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ENZYMES- Part 1
See all quizzes of ENZYMES- Part 1 here:
1. The compound which has the lowest
density is
(A) Chylomicron (B) β-Lipoprotein
(C) α-Lipoprotein (D) pre β-Lipoprotein
2. Non steroidal anti inflammatory drugs,
such as aspirin act by inhibiting the
activity of the enzyme:
(A) Lipoxygenase (B) Cyclooxygenase
(C) Phospholipase A2 (D) Lipoprotein lipase
3. From arachidonate, synthesis of prostaglandins
is catalysed by
(A) Cyclooxygenase
(B) Lipoxygenase
(C) Thromboxane synthase
(D) Isomerase
4. A Holoenzyme is
(A) Functional unit (B) Apo enzyme
(C) Coenzyme (D) All of these
5. Gaucher’s disease is due to the deficiency
of the enzyme:
(A) α-Fucosidase (B) β-Galactosidase
(C) β-Glucosidase (D) Sphingomyelinase
6. Neimann-Pick disease is due to the deficiency
of the enzyme:
(A) Hexosaminidase A and B
(B) Ceramidase
(C) Ceramide lactosidase
(D) Sphingomyelinase
CHAPTER 6
ENZYMES
7. Krabbe’s disease is due to the deficiency
of the enzyme:
(A) Ceramide lactosidase
(B) Ceramidase
(C) β-Galactosidase
(D) GM1 β-Galactosidase
8. Fabry’s disease is due to the deficiency of
the enzyme:
(A) Ceramide trihexosidase
(B) Galactocerebrosidase
(C) Phytanic acid oxidase
(D) Sphingomyelinase
9. Farber’s disease is due to the deficiency
of the enzyme:
(A) α-Galactosidase
(B) Ceramidase
(C) β-Glucocerebrosidase
(D) Arylsulphatase A.
10. A synthetic nucleotide analogue, used in
organ transplantation as a suppressor of
immunologic rejection of grafts is
(A) Theophylline
(B) Cytarabine
(C) 4-Hydroxypyrazolopyrimidine
(D) 6-Mercaptopurine
140 MCQs IN BIOCHEMISTRY
11. Example of an extracellular enzyme is
(A) Lactate dehydrogenase
(B) Cytochrome oxidase
(C) Pancreatic lipase
(D) Hexokinase
12. Enzymes, which are produced in inactive
form in the living cells, are called
(A) Papain (B) Lysozymes
(C) Apoenzymes (D) Proenzymes
13. An example of ligases is
(A) Succinate thiokinase
(B) Alanine racemase
(C) Fumarase
(D) Aldolase
14 An example of lyases is
(A) Glutamine synthetase
(B) Fumarase
(C) Cholinesterase
(D) Amylase
15. Activation or inactivation of certain key
regulatory enzymes is accomplished by
covalent modification of the amino acid:
(A) Tyrosine (B) Phenylalanine
(C) Lysine (D) Serine
16. The enzyme which can add water to a
carbon-carbon double bond or remove
water to create a double bond without
breaking the bond is
(A) Hydratase (B) Hydroxylase
(C) Hydrolase (D) Esterase
17. Fischer’s ‘lock and key’ model of the
enzyme action implies that
(A) The active site is complementary in shape to
that of substance only after interaction.
(B) The active site is complementary in shape to
that of substance
(C) Substrates change conformation prior to active
site interaction
(D) The active site is flexible and adjusts to
substrate
18. From the Lineweaver-Burk plot of
Michaelis-Menten equation, Km and
Vmax can be determined when V is the
reaction velocity at substrate concentration
S, the X-axis experimental data are
expressed as
(A) 1/V (B) V
(C) 1/S (D) S
19. A sigmoidal plot of substrate concentration
([S]) verses reaction velocity (V) may
indicate
(A) Michaelis-Menten kinetics
(B) Co-operative binding
(C) Competitive inhibition
(D) Non-competitive inhibition
20. The Km of the enzyme giving the kinetic
data as below is
(A) –0.50 (B) –0.25
(C) +0.25 (D) +0.33
21. The kinetic effect of purely competitive
inhibitor of an enzyme
(A) Increases Km without affecting Vmax
(B) Decreases Km without affecting Vmax
(C) Increases Vmax without affecting Km
(D) Decreases Vmax without affecting Km
22. If curve X in the graph (below) represents
no inhibition for the reaction of the
enzyme with its substrates, the curve
representing the competitive inhibition, of
the same reaction is
(A) A (B) B
(C) C (D) D
23. An inducer is absent in the type of enzyme:
(A) Allosteric enzyme
(B) Constitutive enzyme
(C) Co-operative enzyme
(D) Isoenzymic enzyme
24. A demonstrable inducer is absent in
(A) Allosteric enzyme (B) Constitutive enzyme
(C) Inhibited enzyme (D) Co-operative enzyme
ENZYMES 141
25. In reversible non-competitive enzyme
activity inhibition
(A) Vmax is increased
(B) Km is increased
(C) Km is decreased
(D) Concentration of active enzyme is reduced
26. In reversible non-competitive enzyme
activity inhibition
(A) Inhibitor bears structural resemblance to
substrate
(B) Inhibitor lowers the maximum velocity
attainable with a given amount of enzyme
(C) Km is increased
(D) Km is decreased
27. In competitive enzyme activity inhibition
(A) The structure of inhibitor generally resembles
that of the substrate
(B) Inhibitor decreases apparent Km
(C) Km remains unaffective
(E) Inhibitor decreases Vmax without affecting Km
28. In enzyme kinetics Vmax reflects
(A) The amount of an active enzyme
(B) Substrate concentration
(C) Half the substrate concentration
(D) Enzyme substrate complex
29. In enzyme kinetics Km implies
(A) The substrate concentration that gives one half
Vmax
(B) The dissocation constant for the enzyme
substrate comples
(C) Concentration of enzyme
(D) Half of the substrate concentration required
to achieve Vmax
30. In competitive enzyme activity inhibition
(A) Apparent Km is decreased
(B) Apparent Km is increased
(C) Vmax is increased
(D) Vmax is decreased
