CHEMISTRY MCQs (PART 2)

CHEMISTRY  MCQs (PART 2)

45. The major end product of protein nitrogen metabolism in man is

(A) Glycine

(B) Uric acid

(C) Urea

(D) NH3

46. An amino acid not involved in urea cycle is

(A) Arginine

(B) Histidine

(C) Ornithine

(D) Citrulline

47. NH3 is detoxified in brain chiefly as

 (A) Urea

(B) Uric acid

(C) Creatinine

(D) Glutamine

48. In humans, NH3 is detoxified in liver as

(A) Creatinine

(B) Uric acid

(C) Urea

(D) Uronic acid

49. The body protein after eighteen years

(A) Remains unchanged

(B) Is decomposed only slightly at intervals of one month

(C) Is in a constant state of flux

(D) Is used only for energy requiremen

50. The only known physiological methylating agents in the animal organism are

(A) Choline and betaine

(B) Choline and δ-adenosyl methionine

(C) Betaine and δ-adenyosyl methionine

(D) Dimehtyl glycine and betaine

51. In the synthesis of 1 molecule of urea in the Kreb’s Hanseleit cycle, the number of ATPs required is (A) 1

(B) 2

(C) 3

(D) 4

52. For biosynthesis of proteins

(A) Amino acids only are required

(B) Amino acids and nucleic acids only are required

(C) Amino acid, nucleic acids and ATP only are required

(D) Amino acids, nucleic acids, ATP, GTP, enzymes and activators are required

53. Transmethylation of guanido acetic acid gives

(A) Creatine phosphate

(B) Creatinine

(C) Choline

(D) n-methyl nicotinamide

 54. The 2 energy rich compounds needed for protein biosynthesis are

(A) ATP and GTP

(B) ATP and UTP

(C) ATP and CTP

 (D) ATP and TTP

 55. The following ketoacid is involved in fixing dietary NH3 into amino acid:

(A) Pyruvate

(B) Oxalo acetate

(C) Oxalo succinate

(D) α-keto glutarate

56. The metabolite which sustains urea cycle is

(A) Ornithine

(B) Citrulline

(C) Carbamoyl phosphate

(D) n-acetyl glutamate

57. Tetra hydroglolate can be freed from N5 methyl tetrahydrofolate only by

(A) Nor epinephrine

(B) Ethanol amine

(C) Nicotinamide

(D) Vitamin B12

458. Neogenesis of methyl group is

(A) The availability of methyl group form δ adenosyl methionine

(B) The availability of methyl group from betaine

(C) Interaction between N5 N10 methylene tetra hydrofolate with a NAD+ dependent reductase

(D) Availability of methyl group from methyl B12

59. More creatinine is excreted by

(A) Adult males

(B) Adult females

(C) Children

(D) Pregnant women

60. A growing peptide in a ribosome can not be shifted to the adjacent ribosome because

(A) It is firmly attached

(B) It will get the amino acid cleaved

(C) The gap between the ribosomes is too big for a shift

(D) The adjacent ribosomes have different composition

61. The first amino acid incorporated in a polypeptide in a ribosome of a human is

(A) N formyl methionine

(B) Methionine

(C) Phenyl alanine

(D) Hydroxy lysine

62. The first amino acid incorporated in a polypeptide in a ribosome of a bacterium is

(A) N formyl methionine

(B) Methionine

(C) Alamine

(D) Glycine

63. The integrator between the TCA cycle and urea cycle is

(A) Fumarate

(B) Malate

(C) Pyruvate

(D) Citrate

64. Bence jones proteinurial characterized by

(A) Non-heat coagulability

(B) Heat coagulability at 100°C

(C) Heat coagulability at 45 to 60°C

(D) Precipitation at 25°C

65. Bence Jones proteins may be excreted in urine of patients suffering from

(A) Tuberculosis

 (B) Diabetes mellitus

(C) Multiple myeloma

(D) Hyperthyroidism

66. Xanthuric acid is an abnormal metabolite of

(A) Xanthine

(B) Uric acid

(C) Tyrosine

(D) Tryptophan

67. Two nitrogen atoms of Urea in the urea cycle come from

(A) NH3

(B) One from NH3 and one from aspartate

 (C) One from NH3 and one from glutamate

(D) One from NH3 and one from alanine

68. Pyruvic acid can be obtained by transamination of alanine with

(A) α- keto glutaric acid

 (B) Acetoacetic acid

 (C) β−OH butyric acid

(D) Phosphoenol Pyruvic acid

69. In the synthesis of 1 molecule of urea in the Kreb’s Henseleit cycle the number of AMPs formed is (A) 1

(B) 2

(C) 3

(D) 4

70. Formation of melanin from tyrosine requires the action of

(A) Dopa decarboxylation

(B) Diamine oxidase

(C) Peroxidase

(D) Tyrosinase

71. In one of the following the quality of the protein synthesized is affected:

(A) Diabetes mellitus

(B) Gont

(C) Multiple myeloma

(D) Primaquine sensitivity

72. Citrulline is an intermediate of

(A) TCA cycle

(B) Urea cycle

(C) Pentose cycle

(D) Calvin cycle

73. The semialdehydes are formed under the action of enzymes characterised as

(A) Aldolases

 (B) Peptidyl lysyl oxidases

(C) Collagenases

(D) Elastases

74. Which of the following statement about the peptide bond is true?

(A) It is a carbon-carbon bond

(B) It has cis hydrogen and oxygen groups

(C) It is planar

(D) It has rotational freedom

75. Isoenzymes for a given reaction

 (A) Have different spedificities

(B) Have identical affinities for the same substrate

(C) Exhibit different electrophoretic motilities

(D) Contain similar ratios of different polypeptide chains

76. The highest concentration of cystine can be found in

(A) Melanin

(B) Chondroitin sulphate

(C) Myosin

 (D) Keratin

77. One round of Edman degradation of the peptide: H2N— Gly—Arg—Lys—Phe— Asp— COOH would result in which of the following structures or their phenyl isothiocyanate derivatives?

(A) H2N—Gly—Arg—COOH + H2N—Lys— Phe— Asp—COOH

(B) H2N—Gly—Arg—Lys—Phe—COOH + Asp

 (C) H2N—Arg—Lys—Phe—Asp—COOH + Gly

(D) H2N—Gly—Arg—Lys—COOH + H2N—Phe —Asp—COOH

78. Which of the following techniques is used to separate proteins based upon differences in their mass?

(A) Isoelectric focusing

(B) Dialysis

(C) SDS-gel Electrophoresis

 (D) Western blotting

79. The greatest buffering capacity at physiologic pH would be provided by a protein rich in which of the following amino acids ?

 (A) Lysine

(B) Histidine

(C) Aspartic acid

(D) Valine

80. Which one of the amino acids could serve as the best buffer at pH 7?

(A) Glutamic acid

(B) Arginine

(C) Valine

(D) Histidine

81. Which one of the following statements concerning glutamine is correct?

(A) Contains three tetratable groups

(B) Is classified as an acidic amino acid

(C) Contains an amide group

(D) Migrates to the cathode during electrophoresis at pH 7.0

82. One of the given example is an amino acid:

(A) Oh-Lysine

(B) Protein

(C) Leucine

(D) Serine

83. The lone pair of electrons at one of the ring nitrogens in the given amino acid makes a potential ligand, which is important in binding the iron atoms in hemoglobin:

 (A) Tryptophan

 (B) Threonine

(C) Histidine

(D) Serine

84. The amino acid which is not optically active is

(A) Alanine

(B) Glycine

 (C) Glutamine

(D) Lysine