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Bch211 - Exam 2

46 Questions
Bch211 - Exam 2

Study for final

Questions and Answers
  • 1. 
    True or false:  Enzymes, being proteins, are sensitive to temperature and will be denatured by high temperatures.
    • A. 

      True

    • B. 

      False

  • 2. 
    True or false:  Energy is generally consumed during anabolism
    • A. 

      True

    • B. 

      False

  • 3. 
    True or false:  Aspirin acts as an reversible inhibitor of the COX 2 enzyme
    • A. 

      True

    • B. 

      False

  • 4. 
    Which of the following is a common function of many vitamins in the body?
    • A. 

      Substrates

    • B. 

      Activators

    • C. 

      Apoenzymes

    • D. 

      Coenzymes

  • 5. 
    The following structure is shown in 
    • A. 

      A D form

    • B. 

      Neither D nor L

    • C. 

      Both D and L

    • D. 

      An L form

  • 6. 
    The following represents the results of an experiment on a metabolic enzyme.  What is the optimum pH of this enzyme?
    • A. 

      5.5

    • B. 

      6.5

    • C. 

      9.5

    • D. 

      3.0

  • 7. 
    A metal ion required for enzyme activity is called
    • A. 

      Proenzyme

    • B. 

      A zymogen

    • C. 

      A cofactor

    • D. 

      A substrate

  • 8. 
    Sugars which contain an aldehyde group that can be oxidized are called
    • A. 

      Glycosides

    • B. 

      Simple sugars

    • C. 

      Reducing sugars

    • D. 

      Oxidizing sugars

  • 9. 
    The cyclic form of glucose results from the formation of
    • A. 

      A hemiacetal

    • B. 

      An acetal

    • C. 

      An amide

    • D. 

      An ester

  • 10. 
    The carbohydrate below may be classified as
    • A. 

      A ketohexose

    • B. 

      An aldopentose

    • C. 

      A ketopentose

    • D. 

      An aldohexose

  • 11. 
    The conditions required for maximum enzyme function are called:
    • A. 

      Optimum conditions

    • B. 

      Low pressure, high temperature

    • C. 

      Room conditions

    • D. 

      Standard conditions

  • 12. 
    The synthesis of an enzyme in response to a cellular need is called
    • A. 

      Allosteric production

    • B. 

      Feedback control

    • C. 

      Biofeedback

    • D. 

      Enzyme induction

  • 13. 
    The following compounds are enantiomers of each other
    • A. 

      Option 1

    • B. 

      Option 2

    • C. 

      Option 3

    • D. 

      Option 4

  • 14. 
    A monosaccharide used to form nucleic acids is
    • A. 

      Ribose

    • B. 

      Maltose

    • C. 

      Galactose

    • D. 

      Glucose

  • 15. 
    Which of the following terms can be used correctly to fill the blank in the following equation?  
    • A. 

      Zymogen

    • B. 

      Cofactor

    • C. 

      Substrate

    • D. 

      Isozyme

  • 16. 
    1. Lineweaver Burke - If everything else has a higher slope, anything lower than it represents the activation space.  everything above it represents the inhibition space
    Gibbs free energy  delta G(negative - ) = spontaneous delta G(positive +) = nonspontaneous
    • A. 

      Option 1

    • B. 

      Option 2

    • C. 

      Option 3

    • D. 

      Option 4

  • 17. 
    Which form of monosaccharides is preferred by human cells?
    • A. 

      Both D and L

    • B. 

      D

    • C. 

      L

    • D. 

      Neither D nor L

  • 18. 
    Refer to Exhibit 6A.  "Hindrate" is an inhibitor of triose phosphate isomerase.  When it is added to cells at a concentration of 0.1 nM, the enzyme's Km for the substrate is unchanged, but the apparent Vmax is altered to 50nM/sec. 
    • A. 

      This is an uncompetitive inhibitor

    • B. 

      This is a noncompetitive inhibitor

    • C. 

      This is a competitive inhibitor

    • D. 

      This is an irreversible inhibitor

  • 19. 
    The structure below is shown in what anomeric form?
    • A. 

      B (beta)

    • B. 

      Cis

    • C. 

      Trans

    • D. 

      Alpha

  • 20. 
    A short description of a diastereomer would be?
    • A. 

      Diastereomers are those compounds that can only have 6 chiral carbons

    • B. 

      Diastereomers are all of the isomers for compounds that can have two or more chiral centers

    • C. 

      Diastereomers are isomers that only have 1 chiral center.

    • D. 

      Diastereomers are isomers that are mirror images of the other

  • 21. 
    Which of the following is correctly called a complex carbohydrate?
    • A. 

      Starch

    • B. 

      Sucrose

    • C. 

      Fructose

    • D. 

      Lactose

  • 22. 
    If an inhibitor changes the slope of the Lineweaver-Burk graph, but not the x-intercept, it is this type of inhibition:
    • A. 

      You cannot tell from the data given

    • B. 

      Competetive

    • C. 

      Irreversible inhibition

    • D. 

      Non-competitive

    • E. 

      More than one answer is correct

  • 23. 
    Draw the structure of B-D-Lactose in the Hawarth projection
    • A. 

      Is this a reducing sugar? (YES)

    • B. 

      1 pt for placing the beta structure

    • C. 

      1 pt for the glycosidic linkage

    • D. 

      2 pts for each sugar

  • 24. 
    Which of the following is true of a noncompetitive inhibitor?
    • A. 

      Resembles the substrate

    • B. 

      Binds at a site other than the active site

    • C. 

      Reduces Km

    • D. 

      Increases Vmax

  • 25. 
    Which of the following terms is a general definition of an enzyme?
    • A. 

      A catalyst

    • B. 

      An activator

    • C. 

      A carbohydrate

    • D. 

      A lipid

  • 26. 
    Structurally, glycogen is most similar to 
    • A. 

      Sucrose

    • B. 

      Amylopectin

    • C. 

      Amylose

    • D. 

      Cellulose

  • 27. 
    Which of the following enzyme properties is explained by the lock-and-key model?
    • A. 

      High molecular weight

    • B. 

      Specificity

    • C. 

      Susceptibility to denaturation

    • D. 

      High turnover rate

  • 28. 
    The simplest carbohydrates are called
    • A. 

      Polysaccharides

    • B. 

      Oligosaccharides

    • C. 

      Disaccharides

    • D. 

      Monosaccharides

  • 29. 
    Under saturation conditions, an enzyme-catalyzed reaction had a velocity V.  Which of the following would increase the rate of the reaction?
    • A. 

      A decrease in enzyme concentration

    • B. 

      A decrease in substrate concentration

    • C. 

      An increase in enzyme concentration

    • D. 

      An increase in substrate concentration

  • 30. 
    The region of an enzyme where the substrate molecule fits is called the
    • A. 

      Substrate site

    • B. 

      Primary site

    • C. 

      Active site

    • D. 

      Substrate bond

  • 31. 
    21000 molecules were acted on by a single molecule of an enzyme in 15 minutes.  What is the turnover number?
    • A. 

      23

    • B. 

      84000

    • C. 

      480

    • D. 

      1400

  • 32. 
    A Lineweaver-Burk plot is useful in the analysis of enzymatic reactions because
    • A. 

      It is easier to see whether points deviate from a straight line than from a curve

    • B. 

      It is not affected by the presence of inhibitors

    • C. 

      It can be used whether or not the enzyme displays Michaelis-Menten kinetics

    • D. 

      It can work with allosteric enzymes

  • 33. 
    In the induced-fit model of substrate binding to enzymes
    • A. 

      The active site changes its conformation to fit the transition state.

    • B. 

      The substrate changes its conformation to fit the active site.

    • C. 

      The active site changes its conformation to fit the product.

    • D. 

      The active site changes its conformation to fit the substrate.

  • 34. 
    Competitive inhibitors have this effect:
    • A. 

      Changing the value for Vmax

    • B. 

      This type of inhibitor both changes the Km and interferes with substrate binding

    • C. 

      Modifying the Km value

    • D. 

      Interfering with substrate binding

    • E. 

      All of these are correct

  • 35. 
    The value of Vmax changes in 
    • A. 

      Competitive inhibition

    • B. 

      Noncompetitive inhibition

    • C. 

      Neither form of inhibition

    • D. 

      Both forms of inhibition

  • 36. 
    What happens to the entropy when ATP is hydrolyzed to ADP?
    • A. 

      Entropy doesn't change.

    • B. 

      ATP has no entropy.

    • C. 

      Entropy increases.

    • D. 

      Entropy decreases.

  • 37. 
    A polysaccharide containing B(14) linkages is
    • A. 

      Glycogen

    • B. 

      Amylopectin

    • C. 

      Amylose

    • D. 

      Cellulose

  • 38. 
    The structure given below has what type of glycosidic linkage?
    • A. 

      A (1-4)

    • B. 

      B (1-4)

    • C. 

      B (1-6)

    • D. 

      A (1-6)

  • 39. 
    Which of the following inhibitors binds to the enzyme at a site other than the active site?
    • A. 

      Irreversible inhibitor

    • B. 

      Noncompetitive inhibitor

    • C. 

      Competitive inhibitor

    • D. 

      All of these

    • E. 

      Non of these

  • 40. 
    Which statement about enzymes is incorrect?
    • A. 

      Enzymes can produce a reaction transition state with a reduced activation energy.

    • B. 

      There are enzymes that interact with one enantiomer, but not the other.

    • C. 

      Enzymes are not used up during the reaction in which they are involved

    • D. 

      Enzymes can reduce the net energy of a reaction

  • 41. 
    The sign of Gibb's Free Energy is positive ("+") when energy is released
    • A. 

      True

    • B. 

      False

  • 42. 
    If the reaction AB has G = +15 Joule/mol and the reaction BC has G = -25 Joule/mol, the overall energy change AC will be  
    • A. 

      -40 Joule/mol

    • B. 

      -15 Joule/mol

    • C. 

      -10 Joule/mol

    • D. 

      -2540 Joule/mol

    • E. 

      You cannot tell from the given data

  • 43. 
    If the y-intercept of a Lineweaver-Burk plot = 1.91 (sec/millimole) and the slope = 75.3L/sec, Km equals:
    • A. 

      0.0254 millimolar (mM)

    • B. 

      0.523 millimolar (mM)

    • C. 

      5.23 millimolar (mM)

    • D. 

      39.4 millimolar (mM)

    • E. 

      75.3 millimolar (mM)

  • 44. 
    Reactions requiring energy often occur with the simultaneous hydrolysis of
    • A. 

      ATP

    • B. 

      Acetyl CoA

    • C. 

      Glucose

    • D. 

      Pi

  • 45. 
    Which of the following is a disaccharide?
    • A. 

      Sucrose

    • B. 

      Glucose

    • C. 

      Galactose

    • D. 

      Fructose

  • 46. 
    The theory that proposes a somewhat flexible enzyme conformation is the 
    • A. 

      Induced-fit theory

    • B. 

      Physically-fit theory

    • C. 

      Expanding-fit theory

    • D. 

      Lock-and-key theory

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