TEST QUESTIONS IN BIOCHEMISTRY

NUTRITION - 30

I. Given patient data, determine the metabolic pathways and processes involved.

1. A two year old boy, short for his age, presented with leg edema and abdominal swelling. He was weaned from breast milk at one year of age, because of the coming of another baby. He was fed rice or lugaw everyday mixed with condensed milk. The edema is caused by:A. lack of protein in his dietB. excessive intake of waterC. kidney failureD. presence of intestinal parasites

RecallAnswer: A. lack of protein in his dietReference: Harper's Illustrated Biochemistry 27th ed., Murray, Granner & Rodwell

2006 The MacGraw-Hill Companies, Inc., p. 241, par. 1, p. 487, par. 3

2. Catabolism of amino acids requires the participation of transaminase enzymes. What coenzyme form of vitamin B is an important participant in this reaction?

A. thiamin pyrophosphateB. nicotinamide adenine dinucleotideC. tetrahydrofolic acidD. pyridoxal phosphate

RecallAnswer: D. pyridoxal phosphateReference: Harper's Illustrated Biochemistry 27th ed., p. 247 par. 2 , p. 498 - 499

3. In marasmus, the affected person has very little fat reserves and there is wasting of muscles. The person is said to be in :A. positive nitrogen balanceB. negative nitrogen balanceC. nitrogen balanceD. equilibrium

RecallAnswer: B. negative nitrogen balanceReference: Harper's Illustrated Biochemistry 27th ed., p. 487 par. 3

4. Persons who consume large amounts of unleavened whole-wheat products may experience calcium deficiency because:A. wheat is poor in calciumB. wheat contains phytic acid which prevents calcium absorptionC. the wheat is deficient in vitamin DD. absorbable form of calcium is not generated

ApplicationAnswer: B. wheat contains phytic acid which prevents calcium absorptionReference: Harper's Illustrated Biochemistry 27th ed., p. 485 par. 5

5. An elderly woman is believed to be suffering from vitamin B12 deficiency. Which of the following can be the basis for this statement?A. she has been diagnosed to be deficient in cobaltB. she is a veganC. she has methylmalonic aciduriaD. any of the above

ApplicationAnswer: D. any of the aboveReference: Harper's Illustrated Biochemistry 27th ed., p. 499-500

6. The patient was in coma. Since diabetes was ruled out, how does one explain the condition?A. patient has ammonia intoxication because of the liver pathologyB. coma is due to marked ketosisC. acid-base balance of the patient is disturbedD. there is increase urea production

ApplicationAnswer: A. patient has ammonia intoxication because of the liver pathologyReference: Harper's Illustrated Biochemistry 27th ed., p. 248 par. 4

7. The obese matron was instructed by her physician to alter her diet and eat only protein foods to bring down her weight. The matron was afraid however that the absence of carbohydrates in her meals will cause hypoglycemia and give her more problems. The physician was certain she does not have to worry about this because:A. she's going to cheat on her diet anywayB. the excess body fat will be converted to glucoseC. amino acids in excess are converted to glucose D. she has a lot of glycogen slores

ApplicationAnswer: C. amino acids in excess are converted to glucose Reference: Harper's Illustrated Biochemistry 27th ed., p. 172 par. 2, p. 175 summary,

p. 269 summary

II. Given a patient with a nutritional deficiency, give the expected clinical manifestation

8. Deficiency of iron results in which of the following?A. failure to metabolize proteinsB. heme-containing enzymes remain inactiveC. there is liver dysfunctionD. individual goes into ATP production using fats

RecallAnswer: B. heme-containing enzymes remain inactiveReference: Harper's Illustrated Biochemistry 27th ed., p. 504 Table

9. An infant with genetic deficiency of glucose-6-phosphatase also known as von Gierke's disease will exhibit this clinical sign:A. poor exercise toleranceB. muscle dystrophyC. hypoglycemia & lactic acidemiaD. glycogen with few branch points

RecallAnswer: C. hypoglycemia & lactic acidemiaReference: Harper's Illustrated Biochemistry 27th ed., p. 166 Table

10. In the absence of creatine kinase enzymes, an athlete would have problem in:A. oxidizing creatineB. releasing ATP from biological oxidationC. aerobic glucose oxidationD. generating ATP reserves for muscle contraction

RecallAnswer: D. generating ATP reserves for muscle contractionReference: Harper's Illustrated Biochemistry 27th ed., p. 583 par. 1-3

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11. A young woman already in her fifth month of a carbohydrate and lipid-free diet was advised by her physician to increase the amount of fats in her diet because she appears to be suffering from vitamin A deficiency despite her regular vitamin intake. Which of the following complaints presented by the woman supports the diagnosis?A. she has lesions of the corner of the mouthB. her wounds take longer time to healC. she finds it hard to see in the dark when in a movie theaterD. she has this sensation of "burning feet".

ApplicationAnswer: C. she finds it hard to see in the dark when in a movie theater

Reference: Harper's Illustrated Biochemistry, 27th edition, p. 491, par. 4, line 3

12. Tests done on a two month-old baby showed deficiency in enzymes of the Uronic Acid Pathway. What clinical manifestation may be observed?A. elevated urinary glucuronic acidB. yellow coloration of the skinC. high direct-reacting bilirubin in plasmaD. accumulation of heme

ApplicationAnswer: B. yellow coloration of the skinReference: Harper's Illustrated Biochemistry, 27th edition, p. 289 par. 2, p. 290 par. 2

13. A 35 year old Muntinlupa inmate was confined to 6 weeks of isolation because of bad behavior. Although he was given regular meals, he stayed in the underground cell for the duration of the 6 weeks. If the prisoner became deficient in vitamin D because of this, what signs should the attending physician look for? in the inmate: A. there may be kidney stones formationB. the inmate may complain of tirednessC. he can easily be fracturedD. serum calcium will be extremely low

ApplicationAnswer: C. he can easily be fracturedReference: Harper's Illustrated Biochemistry, 27th edition, p. 492 - 493

14. Thiamine deficiency can result in Wernicke- Korsakoff's syndrome. The absence of the vitamin prevents the conversion of pyruvate to acetyl CoA on a high carbohydrate diet. Which compound would be found to be high in concentration in the plasma?A. glucoseB. lactate & pyruvateC. acetyl CoAD. alcohol

ApplicationAnswer: B. lactate & pyruvateReference: Harper's Illustrated Biochemistry, 27th edition, p. 496- 497

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III. Given a laboratory finding, identify the involved biochemical mechanism

15. Important in the synthesis of collagen, this vitamin serves as cofactor of the mixed function oxygenase enzymes, proline & lysine hydroxylases:A. vitamin B1

B. vitamin B2

C. vitamin CD. folic acid

RecallAnswer: C. vitamin CReference: Harper's Illustrated Biochemistry 27th ed., p. 242 par. 3, line 9

16. Unlike other vitamins, niacin is a semi-essential vitamin because it can be synthesized from this amino acid:A. prolineB. phenylalanineC. tryptophanD. histidine

RecallAnswer: C. tryptophanReference: Harper's Illustrated Biochemistry 27th ed., p. 498, par. 1

17. Activity of the aldose reductase enzyme in the lens of the eye increases in the presence of high concentration of glucose. This initiates the conversion of glucose to a compound that has been linked to osmotic damage and cataract formation. What compound is this?A. mannitolB. galactitolC. ribitolD. sorbitol

RecallAnswer: D. sorbitolReference: Harper's Illustrated Biochemistry 27th ed., p. 185 last par.

18. A patient was tested for transketolase activity of the erythrocyte lysate. Results showed markedly low activity of the enzyme, consistent with the physicians impression of deficiency of this vitamin:A. vitamin B2

B. vitamin B3

C. vitamin B5

D. vitamin B1

ApplicationAnswer: D. vitamin B1

Reference: Harper's Illustrated Biochemistry 27th ed., p. 497, par. 1

19. Inorganic iron is best absorbed by the body in the ferrous form. What is the rationale behind the addition of vitamin C in many iron preparations?A. vitamin C can take the place of ironB. absorption of other minerals is preventedC. vitamin C chelates ironD. vitamin C keeps the iron in reduced (ferrous) state

ApplicationAnswer: D. Vitamin C keeps the iron in reduced (ferrous) stateReference: Harper's Illustrated Biochemistry 27th ed., p. 485 - 486

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20. In a routine medical check up, an executive showed elevated plasma levels of lactic acid dehydrogenase enzymes 1 & 2 and low levels of LDH 5. This prompted his physician to refer him to a cardiologist because:A. low levels of LDH 5 indicated a clogged vesselB. it is part of the medical check upC. increase levels of LDH 1 & 2 is indicative of myocardial infarctionD. angioplasty was needed

ApplicationAnswer: C. increase levels of LDH 1 & 2 is indicative of myocardial infarctionReference: Harper's Illustrated Biochemistry 27th ed., p. 57

21. A tourist from the Caribbean fell ill and was diagnosed to have malaria. He was given primaquine upon admission to the hospital and was thought to be recuperating when he showed signs of hemolytic anemia. Tests showed he had glucose 6- phosphatase deficiency. What is the biochemical explanation for the hemolysis?A. the malarial parasite had invaded the rbcB. inactivity of the Hexose Monophosphate Shunt prevented the NADPH - reduction of membrane glutathioneC. the drug oxidized membrane proteinsD. absence of G6PD initiated release of peroxides

ApplicationAnswer: B. inactivity of the Hexose Monophosphate Shunt prevented the NADPH - reduction of membrane glutathioneReference: Harper's Illustrated Biochemistry 27th ed., p. 177 par. 2, p. 183 par. 2

V. Given patient data, formulate an appropriate nutritional plan

22. Metabolic screening of a newborn showed absence of galactose uridyltransferase enzyme. What should be the dietary recommendation?A. Galactose should not be included in the dietB. Galactose - free and lactose -free milk should be givenC. Newborn should be breastfedD. Liquid protein preparation instead of milk should be given

RecallAnswer: B. galactose-free and lactose -free milk should be givenReference: Harper's Illustrated Biochemistry 27th ed., p. 186 par. 2

23. A born-again vegetarian was diagnosed to be suffering from vitamin B12 deficiency. Which of the following suggestions should be followed?A. the vegetarian should include meat in the dietB. he should be tested for pernicious anemiaC. the born-again can take in vitamin B12 preparation to meet the requirementD. intrinsic factor should be released from bonding

RecallAnswer: C. the born-again can take in vitamin B12 preparation to meet the requirementReference: Harper's Illustrated Biochemistry 27th ed., p. 499 - 500

24. A woman had just given birth by ceasarean section. For fast recuperation she should be advised to:A. eat nutritious and protein-rich foodsB. rest in bed until the incision healsC. include more carbohydrates in the dietD. drink a lot of water

RecallAnswer: C. eat nutritious and protein-rich foodsReference: Harper's Illustrated Biochemistry 27th ed., p. 487 - 488

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25. A 50 year old male is suffering from gout because of his tendency to over eat. He should be told to:A. eat moderatelyB. stay away from nuclei-rich foods like nuts, beans, meatC. drink plenty of waterD. all of the above

RecallAnswer: D. drink plenty of waterReference: Harper's Illustrated Biochemistry 27th ed., p. 307 par. 2 & 3

Questions # 26-28A 32 year old married woman consulted at the OPD because of increasing thirst and frequent urination. She is 5 feet 2 inches tall and weighs 168 lbs.

26. Which of the following statements best described the metabolic status in this patient?A. Her energy expenditure is greater than food intake hence she is diuresingB. She is obese and she has increased mortalityC. The (BMR) basal metabolic rate of this patient is higher compared to a man of the

same body weightD. She is frequently urinating because she has increased protein reserves

ApplicationAnswer: B. She is obese and she has increased mortalityReference: Harper's Illustrated Biochemistry 27th ed., p. 486

27. The BMI of the patient is:A. 25B. 27C. 29D. 31

ApplicationAnswer: D. 29Reference: Harper's Illustrated Biochemistry 27th ed., p. 486 par. 2

28. You want to give this patient a 1,500 cal/day diet because you want her to lose weight. How do you formulate an appropriate plan for this patient?A. Carbohydrate - 55% Fats = 35%

Protein = 10%

B. Carbohydrate - 30% Fats = 20%Protein = 50%

C. Carbohydrate - 0% Fats = 40%Protein = 60%

D. Carbohydrate - 40% Fats = 40%Protein = 20%

ApplicationAnswer: A. Carbohydrate - 55% Fats = 35%

Protein = 10% Reference: Harper's Illustrated Biochemistry 27th ed., p. 132

29. The edema of a patient with kwashiorkor should respond best when prescribed with:A. diet rich in proteinB. diureticsC. bed restD. virgin coconut oil

ApplicationAnswer: A. diet rich in proteinReference: Harper's Illustrated Biochemistry 27th ed., p. 487

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30. A 32 year old physician suffered a 3rd degree burn. He stayed in the hospital for almost one month. What can be said of his metabolic conditionA. the excretion of nitrogenous compounds is less than the dietary intakeB. negative nitrogen balanceC. positive nitrogen balanceD. there is net retention of the nitrogen in the body as protein

Application Answer: B. negative nitrogen balanceReference: Harper's Illustrated Biochemistry 27th ed., p. 487

METABOLISM - 40

I. Given patient data, determine the metabolic pathways and processes involved.

31. The human body, even at rest, uses up energy. This amount of energy expenditure is termed as:A. Respiratory QuotientB. Basal Metabolic RateC. Respiratory BurstD. Body Mass Index

RecallAnswer: B. Basal Metabolic RateReference: Harper's Illustrated Biochemistry 27th ed., p. 486

32. Uptake of glucose in these tissues is controlled by the hormone insulin:A. liver & kidneysB. adipose tissue & muscleC. muscle & intestinesD. liver & rbc

RecallAnswer: B. adipose tissue & muscleReference: Harper's Illustrated Biochemistry 27th ed., p. 140, par. 3, line 1

33. Between meals, the blood glucose concentration of the body is maintained through these metabolic pathways:A. glycolysis & gluconeogenesisB. glycogenesis & glycogenolysisC. glycolysis & glycogenolysisD. glycogenolysis & gluconeogenesis

RecallAnswer: D. glycogenolysis & gluconeogenesisReference: Harper's Illustrated Biochemistry 27th ed., p. 134, par. 4, line 8

34. During continuous anaerobic physical activity, e.g. when working out in a gym, this metabolic pathway is used by the musclesA. gluconeogenesisB. glycolysisC. Hexose Monophosphate ShuntD. glycogenesis

RecallAnswer: B. glycolysisReference: Harper's Illustrated Biochemistry 27th ed., p. 151, p. 158

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35. When tested, a young woman, complaining of fatigability and poor exercise tolerance was found to have only one sixth the amount of carnitine found in others who had no muscle disease. This means that the above symptoms she is experiencing is due to:A. inability of the body to synthesize lipidsB. inhibition of ATP productionC. failure of fatty acids to enter - oxidationD. impairment of the mitochondria

RecallAnswer: C. failure of fatty acids to enter - oxidationReference: Harper's Illustrated Biochemistry 27th ed., p. 187 par. 4

36. Newborn infants can generate more heat needed by the body because they contain thermogenin, an uncoupling protein. This protein exerts its effect by:A. increasing the amount of substrate oxidizedB. preventing heat lossC. dissociating respiratory chain oxidation from ATP synthesis (phosphorylation)D. activating respiratory chain enzymes

Application Answer: C. dissociating respiratory chain oxidation from ATP synthesis (phosphorylation)Reference: Harper's Illustrated Biochemistry 27th ed., p. 107, par. 4, p. 228 - 229

37. Erythrocytes are hemolyzed when there is impairment of the Pentose Phosphate Pathway and this is manifested in a person as hemolytic anemia. This defect is due to:

A. lack of NADPH from the Pentose Phosphate PathwayB. non-synthesis of ATPC. failure to release riboseD. defect in the membrane transport

Application Answer: A. lack of NADPH from the Pentose Phosphate PathwayReference: Harper's Illustrated Biochemistry 27th ed., p. 183- 184, par. 1

38. A 30 year old patient was diagnosed to be suffering from a mitochondrial disease that specifically involves defect in mitochondrial energy transduction. Which of the following signs/symptoms will be evident?A. High body mass index (BMI), hyperactivity, increased appetiteB. Hyperventilation, clammy sweatC. Muscle weakness, excessive perspiration, and elevated BMR (Basal metabolic

rate)D. lack of appetite, hypoventilation

Application Answer: C. Muscle weakness, excessive perspiration, and elevated BMR (Basal metabolic rate)Reference: Harper's Illustrated Biochemistry 27th ed., p. 100, par. 2

39. A newborn infant tested positive in the phenylketonuria screening. The attending pediatrician ordered a change in the infant milk to one which contains negligible amount of:A. lactoseB. proteinsC. fatsD. glucose

Application Answer: B. proteinsReference: Harper's Illustrated Biochemistry 27th ed., p. 259, par. 3

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40. A drug used as an adjunct in the treatment of obesity inhibits pancreatic lipase. Following its intake, which of the following is expected to be excreted in great amount in the feces?A. cholesterolB. triacylglycerolsC. free fatty acidsD. bile salts

Application Answer: B. triacylglycerolsReference: Harper's Illustrated Biochemistry 27th ed., p. 483, par. 4, p. 484 diagram

II. Given a patient with a nutritional deficiency, give the expected clinical manifestation

41. In the mucopolysaccharidoses, glycosaminoglycans are not degraded due to the absence of lysosomal hydrolases. Individuals suffering from this can be identified because of:A. excessive accumulation and urinary excretion of the proteoglycansB. presence of enzyme fragments in the urineC. release of the core proteins in urineD. increase turnover of affected cells

RecallAnswer: A. excessive accumulation and urinary excretion of the proteoglycansReference: Harper's Illustrated Biochemistry 27th ed., p. 555 par. 5

42. In the rare disease, analbuminemia, there is complete lack of serum albumin. The affected individual presents with this:A. extreme edemaB. edema & presence of free fatty acidsC. accumulation of triglyceridesD. elevated plasma cholesterol

RecallAnswer: B. edema & presence of free fatty acidsReference: Harper's Illustrated Biochemistry 27th ed., p. 592 par. 1, p. 187 par. 3

p. 711 Clinical Correlation , Textbook of Biochemistry, 5th ed., Thomas Devlin, editors, 2002 Wiley-Liss

43. Metabolic screening was requested for a week-old newborn because the grandmother had noticed the dark stains on the wet diaper whenever she attended the infant. Tests identified the condition as alkaptonuria. What urinary metabolic should the physician request in the laboratory tests?A. tryptophanB. tyrosineC. homogentisic acidD. melanin

RecallAnswer: C. homogentisic acidReference: Harper's Illustrated Biochemistry 27th ed., p.259 par. 2

Textbook of Biochemistry, 5th ed., Thomas Devlin, p. 801, Clinical Correlation

44. Skeletal muscles do not have the enzyme glucose-6-phosphatase. This means:A. they cannot degrade glucoseB. glucose cannot be synthesizedC. ATP cannot be generatedD. glycogen is stored in big amount

RecallAnswer: B. glucose cannot be synthesizedReference: Harper's Illustrated Biochemistry 27th ed., p. 161, p. 167

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45. L-xylulose reductase catalyzes the reduction of xylulose to xylitol. In affected individuals, absence of this enzyme results in:A. formation of cataractsB. failure to synthesize nucleic acidsC. excretion of large amounts of urinary pentoseD. presence of skeletal deformities

RecallAnswer: C. excretion of large amounts of urinary pentoseReference: Harper's Illustrated Biochemistry 27th ed., p. 184 par. 2

46. When there is restricted intake of carbohydrates as in starvation and uncontrolled diabetes mellitus, ketosis results because of:A. change in pH of the bodyB. failure to oxidize glucoseC. mobilization of fatty acidsD. inactivity of buffer systems

ApplicationAnswer: C. mobilization of fatty acidsReference: Harper's Illustrated Biochemistry, 27th ed., p. 194 last par. , p.195 , 2nd par. (summary)

47. Measurement of HbA1c or glycosylated hemoglobin provides valuable information for the management of diabetes mellitus because it:A. is elevated in diabetes mellitusB. reflects the mean glucose concentration over the preceding 6 - 8 weeksC. is formed by reaction with HbAD. is released when rbc dies

ApplicationAnswer: B. reflects the mean glucose concentration over the proceeding 6 - 8 weeksReference: Harper's Illustrated Biochemistry 27th ed., p. 48, par.1

48. Inherited enzyme deficiencies of the Krebs-Henseleit cycle always present with this observation:A. increase urea productionB. formation of organic metabolitesC. ammonia intoxicationD. depletion of citrulline

ApplicationAnswer: C. ammonia intoxicationReference: Harper's Illustrated Biochemistry 27th ed., p. 251, par. 4

49. The urine-soaked diaper of a week old baby was noted by the mother to smell like burnt sugar. Her concern turned into worry when the pediatrician told her the baby may be suffering from maple syrup urine disease. To confirm this, activity of the keto acid decarboxylase complex has to be measured. Which amino acids will have increased concentration in plasma and urine?A. serine, threonine & hydroxyprolineB. cysteine, cystine, methionineC. valine, leucine & isoleucineD. glycine, alanine & asparagine

ApplicationAnswer: C. valine, leucine & isoleucineReference: Harper's Illustrated Biochemistry 27th ed., p. 265, par. 2

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50. Calcium deficiency manifestations may also be seen in people who consume:A. large amounts of unleavened whole wheat productsB. high concentrations of fatty acidsC. high amounts of oxalatesD. all of the above

ApplicationAnswer: A. large amounts of unleavened whole wheat productsReference: Harper's Illustrated Biochemistry 27th ed., p. 265, par. 2

III. Given a laboratory finding, identify the involved biochemical mechanism

51. Milk intolerance, common among Asian populations and characterized by an osmotic type of diarrhrea following the intake of milk is attributed to deficiency of:A. pancreatic amylaseB. lactaseC. sucraseD. maltase

RecallAnswer: B. lactaseReference: Harper's Illustrated Biochemistry 27th ed., p. 483, par. 1, line 3

52. Rate-limiting reaction in cholesterol synthesis which is inhibited by the "statins" group of drugs is catalyzed by this enzyme:A. cholesterol esteraseB. squalene cyclaseC. mevalonate kinaseD. beta hydroxyl-beta methyl glutaryl CoA reductase

RecallAnswer: D. beta hydroxyl-beta methyl glutaryl CoA reductaseReference: Harper's Illustrated Biochemistry 27th ed., p. 231, par. 2

53. All the carbon atoms of cholesterol are synthesized from this common metabolite:A. alanineB. acetyl CoAC. glucoseD. palmitate

RecallAnswer: B. acetyl CoAReference: Harper's Illustrated Biochemistry 27th ed., p. 230, par. 3

54. Carbohydrates, lipids & proteins can be oxidized to acetyl CoA or specific metabolites intermediates using a final common pathway. The pathway functions in gluconeogenesis, lipogenesis and interconversion of amino acids. This pathway is known as:A. GlycolysisB. Hexose Monophosphate ShuntC. Citric Acid CycleD. Glucuronic Acid Pathway

RecallAnswer: C. Citric Acid CycleReference: Harper's Illustrated Biochemistry 27th ed., p. 145, par. 1

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55. In the capillaries, hemoglobin releases oxygen and accepts carbon dioxide. The process generates protons e which can then lower the blood pH. The buffering action of hemoglobin will prevent this from taking place. What amino acid residues in hemoglobin are most important in this shift in pH buffering effect at normal blood pH?A. arginineB. lysineC. histidineD. glutamate

RecallAnswer: C. histidineReference: Harper's Illustrated Biochemistry 27th ed., p. 43

56. The highest number of energy released as ATP is obtained by complete oxidation of this compound to carbon dioxide and waterA. an amino acidB. a triglycerideC. glucoseD. a nucleic acid

ApplicationAnswer: B. a triglycerideReference: Harper's Illustrated Biochemistry 27th ed., p. 142, table 16-1, p.189, par.1

57. Laboratory tests done on a 3 year old boy showed excessive nucleic acid bases in the urine and negligible activity of HGPRTase. Which statement explains the results obtained?A. purine bases are very insolubleB. low enzyme activity is due to feedback inhibitionC. Salvage pathway of synthesizing nucleotides is inactiveD. young cells utilize the in vivo method for synthesis

ApplicationAnswer: C. Salvage pathway of synthesizing nucleotides is inactiveReference: Harper's Illustrated Biochemistry 27th ed., p. 308, par. 1

58. In myocardial infarction where a major coronary artery is occluded, ischemia results and a lowered oxygen supply diminishes the amount of ATP available in the cell. This effect on cellular energy is due to:A. release of enzymesB. lack of oxygen which slows down the mitochondrial electron transport chainC. inhibition of substrate level phosphorylationD. kind of occlusion

ApplicationAnswer: B. lack of oxygen which slows down the mitochondrial electron

transport chain Reference: Textbook of Biochemistry, 5th ed., Thomas Devlin, p. 591, Clinical Correlation

59. The patient was diagnosed to be suffering from megaloblastic anemia. Results of urinary tests showed 10 mg of formiminoglutamic acid (FIGLU), making the physician conclude that the patient has folic acid deficiency. Which statement explains the diagnosis given?A. megaloblastic anemia is a unique feature of folic acid deficiencyB. transfer of formimino group of histidine to tetrahydrofolate does not take place and figlu

is excretedC. figlu is a metabolite of folateD. one carbon compounds are carried by folic acid

ApplicationAnswer: B. transfer of formimino group of histidine to tetrahydrofolate does not take

place and figlu is excretedReference: Harper's Illustrated Biochemistry 27th ed., p. 254 par. 6

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60. In the glycogen storage disease, McArdle's disease, muscle phosphorylase is absent. Patients who suffer from this will therefore show the following signs:A. inability to perform strenuous exercise because glycogen cannot be degradedB. there is no increase in plasma lactic acidC. no energy supply for the musclesD. all of the above

ApplicationAnswer: D. all of the above Reference: Harper's Illustrated Biochemistry 27th ed., p. 582, Textbook of Biochemistry, 5th ed., Thomas Devlin editors, 2002 Wiley-Liss

p. 647

V. Given patient data, formulate an appropriate nutritional plan

61. A person is suffering from gouty arthritis. What foods should not be included in his daily meals?A. peas, legumes and beans familyB. meat and internal organsC. strawberries, cauliflower, broccoliD. all of the above

RecallAnswer: D. all of the above

62. What foods, cheap but rich in proteins, can the physician suggest to patients from the low income group?A. pork ribs and pork legsB. milk and cheeseC. anchovies, bean sprouts, mung beansD. instant noodles

RecallAnswer: C. anchovies, bean sprouts, mung beans

63. Patient has been found to be deficient in vitamin E. Which of the following should he included in his market list as source of vitamin E?

A. salmon fishB. beansC. alfalfaD. oats

RecallAnswer: C. alfalfa

64. An elderly woman insists that the house help cook sweetened oatmeal, with milk, every morning for her breakfast, without fail. This makes the elderly woman feel good and it is a complete food according to her because it has:A. proteinB. fiber for her constipationC. sugar as energy sourceD. all of the above

RecallAnswer: D. all of the above Reference: Textbook of Biochemistry, 5th ed., Thomas Devlin, p. 1127

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65. What advice can a physician give to someone who has problems with bowel movement and is always constipated.A. drink plenty of waterB. eat foods rich in fiber e.g. whole wheat , bran, oatsC. include vegetables with high fiberD. all of the above

RecallAnswer: C. include vegetables with high fiberReference: Textbook of Biochemistry, 5th ed., Thomas Devlin, p. 1127

66. A mother brought her 8 month old, 6 kg baby to a Health Center because of diarrhea of one day duration which occurred 4 times. The baby had been breast-fed since birth and "lugaw" with fish and vegetables were started at 5 months. Breast feeding was stopped at the onset of the diarrhea and the baby was given "am" with sugar instead. What suggestion can be given to the mother to improve the overall condition of her child? A. meat and more solid foods can be given B. giving "am" with sugar, and a little salt can be used for diarrheaC. breastfeeding should continued even when there is diarrheaD. all of the above

ApplicationAnswer: D. all of the aboveReference: Harper's Illustrated Biochemistry 27th ed., p. 436 par. 4

67. What is the so called oral rehydration therapy for cases of diarrhea developed by the World Health Organization?A. daily ingestion of 8 glasses of waterB. oral isotonic NaCl solutionC. intake of a NaCl and glucose oral mixed preparationD. daily intake of sucrose solution

ApplicationAnswer: C. intake of a NaCl and glucose oral mixed preparationReference: Harper's Illustrated Biochemistry 27th ed., p. 436, last paragraph

68 - 70 After an all night drinking spree with friends, 45 year old Juan woke up with pain all over, but mainly of the lower extremeties. His arthritis worsens everytime he goes drinking. Earlier he had been advised by his physician to take thiamine because he seems to be exhibiting symptoms of the Wernicke-Korsakoff syndrome.

68. What is the importance of taking thiamine in this case?A. ensures complete metabolism of carbohydrates and the alcoholB. the arthritic pain will be relievedC. this is a cure for the symptoms of the syndromeD. thiamine is a cofactor of alcohol dehydrogenase

ApplicationAnswer: A. ensures complete metabolism of carbohydrates and the alcoholReference: Harper's Illustrated Biochemistry 27th ed., p. 496 par. 2

69. What enzyme of carbohydrate metabolism is activated by vitamin B1?A. alcohol dehydrogenaseB. pyruvate dehydrogenaseC. pyruvate kinaseD. phosphoenol pyruvate kinase

ApplicationAnswer: B. pyruvate dehydrogenaseReference: Harper's Illustrated Biochemistry 27th ed., p. 496

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70. To alleviate the arthritic pain, what suggestion on dietary habits should the physician give Juan in addition to staying away from alcohol?A. eat plenty of fats for energy sourceB. take hypouricemic drugs, eat minimal amount of meat, and drink a lot of waterC. stay away from fruits and vegetablesD. include nucleic acid rich foods in the meals

ApplicationAnswer: B. take hypouricemic drugs, eat minimal amount of meat, and drink

a lot of waterReference: Textbook of Biochemistry, 5th ed., Thomas Devlin, p. 834

GENETICS - 15

I. Given patient data, determine the metabolic pathways and processes involved

71. Patients with hyperuricemia experience pain because of the insolubility of uric acid. Physicians prescribe allopurinol, a structural analog of purines. Levels of uric are lowered through this mechanism:A. non-competitive inhibition of purinesB. allopurinol increases solubility of uric acidC. uric acid is degraded in the presence of allopurinolD. competitive inhibition of xanthine oxidase

RecallAnswer: D. competitive inhibition of xanthine oxidaseReference: Harper's Illustrated Biochemistry 27th ed., p. 298 par. 4 line 11

72. Cytosine arabinoside is an anti metabolite used in the treatment of some forms of cancer. It is a structural analog of dCTP. Its effectivity as an anti-cancer compound is due to the following:A. competes with dCTP for incorporation to DNAB. inhibits DNA polymeraseC. binds to ribose sugarsD. degrades cancer cells

RecallAnswer: A. competes with dCTP for incorporation to DNAReference: Harper's Illustrated Biochemistry 27th ed., p. 298 par. 4 line 13

Textbook of Biochemistry, 5th ed., Thomas Devlin, p. 854 par. 6

73. Methotrexate, an anti cancer drug, is a structural analog of folic acid. Its effective anti-cancer action is attributed to its:

A. inhibiting DNA elongationB. complexing with thymineC. inhibition of the dihydrofolate reductase enzymeD. precipitation of DNA

ApplicationAnswer: C. inhibition of the dihydrofolate reductase enzymeReference: Harper's Illustrated Biochemistry 27th ed., p. 304, par. 4

74. In one type of hemoglobin structure, base A of a codon was changed to base U. What possible results can happen?A. newly formed codon may dictate the same amino acidB. the new hemoglobin is a mutantC. oxygen carrying capacity of hemoglobin may changeD. all of the above

ApplicationAnswer: D. all of the aboveReference: Harper's Illustrated Biochemistry 27th ed., p. 368

Textbook of Biochemistry, 5th ed., Thomas Devlin, p. 238 Clinical Correlation

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75. The thalassemias involve defects in the synthesis of globin chains, involving either genetic deletion or frameshift mutation in the synthesis of the messenger RNA. Which of the following will not be an effect of the genetic defect?A. reading frame of DNA chain will changeB. a functional globin chain will be codedC. change in code carried by mRNAD. individual will present with anemia

ApplicationAnswer: B. a functional globin chain will be codedReference: Harper's Illustrated Biochemistry 27th ed., p. 47 - 48

Textbook of Biochemistry, 5th ed., Thomas Devlin, p. 224 Clinical Correlation

IV. Given a clinical condition, identify the genetic/immunologic processes involved

76. . Xeroderma pigmentosa is a genetic disease characterized by the individual's marked sensitivity to sunlight. The defect lies on:A. mutant helicasesB. DNA ligaseC. nucleotide-excission repair processD. the DNA polymerase

RecallAnswer: C. nucleotide-excision repair processReference: Harper's Illustrated Biochemistry 27th ed., p. 345

77. Sickle cell disease is a classic example of a point mutation causing a structure abnormality of the - globin gene. This results in this amino acid change:A. valine instead of glutamic acidB. leucine instead of glycineC. lysine instead of aspartateD. tyrosine instead of alanine

RecallAnswer: A. valine instead of glutamic acidReference: Harper's Illustrated Biochemistry 27th ed., p. 413

78. The tetracycline drugs work by preventing the binding of amino acyl tRNAs to the A site of the bacterial ribosome. This will result in:A. inhibition of bacterial replicationB. bacterila cell lysisC. activation of transcriptionD. inhibition of protein synthesis

RecallAnswer: D. inhibition of protein synthesisReference: Harper's Illustrated Biochemistry 27th ed., p. 378, par. 2

79. A newly-launched antibiotic, is credited with inhibiting the DNA helicase which then stops the synthesis of proteins in bacterial systems. At what stage of protein synthesis does the antibiotic act?A. replicationB. transcriptionC. translationD. reverse transcription

RecallAnswer: A. replication Reference: Harper's Illustrated Biochemistry 27th ed., p. 334, 336

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80. Menke's disease has been identified to be linked to mutation in the ATP7A gene. This gene codes for?A. a protease inhibitorB. an iron transporterC. a copper- binding P-type ATPaseD. cytochrome oxidase

RecallAnswer: C. a copper-binding P-type ATPaseReference: Harper's Illustrated Biochemistry 27th ed., p. 596

81. Mutation in ATP7B gene affects the copper binding P-type ATPase. This is known as Wilson's disease. Individuals that carry this mutated gene present will all of the following signs except one. Which one is the exception?A. copper is not excreted in the bileB. accumulation of fibrillar proteinsC. deposition of copper ion in liver and other organsD. copper toxicosis

ApplicationAnswer: B. accumulation of fibrillar proteinsReference: Harper's Illustrated Biochemistry 27th ed., p. 597

82. Deficiency of 1- antiproteinase (1- antitrypsin) is associated with emphysema. In smokers, progress to emphysema becomes faster because:A. smoking destroys the methionine of 1- antitrypsin impairing binding to proteaseB. smoking releases polyaromatic hydrocarbons that bind 1- antitrypsinC. smokers carry mutant genes for the enzymeD. oxygen facilitates conversion of enzyme to inactive form

ApplicationAnswer: A. smoking destroys the methionine of 1- antitrypsin impairing binding

to proteaseReference: Harper's Illustrated Biochemistry 27th ed., p. 597

83. In one genetic disease, molecular studies showed that there is premature termination of the transcription process. This should result in:A. failure to have an mRNA codeB. there will be deficiency of the proteinC. RNA will be non-functionalD. all of the above

ApplicationAnswer: D. all of the aboveReference: Harper's Illustrated Biochemistry 27th ed., p. 351

84. In one type of cancer, the normal gene was mutated and transformed into a cancer-inducing gene or oncogene. Since the gene coded for an enhancer that binds DNA polymerase, what is the mechanism for the proliferation of cells in the cancer?A. presence of excessive substratesB. increase synthesis of DNAC. cellular transformatioinD. lack of DNA binding site

ApplicationAnswer: B. increase synthesis of DNAReference: Harper's Illustrated Biochemistry 27th ed., p. 342

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85. A newly-discovered genetic disease presents with premature aging of the affected individual. It was noted in initial studies that activity of the enzyme telomerase was quite low. What mechanism explains the above observation?A. some proteins disappear with timeB. replication at telomeres is absent C. DNA chains shorten with timeD. all of the above

ApplicationAnswer: D. all of the aboveReference: Harper's Illustrated Biochemistry 27th ed., p. 326

IMMUNOLOGIC - 15

I. Given patient data, determine the metabolic pathways and processes involved.

86. A highly atopic individual wil have elevated levels of:A. Ig AB. Ig GC. Ig MD. Ig E

RecallAnswer: D. Ig EReference: Harper's Illustrated Biochemistry 27th ed., p. 601, Table 149 - 9

87. Patients with bronze diabetes have:A. diabetes mellitusB. excessive storage iron in tissuesC. mutations in the HFE geneD. all of the above

RecallAnswer: D. all of the aboveReference: Harper's Illustrated Biochemistry 27th ed., p. 594 - 595 par. 10

88. In a 52 year old congestive heart failure patient presenting with edema, which of the following statements is TRUE:A. The hydrostatic pressure in the arterioles and in the veins are the sameB. The hydrostatic pressure in the veins is greater than that of the arteriolesC. The oncotic pressure in the arterioles is greater than that of the veinsD. Edema results when fluid accumulates in the extravascular tissue spaces

ApplicationAnswer: D. Edema results when fluid accumulates in the extravascular tissue spacesReference: Harper's Illustrated Biochemistry 27th ed., p. 558 par. 6

89. After a massive incompatible blood transfusion, the patient complained of abdominal pain and "bloody urine". Which of the following biochemical processes is TRUE of this patient?A. The "bloody urine" is due to the Hb-Hp complexB. The urine is due to the free hemoglobin passing thru the glomerulusC. The haptoglobin is elevated in this patientD. All of the above

ApplicationAnswer: B. The urine is due to the free hemoglobin passing thru the glomerulusReference: Harper's Illustrated Biochemistry 27th ed., p. 592 par.3

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90. In a patient with chronic liver disease, which of the following biochemical processes is TRUE?A. albumin production is decreasedB. erythropoietin is elevatedC. haptoglobins are elevatedD. nuclear factor kappa- (NFKB) is stimulated

ApplicationAnswer: A. albumin production is decreased Reference: Harper's Illustrated Biochemistry 27th ed., p. 591 par. 2 - 4

IV. Given a clinical condition, identify the genetic/immunologic processes involved

91. A pregnant woman most likely will transmit this immunoglobulin to her baby:A. Ig GB. Ig AC. Ig MD. Ig E

RecallAnswer: A. Ig GReference: Harper's Illustrated Biochemistry 27th ed., p. 601, Table 49-9

92. A patient with emphysema may have a deficiency in:A. albuminB. 1 - antitrypsinC. 2 - macroglobulinD. ceruloplasmin

RecallAnswer: B. 1 - antitrypsinReference: Harper's Illustrated Biochemistry 27th ed., p. 597, par. 6

93. Which organ is seriously affected in patients with multiple myeloma?A. liverB. kidneysC. intestinesD. brain

RecallAnswer: B. kidneysReference: Harper's Illustrated Biochemistry 27th ed., p. 604 par. 1

94. Patient with agammaglobulinemia is a serious immunodeficiency disease of:A. Ig MB. Ig GC. Ig AD. Ig E

RecallAnswer: B. Ig GReference: Harper's Illustrated Biochemistry 27th ed., p. 604 par. 1

95. Which protein is deposited in large amounts in brain tissues in patients with alzheimer's diseaseA. C - reactive proteinB. C - peptideC. Amyloid D. 2 macroglobulin

RecallAnswer: C. Amyloid Reference: Harper's Illustrated Biochemistry 27th ed., p. 599 par. 1

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96. On a routine physical examination, a first year nursing student was told by the examining physician that he has golden pigment ring around his cornea of both eyes. Which of the following laboratory results yield abnormal results?A. serum copperB. serum calciumC. urinary creatinineD. urine sodium

ApplicationAnswer: A. serum copperReference: Harper's Illustrated Biochemistry 27th ed., p. 597, par. 2

97. A medical student came to the emergency room because of difficulty of breath and rashes all over her body after attending a birthday party. The resident on duty gave her a shot of hydrocortisol which provided a dramatic relief to the student. The relief is due to:A. stimulation of the JAK-STAT pathwayB. inhibition of NF-KBC. regulation of nuclear receptor familyD. stimulation of tyrosine kinase activity

ApplicationAnswer: B. inhibition of NF-KBReference: Harper's Illustrated Biochemistry 27th ed., p. 475, par. 3

98. Patient's with Crohn's disease may die because of:A. infectionB. hypoalbuminemiaC. protein losing gastroenteropathyD. all of the above

ApplicationAnswer: D. all of the aboveReference: Harper's Illustrated Biochemistry 27th ed., p. 590 par. 2

99. Which statement is TRUE of a patient with recurrent respiratory tract infections:A. Circulating immunoglobulins are decreasedB. Cell-mediated immunity is decreasedC. T cells are involvedD. All of the above

ApplicationAnswer: A. Circulating immunoglobulins are decreasedReference: Harper's Illustrated Biochemistry 27th ed., p. 599 par. 2

100. A kidney transplant patient developed graft rejection reactions on the 7th day post transplant. Which statement is TRUE of this patient:A. Plasma cells are the primary culprintB. This is hormonal responseC. This is T cell-mediated immunologic responseD. Bone marrow transplant is a must for this patient

ApplicationAnswer: C. This is T cell-mediated immunologic responseReference: Harper's Illustrated Biochemistry 27th ed., p. 599 par. 2

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