MCQOPTIONS
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MCQOPTIONS
This section includes 181 Mcqs, each offering curated multiple-choice questions to sharpen your Biochemistry knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
Which of the following enzyme is responsible for the regulation of biological nitrogen fixation? |
| A. | Dinitrogenase reductase |
| B. | Dinitrogenase oxidase |
| C. | Phosphatase |
| D. | Kinase |
| Answer» B. Dinitrogenase oxidase | |
| 52. |
The attachment of phosphoryl groups to specific amino acid residues is catalyzed by ___________ |
| A. | Diphteria toxin and cholera toxin |
| B. | Dinitrogenase reductase |
| C. | Protein phosphatases |
| D. | Protein kinases |
| Answer» E. | |
| 53. |
Fructose and Glucose can be distinguished by ___________ |
| A. | Selwinoff’s reagent |
| B. | Benedict’s reagent |
| C. | Fehling’s reagent |
| D. | Barfoed’s reagent |
| Answer» B. Benedict’s reagent | |
| 54. |
In maltose, between which of the following carbons there is a linkage? |
| A. | C1, C2 |
| B. | C2, C3 |
| C. | C1, C4 |
| D. | C2, C4 |
| Answer» D. C2, C4 | |
| 55. |
Which of the following is an example of epimers? |
| A. | Glucose & Galactose |
| B. | Glucose & Ribose |
| C. | Mannose & Glucose |
| D. | Galactose & Mannose |
| Answer» B. Glucose & Ribose | |
| 56. |
Anthrone method is preferred in the determination of ___________ |
| A. | Carbohydrates |
| B. | Proteins |
| C. | Vitamins |
| D. | Fats |
| Answer» B. Proteins | |
| 57. |
Which of the following is false about feedback regulation? |
| A. | It is a type of enzymatic activity regulation |
| B. | The synthesis of concerned enzyme is inhibited by interfering with the gene of that enzyme |
| C. | Concentration of enzyme is reduced by the end product |
| D. | The best example is the biosynthesis of L-isoleucine from L-threonine in bacteria |
| Answer» E. | |
| 58. |
Which of the following are the storage polysaccharides? |
| A. | Glycogen |
| B. | Cellulose |
| C. | Chitin |
| D. | Glucose |
| Answer» B. Cellulose | |
| 59. |
In which of the following forms, glucose is stored in the liver? |
| A. | Glycogen |
| B. | Starch |
| C. | Dextrin |
| D. | Cellulose |
| Answer» B. Starch | |
| 60. |
The protein core of proteoglycan is rich in ___________ |
| A. | Serine and threonine |
| B. | Serine and methionine |
| C. | Threonine and methionine |
| D. | Alanine and serine |
| Answer» B. Serine and methionine | |
| 61. |
In which of the following, glucose residues are linked by β1-4 glycosidic bonds? |
| A. | Amylose |
| B. | Starch |
| C. | Cellulose |
| D. | Glycogen |
| Answer» D. Glycogen | |
| 62. |
Which of the following blood group individuals have N-acetylgalactosamine sugar attachment? |
| A. | A |
| B. | B |
| C. | AB |
| D. | O |
| Answer» B. B | |
| 63. |
The production or break down of __________ is often coupled with the metabolic reactions of biosynthesis and catabolism. |
| A. | aspirin |
| B. | DNA |
| C. | ATP |
| D. | CO₂ |
| Answer» D. CO₂ | |
| 64. |
In which of the following forms, glucose is stored in plants? |
| A. | Glycogen |
| B. | Starch |
| C. | Dextrin |
| D. | Cellulose |
| Answer» C. Dextrin | |
| 65. |
The red precipitate formed when glucose is heated with “Benedict’s reagent” is ___________ |
| A. | Cupric hydroxide |
| B. | Cuprous hydroxide |
| C. | Cupric oxide |
| D. | Cuprous oxide |
| Answer» E. | |
| 66. |
Insulin |
| A. | stimulates gluconeogenesis and glycolysis |
| B. | stimulates gluconeogenesis and inhibits glycolysis |
| C. | inhibits gluconeogenesis and glycolysis |
| D. | inhibits gluconeogenesis and stimulates glycolysis |
| Answer» E. | |
| 67. |
Pyruvate is initially converted to which of the following in the gluconeogenesis? |
| A. | Glycerol |
| B. | Phosphoenol pyruvate |
| C. | Oxaloacetate |
| D. | Acetyl CoA |
| Answer» D. Acetyl CoA | |
| 68. |
In the case of allosteric enzymes what is the graphical representation when initial velocity is plotted against substrate concentration? |
| A. | Straight line with negative slope |
| B. | Hyperbola |
| C. | Sigmoid curve |
| D. | Parabola |
| Answer» D. Parabola | |
| 69. |
Which of the following are found in connective tissues? |
| A. | Glycosaminoglycans |
| B. | Proteoglycans |
| C. | Glycoproteins |
| D. | Glycolipids |
| Answer» C. Glycoproteins | |
| 70. |
In cell membranes, carbohydrates in glycoproteins or glycolipids are oriented? |
| A. | Towards outside |
| B. | Towards inside |
| C. | Towards outside and inside |
| D. | Randomly distributed |
| Answer» B. Towards inside | |
| 71. |
Which of the following statements is false about proteoglycans? |
| A. | They hold less amount of water |
| B. | Chondroitin sulfate is a proteoglycan |
| C. | They possess charge |
| D. | They are made of amino acids and sugars |
| Answer» B. Chondroitin sulfate is a proteoglycan | |
| 72. |
Which of the following blood group individuals have galactose? |
| A. | A |
| B. | B |
| C. | AB |
| D. | O |
| Answer» C. AB | |
| 73. |
The conversion of pyruvate to oxaloacetate |
| A. | requires biotin |
| B. | involves the fixation of carbon dioxide |
| C. | occurs in the mitochondria |
| D. | all of the above |
| Answer» B. involves the fixation of carbon dioxide | |
| 74. |
Citric acid accumulation would |
| A. | stimulate phosphofructokinase activity |
| B. | stimulate fructose 1,6 diphosphatase activity |
| C. | inhibit phosphofructokinase activity |
| D. | both (b) and (c) |
| Answer» E. | |
| 75. |
Which of the following is false about the following reaction?Phosphorylase a + 2H₂O → phosphorylase b + 2Pᵢ |
| A. | Phosphorylase a is less active and phosphorylase b is more active |
| B. | Glycogen phosphorylase catalyzes this reaction |
| C. | Phosphorylase b can be transformed back into phosphorylase a by phosphorylase kinase |
| D. | Phosphorylase kinase catalyzes the transfer of phosphoryl groups from ATP to Phosphorylase b |
| Answer» B. Glycogen phosphorylase catalyzes this reaction | |
| 76. |
Which of the following is an analogous to starch? |
| A. | Cellulose |
| B. | Glycogen |
| C. | Sucrose |
| D. | Chitin |
| Answer» C. Sucrose | |
| 77. |
Which of the following is an example of disaccharide? |
| A. | Glucose |
| B. | Fructose |
| C. | Galactose |
| D. | Maltose |
| Answer» E. | |
| 78. |
A common way that cells capture the energy released during the breakdown of large molecules is to add electrons to smaller, specialized molecules that can accept them. This process of electron acceptance is otherwise known as |
| A. | biosynthesis |
| B. | metabolism |
| C. | reduction |
| D. | catalysis |
| Answer» D. catalysis | |
| 79. |
What is the specificity of the Clostripain protease? |
| A. | It cleave after Arg residues |
| B. | It cleave after His residues |
| C. | It cleave after Lys residues |
| D. | None of the above |
| Answer» B. It cleave after His residues | |
| 80. |
The glycosidic bond |
| A. | in maltose is not hydrolyzed in lactose intolerant humans |
| B. | in sucrose is hydrolyzed by bees |
| C. | joins glucose and fructose to form sucrose |
| D. | both (b) and (c) |
| Answer» E. | |
| 81. |
The main site for gluconeogenesis is |
| A. | kidney |
| B. | liver |
| C. | brain |
| D. | muscle |
| Answer» C. brain | |
| 82. |
Which of the following is an example for irreversible inhibitor? |
| A. | Disulfiram |
| B. | Oseltamivir |
| C. | Protease inhibitors |
| D. | DIPF |
| Answer» E. | |
| 83. |
Each reaction in a metabolic pathway is |
| A. | reversible |
| B. | irreversible |
| C. | catalyzed by a specific enzyme |
| D. | controlled by the end product |
| Answer» D. controlled by the end product | |
| 84. |
By what factor chymotrypsin enhances the rate of peptide bond hydrolysis? |
| A. | 10⁷ |
| B. | 10⁸ |
| C. | At least 10⁹ |
| D. | 10⁶ |
| Answer» D. 10⁶ | |
| 85. |
The allosteric inhibitor of an enzyme ___________ |
| A. | Causes the enzyme to work faster |
| B. | Binds to the active site |
| C. | Participates in feedback regulation |
| D. | Denatures the enzyme |
| Answer» D. Denatures the enzyme | |
| 86. |
The vitamin niacin is part of the __________ molecule. |
| A. | ferredoxin |
| B. | pyridoxal phosphate |
| C. | pyrophosphate |
| D. | NAD+ |
| Answer» E. | |
| 87. |
The multistep pathways of metabolism are efficient because they |
| A. | locate all of the enzymes for a pathway in the same place within the cell |
| B. | use the same substrate for all of the enzymes in the pathway |
| C. | use the same enzyme for all of the substrates in the pathway |
| D. | spread the enzymes for a pathway into several different organelles |
| Answer» B. use the same substrate for all of the enzymes in the pathway | |
| 88. |
Which of the following is an example of monosaccharide? |
| A. | Galactose |
| B. | Sucrose |
| C. | Lactose |
| D. | Maltose |
| Answer» B. Sucrose | |
| 89. |
Which of the following are included in the types of glycolipids? |
| A. | N-acetylgalactosamine |
| B. | N-acetylglucosamine |
| C. | Xylose |
| D. | Cerebrosides |
| Answer» E. | |
| 90. |
What is the chemical difference between cellulose and chitin? |
| A. | Replacement of the hydroxyl group at C2 with an acetylated amino group |
| B. | Replacement of the hydroxyl group at C3 with an acetylated amino group |
| C. | Replacement of the hydroxyl group at C4 with an acetylated amino group |
| D. | Replacement of the hydroxyl group at C5 with an acetylated amino group |
| Answer» B. Replacement of the hydroxyl group at C3 with an acetylated amino group | |
| 91. |
Hexokinase activity in glycolysis is inhibited by |
| A. | glucose 6- phosphate |
| B. | fructose 6-phosphate |
| C. | fructose 1,6 biphosphate |
| D. | phosphofructokinase |
| Answer» B. fructose 6-phosphate | |
| 92. |
Which of these hormones is a catecholamine? |
| A. | Follitropin |
| B. | Norepinephrine |
| C. | Tetraiodothyronine |
| D. | Tetrahydrofolate |
| Answer» C. Tetraiodothyronine | |
| 93. |
The rate determining step of Michaelis-Menten kinetics is __________ |
| A. | The complex dissociation step to produce products |
| B. | The complex formation step |
| C. | The product formation step |
| D. | None of the mentioned |
| Answer» B. The complex formation step | |
| 94. |
Two major products of pentose phosphate pathway are |
| A. | nicotinamide adenine dinucleotide and ribose 5-phosphate |
| B. | flavine adenine dinuclueotide and glucose 5-phosphate |
| C. | FAD and CoA |
| D. | NADPH and NAD |
| Answer» B. flavine adenine dinuclueotide and glucose 5-phosphate | |
| 95. |
Which of the following can act as precursors for gluconeogenesis? |
| A. | Lactate |
| B. | Glycerol |
| C. | Alanine |
| D. | All of these |
| Answer» E. | |
| 96. |
Cellulose fibers resemble with the protein structure in the form of |
| A. | β-sheets |
| B. | α-helices |
| C. | β-turns |
| D. | None of these |
| Answer» B. α-helices | |
| 97. |
Lactose is a disaccharide of which of the following sugar units? |
| A. | Glucose and fructose |
| B. | Glucose and galactose |
| C. | Glucose and sucrose |
| D. | Glucose and ribose |
| Answer» C. Glucose and sucrose | |
| 98. |
Which of the following is not a monosaccharide with 5 carbon atoms? |
| A. | Arabinose |
| B. | Xylulose |
| C. | Trehalose |
| D. | Ribulose |
| Answer» D. Ribulose | |
| 99. |
The nucleophile in serine proteases is |
| A. | Serine |
| B. | water |
| C. | both (a) and (b) |
| D. | Asparagine |
| Answer» D. Asparagine | |
| 100. |
The NAG6 substrate is hydrolyzed by human lysozyme to form |
| A. | 6 glucosamines + 6 acetic acids |
| B. | NAG4 + NAG2 |
| C. | NAG3 + NAG3 |
| D. | NAG3 |
| Answer» C. NAG3 + NAG3 | |