Quick Biochemistry - Enzymes (Section 11)

  • 1
    The 'Lock and Key' model of enzyme action was theorized by
    Sagot
    (B)
    Fischer
  • 2
    Which of the following is a component of a coenzyme?
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    (C)
    Vitamin B2
  • 3
    The structure of an enzyme, and its resulting function, can be temporarily modified by
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    (C)
    Allosteric regulators
  • 4
    Which of the following control mechanisms utilizes a reversible covalent adjustment to the enzyme?
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    (A)
    Phosphorylation of ser-OH on the enzyme
  • 5
    An enzyme is typically a
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    (C)
    Protein
  • 6
    An enzyme facilitates a chemical reaction by
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    (A)
    Decreasing the required energy for activation
  • 7
    In most metabolic sequences, all necessary enzymes are organized within a
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    (B)
    Membrane
  • 8
    An enzyme that transforms an aldose sugar into a ketose sugar would be categorized as a
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    (B)
    Isomerases
  • 9
    The primary role of an enzyme is to
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    (B)
    Alter the speed of chemical reactions
  • 10
    In which type of enzyme reaction might water be added to a C-C double bond without breaking the bond?
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    (A)
    Hydrolase
  • 11
    How do enzymes affect reaction rates?
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    (B)
    By lowering the activation energy
  • 12
    What part of an enzyme is directly involved in substrate binding?
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    (A)
    The amino acid R groups
  • 13
    What structural characteristic do allosteric enzymes possess?
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    (A)
    Multiple protein subunits
  • 14
    Which conditions can be identified using isoenzymes of lactate dehydrogenase?
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    (D)
    Both heart and liver issues
  • 15
    How many main categories of enzymes did the IUB classify?
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    (A)
    Six
  • 16
    Which enzyme was the first to be isolated, purified, and crystallized from Jack bean (Canavalia) in 1926?
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    (A)
    Urease
  • 17
    Who proposed that enzymes are composed of protein?
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    (C)
    Sumner
  • 18
    Which factor regulates feedback inhibition of enzyme activity?
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    (C)
    The end products of the reaction
  • 19
    What enzyme catalyzes the conversion of glucose to glucose-6-phosphate?
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    (B)
    Hexokinase
  • 20
    Why are enzymes needed in small amounts?
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    (D)
    All of the above are correct
  • 21
    What term describes an organic molecule that binds to an enzyme and is crucial for its function?
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    (C)
    Coenzyme
  • 22
    The duration of enzyme-catalyzed reactions is typically measured in
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    (C)
    Milli seconds
  • 23
    Enzymes can speed up a reaction by a factor of up to
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    (A)
    1010 times
  • 24
    Where within a plant are enzymes found?
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    (C)
    All living cells
  • 25
    What is a zymogen?
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    (B)
    Enzyme precursor
  • 26
    Within a holoenzyme, what describes a cofactor (prosthetic group)?
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    (B)
    Accessory non-protein substance attached firmly
  • 27
    Which protein exhibits both structural and enzymatic properties?
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    (A)
    Myosin
  • 28
    In what way do enzymes differ from other catalysts?
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    (A)
    Being proteinaceous
  • 29
    What common characteristic unites enzymes, vitamins, and hormones?
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    (D)
    Regulating metabolism
  • 30
    Why do dry seeds withstand higher temperatures compared to germinating seeds?
    Sagot
    (A)
    Hydration is essential for making enzymes sensitive to temperature
  • 31
    From which vitamin are the coenzymes FMN and FAD derived?
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    (D)
    Vitamin B2
  • 32
    Which observation supports the template/lock and key model of enzyme action?
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    (D)
    Substances similar to the substrate hinder enzyme activity
  • 33
    What is formed when an apoenzyme combines with a coenzyme?
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    (B)
    Holoenzyme
  • 34
    What type of enzyme inhibition occurs when a substance, similar in structure to the substrate, binds to the enzyme?
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    (A)
    Competitive inhibition
  • 35
    What is the effect of an enzyme on a chemical reaction?
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    (D)
    Reduced activation energy
  • 36
    Which factor regulates feedback inhibition of an enzyme?
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    (C)
    The end product of the reaction
  • 37
    What is a coenzyme typically composed of?
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    (A)
    Frequently a vitamin
  • 38
    Which enzyme is essential for genetic engineering techniques?
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    (D)
    Restriction endonuclease
  • 39
    Which statement does NOT accurately describe a characteristic of inorganic catalysts compared to enzymes?
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    (B)
    Inorganic catalysts require specific conditions that enzymes do not
  • 40
    Who proposed the lock and key model of enzyme action?
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    (A)
    Fischer
  • 41
    In a biochemical pathway, what process exemplifies feedback inhibition?
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    (A)
    How does glucose-6-phosphate affect hexokinase activity?
  • 42
    In the context of enzyme kinetics, what does the term 'feedback' primarily describe?
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    (B)
    How the end product influences the rate of a reaction
  • 43
    What is the primary function of allosteric inhibition?
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    (C)
    Both of the above
  • 44
    In certain enzymatic reactions, what is the smallest possible ratio of enzyme molecules to substrate molecules?
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    (A)
    1:100,000
  • 45
    Which coenzyme includes Vitamin B?
    Sagot
    (D)
    FMN/FAD
  • 46
    In enzyme kinetics, what substrate concentration is associated with the K value?
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    (D)
    4 Vmax
  • 47
    In an enzyme, which part combines with a non-protein component to create a functional enzyme?
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    (C)
    Prosthetic group
  • 48
    Which scientist was awarded a Nobel Prize in 1978 for their contributions to the field of enzymes?
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    (A)
    Koshland
  • 49
    In a cell, where does the synthesis of enzymes primarily occur?
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    (B)
    RER
  • 50
    Why does fruit left out in the open become bitter after a couple of hours?
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    (D)
    Due to contamination by bacterial enzymes