Quick Biochemistry - Enzymes (Section 1)

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