Biochemistry MCQs

1. ….…… is the quantitative study of energy transduction.

(a) Thermodynamics
(b) Bioenergetics
(c) Entropy
(d) Enthalpy

2. The measure of heat content of the reactants and products is

designatebd as……….
(a) Free energy
(b) Enthalpy
(c) Entropy
(d) Heat

3. If heat is produced during a reaction, such a reaction is called……….

(a) Endothermic
(b) Exothermic
(c) Thermodynamics
(d) None of these

4. The disorder in the system is designated as……….

(a) Endothermic
(b) Exothermic
(c) Enthalpy
(d) Entropy

5. When the products of a reaction are less complex and more

disordered than the reactants, the reaction is said to have processed
with………. in entropy.
(a) Loss
(b) Gain
(c) No change
(d) None of these

6. The term free energy is also called as………. free energy.

(a) Gibbs
(b) Kelvin
(c) Newton
(d) Einstein

7. If heat is taken up from surroundings then such a reaction is called

as……….
(a) Endothermic
(b) Exothermic
(c) Gain in entropy
(d) Loss in entropy

8. ….…… is the part of total energy that is capable of doing work during
a reaction at constant temperature and pressure.
(a) Heat
(b) Pressure
(c) Free energy
(d) Enthalpy

9. ….…… is the enzyme that can utilize both NAD+ and NADP+ as a
coenzyme.
(a) Glucose dehydrogenase
(b) Glactose dehydrogenase
(c) Glutamate dehydrogenase
(d) None of these

10. The products of glucose oxidation are essential for oxidative

phosphorylation are ………..
(a) NADH
(b) FADH
(c) NADH and FADH2
(d) NADH and FADH

11. The ETC does not directly impact the intermembrane space’s pH
in……….
(a) Complex I
(b) Complex II
(c) Complex III
(d) Complex IV
12. The proportion of ATP produced by oxidative phosphorylation
is………
(a) 30%
(b) 40%
(c) 50%
(d) 60%

13. ….…… is unable to pump protons across the mitochondrial

membrane.
(a) Complex I
(b) Complex II
(c) Complex III
(d) Complex IV

14. ….…… inhibit the cytochrome c oxidase.

(a) Cyanide
(b) CO
(c) CO and Cl
(d) Cyanide and CO

15. Lactatae formed in muscles can be utilized through……….

(a) Rapoport-Lubeling cycle
(b) Glucose -Alanine cycle
(c) Cori’s cycle
(d) Citric acid cycle

16. Glucose-6-phosphate is absent or deficient in

(a) Von Gierke’s disease
(b) Pompe’s disease
(c) Cori’s disease
(d) McArdle’s disease

17. The heptose ketose sugar formed as a result of chemical reaction in

HMP shunt is……….
(a) Sedoheptulose
(b) Glucoheptulose
(c) Mannoheptose
(d) Galactoheptulose

18. The number of isomers of glucose is……….

(a) 4
(b) 8
(c) 12
(d) 16

19. Which of the following enzyme is required for glycolysis?

(a) Pyruvate kinase
(b) Pyruvate carboxylase
(c) Glucose-6-phosphate
(d) Glycerokinase

20. Glycogen is converted to glucose-1-phosphate by……….

(a) UDPG
(b) Branching enzyme
(c) Phosphorylase
(d) Phosphatase

21. Tricarboxylic acid cycle to be continuous requires the regeneration

of……….
(a) Pyruvic acid
(b) Oxaloacetic acid
(c) Malic acid
(d) Fumarate

22. A specific inhibitor for succinate dehydrogenase is……….

(a) Arsinite
(b) Melouate
(c) Citrate
(d) Cyanide

23. The glycolysis is regulated by……….

(a) Hexokinase
(b) Phosphofructokinase
(c) Pyruvate kinase
(d) All of these

24. The formation of peptide bond during the elongation step of

protein synthesis results in the splitting of how many energy bonds?
(a) 2
(b) 3
(c) 4
(d) 5

25. Which of the following genes of the E.coli “Lac Operon” codes for a
constitutive protein?
(a) The a gene
(b) The i gene
(c) The c gene
(d) The z gene

26. The region of the lac operon which must be free (unbound) for
structural gene transcription to occur is……….
(a) The operator locus
(b) The promoter site
(c) The a gene
(d) The i gene

27. The normal function of restriction endonucleases is to:

(a) Excise interons from hn-RNA
(b) Polymerise nucleotides to form RNA
(c) Remove primer from Okazaki fragments
(d) Protect bacteria from foreign DNA

28. How many high energy phosphate bond equivalent are required for
amino acid activation in protein synthesis?
(a) One
(b) Two
(c) Three
(d) Four

29. In the biosynthesis of c-DNA, the joining enzyme ligase requires:

(a) GTP
(b) ATP
(c) CMP
(d) UTP

30. Which of the following statements is accurate for PCR?

(a) Automated PCR machines are called thermal cyclers
(b) A thermostable DNA polymerase is required
(c) Millions to billions of desired DNA copies can be produced from
microgram quantities of DNA
(d) All of the above

31. Which of the following is not a thermostable polymerase?

(a) Pfu polymerase
(b) Taq polymerase
(c) Vent polymerase
(d) DNA Polymerase III

32. What is the process of binding of primer to the denatured strand

called?
(a) Annealing
(b) Renaturation
(c) Denaturation
(d) None of the above

33. Reverse transcription PCR uses:

(a) RNA as a template to form DNA
(b) mRNA as a template to form cDNA
(c) DNA as atemplate to form ssDNA
(d) All of these

34. Which of the following is an application of PCR?

(a) Site-directed mutagenesis
(b) Site-specific recombination
(c) Site-specific translocation
(d) All of the above

35. Which of the following antibiotic inhibits transcription by binding

DNA at the transcription initiation complex and preventing elongation
of RNA chain by RNA polymerase?
(a) Rifampicin
(b) Streptomycin
(c) Carbenicillin
(d) Actinomycin D

36. Which of the following is not a protein synthesis inhibitor by

binding to 30 S small ribosomal subunit?
(a) Kanamycin
(b) Streptomycin
(c) Erythromycin
(d) Tetracycline

37. All the following are true phenylketonuria except:

(a) Deficiency of phenylalanine hydroxylase
(b) Mental retardation
(c) Increased urinary excretion of p-hydroxyphenyl pyruvic acid
(d) Decrease serotonin formation

38. Accomolation of tryptophan in blood is known as:

(a) Pompe’s disease
(b) Wilson’s disease
(c) Wolman’s disease
(d) Hartnup’s disease

39. Control of urea cycle involve’s the enzyme:

(a) Carbomyl phosphate synthetase
(b) Ornithine transcarbamoylase
(c) Argininosuccinase
(d) Arginase

40. The enzymes of urea synthesis are found in:

(a) Mitochondria
(b) Cytosol
(c) Both mitochondria and cytosol
(d) Nucleus

41. The number of ATP required for ATP synthesis is:

(a) 1
(b) 2
(c) 3
(d) 4

42. Conversion of tyrosine to dihydrophenylalanine is catalysed by

tyrosine hydroxylase which requires:
(a) NAD
(b) FAD
(c) ATP
(d) Tetrahydrobiopterin
43. The amino acid that undergoes oxidative deamination at significant
rate is:
(a) Alanine
(b) Aspartate
(c) Glutamate
(d) Glutamine

44. Ammonia is transported from muscles to liver mainly in the form

of:
(a) Free ammonia
(b) Glutamine
(c) Asparagine
(d) Alanine

45. Cystinuria results from inability to:

(a) Metabolite cysteine
(b) Convert cysteine to cysteine
(c) Incorporate cysteine into proteins
(d) Reabsorb cysteine from renal tubules

46. The useful reagent for the detection of amino acids is:
(a) Molisch reagent
(b) Dichlorophenol Indophenol
(c) Ninhydrin
(d) Biuret

47. An amino acid not involved in urea cycle is:

(a) Arginine
(b) Histidine
(c) Ornithine
(d) Citrulline

48. The major end product of protein nitrogen metabolism in man is:
(a) Glycine
(b) Uric acid
(c) Urea
(d) Ammonia

49. Deamination is………of amino group.

(a) Removal
(b) Addition
(c) Supplementation
(d) None of these

50. The symptom of ammonia intoxification includes:

(a) Blurring of vision
(b) Constipation
(c) Mental Confusion
(d) Diarrhea

51. A coenzyme required for the synthesis of glycine from serine is:
(a) ATP
(b) Pyridoxal phosphate
(c) Tetrahydrofolate
(d) NAD

52. Non-protein nitrogenous substances in blood are raised in:

(a) Starvation
(b) Liver damage
(c) Renal failure
(d) All of these

53. Histidine is converted into histamine through the process of:

(a) Transamination
(b) Decarboxylation
(c) Oxidative deamination
(d) Urea cycle

54. The transaminase activity needs the coenzyme:

(a) ATP
(b) B6-PO4
(c) FAD+
(d) NAD+

55. Urinary oxalates in small quantities may arise from:

(a) Tyrosine
(b) Glycine
(c) Serine
(d) Citrates
56. Breakdown of amino acid tryptophan begins with formation of:
(a) Urocanic acid
(b) Nicotinic acid
(c) Anthranilic acid
(d) N-formyl kinureine

57. Which of the following amino acids on degradation produces a

glucogenic intermidiate of TCA cycle and ketone body?
(a) Glycine
(b) Phenylalanine
(c) Alanine
(d) Serine

58. Which of the following is required for crystallization and storage of

the hormone insulin:
(a) Mn++
(b) Mg++
(c) Ca++
(d) Zn++

59. All of the following hormones use cyclic-AMP as a second

messenger except:
(a) FSH
(b) LH
(c) Glucagon
(d) Estrogen

60. Which of the following hormone is involved in increased

reabsorption of water from renal tubular epithelial cells?
(a) Insulin
(b) Glucagon
(c) Vasopressin
(d) Epinephrine

61. Insulin causes all of the following except:

(a) Increased glucose uptake and utilization
(b) Increased amino acids uptake
(c) Increased glycogenesis
(d) Increased ketogenesis
62. What is untrue of a steroid hormone?
(a) Synthesised from cholestrol
(b) Binds to specific receptor protein in cytosol
(c) Steroid receptor complex enters nucleus
(d) Stimulates adenyl cyclase activity

63. All of the following hormones are produced from anterior pituitary
gland except:
(a) Prolactin
(b) TSH
(c) Growth hormone
(d) MSH

64. All of the following are expected to be elevated in blood and

tissues during starvation except:
(a) Glucagon
(b) Glycogen
(c) Ketone bodies
(d) Epinephrine

65. What is the enzyme responsible for the breakdown of triglycerides

into fatty acids and mono-acylglycerol in the intestine?
a) Pancreatic lipase
b) Lipoprotein lipase
c) Hormone-sensitive lipase
d) Phospholipase

66.  What is the function of bile salt in the intestine?

a) Activator of lipase
b) Emulsifier
c) Co-factor for cholesteryl esterase
d) Inhibitor of lipid absorption

67. What is the precursor for bile salt synthesis?

a) Fatty acid
b) Glucose
c) Cholesterol
d) Glycerol
68. The anti-obesity drug Orlistat inhibits:
a) Pancreatic lipase
b) Lipoprotein lipase
c) Hormone-sensitive lipase
d) Phospholipase

69. Lack of appropriate lipid absorption leads to a condition known as

a) Metabolic syndrome
b) Obesity
c) Fatty liver
d) Steatorrhea

70.  Which of the following molecule is not a gluconeogenic substrate?

a) alanine
b) oxaloacetate
c) glycerol
d) acetyl-CoA

71.  The class of lipoproteins that is beneficial to atherosclerosis is …

a) Low-density of lipoproteins
b) Very low-density lipoproteins
c) High-density lipoproteins
d) Chylomicrons

72. Genetic deficiency of lipoprotein lipase cause hyper-

lipoproteinemia of the following type:
a) Type I
b) Type IIa
c) Type IIb
d) Type V

73.  Tangier disease is a disorder of lipoprotein metabolism. The

phenotype corresponds to
a) Low level of VLDL
b) Low level of LDL
c) Low level of IDL
d) Low level of HDL

74. NADPH is synthesized by the action of which of the following

enzymes?
(a) Glucose-6-Phosphate dehydrogenase
(b) Pyruvate dehydrogenase
(c) Lipoprotein lipase
(d) Glycerol kinase

75. The complete oxidation of odd chain fatty acid produces which of
the following?
(a) Acetyl CoA only
(b) Acetyl CoA and Propionyl CoA
(c) Butyryl CoA and Acetyl CoA
(d) Propionyl CoA and Butyryl CoA

76. The activation of long chain fatty acids requires which of the
following components?
(a) 2 ATP
(b) 2 ATP and CoA
(c) 2 ATP, COA and fatty acyl CoA
(d) Fatty acylcarnitine

77. Beta-oxidation of fatty acids is promoted by which of the

following?
(a) ATP
(b) NAD+
(c) FADH2
(d) Acetyl CoA

78. Which of the following product is released from in a alfa-oxidation

of fatty acids?
(a) CoA
(b) CO2
(c) H2O
(d) Acetyl CoA

79. What is the location of synthesis of cholestrol?

(a) Cytoplasm
(b) Mitochondria
(c) ER
(d) Cytoplasm and ER

80. What is the starting molecule of cholestrol synthesis?

(a) Acetyl CoA
(b) Acyl CoA
(c) Glucose
(d) Pyruvate

81. Which enzyme catalyzes the conversion of acetyl CoA to aceto-

acetyl CoA?
(a) Mitochondrial thiaolase
(b) Hydratase
(c) Cytosolic thiolase
(d) None of these

82. Which of the following inhibits the cholestrol synthesis?

(a) Insulin
(b) T3
(c) Intake of calories
(d) None of the above

83. Which enzyme is termed as the rate limiting enzyme of cholestrol

synthesis?
(a) Thiolase
(b) HMG-CoA Reductase
(c) HMG-CoA Carboxylase
(d) All of these

84. Which form of energy is required in the rate limiting step of

cholestrol synthesis?
(a) ATP
(b) NADH
(c) AMP
(d) FAD

85. Which of the following plasma membrane receptors activate

signalling pathways usually by forming molecular dimers that result in
protein phosphorylation reactions upon binding of their specific
ligand?
(a) Steroid hormone Receptor
(b) Receptor tyrosine kinase
(c) Ligand-gated ion channels
(d) G-protein coupled receptor
86. Which of the following has an antagonistic action on adenylate
cyclase?
(a) cAMP
(b) Protein kinase
(c) The active GTP- a subunit of a G-protein
(d) Phosphodiestrase

87. Neurotransmitters are released into the synapse at which of the

following?
(a) Presynaptic membrane
(b) Postsynaptic membrane
(c) Golgi apparatus
(d) Axon hillock

88. Which of the following cells do not reside in the extracellular

matrix?
(a) Mesenchymal stem cells
(b) Fibroblasts
(c) Hepatocytes
(d) Adipose cells

89. Collagen is rich in………

(a) Glutamate and glycine
(b) Alanine and glycine
(c) Proline and glycine
(d) Glutamate and proline

90. Elastin is rich in all components except:

(a) Proline
(b) Glutamate
(c) Lysine
(d) Glycine

91. ….…… is caused by defect in fibrillin.

(a) Alzhimer’s disease
(b) a1 antitrypsin deficiency
(c) Marfan’s disease
(d) All of these

92. Regarding proteoglycans, false is:

(a) Chondrioitin sulphate is a proteoglycan
(b) They hold less amount of water
(c) They are made up of sugar and amino acids
(d) They carry charge

93. The basic structure of proteoglycan consists of a core protein and a:

(a) Glycolipid
(b) Glycosaminoglycans
(c) Lectin
(d) Peptidoglycan

94. What is the main component of bones and teeth?

(a) Calcium Phosphate
(b) Calcium Carbonate
(c) Calcium Sulphate
(d) Calcium Nitrate

95. Calcification of all teeth except last molar teeth is completed by:
(a) 2 years
(b) 4 years
(c) 8 years
(d) 12 years

96. Which of the following is a contractile protein of a muscle?

(a) Tubulin
(b) Myosin
(c) Troponin
(d) All of these

97. Muscles fatigue sets in due to non-availability of:

(a) ATP
(b) Calcium
(c) Actin binding site
(d) Mg cofactor

98. The rigid state of muscles that develops shortly after death is due
to this highly cross-linked state of thin and thick filaments and is
known as:
(a) Mortility
(b) Death syndrome
(c) Flaccid paralysis
(d) Rigor Mortis

99. Cytoskeletons are chemically:

(a) Nucleoproteins filaments
(b) Nucleoprotein filaments and lipids
(c) Ribonucleoprotein filaments
(d) Protein Filaments

100. Which of the following is microfilament inhibitor:

(a) Cytochalasin-B
(b) Cinchonine
(c) Cholchicine
(d) Aspirin
 MCQs Key

Sr.No Answers Sr.No Answer Sr.No Answers Sr.No. Answers

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