Quick Biochemistry - Enzymes (Section 1)

  • 1
    Which compound exhibits the lowest density among the following?
    إجابة
    (A)
    Chylomicron
  • 2
    What enzyme's activity is inhibited by non-steroidal anti-inflammatory drugs like aspirin?
    إجابة
    (B)
    Cyclooxygenase
  • 3
    What enzyme catalyzes the synthesis of prostaglandins from arachidonate?
    إجابة
    (A)
    Cyclooxygenase
  • 4
    What best describes a Holoenzyme?
    إجابة
    (D)
    All of these
  • 5
    Which enzyme deficiency is associated with Gaucher's disease?
    إجابة
    (C)
    ẞ-Glucosidase
  • 6
    What enzyme deficiency is the cause of Neimann-Pick disease?
    إجابة
    (D)
    Sphingomyelinase
  • 7
    Which enzyme is deficient in Krabbe's disease?
    إجابة
    (C)
    ẞ-Galactosidase
  • 8
    Fabry's disease results from a deficiency of which enzyme?
    إجابة
    (A)
    Ceramide trihexosidase
  • 9
    Farber's disease is caused by a deficiency in which enzyme?
    إجابة
    (B)
    Ceramidase
  • 10
    Which synthetic nucleotide analogue is used to prevent immunologic rejection in organ transplantation?
    إجابة
    (D)
    6-Mercaptopurine
  • 11
    Which of the following is an example of an enzyme that functions outside of a cell?
    إجابة
    (C)
    Pancreatic lipase
  • 12
    What term describes enzymes that are produced in an inactive state within living cells?
    إجابة
    (D)
    Proenzymes
  • 13
    Which of the following enzymes is classified as a ligase?
    إجابة
    (A)
    Succinate thiokinase
  • 14
    Which enzyme listed is an example of a lyase?
    إجابة
    (B)
    Fumarase
  • 15
    Covalent modification of which amino acid often regulates enzyme activity?
    إجابة
    (D)
    Serine
  • 16
    What type of enzyme catalyzes the addition or removal of water across a carbon-carbon double bond without breaking the bond?
    إجابة
    (A)
    Hydratase
  • 17
    According to the 'lock and key' model of enzyme action, what is the relationship between the enzyme's active site and the substrate?
    إجابة
    (B)
    The active site is complementary in shape to that of substance
  • 18
    In the Lineweaver-Burk plot based on the Michaelis-Menten equation, how are the substrate concentrations typically represented on the x-axis?
    إجابة
    (C)
    1/S
  • 19
    A sigmoidal curve when plotting substrate concentration against reaction velocity is suggestive of what type of enzyme behavior?
    إجابة
    (B)
    Co-operative binding
  • 20
    Determine the K value of the enzyme giving the kinetic data as below.
    إجابة
    (D)
    +0.33
  • 21
    What impact does a purely competitive inhibitor have on an enzyme's kinetic properties?
    إجابة
    (A)
    Raises the Km without changing the Vmax
  • 22
    If a graph illustrates an enzymatic reaction without inhibition (curve X), which curve would represent competitive inhibition of the same reaction?
    إجابة
    (A)
    A
  • 23
    What type of enzyme typically does not require an inducer?
    إجابة
    (B)
    Constitutive enzyme
  • 24
    In which type of enzyme is a measurable inducer typically absent?
    إجابة
    (B)
    Constitutive enzyme
  • 25
    What is the outcome of reversible non-competitive enzyme inhibition?
    إجابة
    (D)
    The concentration of the active enzyme is lowered
  • 26
    Regarding reversible non-competitive enzyme activity inhibition:
    إجابة
    (B)
    The inhibitor reduces the maximum reaction rate achievable with a specific enzyme amount
  • 27
    What is a characteristic of competitive enzyme activity inhibition?
    إجابة
    (A)
    The inhibitor's structure generally mirrors that of the substrate
  • 28
    In enzyme kinetics, what does Vmax represent?
    إجابة
    (A)
    The amount of active enzyme
  • 29
    What is the meaning of Km in enzyme kinetics?
    إجابة
    (A)
    The substrate concentration that results in half-maximal velocity
  • 30
    Which of the following statements describes competitive enzyme activity inhibition?
    إجابة
    (B)
    Apparent Km is increased
  • 31
    In non-competitive enzyme inhibition, what impact does the inhibitor have on the enzyme's Km value?
    إجابة
    (C)
    Leaves Km unchanged
  • 32
    What type of enzyme uses oxygen during oxidoreduction reactions as an acceptor of hydrogen atoms?
    إجابة
    (A)
    Cytochrome oxidase
  • 33
    Which enzyme utilizes a substance other than oxygen as the hydrogen acceptor?
    إجابة
    (B)
    Succinate dehydrogenase
  • 34
    Which enzyme utilizes hydrogen acceptors as its substrate?
    إجابة
    (C)
    Catalase
  • 35
    Which of the following enzymes is primarily responsible for linking two substrates?
    إجابة
    (A)
    Glutamine synthetase
  • 36
    What is the typical optimal pH range for the activity of most enzymes?
    إجابة
    (B)
    Between 5 and 9
  • 37
    What is the nature of coenzymes?
    إجابة
    (A)
    Heat-stable, dialyzable, non-protein organic molecules
  • 38
    Which of the following is an example of a coenzyme that transfers hydrogen atoms?
    إجابة
    (B)
    NAD+
  • 39
    Which of the following is an example of a coenzyme involved in the transfer of chemical groups?
    إجابة
    (D)
    COA
  • 40
    Cocarboxylase is also known as:
    إجابة
    (A)
    Thiamine pyrophosphate
  • 41
    Which coenzyme features a non-aromatic heterocycle?
    إجابة
    (D)
    Biotin
  • 42
    Which coenzyme contains an aromatic heterocycle?
    إجابة
    (A)
    TPP
  • 43
    What best describes isoenzymes?
    إجابة
    (A)
    Forms of an enzyme that are chemically, immunologically, and electrophoretically distinct
  • 44
    How can isoenzymes be characterized?
    إجابة
    (B)
    Enzymes activated by hydrolysis
  • 45
    Regarding the isoenzymes of LDH, which statement is correct?
    إجابة
    (C)
    They exist in 5 forms based on M and H monomer ratios
  • 46
    What is a typical range for CPK values in blood serum?
    إجابة
    (A)
    4-60 IU/L
  • 47
    Which factors influence enzyme activity?
    إجابة
    (D)
    All of these
  • 48
    What is the typical range for GOT activity in blood serum?
    إجابة
    (B)
    4.0-17.0 IU/L
  • 49
    What is the typical range for GPT activity in blood serum?
    إجابة
    (C)
    3.0-15.0 IU/L
  • 50
    What is a typical range for serum acid phosphatase activity?
    إجابة
    (B)
    1.0-5.0 KA units/100 ml