B. Protons

C. Anions

D. Cations

E. Hydrogen

60. A copper containing oxidase is:

1. Cytochrome oxidase

2. Flavin mononucleotide

3. Flavin adenine dinucleotide

4. Xanthine oxidase

5. Lysine oxidase

61. Peroxidase belongs to the next class of enzymes:

1. Oxido-reductases

2. Transferases

3. Hydrolases

4. Lyases

5. Isomerases

62. The redox carriers are grouped into respiratory chain complex:

A. In the inner mitochondrial membrane

B. In mitochondiral matrix

C. On the outer mitochondrial membrane

D. On the inner surface of outer mitochondrial membrane

E. Cytosol

63. The next enzyme complex serves as a point of entry for most of the electrons generated by the action of the citric acid cycle:.

1. Complex I

2. Complex II

3. Complex III

4. Complex IY

5. ATP synthase

64. Reducing equivalents from succinate enter the mitochondrial respiratory chain at:

1. FAD

2. NAD

3. Coenzyme Q

4. Cyt c

5. Cyt b

65. If the reducing equivalents enter from NAD in the respiratory chain, the phosphate:oxygen ration (P:O) is:

1. 3

2. 1

3. 2

4. 4

5. 5

66. If the reducing equivalents enter from FAD in the respiratory chain, the phosphate:oxygen ration (P:O) is:

1. 2

2. 1

3. 3

4. 4

5. 5

67. Reducing equivalents from succinate enter the mitochondrial respiratory chain at:

A. FAD

B. Coenzyme Q

C. NAD

D. Cyt c

E. Cyt b

68. Some of the free energy released in the mitochondrial electron transport chain can be harnessed to the formation of ATP. How many moles of ATP can be formed per a pair of electrons transferred from reduced FAD to oxygen?

1. 2

2. 0

3. 1

4. 3

5. 4

69. Some of the free energy released in the mitochondrial electron transport chain can be harnessed to the formation of ATP. How many moles of ATP can be formed per pair of electrons transferred from reduced NAD to oxygen?

A. 3

B. 1

C. 2

D. 0

E. 4

70. Cytochrome oxidase is an enzyme of respiratory chain with the next characteristics:

1. contains copper ions

2. trasfers electrons to cytochrome c

3. is not inhibited by cyanides

4. contains two iron sulfur centers

5. is a simple protein

71. An enzyme catalyzing oxidoreduction, using oxygen as hydrogen acceptor is:

1. Cytochrome oxidase

2. Lactate dehydrogenase

3. Malate dehydrogenase

4. Succinate dehydrogenase

5. Fumarase

72. Which of the following enzymes is tightly associated with inner mitochondrial membrane?

1. Succinate dehydrogenase

2. Citrate synthase

3. Alpha-ketoglutarate dehydrogenase

4. Fumarase

5. Malate dehydrogenase

73. Reducing equivalents from pyruvate enter the mitochondrial respiratory chain at:

A. NAD

B. FMN

C. Coenzyme Q

D. Cyt b

E. Cyt aa₃

74. Brown adipose tissue is:

1. Characterised by high content of mitochondria

2. A prominent tissue in human

3. Associated with high activity of ATP synthase

4. Characterised by low content of cytochromes

5. TCA doesn’t occur here

75. One of the respiratory chain enzymes, namely cytyochrome c, is a transporter of:

1. Electrons

2. Protons

3. Cations

4. Hydrogen atoms

5. Oxygen anion

76. Most of hydrogen atoms (protons and electrons) involved in process of tissue respiration are transported to the respiratory chain by the next compound:

1. NADH+H⁺

2. NADPH+H⁺

3. FMNH₂

4. FADH₂

5. Pyruvate

77. Which from the respiratory chain enzymes needs FAD as coenzyme?

1. Succinate dehydrogenase

2. NAD H₂-ubiquinone reductase

3. Ubiquinone-cytochrome c reductase

4. Cytochrome oxidase

5. Complex 3 enzymes

78. Dehydrogenases utilize, as coenzymes, all of the following except:

A. FH₄

B. NADP⁺

C. FAD

D. NAD⁺

E. FMN

79. A mitochondrial marker enzyme is:

A. Succinate dehydrogenase

B. Amylase

C. Aldolase

D. Pyruvate dehydrogenase

E. Pepsin

80. Activity of what enzyme can be detected due to the color development of benzidine after its oxidation?

А. Phenol oxidase

В. Cytochrome c

С. Aldehyde dehydrogenase

D. Peroxidase

Е. Lactate dehydrogenase

81. What reaction conditions are needed for oxidation of pyrocatechin by molecular oxygen in presence of phenoloxidase and production of oxidation products with brown color?

А. In presence of pyrocatechin and potatoe juice

В. After boiling of potatoe juice

С. Absence of pyrocatechin

D. In presence of Na₂S

Е. In strong acidic medium

82. Which of the following actions describes the uncoupling of oxidative phosphorylation in a mitochondrial system?

1. The phosphorylation of ADP stops but oxygen uptake continues

2. The phosphorylation of ADP to ATP accelerates

3. The phosphorylation of ADP continues but oxygen uptake stops

4. Oxygen uptake stops

5. Produced ATP is not translocated across inner membrane to cytoplasm

83. Chemiosmotic theory for oxidative phosphorylation has been proposed by:

A. P. Mitchell

B. Pauling and Corey

C. S. Waugh

D. Chance and Williams

E. H. Krebs

84. Activity of cytochrome oxidase is inhibited by:

A. Cyanide

B. Sulphate

C. Arsenite

D. Sulphite

E. Chloride

85. The chemical inhibiting oxidative phosphorylation, a dependent on the transport of adenine nucleotides across the inner mitochondrial membrane is:

A. Oligomycin

B. Atractyloside

C. Dinitrophenol

D. Pentachlorophenol

E. Progesteron

86. ATP synthetase is a multichain enzyme complex with the next characteristic features:

1. It possess ion selective channel which selectively conduct protons

2. Cyanides inhibit its enzymatic activity irreversibly

3. It contains four iron-sulfur centers

4. It is integral membrane protein associated with outer membrane of mitochondria

5. It is inhibited by high concentration of ADP and inorganic phosphate

87. Note a compound which is considered as natural uncoupler of oxidative phosphorylation:

1. Thermogenin

2. Progesteron

3. Succinic acid

4. Sapogenin

5. Stearic acid

88. Reactive oxygen species (ROS) include the next substances EXEPT:

1. Hydrogen ions

2. Hydrogen peroxide

3. Superoxide anion

4. Hydroxyl radical

5. Organic hydroperoxides

89. Uncouplers of oxidative phosphorylation are acting as follows:

1. Collapse proton gradient across outer mitochondrial membrane

2. Allow electron transport to proceed and block ATP synthesis

3. Arrest electron transport and ATP synthesis simultaneously

4. Competitively inhibit FMN-dependent ubiquinone reductase

5. Inhibit the electron transport in cytochromes chain

90. An enzyme catalyzing oxidoreduction, using oxygen as hydrogen acceptor is:

1. Cytochrome oxidase

2. Lactate dehydrogenase

3. Malate dehydrogenase

4. Succinate dehydrogenase

5. Fumarase

91. The chemiosmotic hypothesis of oxidative phosphorylation suggests that ATP is formed because:

1. Formation of proton gradient across the inner membrane

2. The change in the permeability of inner mitochondrial membrane toward ADP and inorganic phosphate

3. Due to formation of high energy bonds in mitochondrial proteins

4. ADP is pumped out of the matrix into the intermembrane space

5. Protons are pumped into the mitochondrial matrix

92. Some hormones are acting as uncouplers of oxidative phosphorylation. Chose from listed below hormones one considered as potent uncoupler.

1. Thyroxine

2. Norepinephrine

3. Testosterone

4. Insulin

5. Cortisol

93. Catalase represents the next class of enzymes:

1. Oxidoreductases

2. Transferases

3. Hydrolases

4. Lyases

5. Isomerases

94. Rotenone inhibits the respiratory chain at:

A. FMN → coenzyme Q

B. NAD → FMN

C. Coenzyme Q → cyt b

D. Cyt b → Cyt c₁

E. Cyt c₁→Cyt a₃

95. The transfer of reducing equivalents from NADH to coenzyme Q is specifically inhibited by:

A. Piericidin A

B. Oligomycin

C. Carboxin

D. Rotenone

E. Theroxine

96. Note an endogenous compound which induces heat production due to uncoupling of oxidative phosphorylation

1. Thermogenin

2. Succinate

3. Stearate

4. Progesteron

5. Sapogenin

97. Chose a toxic substance acting as potent uncoupler of oxidative phosphorylation:

1. Dinitrophenol

2. Phenol

3. Picric acid

4. Sodium cyanide

5. Heme

98. Cychrome aa₃ belongs to the next class of enzymes:

1. Oxido-reductases

2. Transferases

3. Hydrolases

4. Lyases

5. Isomerases

99. Catalase is an enzyme with the next properties:

1. It catalyses the decomposition of hydrogen peroxide with formation of water and oxygen as products

2. It reduces hydrogen peroxide using substances providing hydrogen atoms with formation of water and oxidized substance

3. Catalyses interaction of CO₂ and water and produce oxygen and formaldehyde as final products.

4. Contains FMN as coenzyme

5. It is NAD-dependent enzyme

100. The driving force for ATP synthesis in mitochondria is created due to:

1. Asymmetric distribution of protons across inner mitochondrial membrane

2. Transport of electrons along the chain of cytochromes

3. Reduction of oxygen and production of water with free energy release

4. Generation of high energy intermediates during electron transport

5. Difference in electric charge between inner and outer mitochondrial membranes

101. What products are produced from superoxide anion under the action of superoxide dismutase?

1. Free oxygen

2. Hydroxyl radical

3. Protons

4. NAD

5. FMN reduced

102. Cytochrome oxidase is an enzyme of respiratory chain with the next characteristics:

1. It contains copper ions

2. It trasfers electrons to cytochrome c

3. It is not inhibited by cyanides

4. It contains two iron sulfur centers

5. It is an integral membrane protein associated with outer mitochondrial membrane

103. What enzyme can decompose hydrogen peroxide without involvement of organic compounds as donors of hydrogen?

1. Catalase

2. Peroxidase

3. Monooxygenase

4. Cytochrome P₄₅₀

5. Lipoxygenase

104. Superoxide radicals can be detoxified by:

1. Cytochrome c

2. Cytochrome b

3. Cytochrome a

4. Superoxide dismutase

5. Peroxidase

105. Rate of tissue respiration is raised when the intracellular concentration of:

1. ADP increases

2. ATP increases

3. ADP decreases

4. AMP decreases

5. None of these

106. Hydrogen peroxide may be detoxified in the absence of an oxygen acceptor by:

1. Peroxidase

2. Catalase

3. Cytochrome a

4. Superoxide dismutase

5. Oxygenase