PACOP RED (Biochemistry)

1. Isoelectric or pI is the pH midway between pKa values on either side of isoelectric species where amino acids exits as neutral species. Lysine has three pK values. pK1=2.2, pK2=9.2 and pK3=10.8. What is the pI of lysine? A. 5.7 B. 6.5 C. 10 D. 11.4 E. 9.2

C. 10

2. Most amino acids do not absorb visible light and thus are colorless. However, there are some that can absorb light. Which of the following groupings of amino acids contribute to the ability of most proteins to absorb high wavelength (250-290nm) ultraviolet light? A. Alanine, valine, leucine B. Tryptophan, tyrosine and phenylalanine C. Serine, cysteine, and threonine D. Arginine, lysine and arginine E. Glutamate and aspartate

B. Tryptophan, tyrosine and phenylalanine

3. In protein nomenclature, if the name of the peptide is phenylalanyl-aspartyl-lysyl-asparagine, which residue has its a-carboxyl group not involved in the peptide bond formation? A. Phe B. Asp C. Lys D. Asn E. None

D. Asn

4. Which of the following pairs of amino acids with the indicated side-chain is CORRECT? A. Cysteine-sulfhydryl group B. Valine-methyl group C. Tryptophan-phenol group D. Serine-guanido group E. Methionine-hydroxymethyl

A. Cysteine-sulfhydryl group

5. Which of the following statement/s is/are TRUE about glutamine and asparagine? I. Their amide chains can be protonated II. They are uncharged at physiologic pH. III. They are easily differentiated from aspartate and glutamate by chemical procedures since amides closely resemble acids in the chemical properties. IV. They are structural analogs of aspartate and glutamate with their carboxylic side-chain groups aminated A. I, II, III B. I & III C. II & IV D. I, II, III & IV

C. II & IV

6. _____ configuration of the peptide bond is more stable than the _____ configuration. A. Syn; anti B. Trans; cis C. R; S D. D; L E. Erythro; threo

B. Trans; cis

7. Evaluate the following statements. 1. The alpha carbonyl to nitrogen portion of the peptide bond can rotate at physiologic temperatures. 2. The double bond character of the peptide bond makes the peptide bond planar. A. only the first statement is correct. B. only the second statement is correct. C. Both the first statements is correct. D. Both the first statements is incorrect.

B. only the second statement is correct.

8. Glutamic acid has 3 pK values: pK1=2.2, pK2=4.3 and pK3=9.7. Which of the following ionic forms of glutamic acid will predominate at a pH below its isoelectric point of 3.25? A. COOH COOH B. COO COOH C. COO COO D. COO COO E. COO COOH

A. COOH COOH

9. Most _____ amino acids are buried away from water solvent that interacts with the surface of a soluble protein while most _____ side chains are on the surface of soluble globular proteins. A. Charged; hydrophobic B. Hydrophobic; charged C. Hydrophobic; apolar D. Charged; polar E. None of these

B. Hydrophobic; charged

10. Which amino acids is antagonized by drugs of abuse such as ketamine and phencyclidine and is implicated in schizophrenia? A. Glycine B. Aspartate C. Tryptophan D. Glutamate E. Tyrosine

D. Glutamate

11. Which amino acid is a major neurotransmitter in the brain? A. Tyrosine B. Glutamate C. Aspartate D. Serine E. Tryptophan

B. Glutamate

12. A 57 year old man with a long history of alcohol abuse comes to the emergency room with symptoms of confusion and hepatomegaly on examination. The patient also has a flapping tremor at the wrist (asterixis). He is diagnosed with hepatic encephalopathy, which can be partially treated with a diet of branched-chain amino acids. Which of the following sets of amino acids would you suggest? A. Tryptophan, phenylalanine, tyrosine B. Aspartate, glutamine, asparagine C. Valine, leucine, isoleucine D. Methionine, proline, cysteine E. Alanine, glycine

C. Valine, leucine, isoleucine

13. Which of the following amino acids is inhibitory & antagonized by the rodenticide strychnine, leading to muscle twitching and spasm? A. Glycine B. Asparagine C. Lysine D. Tyrosine E. Tryptophan

A. Glycine

14. A man diagnosed of Hartnup disease wherein his urinalysis results showed significant increase in the neutral amino acids. Which of the following amino acids would have been found in his urine sample? A. Histidine B. Arginine C. Phenylalanine D. Glutamate E. Lysine

C. Phenylalanine

15. The presence of which characteristic distinguishes a eukaryote from prokaryote A. DNA B. Well-defined nucleus C. Cytoplasm D. Cell membrane E. Ribosome

B. Well-defined nucleus

16. An organelle is the portion of the cell enclosed by a membrane. Based on this, which of the following is not strictly an organelle? A. Mitochondrion B. Lysosome C. Ribosome D. Endoplasmic reticulum E. None of these

C. Ribosome

17. Hydrogen bonding plays a role in the behavior of water as a solvent. It is also a key to the specificity of transfer of genetic information. Which does not properly illustrate hydrogen bonding? A. -O-H---O-H B. C-H---O-H C. N-H---N D. N-H---O=C E. None of the above

B. C-H---O-H

18. Which of the following vitamins may cause CNS disturbances, liver and skin damage when taken in excess? A. A B. B3 C. B6 D. D E. E

A. A

19. Which of the vitamins may cause extensive vasoconstriction and elevated blood pressure and calcinosis of soft tissues when taken in excess? A. Vitamin A B. Vitamin B3 C. Vitamin B6 D. Vitamin D E. Vitamin E

D. Vitamin D

20. The organelle-free cell sap where many reactions and metabolic pathways such as glycolysis, glycogenesis and fatty acid synthesis occur is known as the A. Mitochondrion B. Cytosol C. Nucleus D. Smooth endoplasmic reticulum E. Cell membrane

B. Cytosol

21. Part of the cell that contains the organelles that carry out functions essential to cell metabolism. A. Cell membrane B. Cytoplasm C. Nucleus D. Cytoskeleton E. Nucleolus

B. Cytoplasm

22. Site of lipid synthesis in cells A. Smooth endoplasmic reticulum B. Rough endoplasmic reticulum C. Golgi apparatus D. Mitochondrion E. Lysosomes

A. Smooth endoplasmic reticulum

23. Primary reserve carbohydrate in plants A. Chitin B. Glycogen C. Starch D. Chondroitin E. Heparin

C. Starch

24. Water has high _____ hence it is good in minimizing temperature fluctuations. A. Polarity specific heat B. H-bond potential C. Acidity D. Nucleophilicity

A. Polarity specific heat

25. Molecules that are part hydrophilic and part hydrophobic. A. Amphipathic B. Protophilic C. Nucleophilic D. Amphiphilic E. Protogenic

A. Amphipathic

26. When C1 of monosaccharides becomes chiral, it is now known as a(an): A. Epimeric carbon B. Enantiomeric carbon C. Asymmetric carbon D. Anomeric carbon E. Acetalic carbon

D. Anomeric carbon

27. Two sugars that differ only in the configuration of one carbon atom other than the terminal carbon atom or penultimate carbon atom are called A. Anomers B. Epimers C. Enantiomers D. Erythro isomers E. Threo isomers

B. Epimers

28. The glycosidic linkage that binds glucose and glucose to form maltose. A. Beta-(1-2) B. Beta-(1-4) C. Alpha-(1-4) D. Alpha-(1-2) E. Alpha-(4-1)

C. Alpha-(1-4)

29. The glycosidic linkage that binds glucose and galactose to form lactose. A. Beta-(1-2) B. Beta-(1-4) C. Alpha-(1-4) D. Alpha-(1-2) E. Alpha-(4-1)

B. Beta-(1-4)

30. The component of starch that reacts with iodine to form a deep-blue colored complex A. Glycogen B. Achroodextrin C. Maltotriose D. Amylose E. Amylopectin

D. Amylose

31. A sulfated polysaccharide found in Gelidium cartilagineum which can be used as culture media for growing microorganisms. A. Chitin B. Agar C. Pectin D. Hyaluronic acid E. Dextran

B. Agar

32. Amino sugar found in chondroitin A. N-acetylfructosamine B. N-acetylglucosamine C. N-acetylgalactosamine D. N-acetylmuramic acid E. N-acetylmannosamine

C. N-acetylgalactosamine

33. Dextran is primarily used as a(an): A. Suspending agent B. Culture medium C. Glomerular filtration evaluation D. Plasma expander E. Sweetener

D. Plasma expander

34. An enzyme considered to be a "spreading" factor to increase the absorption of solutions administered by clysis. A. Sucrase B. Amylase C. Hyaluronidase D. Amylopectase

C. Hyaluronidase

35. Heparin, a mucopolysaccharide is used as an anticoagulant because: A. It inhibits platelet aggregation B. It dissolves blood clots C. It dissolves fibrin D. It activates antithrombin E. It hydrolyzes prothrombin

D. It activates antithrombin

36. Branching frequency of glycogen's structure: A. Every 4-6 glucose units B. Every 6-10 glucose units C. Every 12-14 glucose units D. Every 2-6 glucose units E. Every 25-30 glucose units

B. Every 6-10 glucose units

37. The principal component of exoskeletons of arthropods, lobster & crabs A. Peptidoglycan B. Cellulose C. Chondroitin D. Chitin E. Cell wall

D. Chitin

38. It is the dietary precursor for arachidonic acid. A. Oleic acid B. Timnodonic acid C. Linoleic acid D. Linolenic acid E. Cervonic acid

C. Linoleic acid

39. Glucose and galactose are epimers at carbon number: A. 6 B. 3 C. 4 D. 5 E. 2

C. 4

40. Which carbohydrate would not rotate plane polarized light? A. Erythrose B. Glycerose C. Dihydroxyacetone D. Fructose E. Glucose

C. Dihydroxyacetone

41. Glucose and mannose are epimers at carbon number: A. 6 B. 3 C. 4 D. 5 E. 2

E. 2

42. Bonds that link fatty acids with glycerol in triglycerides. A. Ester bonds B. Amide bonds C. Ether bonds D. Aldehydic bonds E. H-bonds

A. Ester bonds

43. Amylose differs from amylopectin in that amylose contains alpha-1,4 linkages while amylopectin contains linkage/s: I. Alpha-(1-2) II. Alpha-(1-4) III. Alpha-(1-6) A. I, II & III F. I & II G. II & III H. II only I. III only

G. II & III

44. The alcohol contained by glycosphingolipids A. Glycerol B. Sphingosine C. Glycol D. Fatty alcohols E. Sterols

B. Sphingosine

45. Phosphatidylcholine is also known as: A. Lecithin B. Cephalin C. Plasmalogen D. Cardiolipin E. Sphingomyelin

A. Lecithin

46. Phosphatidylethanolamine is also known as: A. Lecithin B. Cephalin C. Plasmalogen D. Cardiolipin E. Sphingomyelin

B. Cephalin

47. It is a formula used to describe the behavior of weak acids and buffers in solution: A. Henderson-Hasselbalch Equation B. Van't Hoff Equation C. Michaelis-Menten Equation D. Nernst Equation E. Arrhenius Equation

A. Henderson-Hasselbalch Equation

48. Fructose intolerance can lead to: A. Diarrhea B. Flatulence C. Hypoglycemia D. Constipation E. GIT spasm

C. Hypoglycemia

49. Failure to metabolize galactose causes galactosemia and further: A. Renal failure B. Liver failure C. Cataracts D. Neuropathy E. Arthropathy

C. Cataracts

50. Eicosapentaenoic acid (EPA) found in fish preparations such as Omacor® is commonly known as? A. Palmitoleic acid B. Timnodonic acid C. Linoleic acid D. Cervonic acid

B. Timnodonic acid

51. Docosahexaenoic acid (DHA) found in fish oil preparations such as Omacor® is commonly known as? A. Palmitoleic acid B. Timnodonic acid C. Linoleic acid D. Linolenic acid E. Cervonic acid

E. Cervonic acid

52. EPA and DHA belong to what omega superfamily of fatty acids? A. Omega-9 B. Omega-6 C. Omega-3 D. Omega-5 E. Omega-7

C. Omega-3

53. Which of the following monosaccharide is found in wood gums and in vivo, in several glycoproteins? A. Arabinose B. Xylulose C. Xylose D. Lyxose E. Erythrose

C. Xylose

54. A deoxy sugar found in the DNA molecule A. Fucose B. Deoxygalactose C. Deoxyribose D. Deoxyglucose E. Idose

C. Deoxyribose

55. DNA differs from RNA in that the OH in C2 of the monosaccharide found in the RNA is replaced by: A. Amino group B. Nitrogenous base C. Carboxyl carbon D. Hydrogen atom E. Carbonyl carbon

D. Hydrogen atom

56. Monosaccharide found in cases of pentosuria which is usually due to a genetic deficiency of the reductase that reduces the monosaccharide to a non-reducing sugar alcohol: A. Arabinose B. Lyxose C. Xylulose D. Xylose E. Ribulose

C. Xylulose

57. Molisch test is also known as: A. Alpha-naphthol reaction B. Aminoguanidine reaction C. Anthrone reaction D. Salkowski test E. Liebermann-Burchard test

A. Alpha-naphthol reaction

58. Tauber's test for ketoses is also known as: A. Alpha-naphthol reaction B. Aminoguanidine reaction C. Anthrone reaction D. Salkowski test E. Liebermann-Burchard test

B. Aminoguanidine reaction

59. What is the central nucleus to all sterols? A. Cyclopentanephenanthrene B. Cycloperhydrophenanthrene C. Cyclopentanophenanthrene D. Cyclopentanoperhydrophenanthrene E. Steroid Ring

D. Cyclopentanoperhydrophenanthrene

60. The acetic acid-sulfuric acid test for sterols is also known as: A. Alpha-naphthol reaction B. Aminoguanidine reaction C. Anthrone reaction D. Salkowski test E. Liebermann-Burchard test

E. Liebermann-Burchard test

61. The sulfuric acid test for sterols is also known as: A. Alpha-naphthol reaction B. Aminoguanidine reaction C. Anthrone reaction D. Salkowski test E. Liebermann-Burchard test

D. Salkowski test

62. Eicosanoid that is the major mediator of pain, inflammation. A. Prostaglandin B. Arachidonic acid C. Prostacyclin D. Thromboxane E. Leukotriene

A. Prostaglandin

63. The enzyme that converts arachidonic acid to leukotriene. A. Prostaglandin synthase B. Lipoxygenase C. Cyclooxygenase D. Thromboxane synthase E. Phospholipase A2

B. Lipoxygenase

64. It is the major surfactant found in the lungs of newborn babies and neonates that prevents the adherence of inner lung surfaces together. A. Lecithin B. Dipalmitoylphosphatidylcholine C. Dipalmitoylphosphatidylethanolamine D. Cephalin E. Phosphatidylinositol

B. Dipalmitoylphosphatidylcholine

65. These are the major lipids of the mitochondria. A. Cardiolipin B. Cephalin C. Lecithin D. Inositol E. Phosphatidylserine

A. Cardiolipin

66. Secondary messengers that are biosynthesized by action of phospholipase C include diacylglycerol and: A. Inositol 4,5-bisphosphate B. Inositol 1,4,5-trisphosphate C. Inositol 5-phosphate D. Inositol 1,4,5,6-tetrakisphosphate E. Inositol monophosphate

B. Inositol 1,4,5-trisphosphate

67. These are molecules that resemble cephalin, and are found in the brain and muscles; the only difference is that instead of an ester group on sn-1, an ether group is present and the alkyl group is unsaturated. A. Sphingomyelin B. Plasmalogen C. Lysophospholipid D. Ceramide E. Sphingosine

B. Plasmalogen

68. It is the basic unit of glycolipids. A. Glycerol B. Sphingosine C. Ceramide D. Fatty acids E. Phosphatidate

C. Ceramide

69. It is the glycolipid found in neural tissues. A. Neutramide B. Neurosylceramide C. Glucosylceramide D. Globoside E. Galactosylceramide

E. Galactosylceramide

70. A sample drug that inhibits cyclooxygenase A. Zileuton B. Montelukast C. Zafirlukast D. Aspirin E. Salicylic acid

D. Aspirin

71. Pro-vitamin D2 A. Ergosterol B. 7-dehydrocholesterol C. Sitosterol D. Coprosterol E. 5-dehydrocholesterol

A. Ergosterol

72. Pro-vitamin D3 A. Ergosterol B. 7-dehydrocholesterol C. Sitosterol D. Coprosterol E. 5-dehydrocholesterol

B. 7-dehydrocholesterol

73. Which of the following completely inhibits cholesterol absorption? A. Ergosterol B. 7-dehydrocholesterol C. Sitosterol D. Coprosterol E. 5-dehydrocholesterol

C. Sitosterol

74. 5,8,11,14-20:4 corresponds to what fatty acid? A. Palmitoleic acid B. Linoleic acid C. Oleic acid D. Linolenic acid E. Arachidonic acid

E. Arachidonic acid

75. C11H23COOH corresponds to what fatty acid? A. Myristic acid B. Stearic acid C. Lauric acid D. Palmitic acid E. Capric acid

C. Lauric acid

76. CH3(CH2)4CH=CHCH2CH=CH(CH2)7COOH corresponds to what fatty acid? A. Palmitoleic acid B. Linolenic acid C. Arachidonic acid D. Oleic acid E. Linoleic acid

E. Linoleic acid

77. 16:1 corresponds to what fatty acid? A. Palmitoleic acid B. Linolenic acid C. Arachidonic acid D. Oleic acid E. Linoleic acid

A. Palmitoleic acid

78. What is the positive result for Molisch Test? A. Green color B. Violet ring at the junction of two liquids C. Black precipitate D. Sandy crystals E. Brick red precipitate

B. Violet ring at the junction of two liquids

79. Which of the following is used for determination or testing for the presence of ketoses? I. Nylander's test II. Tauber's test III. Barfoed's test IV. Seliwanoff's test A. I, II & III B. I & III C. II & IV D. II & III E. II, III & IV

C. II & IV

80. What is the positive result for the aminoguanidine reaction? A. Red color B. Violet color C. Black precipitate D. Bright red purple color E. Purple color

D. Bright red purple color

81. To which of the following test(s) will sucrose give a negative result? I. Fehling's test II. Barfoed's test III. Molisch test A. I, II & III B. I & II C. II & III D. I & III E. I only

B. I & II

82. Which of the following is a drug used for hypercholesterolemia, owing to its ability of inhibiting HMG-CoA reductase, the first committed step in the biosynthesis of cholesterol? A. Rosuvastatin B. Cilastatin C. Nystatin D. Clindamycin E. Chloramphenicol

A. Rosuvastatin

83. These are lipids with glucose or galactose combined with ceramide A. Cerebrosides B. Gangliosides C. Globosides D. Cytolipins E. Cardiolipins

A. Cerebrosides

84. What monosaccharide readily forms osazones? A. Galactose B. Fructose C. Glucose D. Mannose E. Ribose

C. Glucose

85. Which of the following is considered to be the good cholesterol? A. VLDL-C B. LDL-C C. IDL-C D. HDL-C E. TAGS

D. HDL-C

86. Amino acids that cannot be synthesized in the organism are called A. Nutritionally non-essential amino acids B. Nutritionally essential amino acids C. Alpha amino acids D. Standard amino acids E. Nutritional amino acids

B. Nutritionally essential amino acids

87. When trypsinogen is converted into trypsin, the enzyme that catalyzes this is called: A. Pepsin B. Zymogen C. Amylase D. Enterokinase E. Gastrin

D. Enterokinase

88. A malnutrition state that arises from chronic deficiency of calories even in the presence of adequate protein intake. A. Marasmus B. Hemochromatosis C. Obesity D. Kwashiorkor E. Anorexia

A. Marasmus

89. Complementary base pairs in the DNA double helix are bonded by A. H-bond B. Ester bond C. Dipole-dipole forces D. Van der Waals forces E. Glycosidic bond

A. H-bond

90. Which nitrogen base is not found in the DNA? A. Adenine B. Guanine C. Cytosine D. Uracil E. Thymine

D. Uracil

91. Pepsinogen is an example of: A. Co-factor B. Co-substrate C. Zymogen D. Holoenzyme E. Apoenzyme

C. Zymogen

92. Type of RNA which serves as template for the amino acid sequence being synthesized: A. mRNA B. tRNA C. rRNA D. dRNA E. None of the above

A. mRNA

93. Which of the following is true about uricase? I. Converts uric acid to water-soluble allantoin II. It is found only in higher primates III. rDNA derived uricase are now being employed for the management of gouty arthritis. A. I only B. II only C. I & II D. I, II & III E. I & III

E. I & III

94. Which of the following is/are rDNA-derived uricase? I. Pegloticase II. Febuxostat III. Rasburicase A. I & II B. II & III C. I & III D. I, II & III E. I only

C. I & III

95. The amino acid groups from amino acids obtained by protein metabolism are removed in the form of: A. Urate B. Urea C. Creatinine D. Ornithine E. Ammonia

E. Ammonia

96. Glutamine is represented by what letter in the amino acids "alphabet"? A. K B. Q C. D D. E E. Y

B. Q

97. Which of the following amino acids are uncharged and polar? I. H II. N III. S IV. D A. I & II B. I & III C. I & IV D. II & III E. II & IV

D. II & III

98. Which of the following amino acids possesses an indole ring? A. D B. Q C. F D. K E. W

E. W

99. Which amino acid gives a positive result for Sakaguchi reaction? A. Gelatin B. Arginine C. Alanine D. Tyrosine E. Tryptophan

B. Arginine

100. Which of the following amino acids is an important component of the activated co-enzyme involved in methylating catecholamines for termination of their biological activity and in other biochemical reactions that require methyl transfer? A. Alanine B. Cysteine C. Cystine D. Methionine E. Leucine

D. Methionine