11th class (FSc) Biology Unit 3 MCQs
Chapter 3 MCQs 11th Class Biology
Enzymes:
1. Which statement about enzymes is not true?
a. They are sensitive to heat
b. They consist of proteins with or without anon-protein part
c. They are non-specific in their action
d. They change the rate of catalyzed reaction
2. If more substance to an already occurring enzymatic reaction is added:
a. There is probably more product present than their in either substrate or enzyme
b. There is probably more substrate present than there is enzyme
c. The enzyme substrate complex is probably failing to form during there action
d. There is probably more enzyme available than there is substrate.
3. If you add more substance to already occurring enzymatic reaction and it has no effect on the rate of reaction? What is the form given for this situation?
a. Composition
b. Saturation
c. Inhibition
d. Denaturation
4. Enzyme that are integral part of ribosome responsible for synthesis of:
a. Carbohydrates
b. Lipids
c. Nucleic acids
d. Proteins
5. The non-protein part of enzyme is known as:
a. Co-factor
b. Activator
c. Polypeptides
d. Co-enzyme
6. Enzyme lowers down the energy of:
a. Activation
b. Kinetic
c. Lonic
d. Potential
7. All enzymes are globular:
a. Nucleic acid
b. Carbohydrates
c. Protein
d. Lipid
8. Which one is essential raw material for coenzymes?
a. Carbohydrates
b. Proteins
c. Lipids
d. Vitamins
9. If non-protein part is loosely attached to protein, it is known as:
a. Holoenzyme
b. Cofactor
c. Active site
d. Coenzyme
10. The vitamins are essential raw material for the synthesis of:
a. Co-enzymes
b. Activators
c. Prosthetic group
d. Co-factors
11. In respiratory chain NAD is oxidized by?
a. Cytochrome “b”
b. Co-factor
c. Cytochrome “c”
d. Co-enzyme
12. The detachable cofactors of an enzyme is known as:
a. Coenzyme
b. Activator
c. Apoenzyme
d. Prosthetic group
13. Enzyme that produces amino acids:
a. Chymotrypsin
b. Trypsin
c. Amino peptidase
d. Erypsin
14. The activation energy of the reaction is lowered by:
a. substrate
b. Co-enzyme
c. Product
d. Enzyme
15. Enzymes involved in respiration, are found in:
a. Mitochondria
b. Chloroplasts
c. Nucleus
d. Ribosome
16. The carbohydrate- digesting Enzyme is called:
a. Protease
b. Isomerase
c. Amylase
d. Lipase
17. Biologically active proteins:
a. Activators
b. Glycoprotein
c. Inhibitors
d. Enzymes
18. Metals ions are related to:
a. Cofactors
b. Coenzymes
c. Substrate
d. Vitamins
19. An activated enzyme with a co-enzyme is called:
a. Apoenzymes
b. Holoenzymes
c. Activators
d. Coenzymes only
20. If the non-protein part of enzyme is covalently bonded, it is called:
a. Co-enzyme
b. Co-factor
c. Prosthetic group
d. Activator
21. The inorganic and detachable cofactor are called:
a. Prosthetic group
b. Activators
c. Inhibitors
d. Coenzymes
22. Coenzymes are closely related to:
a. Vitamins
b. Amino acids
c. Enzymes
d. Non protein particles
23. An activated enzyme consisting of a polypeptide chain and a cofactor is called:
a. Coenzyme
b. Apoenzyme
c. Holoenzyme
d. Both a & b
24. The inactive form of enzyme pepsin is:
a. Apoenzyme
b. Holoenzyme
c. Pepsinogen
d. None
25. The catalytic activity of enzyme is restricted to a small portion of the enzyme, known as:
a. Binding site
b. Active site
c. Reacting site
d. Catalytic site
26. Enzymes involved in the synthesis of proteins are integral part of:
a. Ribosome
b. Chloroplast
c. Golgi complex
d. Mitochondria
27. An enzyme with its co-enzyme or prosthetic group removed is designated as:
a. Co-enzyme
b. Holenzyme
c. Activator
d. Apoenyme
28. If non-protein part of co-factor is covalently bonded to enzyme, it is called as:
a. Activator
b. Co-enzyme
c. Apoenzyme
d. Prosthetic group
29. Some enzymes also have a non-protein part known as a cofactor, which is essential for the proper functioning of the:
a. Reactant
b. Substrate
c. Product
d. Enzymes
30. Some enzymes use metal-ions as co-factor like:
a. Cu2+
b. Mg2+
c. Fe2+
d. All of these
31. The detachable co-factor is known as an activator if it is:
a. Inorganic
b. Organic ion
c. Non-ionic
d. Both A & B
32. An enzyme with its coenzyme or prosthetic group, removed is designated as:
a. Co- enzyme
b. Apoenzyme
c. Activator
d. Holoenzyme
33. The chemical reaction can be accelerated by an enzyme even in:
a. Large amount
b. Small amounts
c. Moderate amount
d. All of these
34. Even for minor change in pH, temperature and substrate concentration, enzymes are:
a. Susceptible
b. Aware
c. Receptive
d. Sensitive
35. The activation energy of the reactions is lowered by:
a. Enzymes
b. Coenzymes
c. Product
d. Substrate
36. By increasing the enzyme molecules, there is an increase in the number of:
a. Catalytic sites
b. Binding sites
c. Active sites
d. None
37. Enzymes are the most important group of proteins which are biologically:
a. Dynamic
b. Active
c. Energetic
d. Inactive
38. The catalytic actively of enzymes is restricted to a small portion of the enzyme known as:
a. Catalytic site
b. Binding site
c. Non-binding site
d. Active site
39. The reactant called ……… is attached to the active site of enzyme.
a. Substrate
b. Food particle
c. Product
d. Substance
40. If the non-protein part is covalently bonded to enzyme, it is known as a:
a. Holoenzyme
b. Coenzyme
c. Prosthetic group
d. Co-factor
41. An activated enzyme consisting of polypeptide chain and a cofactor is known as:
a. Coenzyme
b. Holoenzyme
c. Zymogen
d. Apoenzyme
42. Enzymes are very ……… in their action:
a. Precise
b. General
c. Exact
d. Specific
43. The cofactor usually acts as “bridge” between the:
a. Enzyme & product
b. Enzyme & substrate
c. Cofactor & substrate
d. Coenzyme & substrate
44. If none-protein part is loosely attached to the protein part it is known as:
a. Holoenzyme
b. Co-factor
c. Prosthetic group
d. Coenzyme
45. The enzymes are:
a. Angular proteins
b. Fibrous proteins
c. Spherical proteins
d. Globular proteins
46. If the amount of enzyme is increased by two fold the reaction rate is:
a. Four fold
b. Same
c. Three fold
d. Doubled
47. The active site of an enzyme:
a. Determines, by its structure the specificity of the enzyme
b. Never changes
c. Looks like a lump projecting from the surface of an enzyme
d. Forms no chemical bond with substrate
48. Three dimensional globular protein is:
a. Antibiotic
b. Starch
c. Enzyme
d. Glucose
49. Lock and key model was proposed by:
a. Enterokinase
b. Emil Fischer
c. Chymocryptase
d. Kosland
50. An enzyme and substrate react with each other through charge bearing sites called:
a. Active sites
b. Locus
c. Centromere
d. None
51. Induced fit model was proposed by:
a. Jenner
b. Emil fischer
c. Pasteur
d. Koshland
52. An enzyme reacts only with its specific:
a. Substrate
b. Surface
c. Inhibitor
d. Product
53. According to Lock and Key Model, the active site is:
a. Liquid
b. Rigid structure
c. Flexible
d. All of these
54. According to lock and key model active site is a:
a. Rigid structure
b. Soft structure
c. Attractive structure
d. Flexible structure
55. Any enzyme reacts only with its specific:
a. Substrate
b. Surface
c. Reactant
d. Product
56. The active site of the enzyme is made up of two definite regions i.e., the binding site and the:
a. Inactive site
b. Non-binding site
c. Catalytic site
d. Non-catalytic site
57. On this basis of new evidences induce fit model was proposed by:
a. Robert Koch
b. Koshland
c. Louis Pasteur
d. Emil fischer
58. An enzyme is a three dimensional ……… protein:
a. Globular
b. Fibrous
c. Branched
d. Straight
59. An enzyme and its substrate react with each other through definite charge bearing sites called —- sites.
a. Binding
b. Catalytic
c. Active
d. Passive
60. The binding site helps the enzyme in the recognibiton and binding of a proper substrate to product an:
a. RS complex
b. BS complex
c. ES complex
d. PS complex
61. According to lock and key model the active site is:
a. Terrible structure
b. Rigid structure
c. Attractive structure
d. Soft structure
62. The optimum pH for sucrase enzyme is:
a. 4.83
b. 4.50
c. 4.90
d. 5.10
63. Optimum pH for proper functioning of pepsin is:
a. 5.50
b. 4.00
c. 2.00
d. 4.50
64. The reversible inhibitors have:
a. No linkage
b. Strong linkage with enzyme
c. Medium linkage
d. Weak linkage
65. The optimum pH of catalase is :
a. 8.60
b. 6.60
c. 9.60
d. 7.60
66. Extreme changes in pH causes the bounds in enzyme to break resulting in the:
a. Denaturation of enzyme
b. Activation of enzyme
c. None of these
d. Inhibition of enzyme
67. Optimum pH value for enzyme argniase is:
a. 6.40
b. 7.60
c. 5.2
d. 9.70
68. The competitive inhibitor of succnic acid is:
a. Citric acid
b. Numeric acid
c. Acetic acid
d. Malonic acid
69. Optimum pH for action of pancreatic lipase is:
a. 7.00
b. 3.00
c. 9.00
d. 5.00
70. The optimum pH of Enterokinase is:
a. 5.50
b. 1.50
c. 7.50
d. 3.50
71. A little change in pH may leads to:
a. Retard or even block enzyme activity
b. Ionization of active sites of enzyme
c. Effects enzyme only in high concentration
d. ionization of substrate
72. The rate of reaction depends directly on the amount of:
a. Enzyme concentration
b. pH
c. Substrate concentration
d. Temperature
73. Optimum pH for the proper functional of enzyme sucrose is:
a. 5.50
b. 2.00
c. 7.60
d. 4.50
74. Reversible inhibitors form weak likages with the:
a. Product
b. Enzyme
c. Substrate
d. reactant
75. The optimum pH of salivary amylase is:
a. 6.80
b. 2.80
c. 8.80
d. 4.80
76. The optimum pH of enzyme pepsin is:
a. 7
b. 2
c. 9
d. 6.8
77. Poisons like cyanide, antibiotic anti-metabolites and some drugs are example of:
a. Coenzyme
b. Enzymes
c. Holenzymes
d. Inhibitors
78. The enzyme with optimum pH = 7.60 is:
a. Catalase
b. Arginase
c. Sucrose
d. Enterokinase
79. 4.50 is optimum pH value for the enzyme:
a. Enterokinase
b. Arginase
c. Chymocryptase
d. Sucrose
80. The product of succinic acid by action of enzymes is:
a. Citric acid
b. fumeric acid
c. Pyruvic acid
d. Malonic acid
81. The optimum pH of pancreatic lipase is:
a. 8.0
b. 6.0
c. 9.0
d. 7.0
82. The optimum temperature for enzyme to work at maximum rate is:
a. 40C
b. 350C
c. 300C
d. 370C
83. Optimum pH for sucrose is:
a. 5.50
b. 3.50
c. 6.50
d. 4.50
84. The optimum temperature of human body is:
a. 570C
b. 270C
c. 470C
d. 370C
85. An ……… is a chemical substance which can react (in place of substance) with the enzymes but is not transformed into product (s) and thus block the active site:
a. Retarder
b. Inhibitor
c. Reducer
d. Accelerator
86. For enzymes of human body ……… 0C is the optimum temperature.
a. 37
b. 27
c. 47
d. 17
87. ……… inhibitors occupy the active sites by forming covalent bonds or they may physically block the active sites.
a. Reparable
b. Reversible
c. Irreversible
d. Irreparable
88. All enzymes can work at their maximum rate at a specific temperature called:
a. Optimum temperature
b. Minimum temperature
c. Best temperature
d. Maximum temperature
89. Every enzyme function most effectively over a narrow range of pH known as the:
a. Maximum pH
b. Best pH
c. Optimum pH
d. Minimum pH
90. Because of the structure similarity with the substrate, competitive inhibitors may be selected by the binding sites, but are not able to activate the:
a. Inactive sites
b. Catalytic sites
c. Active sites
d. Accelerating sites
91. Any factor that can alter the chemistry and shape of an enzyme can affect its rate of:
a. Catalysis
b. Reaction
c. Activation
d. Both B & C
92. At low concentration of substrate the reaction rate is directly proportional to the available:
a. Product
b. Enzyme
c. Substrate
d. Reactant
93. Extreme changes in pH cause the bonds in the enzyme to break, resulting in the enzyme:
a. Deconformation
b. Denaturation
c. Deconfiguration
d. Deceleration
94. Reversible inhibitors form weak linkages with the:
a. Product
b. Enzyme
c. Substrate
d. Reactant
95. Non-competitive inhibitors form enzyme inhibitor complex at a point other than the:
a. Binding site
b. Catalytic site
c. Active site
d. Both A & B
96. Heat provides activation energy and therefore, chemical reactions are accelerated at:
a. High temperature
b. Low temperatures
c. Moderate temperature
d. None
97. The ionization of the amino acids at the active site can be changed by a slight change in:
a. Enzyme concentration
b. Temperature
c. pH
d. Substrate concentration
98. The optimum pH of Pepsin is:
a. 6.00
b. 2.00
c. 8.00
d. 4.00
99. The optimum pH of Sucrase is:
a. 6.50
b. 2.50
c. 8.50
d. 4.50
100. The optimum pH of catalase is:
a. 5.70
b. 2.50
c. 7.60
d. 4.60
101. The optimum pH of Chymotrypsin is:
a. 5.00-6.00
b. 7.00-8.00
c. 4.00-5.00
d. 6.00-7.00
102. The optimum of pH Pancreatic lipase is:
a. 5.00
b. 7.00
c. 3.00
d. 9.00
103. The optimum pH of Arginase is:
a. 5.60
b. 7.70
c. 4.25
d. 9.70
104. Poisons, like cyanide antibodies antimetabolites and some drugs are examples of:
a. Inhibitors
b. Enzymes
c. Holoezymes
d. Coenzymes
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