylCoA

    • D. 

      Oxaloacetate

  • 18. 
    The isomerization of citrate to isocitrate occurs because
    • A. 

      Secondary alcohol is easier to oxidize than a tertiary one

    • B. 

      A tertiary alcohol has more steric strain than the secondary one

    • C. 

      Enzyme is assymetric

    • D. 

      Oxidation of the secondary alcohol releases more energy than a tertiary one

  • 19. 
    This enzyme is activated by ADP 
    • A. 

      Fumarase

    • B. 

      Succinyl synthetase

    • C. 

      Isocitrate dehydrogenase

    • D. 

      Pyruvate synthase

  • 20. 
    An enzyme that has the same mechanism is 
    • A. 

      The succinyl dehydrogenase

    • B. 

      Pyruvate dehydrogenase mechanism

    • C. 

      Isocitrate dehydrogenase mechanism

    • D. 

      Alpha ketoglutarase dehydrogenase

  • 21. 
    In order to have AcCoA in the cytosol
    • A. 

      Citrate is exported from the mitochondria and converted to AcCoA

    • B. 

      Malate is exported from the mitochondria and then converted

    • C. 

      Pyruvate is converted into AcCoA in the cytosol

    • D. 

      AcCoA is exported from the mitochondria

  • 22. 
    ATP synthase in mitochondria is located on
    • A. 

      Cytoplasm

    • B. 

      The mitochondrial inner membrane space

    • C. 

      The mitochondrial inner membrane

    • D. 

      Matrix

  • 23. 
    What molecule is the best oxidant?
    • A. 

      A-ketoglutarate

    • B. 

      Succinate

    • C. 

      Fumarate

    • D. 

      Oxaloacetate

  • 24. 
    What molecule can reduce oxaloacetate under standard state conditions?
    • A. 

      A-ketoglutarate

    • B. 

      Succinate

    • C. 

      Fumarate

    • D. 

      Both a and b

  • 25. 
     Calculate the E0’ value for the overall reaction of the oxidation of NADH by molecular oxygen. The relevant half reactions and their corresponding standard reduction potentials are given below.
    • A. 

      1.14

    • B. 

      -1.14

    • C. 

      .50

    • D. 

      -.5

  • 26. 
    The final electron acceptor in the electron transport chain is
    • A. 

      Molecular O2

    • B. 

      H2o

    • C. 

      Cytochrome c

    • D. 

      Ubiquinone

  • 27. 
    In comparing the outer and the inner membranes in the mitochondrion, which statement is incorrect about the inner membrane?
    • A. 

      A. It is enriched in acidic phospholipids such as diphosphatidyl- glycerol (cardiolipin).

    • B. 

      Its phospholipids are enriched in unsaturated fatty acids.

    • C. 

      It has a higher lipid to protein ratio.

    • D. 

      More highly folded

  • 28. 
    A species in the electron transport chain which can participate in a two-electron transfer is
    • A. 

      Cytochrome

    • B. 

      Protein bound copper

    • C. 

      Ubiquinone

    • D. 

      Iron sulfur proteins

  • 29. 
    The complex in the electron transport chain which does not have a direct link to ubiquinone in some form is
    • A. 

      IV

    • B. 

      II

    • C. 

      III

    • D. 

      I

  • 30. 
    The species below which is a mobile electron carrier in the electron transport chain is
    • A. 

      FMN

    • B. 

      FeS protein

    • C. 

      Cytochrome c

    • D. 

      Cytochrome bcL-complex

  • 31. 
    The complete reduction of one molecule of oxygen gas requires how many electrons?
    • A. 

      1

    • B. 

      2

    • C. 

      4

    • D. 

      6

  • 32. 
    Another name for complex II in the electron transport chain is
    • A. 

      Cytochrome c oxidase

    • B. 

      Succinate CoQ reductase

    • C. 

      NADH-CoQ reductase

    • D. 

      Cytochrome bcL complex

  • 33. 
    Which of the following is an inhibitor of ATP synthase?
    • A. 

      Rotenone

    • B. 

      Oligomycin

    • C. 

      Antimycin

    • D. 

      Azide

  • 34. 
    33. Which statement is true about adipose cell lipase?  
    • A. 

      A. It is another name for lipoprotein lipase.

    • B. 

      B. It becomes activated as the cellular concentration of cAMP increases.

    • C. 

      C. It is allosterically inhibited by the binding of malonyl CoA.

    • D. 

      D. It is allosterically activated by the binding of citrate.

  • 35. 
    How many NAD+ are reduced in the degradation of palmitoyl-CoA to  form eight molecules of acetylCoA ?
    • A. 

      1

    • B. 

      7

    • C. 

      9

    • D. 

      18

  • 36. 
    What are the three most common ketone bodies?
    • A. 

      Acetone, butyric acid, and acetyl-CoA

    • B. 

      Acetoacetate, hydroxyacetone phosphate, and butyric acid

    • C. 

      Acetone, á-hydroxybutyric acid, and acetoacetate

    • D. 

      Acetoacetate, acetyl-CoA, and acetone

  • 37. 
    For the complete oxidation of a saturated fatty acid with 18 carbons, how many times must the β -oxidation cycle be repeated?
    • A. 

      1

    • B. 

      8

    • C. 

      9

    • D. 

      18

  • 38. 
    The first oxidation in the β -oxidation of saturated fatty acids, catalyzed by acyl-CoA dehydrogenase, is the conversion of
    • A. 

      A primary alcohol to an aldehyde

    • B. 

      a secondary alcohol to a ketone

    • C. 

      A saturated to an unsaturated carbon-carbon bond

    • D. 

      An aldehyde to a carboxylic acid

  • 39. 
    Long chain fatty acids are transported across the inner mitochondrial membrane. Which statement is incorrect about this process?
    • A. 

      The fatty acids are covalently attached to coenzyme A when they pass through the membrane.

    • B. 

      Their transport would be best characterized as a facilitated diffusion.

    • C. 

      They tend to be transported less as the concentration of malonyl-CoA increases in the cytoplasm.

    • D. 

      It involves the transfer of a fatty acid from CoA to carnitine prior to the transport step.

  • 40. 
    The first three reactions in the β -oxidation of saturated fatty acids produce
    • A. 

      2 moles of NADH

    • B. 

      2 moles of FADH2

    • C. 

      2 moles of ATP

    • D. 

      1 mole of both NADH and FADH2

  • 41. 
    The function of carnitine acyltransferase II is to
    • A. 

      provide an inner membrane channel for the transport of acylcarnitine

    • B. 

      catalyze the formation of acylcarnitine

    • C. 

      catalyze the conversion of acylcarnitine to acyl-CoA and carnitine

    • D. 

      transfer carnitine to acyl-CoA

  • 42. 
    Which statement is  incorrect concerning the activation of a fatty acid (attachment of a fatty acid to CoA)? 
    • A. 

      It involves the formation of a high energy thioester bond.

    • B. 

      Activation is accompanied also by the hydrolysis of ATP to ADP + Pi.

    • C. 

      . An acyl-adenylate intermediate is formed.

    • D. 

      Hydrolysis of ATP produces AMP and PPi, with the further hydrolysis of PPi to drive this reaction to completion.

  • 43. 
    Where in the cell are long chain fatty acids condensed with coenzyme A to form acyl-CoA?
    • A. 

      Mitochondrial matrix

    • B. 

      Cytoplasm

    • C. 

      Out membrane of mitochondria

    • D. 

      Inner membrane of mitochondria

  • 44. 
    What would be the last product to be released from the β -oxidation of  CH3(CH2)13•-COO- H ?
    • A. 

      benzoyl-CoA

    • B. 

      phenylacetyl-CoA

    • C. 

      phenyl-CoA

    • D. 

      propionyl-CoA

  • 45. 
    . A characteristic of the glycerolphosphate shuttle is
    • A. 

      It shuttles NADH across the mitochondrial membrane to yield 2.5 ATP/NADH.

    • B. 

      It shuttles "NADH electron equivalents" across the mitochondrial membrane to yield 1.5 ATP/NADH.

    • C. 

      Malate is a key component in the shuttle process.

    • D. 

      It only operates efficiently when the [NADH] in the cytoplasm is higher than in the matrix.

  • 46. 
    Which of the following molecules is least likely to be transported across the inner mitochondrial                                     membrane?
    • A. 

      Citrate

    • B. 

      NADH

    • C. 

      Pyruvate

    • D. 

      Phosphate

  • 47. 
    • A. 

      The elimination of 2-C units at each step

    • B. 

      β -oxidation occurs in the mitochondrial matrix

    • C. 

      β -oxidation is quantitatively the primary route to degradation

    • D. 

      β -oxidation is initiated at the methyl end of the fatty acid