Biomolecules

TOPIC – Nucleic Acid , Enzymes, Mechanism of Enzyme Action , Enzyme Inhibition

1. Choose correct regarding “active site” 4. How many coordination found in

activity of carboxypeptidase?
1) Substrate fits
(1) Only one ; between cofactor and side
2) Enzymes catalyst through active site
chain at active site
show low rate
(2) Two between cofactor and side chain at
3) It forms by crevices or pocket made
active site and at to many ; same time form
by primary protein only.
one or more bond with substrate.
4) It form by crevices or pocket made by
(3) Zero
tertiary protein structure
(4) Only one ; between cofactor & substrate
(1) 1, 2, 3
5. Match the List-I with List-II and
(2) 1, 2, 4
choose the correct option.
(3) 1, 3
List-I List-II
(4) 1, 4
I. DNA A. Purine
2. Prosthetic groups differ from co-
II. RNA B. Deoxy-ribose sugar
enzymes in that :-
III. Uracil C. Pyrimidine
(1) they require metal ions for their
activity. IV. Adenine D. Ribose sugar
(2) they (prosthetic groups) are tightly (1) I-A, II-B, III-D, IV-C
bound to apoenzymes.
(2) I-C, II-D, III-B, IV-A
(3) their association with apoenzymes is
(3) I-B, II-D, III-C, IV-A
transient.
(4) I-C, II-D, III-A, IV-B
(4) they can serve as co-factors in a
number of enzyme-catalyzed reactions. 6. The catalytic efficiency of two
different enzymes can be compared by
3. Enzymes catalyse biochemical
the
reactions by
(1) Formation of the product
(1) Lowering the activation energy
(2) pH of optimum value
(2) Increasing the activation energy
(3) Km value
(3) Establishing stable bonds with the
substrate (4) Molecular size of enzyme
(4) Increasing temperature
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7. Which of the following describes the 10. Read the following :
given graph correctly?
(a) Low temperature preserves the
enzyme
(b) Enzyme activity increases above
optimum temperature
(c) Enzyme gets denatured at high
temperature
(1) Endothermic reaction with energy A in
(d) Competitive inhibitor competes with
absence of enzyme and B in presence of
the product formed
enzyme
Which of the following statement are
(2) Exothermic reaction with energy A in
true?
absence of enzyme and B in presence of
enzyme (1) (a) & (c)
(3) Endothermic reaction with energy A in (2) (b) & (d)
presence of enzyme and B in absence of
(3) (c) & (d)
enzyme
(4) (a) & (b)
(4) Exothermic reaction with energy A in
presence of enzyme and B in absence of 11. Given below are two statements
enzyme. Assertion (A): Metal ions play a crucial
8. Holoenzyme is the complete enzyme role in the catalytic activity of the enzyme.
consisting of an apoenzyme and a co- Reason (R): Metal ions are required for
factor. Select the option that correctly the chemical reaction as they form
identifies the nature of apoenzyme and coordination bonds with side chains at the
co-factor. active site and at the same time form one
Apoenzyme Co-factor or more coordination bonds with the
substrate.
(1) Protein Non-protein
Choose the correct answer
(b) Non-protein Protein
(1) Both Assertion (A) and Reason (R) are
(c) Protein Protein
true and Reason (R) is a correct
(d) Non-protein Non-protein explanation of Assertion (A).
9. Ribozymes are _______ that behave like (2) Both Assertion (A) and Reason (R) are
enzymes true but Reason (R) is not a correct
explanation of Assertion (A).
(1) Proteins
(3) Assertion (A) is true but Reason (R) is
(2) Ribonucleic acids
false.
(3) Oligosaccharide
(4) Assertion (A) is false but Reason (R) is
(4) Simple lipids true.
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12. The given graph represents effects of 15. Which of the following is correct
change in various factors on enzymatic about Watson and Crick model of DNA?
activity. Select the option that correctly
(1) The backbone is formed by the sugar-
identifies X-axis and Y-axis.
phosphate-sugar chain.
(2) Adenine will only pair up with thymine
with 2 H-bonds.
(3) Guanine will only pair up with cytosine
with 3 H-bonds.
(4) All of these
16. Consider the following statements :
X Y
(A) Coenzyme or metal ion that is tightly
(1) Rate of reaction Enzymatic activity
bound to enzyme protein is called
(b) Enzymatic activity Rate of reaction prosthetic group.
(c) Enzymatic activity pH/Temperature (B) A complete catalytic active enzyme
(d) pH/Temperature Enzymatic activity with its bound prosthetic group is called
apoenzyme. Select the correct option.
13. Rate of physical or chemical process
refer to – Choose the correct answer

(1) Amount of reactant formed per unit (1) Both (A) and (B) are true.
time (2) (A) is true and (B) is false.
(2) Amount to product dissociate per unit (3) Both (A) and (B) are false.
time
(4) (A) is false and (B) is true.
(3) Differential of time with respect to
17. Given below are two statements:
produce
Statement I: Enzymes generally function
(4) Differential of product with respect to
in narrow range of temperature and pH.
time
Statement II: Low temperature preserves
14. With increase in substrate
the enzyme in a temporarily inactive state.
concentration, the velocity of the
enzymatic reaction – (1) Statement I and Statement II both are
correct.
(1) Constantly increase
(2) Statement I is correct, but Statement II
(2) Rise at first until Vmax and further no
is incorrect.
rise
(3) Statement I is incorrect, but Statement II
(3) No effect
is correct.
(4) Decrease first until Vmax and increase
(4) Statement I and Statement II both are
further
incorrect.
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18. Hydrolases catalyse – (3)200
i) Hydrolysis of ester, ether, peptide, (4) samp
glycosidic
20. Which of the following statements
ii) C – C breakdown regarding enzyme inhibition is correct ?
iii) C – halide breakdown (1) Non-competitive inhibition of an
enzyme can be overcome by adding large
iv) P – N breakdown
amount of substrate
(1) (i) only
(2) Competitive inhibition is seen, when a
(2) (i) & (ii) only substrate competes with an enzyme for
(3) (iii) & (iv) only binding to an inhibitor protein

(4) i, ii, iii & iv (3) Competitive inhibition is seen, when

the substrate and the inhibitor compete for
19. If optimum temp is 25°C & Enzyme the active site on the enzyme
Activity is 200 molecule /min then at
45°C it is (4) Non-competitive inhibitors often bind
to the enzyme irreversibly.
(1) 50
(2) 400

ANSWER KEY
1. (4) 2. (2) 3. (1) 4. (2) 5. (3) 6. (3) 7. (4) 8. (1) 9. (2) 10. (1)
11. (1) 12. (4) 13. (4) 14. (2) 15. (4) 16. (2) 17. (1) 18. (4) 19. (1) 20. (3)

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