Biochemistry PACOP Violet PDF

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1. What biomolecules are considered the most abundant and functionally diverse in the living system? A. Proteins B. Carbohydrates C. Nucleic acid D. Fatty acid E. Terpenoids 2. Which of the following statements is correct about protein structure? I. The primary structure of a protein involves and ot...

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1. What biomolecules are considered the most abundant and functionally diverse in the living system? A. Proteins B. Carbohydrates C. Nucleic acid D. Fatty acid E. Terpenoids 2. Which of the following statements is correct about protein structure? I. The primary structure of a protein involves alpha-helics, beta-sheets and other types of folding patterns that occur due to a regular repeating pattern of hydrogen bond formation. II. The secondary structure consist of the amino acids sequence along the chain. III. The tertiary structure involves electrostatic and hydrophobic interations, van der waals interaction, and hydrogen and disulfide bonds, IV. Quaternary structure refers to the interaction of one or more subunits to form a functional protein, using the same force that stabilize the tertiary structure. A. I only B. I and II C. II and III D. I and IV E. III and IV 3. Accumulated misfolded proteins occur in variety of disease. Which of the following proteins is misfolded in patients with Alzheimer’s disease? A. Prion protein B. Alpha-synuclein hes D. Beta-amyloid E. None of these 4. Hemoglobinopathies result from mutations that produce alterations in the structure of hemoglobin. One common mutation result is sickle cell anemia, in which a mutated form of hemoglobin distorts the RBC into a crescent shape at low oxygen levels. Sickle cell anemia happens when: A. Valine is being substituted by glutamine at codon number 6 B. Glutamic acid is being substituted by valine at position number 6 C. Glutamine is intercalated by histidine at codon number 6

D. Gene transcription is distrupted E. None of these 5. Acid-base disturbances occur under a variety of conditions. Which of the following is the result of hyperventilation due to retention of carbon dioxide in the lungs. A. Respiratory acidosis B. Respiratory alkalosis C. Metabolic acidosis D. Metabolic alkalosis E. Lactic acidosis 6. In amino acids, the pH at whioch the number of positive charges equals the number of negative charge is termed as_______? A. Chirality B. Amphoteric property C. Optical activity D. Isoelectric point E. Zwitterions 7. Molecules that contain an equal number of ionizable groups of opposite charge and that therefore bear no net charge are termed as____________ A. Chirality B. Amphoteric property C. Optical activity D. Isoelectric point E. Zwitterions 8. Problems associated with connective tissues and structural protein are present in a number of disease. In scurvy, hydroxylation of proline residues is decrease and an unstable form of collagen is produced. Bones, teeth, blood vessels and other structures rich in collagen develop abnormally. Bleeding gums and poor wound healing are often observed. Which of the following vitamin deficiencies is associated to scurvy? A. Vitamin C B. Vitamin E C. Vitamin A D. Vitamin D E. Vitamin K 9. Which of the following is true about insulin functions I. Insulin is release form the pancreas when blood glucose levels are elevated II. Insulin promotes the transport of glucose into muscle and fat cells

III. Insulin promotes the storage of energy IV. Insulin increases glycogen catabolism in the liver and muscles A. I and II B. I, II and III C. I, II and IV D. I only E. !, !!, !!!, and IV 10. The enzyme kinetics can be described by what equation? A. Noyes-Whitney Equations B. Henderson- Hasselbach Equation C. Arrhenius Equation D.Van Slyke Equation E. Michaelis-Menten Equation 11. Evaluate the given statements. (1) Competitive inhibitors compete with the substrate for binding at the allosteric site of the enzyme. (2) Noncompetitive inhibitors bind to the enzyme or the enzyme substrate complex at the active site. A. Only I is correct B. Only II is correct C. I and II are correct D. I and II are incorrect 12. In phenylketonuria, the enzyme phenylalanine hy6droxylase ios deficient. Which of the following statements is not true about the condition? A. Phenylketonuria happens as a result of accumulated phenylalanine in the body B. Tyrosine becomes a essential amino acid among phenylketonuric patients C. Aspartame is recommended for phenylkotenuric patients D. Phenylalanine non metabolism leads to mental retardation. E. None of these 13. Which of the following is not a basic amino acid? A. Histidine B. Leucine C. Lysine D. Arginine E. None of these 14. What are the amide linkages between the alpha-carbonyl group of one amino acid and alpha amino group of another? A. Peptide bonds

B. Disulfide bonds C. Hydrogen bonds D. Hydrophobic bonds E. Ionic bonds 15. Edman’s reagent is used to label the amino terminal residue under mildly alkaline conditions. What is the component of this reagent? A. Monosodium glutamate B. Alpha-naphthol C. Picric acid D. Phenylisothiocyanate E. None of these 16. Several different polypeptide helices are found in nature, but the alpha-helix is the most common. What bond stabilizes this helix? A.Hydrogen bond B. Peptide bond C. Phosphodiester bond D. Hydrophobic bond E.Ionic bond 17. What protein structures reverse the direction of a polypeptide chain, helping it form a compact, globular shape? A. alpha-helices B. beta-sheets C. Beta-bends D. All of these E. Ionic bond 18. What specialized group are required for the proper folding of many species of proteins? A. Chaperones B. Heat shockproteins C. Beta bends D. A and B E. A and C 19. Many proteins consist of a single polypeptide chain, and are defined as monomeric proteins. However, others may consist of two or more polypeptide chains that may be structurally identical or totally unrelated. These statements describe what protein structure? A. Primary structure B. Secondary structure C. Tertiary structure D. Quaternary structure E. None of these

20. What protein is misfolded in Creutzfeldt-Jakob disease? A. Prion B. Glutamine stretches C. Beta-globin D. Beta-amyloid E. None of these 21. What are the two most abundant hemeproteins in humans? A. B. Hemoglobin and cytochrome oxidase C. Hemoglobin and catalase D. Cytochrome and catalase E. All of these 22. The complex of protoporphyrin IX and ferrous iron is termed as ___? A. Heme B. Hemoglobin C. Transferin D. Ferritin E. Myoglobin 23. What is the hemeprotein found in heart and skeletal muscles which functions both as a reservoir for oxygen and as an oxygen carrier that increases the rate of transport of oxygen within the muscle cell? A. Hemoglobin B. Myoglobin C. Actin D. Myosin E. Keratin 24. This is found exclusively in red blood cells (RBCs) where its main function is to transport oxygen (O2) from the lungs to the capiliaries of the tissues. A. Myoglobin B. Keratin C. Collagen E. Myosin 25. The major hemoglobin in adults compromising of four polypeptide chains held together by noncovalent interaction. A. Hemoglobin A B. Hemoglobin T C.Hemoglobin R D. Hemoglobin F E. Hemoglobin C

26. These are hereditary hemolytic disease in which an imbalance occurs in the synthesis of globin chains. A. Sickle cell anemia B. Thalassemia C. Microcytic anemia D. Iron deficiency anemia E.Hyperchromic anemia 27. Oxidation of the heme component of hemoglobin to the ferric ion (fe3+) state forms: A. Carboxyhemoglobin B. Methemoglobin C. Ferritin D. Transferrin E. Porphyrin 28. Collagen and elastin are examples of: A. Fibrous proteins B. Globular proteins C. Albumins D. Mettalloproteins E. Enzymes 29. What is the most abundant protein in the human body? A. Keratin B.Elastin C. Collagen D. Hemoglobin E. Myoglobin 30.Fibril forming collagen, EXCEPT: A. Type I B. TYPE II C. Type III D. Type IV E. None of these 31. Which of the following pairs is correct about collagen types? A. type I: Fibril associated collagen B. Type II: Network forming collagen C. Type III: Fibril-forming collagen D. Type IV: Fibril forming collagen E. Type IX: Network forming collagen 32. Collagen is rich in ___ and __ both of which are important in the formation of the triple-stranded helix. A. Proline and leucine B. Proline and isoleucine C. Proline and glycine D.Proline and histamine

E. Proline and tyrosine 33. A heterogenous group of generalized connective tissues disorders that result from inheritable defects in the metabolism of fibrillar collagen molecules, and can result from a deficiency of collagen processing enzymes (for example, lysyl hydroxylase or or procollagen peptidase), or from mutations in the amino acids sequences of collagen types I,III or V. A. Ehlers-Danlo B. Von Gierke’s syndrome C. Osteogenesis imperfect D. Huntington’s disease E. Hurler’s syndrome 34. A connective tissue protein with rub like properties in tissues such as the lung. A. Collagen B. Keratin C. Elastin D. Albumin E. Hemoglobin 35. A connective tissue disorder that characterize by impaired structural integrity in the skeleton, the eye, and the cardiovascular system. A. Hurler’s disease drome C. Rheumatiod arthritis D. Gaucher’s disease E. Huntington’s disease 36. Lactate pyruvate conversion is possible due to the presence of lactic dehydrogenase. What enzyme category does lactic dehydrogenase belong? A. Hydrolase B. Oxidoreductase C. Transferases D. Lyases E. Isomerases 37. Which of the following pairs is incorrect about the intacellular location of the biochemical pathways? A. Lysosome: Macromolecular degradation B. Nucleus: Protein synthesis C. Cytosol: Glycolysis D. Mitochondria: Fatty acid oxidation E. Cytosol: HMG shunt

38. What is the process of recycling protein into their constituent amino acid, for reuse by the cell? A. Protein catabolism C. Protein synthesis D. Protein denaturation E. Protein degradation 39. A large protein that may contain two or more regions of the polypeptide chain that individual individually have a compact folded structure is called ______. A. Domains B. Chaperones C. Residues D. Proteasome E. None of these 40. The following are true about amino acid, EXCEPT: A. They may polymerized to form polypeptides B. They serve as precursors for other small biomolecules C. They may be oxidized to serve as an energy source for the cell D. They act as building blocks of fatty acids E. None of these 41. Of the 20 impotant amino acids, which is considered optically active? A. Proline B. Lysine C. Arginine D. Leucine E. Glycine 42. The following amino acids contain sulfur on their structure, EXCEPT: A. Cysteine B. Methionine C. Tyrosine D. Leucine E. Glycine 43. Which of the following amino acids does not contain benzene ring on its structure? A.Tyrosine B. Phenylalanine C. Trytophan D. All of these E. None of these

44. RNAs with catalytic activity are called A. Apoenzymes B. Zymogens C. Proenzymes D. Ribozymes E. Holoenzymes 45. The number of molecules of substrate converted to product per enzyme molecule per second A. Bloom strength B. Turnover number C. Saponification number D. Conformational change E. None of these 46. Which of the following is incorrectly paired? A. Holoenzyme: active enzyme B. Apoenzyme: inactive enzyme C. Cofactor: inorganic molecule D. Coenzyme: Small organic molecule E. Prosthetic group: transiently associated with the enzyme 47. Which of the following is false about the kinetic order of enzyme? A. When the substrate concentration [S] is much lesser than the Km, the rate of reaction is first order. B. When [S] is much greater than Km, the velocity is constant and equal to Vmax. C. When [S] is much less than Km, the velocity of the reaction is approximately proportional to the substrate concentration. D. When the substrate concentration [S] is greater than the Km, the rate of reaction is zero order. E. None of these 48. Irreversible inhibitors bind to enzymes through what bond? A. Covalent bond B. Ionic bond C. Hydrogen bond D. Hydrophobic bond E. Sigma and pie bonds 49. Which of the following is true about competitive inhibitions? A. The reaction of the substrate and inhibitor is irreversible B. Substrate binds to active site, inhibitor binds to allosteric site C. Inhibitor is covalently bonded to the

enzyme D. The reaction is not surmountable E.None of these 50. This occurs when inhibitor and substrate bind at different site on the enzyme. A. Competitive inhibition B. Non-competitive inhibition C. Functional inhibition D. Chemical inihibition E. Physiological inhibition 51. Enzyme are often measured in clinical diagnosis. Which of the following is correlatable to an elevated alanine aminotransferase? A. Brain tumor B. Hepatic damage C. Prostate cancer D. Colon cancer E. Eye injury 52. ADH requires NAD+ for catalytic activity. In the reaction catalyzed by ADH, an alcohol is oxidized to an aldehyde as NAD+ is reduced and dissociates from the enzyme. The NAD+ is functioning as a (an): A. Apoenzyme B.Coenzyme-cosubstrate C. coenzyme-prosthetic group D. cofactor E. Eye injury 53. Which of the following is not true about the digestion of protein? A. Protein digestion begins in the mouth B. The digestion of protein may be due gastric acid secretion C. Pancreatic enzyme aid in the digestion of protein D. Aminopeptidases digest oligopeptides in the small intestine E. None of these 54. What is most common genetic error of amino acid transport? A. Phenylketonuria B. Alkaptonuria C. Cystinuria D. Methemoglobinemia E. Pellagra 55. A disease of malabsorption resulting from immune-mediated damage to the small

intestine in the response to ingestion of gluten A. Cystic fibrosis B. Celiac disease C. Ulcerative disease D. Crohn’s disease E. Conn’s disease 56. What is the first step of metabolic catabolism? A. Conjugation B. Transamination C.Transpetidation D. Hydrolysis E. Reduction 57. All amino acids participate in transamination at some point in their catabolism, EXCEPT: A. Lysine B. Threonine C. Trytophan D. A and B E. A and C 58. What is the only amino acid that undergoes rapid oxidative deamination? A. Lysine B. Tyrosine C. Glutamate D. Trytophan E. Ornithine 59. In the transport of ammonia from the peripheral tissues to the liver, which of the following ,mechanism is true? A. Glutamine is transported in the blood to the liver where it is cleaved by glutaminase to produce glutamate and free ammonia B. Alanine is transported by the blood to the liver, where it is converted to pyruvate by transamination C. Transamination of pyruvate to alanine is required to allow transport of alanine to the liver. D. A and B E. All of these 60. Where is the production and excretion site? A. Liver for production, kidney for excretion B. Muscle for production, kidney for excetion C. Liver for production, mammary gland for excretion D. Liver for both production and excretion E. None of these 61. What amino acid is the immediate precursor of both ammonia and aspartate nitrogen? A. Glutamate

B. Aspartate C. Pyruvate D. Oxaloacetate E. Lactate 62. The synthesis of urea is located on which cell site? A. Mitochondria B. Cytosol C. DNA D. A and B C. All of these 63. Ammonia is produced by all tissues during the metabolism of a variety of compounds. However, The level of ammonia in the blood must be kept really low, because even slightly elevated concentrations (Hypoammonemia) are toxic to what part of the body system? A. Autonomic nervous system B. Central nervous system C. Integumentary system D. Skeletal system E. Digestive system 64. The following are potential sources of ammonia, EXEPT A. Glutamine B. Monoamines C. Purines D. Pyrimidines E. Resorcinol 65. What two nitrogen-containing compounds are incorporated in the urea cycle? A. Alanine and glutamate B. Glutamine and alanine C. Aspartate and ammonia D. Ammonia and aspartate E. Alanine and arginine 66. Evaluate the two statements. (1.) Essential amino acids must be obtained from diet in order for normal protei synthesis to occur (2.) Essential amino acids are produced from the intermediates of metabolism of protein. A. Only 1 is correct B. Only 2 is correct C. Both are correct D. Both are incorrect 67. Amino acids whose catabolism yields either acetoacetate or one of its precursors (Acetyl CoA or acetoacetyl CoA) are termed as. . . A. Glucogenic amino acids

B. Ketogenic amino acids C. Metabotropic compounds D. Amphoteric amino acids E. Zwitterionic amino acids 68. Which of the following amino acids doesn’t belong to the group? A. Tyrosine B. Isoleucine C. Phenylalanine D. Lysine E. Tryptophan 69. The amino acids leucine, isoleucine and valine are: A. Branched-chain amino acids B. Essential amino acids C. Aromatic amino acids D. A and B E. C and D 70. Succinyl CoA, A Kreb’s cycle intermediate may be derived from the degration of the following, EXCEPT A. Valine B. Isoleucine C. Theonine D. Aspargine E. None of these 71.The most common clinically encountered inborn error of amino acid metabolism A. Tyrosinemia type I B. Phenylketonuria C. Albinism D. Maple syrup urine disease E. Pellagra 72. Tyrosine is needed in the synthesis of the following, EXCEPT: A. Tissue protein B. Melanin C. Catecholamines D. Fumarate E. Phenylacetate 73. The following are clinical characteristics of classical phenylketonuria: A. Elevated phenylalanine B. CNS symptoms C. Hypopigmentation D. Blue eyes E. All of these 74. A disease which is characteristic by feeding problems, vomiting, dehydration, severe metabolic

acidosis. This condition is due to partial or complete deficiency in the branched-chain alpha-keto acid dehydrogenase. A. Phenylketonuria B. Maple syrup urine disease C. Pellagra D. Albinism E. Hypopigmentation 75. Albinism refers to a group of conditions in which a defect in tyrosine metabolism results in a deficiency in the production of A. Melatonin B. Melanin C. Melanocyte D. All of these E. None of these 76. The homocystinurias are a group of disorders involving defects in the metabolism of homocysteine. The most common cause of homocystinuria is a defect in the enzyme cystathionine beta-synthase. Patients can be responsive (or nonresponsive) to oral administration of vitamin coenzyme of crystathionine beta-synthase. What vitamin is referred to in this condition? A. Thiamine B. Niacin C. Panthotenic acid D. Pyridoxine E. Biotin 77. Which of the following amino acid should be avoided of by patients with alkaptonuria? A.Phenylalanine B. Tyrosine C.Alanine D. A and B E. B and C 78. Which of the following pairs (precursor  product) is incorrect? A. Histidine -> histamine B. Trytophan -> serotonin C.Arginine -> nitric oxide D. Methionine -> purine/pyrimidine E. Tyrosine -> dopamine 79. Which one of the following statements concerning a 1 week old male infant with undetected classic phenylketonuria is correct? A. Tyrosine is a nonessential amino acid for the infant B. High levels of phenylpyruvate appear in his urine

C. Theraphy must begin within the first year of life D. A diet devoid of phenylalanine should be initiated immediately E. When the infant reaches adulthood, it is recommended that diet theraphy be discontinued 80. The structure of porphyrin is shown below. Which cyclic organic molecule is present on th structure? A. Indole B. Pyrrole C. Quinolone D. Pyridine E. Piperidine 81. The most prevalent metalloporphyrin in humans is heme. It serves as a prosthetic group for: A.Cytochrome B.Hemoglobin C. Peroxidase D. All of these E. A and B 82. Inherited (or occasionally acquired) defect is heme synthesis may result to: A. Porphyria B. Phenylketonuria C.Methemoglobinemia D. Lead poisoning E.Albinism 83. What is the approximate number of days of red blood cells to be in the circulation before degradation? A. 40 days B. 80 days C. 120 days D. 150 days E. 365 days 84. Bilirubin and biliverdin are examples of: A. Bile salts B. Bile pigments C.Bile duct D. All of these E. None of these 85. Certain anionic drugs, such as salicylates and sulfonamides, can displace bilirubin from albumin, permitting bilirubin to enter the central nervous system. This cause the potential ffor neural damage in infants known as: A.Saint Louis Encephalitis B. Systemic Lupus Erythematosus C.Steven-johnson’s syndrome D. Kernicterus

E. All of these 86. Van de Bergh reaction determines the concentration o: A.Protein B. Bilirubin C. Heme D. Glucose E. Cholesterol 87. The following are atecholamines, EXCEPT: A. Epinephrine B. Norepinephrine C. Acetylcholine D. Dopamine E. None of these 88.What organic polymer protects underlying cell from the harmful effects of sunlight? A. Melanin B. Keratin C. Collagen D. Catecholamines E. Heme 8...