Biochemistry Pre-Test (Practice Test 1) March 2023 APRIL PARANGAN PDF

TOPNOTCH MEDICAL BOARD PREP BIOCHEMISTRY PRACTICE TEST HANDOUT BY DR. JAMES DANIEL E. OMALIN For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/ This handout is only valid fo...

TOPNOTCH MEDICAL BOARD PREP BIOCHEMISTRY PRACTICE TEST HANDOUT BY DR. JAMES DANIEL E. OMALIN For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/ This handout is only valid for March 2023 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly. You are helping a 24/F colleague study for her IMPORTANT LEGAL INFORMATION upcoming Physician Licensure Examinations. In one question, there are three statements: I. The entropy of The handouts, videos and other review materials, provided by Topnotch Medical Board a system can never decrease; II. 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Energy is transferred to a solid via electromagnetic THIS HANDOUT IS NOT FOR SALE! waves III. A boiling liquid is heated on a hot plate This handout is only valid for the March 2023 PLE batch. IV. A warm gas is mixed with cold gas This will be rendered obsolete for the next batch 5. Which of the following processes is/are more likely to since we update our handouts regularly. be accompanied by a change in temperature? A. I, II, III B. I, II, IV BIOCHEMISTRY – PRE-TEST C. II and III only (PRACTICE TEST 1) D. III only E. None of the choices By James Daniel E. Omalin, MD 19/F presents with diarrhea lasting for about 2 weeks. 3 weeks ago, she went to a camping trip with college 36/M presents with chronic diarrhea, fever, and groupmates and allegedly accidentally drank some weight loss. Pertinent PE findings include multiple dirty river water when they were trekking. She also oral aphthous ulcers and fundoscopy findings noticed that there are drops of oil in the toilet consistent with uveitis. Pertinent laboratory findings whenever she defecates. Pertinent PE findings include include a positive anti-Saccharomyces cerevisae hypogastric tenderness. Fecalysis revealed Giardia antibody (ASCA) test and elevated fecal calprotectin. lamblia trophozoites and steatorrhea. Steatorrhea is You decided to enroll the patient to your research and 6. usually evident physically as drops of oil in the toilet you requested a laboratory test similar to fecal that does not mix with water seen usually after calprotectin; both of which are related to neutrophil defecating. What is the entropy change in a mixture of 1. activation. The substrate for your laboratory test is oil and water that separates? actually an antimicrobial agent found in milk and A. Positive extracted using a column of charged resin. What type B. Zero of chromatographic technique is used to extract the C. Either positive or zero said substrate? D. Neither positive or zero A. Thin-layer chromatography E. More information is necessary B. Ion-exchange chromatography 45/F, known type 1 diabetic, presents with nausea, C. Affinity chromatography vomiting, and abdominal pain for the past 12 hours. 1 D. Size-exclusion chromatography week ago, she had an extreme misunderstanding with E. Either A or D her husband which caused her to miss her insulin 27/M presents with multiple burns after a community shots for multiple days. At the emergency room, you fire incident. Pertinent PE findings include a third- note that her breath smells similar to a nail polish degree burn on the palm of the right hand and diffuse remover. Vital signs are as follows: BP 140/90, HR erythema along the base of the neck and forearms. He 101, RR 33, T 36.6, SpO2 99%. Pertinent PE findings told you the series of events that occurred in order: He include diffuse direct and rebound abdominal went inside the house wherein there is hot smoke tenderness. A capillary blood glucose was drawn 7. inside, then he accidentally touched a hot steel which revealed to be 542 mg/dL. Arterial blood gas is doorknob, and lastly, he accidentally went to a room consistent with high anion gap metabolic acidosis. The with burning furniture and felt the heat around his compound responsible for the nail polish remover- neck. You managed the patient accordingly. What are like odor of her breath is derived from which of the 2. following? the three modes of heat transfer experienced by this patient, in order? A. Ether I. Radiation B. Ester II. Conduction C. Carboxylic acid III. Convection D. Amino acid A. I, II, III E. Alcohol B. III, II, I 25/F presents with a self-inflicted laceration C. III, I, II accidentally while chopping vegetables. You use D. I and II only hydrogen peroxide to clean the wound. Which of the ff. E. III only is the most likely mechanism of action of hydrogen All of the following are state functions, EXCEPT? peroxide? 8. A. Work A. Halogenation of nucleic acids B. Heat B. Crosslinking of proteins 3. C. Intercalation of DNA C. Temperature D. All of the choices D. Formation of free radicals E. A and B only E. Denaturation of proteins TOPNOTCH MEDICAL BOARD PREP BIOCHEMISTRY PRACTICE TEST HANDOUT BY DR. JAMES DANIEL E. OMALIN Page 1 of 17 For inquiries visit www.topnotchboardprep.com.ph or email us at [email protected] This handout is only valid for the March 2023 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly.  TOPNOTCH MEDICAL BOARD PREP BIOCHEMISTRY PRACTICE TEST HANDOUT BY DR. JAMES DANIEL E. OMALIN For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/ This handout is only valid for March 2023 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly. 78/M smoker presents with productive cough, fever, 65/M presents with blurring of vision for the past 6 and generalized body weakness for 2 days. His phlegm months. Past medical history: Hypertension, type 2 is noted to be greenish-yellow in color. Vital signs are DM, and dyslipidemia. Slit lamp exam: Cloudy lens as follows: BP 110/80, HR 126, RR 31, T 38.3, SpO2 opacities, bilateral. Increased activity of which of the 94%. He is weak-looking. Pertinent PE findings following may have caused this patient’s condition? 15. include bilateral bibasal crackles. His grandson, a A. Aldose reductase medical student, asks you why is his grandfather’s B. Aldolase B phlegm greenish-yellow in color. You answered C. Sorbitol dehydrogenase accordingly and correctly. The compound responsible D. Glucokinase 9. for the greenish-yellow color of the patient’s phlegm E. Galactokinase produces a product which participates in three 10/M presented to you with leg cramps whenever he runs. reaction steps, namely (not in any particular order): I. He also presents with nausea and vomiting. Upon further Propagation, II. Termination, III. Initiation. What is history, you elicited that his leg cramps are very intense the correct order of this three-step reaction? after a high-carbohydrate meal. Labs revealed A. II, III, I myoglobinuria, hyperuricemia, and hyperbilirubinemia. B. I, III, II 16. What enzyme is deficient in this patient? C. III, I, II A. Glucose-6-phosphatase D. II, I, III B. Glycogen synthase E. I, II, III C. Liver glycogen debranching enzyme 15/M presents with high volume watery diarrhea D. Muscle phosphofructokinase after eating shellfish. Your primary impression is E. Muscle phosphorylase cholera. Cholera toxin causes massive diarrhea by 45/M presents with severe headache. BP is 200/100. causing the continual synthesis of cAMP. Which of the Fundoscopy: Retinal hemorrhages. You started the following mechanisms would account for this effect? patient on nitroprusside infusion. What enzyme is 10. A. Activation of Gi protein directly affected by the active metabolite of this drug? B. Irreversible activation of adenylyl cyclase 17. A. Phospholipase A2 C. Locking of Gs protein into an inactive form B. cAMP phosphodiesterase D. Prevention of GTP from interacting with Gq protein C. Guanylyl cyclase E. Rapid hydrolysis of G protein GTP to GDP D. cGMP phosphodiesterase 56/M just ate a large meal. You know in biochemistry E. Phospholipase C that the fed state stimulates anabolic pathways. Which 49/M presents with squeezing chest pain induced by of the following is/are true for anabolic pathways? exercise and relieved by rest. You ordered an exercise A. Irreversible reactions are regulated stress test. During this test, there is an increase in the 11. B. Also known as “cycles” if they regenerate an metabolism of glycogen in muscle cells. What explains intermediate this finding? 18. C. Convergent and generate few simple products A. Decrease in protein kinase A D. Synthetic and require energy B. Activation of phosphorylase kinase E. Typically require/s oxidized coenzymes C. Increase in glucose-6-phosphate 5/F presents with throat pain. She has history of D. Activation of protein phosphatase frequent oral thrush. Labs show that the exposure to E. Inactivation of glycogen synthase kinase nitroblue tetrazolium turns her neutrophils dark 55/M presented to you with intermittent chest pain. blue. Which enzyme deficiency explains her recurrent Baseline ECG is unremarkable. You ordered an infections? exercise treadmill stress test. At peak exercise, which 12. A. Adenosine deaminase of the following is expected enzyme activity of (1) B. Glucose-6-phosphate dehydrogenase isocitrate dehydrogenase in cardiac muscles and (2) C. NADPH oxidase 19. pyruvate carboxylase respectively? D. Myeloperoxidase A. Increased; increased E. Angiotensin-converting enzyme 2 B. Increased; decreased 16/F presents with muscle pain. One month ago, she C. No change; increased had sudden right-sided weakness. She has a history of D. Decreased; decreased generalized tonic-clonic seizures. Her mother and E. Decreased; increased brother have similar symptoms. Labs show a serum 4/F presents with cataracts. Further history reveals lactate of 3.0 mmol/L (NV: 0.5-2.2). Graded exercise that he has galactokinase deficiency. Which of the testing shows a significantly decreased maximum rate following may have caused the formation of cataracts of oxygen consumption. The activity of which of the in this patient? 13. following metabolic pathways is most likely increased 20. A. Accumulation of phenylalanine in this patient? B. Excess valine A. Oxidative phosphorylation C. Excess leucine B. Glycolysis D. Accumulation of galactitol C. Beta oxidation E. Excess leucine D. Pyrimidine synthesis A 4-day-old term newborn presents with jaundice. E. Ketogenesis Labs reveal elevated liver enzymes. Further labs 16/M presents with muscle pain and dark urine after confirm classic galactosemia. What is the underlying exercise. Further studies confirm that the patient has cause of this condition? McArdle disease. What is the rate limiting enzyme for 21. A. Pyruvate kinase deficiency the defective pathway in this disease? B. Galactokinase deficiency 14. A. Isocitrate dehydrogenase C. Glucokinase deficiency B. Phosphofructokinase-1 D. Galactose-1-phosphate uridyltransferase (GALT) deficiency C. Glycogen synthase E. Aldose reductase deficiency D. Glycogen phosphorylase 59/F is brought in for routine examination. She works E. Glucose-6-phosphate dehydrogenase out regularly, eats vegetables, fish, and grains, and avoids processed foods. PE is unremarkable. She is most likely to have an increase in which of the 22. following laboratory markers? A. LDL B. VLDL C. HDL D. Triglyceride E. IDL TOPNOTCH MEDICAL BOARD PREP BIOCHEMISTRY PRACTICE TEST HANDOUT BY DR. JAMES DANIEL E. OMALIN Page 2 of 17 For inquiries visit www.topnotchboardprep.com.ph or email us at [email protected] This handout is only valid for the March 2023 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly.  TOPNOTCH MEDICAL BOARD PREP BIOCHEMISTRY PRACTICE TEST HANDOUT BY DR. JAMES DANIEL E. OMALIN For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/ This handout is only valid for March 2023 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly. 14/M presents with labs of triglyceride level of 830 53/M presented to you with chest pain. ECG revealed mg/dL. You have a drug that is noted to increase ST-segment depressions in leads II, III, and aVF. You gallstone risk as an adverse effect. The beneficial recalled that one of the drugs that significantly effect of this drug is due to what action? reduces mortality risk from atherosclerotic 23. A. Increased lipoprotein lipase activity cardiovascular disease are statins. Statins inhibit the B. Increased PPAR-gamma activity enzyme HMG-CoA reductase. Which of the following C. Decreased HMG-CoA reductase activity 30. directly inhibits the expression of the HMG-CoA D. Increased bile acid sequestration reductase gene? E. Increased HMG-CoA reductase activity A. Squalene Which of the following is an important intermediate in B. HMG-CoA the biosynthesis of unesterified fatty acids? C. Lanosterol A. Carnitine D. Isopentyl pyrophosphate 24. B. Cholesterol E. Cholesterol C. Fatty acyl-CoA Which of the following is true with respect to the D. Glucose actions of the mineralocorticoids? E. Malonyl-CoA A. Decrease in carbohydrate metabolism 50/F presents to you for routine checkup. She has B. Increase appearance of secondary sex 31. menopausal hot flashes treated with estrogen. characteristics Medical history includes hypertension treated with C. Increase androgen synthesis bisoprolol. She drinks 3-4 glasses of beer per night. D. Regulation of aldosterone secretion Her maternal uncle had heart disease at age 45 and E. Regulation of sodium retention by the kidneys she has a cousin that had a transient ischemic attack 23/M obese medical student presents to you with at age 50. Labs reveal an elevated total cholesterol of routine labs which revealed total cholesterol is 433 25. 210 mg/dL and elevated LDL cholesterol of 185 mg/dL, triglycerides of 689 mg/dL. Further history mg/dL. Which of the following is most likely in this revealed that he already underwent coronary patient? angioplasty 2 years ago. Physical examination A. Carotid bruit revealed xanthomas. You are considering a rare B. History of transient ischemic attack symptoms 32. autosomal recessive condition which is characterized C. Exertional chest pain by a mutation in which of the following? D. Tendon xanthomas A. Lipoprotein lipase E. Normal physical exam B. Apo-CII 18/M presented to you with abdominal pain and C. Apo-E vomiting. He is previously diagnosed with type 1 D. Apo-B100 diabetes mellitus. Labs revealed elevated serum E. Apo-B48 ketones. Hepatocytes are able to secrete ketone 9/M presents with red-purple small spots on his skin bodies into the circulation because of the absence of as well as burning sensations in both feet. Labs: Urine 26. what enzyme? dipstick protein 3+. Further studies reveal a A. Beta-hydroxybutyrate dehydrogenase deficiency of alpha-galactosidase. Which of the B. HMG-CoA lyase following is diagnosis? 33. C. HMG-CoA synthetase A. Fabry disease D. Succinyl-CoA-acetoacetate-CoA transferase B. Farber disease E. Beta-ketothiolase C. Gaucher disease 1/M with cystic fibrosis presents with steatorrhea. PE: D. Krabbe disease Generalized dry and scaly rash. Impression is E. A or B essential fatty acid deficiency. Which of the following 66/M presents with heart failure and pulmonary is a direct derivative of an essential fatty acid is most embolism. He has chronic stable angina. In the ER, the likely deficient in this case? patient expired. Autopsy: Cardiac storage of ceramide 27. A. Lauric acid trihexoside. Which of the following would result in B. Prostaglandin H2 these findings? 34. C. Palmitoleic acid A. Fabry disease D. Leukotriene A4 B. Gaucher disease E. Arachidonic acid C. Krabbe disease 50/M presented to you with lipid profile results which D. Niemann-Pick disease revealed: LDL of 200 mg/dL. You prescribed E. Tay-Sachs disease simvastatin and follow-up lipid profile after a month 66/M presents to you with progressive heart failure and revealed an LDL level of 120 mg/dL and a triglyceride repeated pulmonary embolism. He has had stable angina level of 542 mg/dL. You added gemfibrozil. Two weeks pectoris for more than 20 years. While in the emergency later, the patient presented in the emergency room room, the patient deteriorated and expired. Autopsy with diffuse myalgias. Serum creatine kinase is revealed enormous cardiomyopathy, cardiac storage of 28. elevated and the patient now has acute renal failure. ceramide trihexoside, and restricted cardiomyocytes. What may have caused this man’s presentation? 35. Which of the following lipid storage diseases would result A. Increased simvastatin levels in these findings? B. Direct toxicity of gemfibrozil A. Fabry disease C. Myocyte hypoxia B. Gaucher disease D. Increased statin metabolism C. Krabbe disease E. Toxic gemfibrozil metabolite D. Niemann-Pick disease type IA 32/M presents with progressive thinning of hairline. E. Tay-Sachs disease Family history is significant for male-pattern baldness. You know that dihydrotestosterone (DHT) plays a role in this condition. Which of the following is true for DHT? 29. A. Promotes anabolic effects on skeletal muscle B. Promotes development of the prostate C. Promotes development of the testes D. A and B only E. B and C only TOPNOTCH MEDICAL BOARD PREP BIOCHEMISTRY PRACTICE TEST HANDOUT BY DR. JAMES DANIEL E. OMALIN Page 3 of 17 For inquiries visit www.topnotchboardprep.com.ph or email us at [email protected] This handout is only valid for the March 2023 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly.  TOPNOTCH MEDICAL BOARD PREP BIOCHEMISTRY PRACTICE TEST HANDOUT BY DR. JAMES DANIEL E. OMALIN For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/ This handout is only valid for March 2023 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly. 68/F presents with generalized fatigue and swollen Twenty minutes after being rescued from a house fire, gums. She is a widow who lives alone for several years 35/F arrives at the ER. She feels queasy, headachey, now and eats mostly bread and tea as she was too and lightheaded. At room air, oxygen saturation is 99 depressed to prepare her own food. She was cut by a percent. What is the mechanism of toxicity of the gardening tool in the right index finger while tending to substance that most likely causes her symptoms? 41. her houseplants 2 weeks ago and she noticed that the A. Competitive binding to heme wound took too long to stop bleeding. Her vital signs are B. Oxidation of Fe2+ within normal ranges. Pertinent PE findings include C. Inhibition of mitochondrial complex V 36. curly body hair. Considering the most probable diagnosis D. Degradation of 2,3-bisphosphoglycerate in this patient, what type of non-essential compound is E. Destruction of the alveoli defective in this patient’s condition? 10/M presents with blurring of vision. He is at 99th A. Non-aromatic heterocyclic compound percentile for height. PE shows joint hypermobility, a B. Aromatic heterocyclic compound high-arched palate, and long, slender fingers and toes. C. Non-branched linear compound Slit lamp exam shows bilateral superotemporal lens D. Branched linear compound subluxation. These findings are most likely caused by E. B and C only 42. a defect in which of the ff. proteins? 37/M presents with pain swelling of the right big toe. A. Fibrillin He notes that he went to his friend’s house in Tagaytay B. Type III collagen City, Cavite and they drank a lot of expensive whiskey C. Type II collagen 2 days ago. Vital signs are within normal ranges. D. Type I collagen Pertinent PE findings include a visibly erythematous E. Laminin medial big toe, right that is warm and tender to the 43. 10-day/M presents with vomiting and poor feeding. He touch. Pertinent laboratory findings include appears lethargic. PE shows diffusely increased muscle hyperuricemia and scleral icterus. At the wards, his tone. His urine is noted to have a sweet. His symptoms condition deteriorated. Further history reveals that are most likely caused by the accumulation of which of he is a chronic alcoholic and drinks 4 shots of very the following? 37. expensive cognac every night. Further laboratory A. Isoleucine studies reveal: AST 355 IU/L, ALT 177 IU/L, PT 19 B. Phytanic acid seconds, PT control/reference 12 seconds, total C. Phenylalanine bilirubin (TB) 3.5 mg/dL, and serum pH of 7.06. What D. Homogentisic acid is the charge of the primary amino acid substrate of E. Homocysteine the enzyme AST at this patient’s serum pH? You are studying the structure of the amino-terminal A. Positive of the Huntingtin protein through x-ray B. Negative crystallography. You determined that the terminal C. Neutral region has an alpha-helix conformation. Which of the D. Either A or B following forces is responsible for maintaining this E. More information is required to answer the question 44. conformation? 28/F first year radiology resident physician presents A. Disulfide bonds to you with blistering skin lesions after coming home B. Hydrogen bonds from a 30-hour duty. Her post is in the x-ray reading C. Hydrophobic interactions room. She says that she had this condition ever since D. Electrostatic side chain attraction she was a medical student, but only got worse when E. Any of the choices she became a resident, as she started to drink a glass 39/M presents with heat intolerance and tremors. PE: of wine every from/post-duty. Vital signs are within Warm and moist palms, non-palpable thyroid gland. normal ranges. Pertinent PE findings include Which of the following essential amino acids are the scattered vesicles and bullae around the neck and thyroid hormones synthesized? dorsum of the hands and forearms and hypertrichosis 45. A. Isoleucine 38. around the cheeks and eyebrows. The type of B. Lysine compound that accumulates in this patient’s condition C. Methionine is synthesized from two other compounds, one of D. Phenylalanine which does not have an L-enantiomer. Which of the E. Valine following compounds does not have an L-enantiomer? 65/F, living alone, presents with easy bruising and A. Methionine gum bleeding. PE: Bruises on legs, swollen gums, B. Valine petechiae on the roof of the mouth. This patient’s C. Isoleucine condition is characterized by the deficiency of a D. Glycine compound which is composed significantly of which E. All of the choices 46. amino acid? 2/M presents with seizures. He is not yet able to walk and A. Glycine does not use recognizable words. His paternal uncle has B. Proline intellectual disability. Labs show an elevated C. Tyrosine phenylacetate level. Which amino acid is nutritionally D. Lysine essential for this patient? E. Collagen 39. A. Phenylalanine 21/M presents with cola-colored urine. He just B. Tyrosine completed a long marathon. Urine is positive for C. Alanine myoglobin. Your impression is rhabdomyolysis. D. Cysteine Which parts of the amino acids in this protein interact E. A and B to form its tertiary structure? 4-day/M presents with failure to thrive. Labs show 47. A. Amine group decreased activity of carbamoyl phosphate synthetase I. B. R group Which of the following is an immediate substrate for the C. Carboxyl group synthesis of the molecule needed for the excretion of D. Hydrogen atom amino groups? E. Carbon group 40. A. A. N-acetylglutamate B. Homocysteine C. Phenylalanine D. Aspartate E. Alanine TOPNOTCH MEDICAL BOARD PREP BIOCHEMISTRY PRACTICE TEST HANDOUT BY DR. JAMES DANIEL E. OMALIN Page 4 of 17 For inquiries visit www.topnotchboardprep.com.ph or email us at [email protected] This handout is only valid for the March 2023 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly.  TOPNOTCH MEDICAL BOARD PREP BIOCHEMISTRY PRACTICE TEST HANDOUT BY DR. JAMES DANIEL E. OMALIN For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/ This handout is only valid for March 2023 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly. 7-day/M presented to you with newborn screening 10/F presents to you with distinctive facial features, broad results consistent with elevated phenylalanine levels. thumbs, broad big toes, and mental retardation. Your You placed the patient on phenylalanine restriction primary impression is Rubenstein-Taybi syndrome (RTS) and tyrosine supplementation. 3 months later, wherein the CREB-binding protein (CBP) gene is affected. phenylalanine levels are found to be normal. Physical CBP is known to have a histone acetyltransferase activity, examination revealed neurologic abnormalities 54. which functions as which of the following? which led you to request further workup. Further A. Inhibits RNA polymerase II 48. evaluation revealed elevation in serum prolactin. B. Helps expose the promoters of genes What enzyme is deficient in this patient? C. Inhibits the splicing of hnRNA to mRNA A. Homogentisate oxidase D. Prevents the addition of poly-A tain to mRNA B. Dopamine hydroxylase E. Activates the formation of nucleosomes C. Phenylalanine hydroxylase 56/F with Crohn disease presents with recurrent flares. PE: D. Dihidrobiopterin reductase Oral mucosal ulcers. You added azathioprine. Deficiency of E. Tyrosinase which enzyme would decrease the effect of this drug? 75/M presents with cognitive dysfunction and A. Xanthine oxidase 55. behavioral alterations. He also has progressive B. Thymidilate synthase disorientation and memory loss for the past 4 months. C. Hypoxanthine-guanine phosphoribosyl transferase Your initial impression is Alzheimer disease. What is D. Phosphoribosyl pyrophosphate synthetase true about this condition? E. Dihydrofolate reductase A. Involves beta-amyloid, a protein with altered 45/F presents with sudden onset nausea, vomiting, 49. amino acid sequence fatigue, and pruritus. Further history revealed that B. Results from accumulation of denatured proteins she had a sore throat 3 years ago which allegedly with random conformations spontaneously resolved without medications. Vital C. Results from accumulation of amyloid precursor protein signs are as follows: BP 190/100, HR 99, RR 27, T 36.0, D. Associated with neurotoxic amyloid beta peptide SpO2 99%. Pertinent PE findings include diffuse aggregates hyperpigmentation of the skin and asterixis. Pertinent E. A and D only 56. laboratory findings are consistent with uremia. The 35/M African presents with acute chest pain and primary metabolic waste product in this patient difficulty of breathing. Hemoglobin electrophoresis contains which of the following functional groups? confirms sickle cell disease. Which of the following is A. Amide true about sickle cell disease? B. Imide A. Aggregation of hemoglobin tetramers due to a C. Imine hydrophobic effect D. A and B only 50. B. Arises from a point mutation changing glutamate to E. B and C only lysine on the beta-subunit of hemoglobin 29/F presents with dark urine, abdominal pain, and C. Binding of 2,3-BPG to hemoglobin is diminished tingling sensation in her arms and legs. She has D. Expression of the sickled phenotype involves a epilepsy maintained on phenytoin. She appears hydrophilic interaction confused. Following the administration of hemin and E. Fetal hemoglobin is significantly affected glucose, her symptoms improved. The beneficial effect 7-month/M presented to you with fever and of this treatment is most likely due to inhibition of 57. irritability. Physical examination reveal jaundice and which of the following enzymes? swollen fingers. CBC is remarkable for hemoglobin A. Aminolevulinate acid synthase level of 6 g/dL and elevated LDH levels of 900 IU/L. B. Ferrochelatase Hemoglobin electrophoresis shows the presence of C. Porphobilinogen deaminase hemoglobin S. Which of the following features of D. Uroporphyrinogen decarboxylase 51. hemoglobin S, compared to normal hemoglobin, is E. Aminolevulinate acid dehydratase primarily responsible for the patient’s presentation? 5-day/M presents with lethargy and vomiting after A. Increased hydrophobicity breastfeeding. Labs show elevated serum ammonia. B. Increased polarity Further studies show a deficiency in N- C. Large molecular weight acetylglutamate synthase. The activity of which of the D. Increased nitrogen content following enzymes is most likely directly affected by E. Decreased carbon content 58. this genetic defect? 26/F presents with headache, dizziness, and nausea. A. Carbamoyl phosphate synthetase I She likes vintage stuff and uses a wood stove for B. Ornithine transcarbamylase cooking. Further labs reveal a carboxyhemoglobin C. Argininosuccinate synthetase level of 10%. What may have caused this patient’s D. Arginino succinase presentation? E. Arginase 52. A. Inhibited mitochondrial succinate dehydrogenase 55/M presents with fever, jaundice, and RUQ pain. B. Inhibited mitochondrial ATP synthase Ultrasound shows cholelithiasis and dilation of biliary C. Increased oxygen binding capacity duct. ERCP was done which revealed pus with multiple D. Inhibited mitochondrial cytochrome c oxidase brown concrements draining from the CBD. Which of E. Increased mitochondrial membrane permeability the following is the most likely underlying cause of the 45/M known case of prostate cancer undergoing 59. patient's findings? radiation therapy presents with severe joint pain in A. Decreased UDP-glucuronyl transferase activity the MTP of his left big toe. Arthrocentesis: B. Decreased HMG-CoA reductase activity Monosodium urate crystals. The presentation of this C. Increased cholesterol 7a-hydroxylase activity patient is caused by the overproduction of the end- D. Increased B-glucuronidase activity 53. product of which pathway? E. Increased UDP-glucuronyl transferase activity A. De novo pyrimidine biosynthesis 1 month/M presents with seizures, lethargy, and poor B. Pyrimidine degradation cry. PE: hypotonia and hepatomegaly. ABG is C. De novo purine biosynthesis consistent with metabolic acidosis. Further labs D. Purine salvage revealed elevated methylmalonic acid levels. Which E. Purine degradation type of enzyme is deficient in this case? 60. A. Dehydrogenase B. Synthase C. Carboxylase D. Mutase E. Phosphorylase TOPNOTCH MEDICAL BOARD PREP BIOCHEMISTRY PRACTICE TEST HANDOUT BY DR. JAMES DANIEL E. OMALIN Page 5 of 17 For inquiries visit www.topnotchboardprep.com.ph or email us at [email protected] This handout is only valid for the March 2023 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly.  TOPNOTCH MEDICAL BOARD PREP BIOCHEMISTRY PRACTICE TEST HANDOUT BY DR. JAMES DANIEL E. OMALIN For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/ This handout is only valid for March 2023 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly. 50/M radiologist develops recurrent skin blistering A. I and IV only after a night shift duty. Labs reveal elevated total B. II and IV only plasma porphyrins. Which of the following enzymes C. I, II, and IV is most likely deficient in this patient? D. I and II only 61. A. Delta-aminolevulinate synthase E. I, II, III, and IV B. Delta-aminolevulinate dehydrase 45/M presents with blurring of vision, abdominal C. HMB synthase pain, and vomiting after he drank a bottle of paint D. Uroporphyrinogen decarboxylase thinner. Visual acuity is 20/200 bilaterally despite E. Bilirubin glucoronyl transferase corrective lenses. ABG is consistent with high anion 6/M presents with intellectual disability. Labs: gap metabolic acidosis. What is the mechanism of Microcytic anemia and basophilic stippling. Further 67. action of the antidote for this patient? history reveals the boy eats paint chips from their A. Activation of alcohol dehydrogenase 200-year-old house. What most likely caused this B. Inhibition of acetaldehyde dehydrogenase patient’s anemia? C. Activation of acetaldehyde dehydrogenase 62. A. Inhibition of iron transport D. Inhibition of alcohol dehydrogenase B. Reduction of heme synthesis E. Both B and D C. Inhibition of the phosphatidylinositol cycle 35/M suffered from severe burns involving 45% D. Blockage of reticulocyte DNA synthesis TBSA. Weight: 70 kg; Height: 183 cm. What is the best E. Inhibition of beta-globin gene expression estimate of the immediate daily caloric needs of this 53/F presents to you with acute onset of abdominal patient? pain and vomiting. She is previously diagnosed with 68. A. 1345 kcal type 2 diabetes mellitus. RBS revealed 550 mg/dL and B. 1680 kcal positive urine ketones. Your impression is diabetic C. 2690 kcal ketoacidosis. In acidosis, the liver and kidneys D. 3360 kcal function to increase pH of the circulation. Which of the E. 69420 kcal following constitutes the hepatic reaction occurring 45/F presents with loss of appetite, muscle weakness, during periods of acidosis? and fatigue. PE: Jaundice and hepatomegaly. Labs: 63. A. Ammonia incorporation into glutamate; forming Macrocytic anemia and decreased folate levels. What glutamine is the underlying cause of this patient’s condition? B. Ammonia incorporation into alpha-ketoglutarate; 69. A. Decreased methionine synthesis forming glutamate B. Decreased conversion of dUMP to dTMP C. Glutamine conversion to glutamate releasing ammonia C. Decrease synthesis of phosphatidylcholine D. Glutamine conversion to alpha-ketoglutarate- D. Decrease in succinyl-CoA levels releasing ammonia E. Decrease dUTP synthesis E. Increased production of urea to dispose of ammonia 56/M previously diagnosed with type 2 diabetes 53/F known T2DM on glimepiride 2 mg BID presents mellitus presents with laboratory results. HBA1C of with sudden onset seizures. CBG: 42 mg/dL. Which of 7.1 and an FBS of 98 mg/dL. He does self-monitoring the following statements is true for insulin? of blood glucose and noticed that his 2-hour A. Peptide hormone secreted by the pancreas postprandial glucose at lunch and dinner is more than 64. B. Secretion is decreased by catecholamines 200 mg/dL. His usual diet is comprised of meat, C. Actions are mediated by binding to a receptor on potato, broccoli, milk, and diet soda. Which of these 70. cell membrane of the liver cells foods is most likely responsible for his postprandial D. Effects include alterations in gene expression high glucose? E. A and B only A. Meat 36/F presents with nausea, abdominal cramps, altered B. Potato mental status, and blurring of vision. She just came back C. Broccoli from a high school reunion 30 minutes earlier and her D. Milk companion said that she drank several shots of lambanog E. Diet soda which is “homemade” by her other friend. Her GCS is 9 35/F presents with yellowish discoloration of skin. (E3V3M3). Pertinent PE shows optic disc hyperemia on She follows a vegan diet that consists mainly of fundoscopy. An arterial blood gas was drawn and results spinach, kale, and sweet potatoes. Eye examination 65. are consistent with high anion gap metabolic acidosis. The shows no abnormalities. Which of the following primary toxic substance responsible for the patient’s findings is most likely in this patient’s serum? 71. presentation can be classified as which of the following? A. Decreased haptoglobin concentration A. Primary alcohol B. Increased alkaline phosphatase concentration B. Secondary alcohol C. Positive antimitochondrial antibodies C. Tertiary alcohol D. Increased beta-carotene concentration D. Quaternary alcohol E. Increased hemoglobin concentration E. Glycol 75/F presents with chronic diarrhea and recurrent 37/M presents with pain swelling of the right big toe. upper respiratory tract infections. She also trips easily He notes that he went to his friend’s house in Tagaytay at night when she goes to the bathroom. PE shows dry City, Cavite and they drank a lot of expensive whiskey skin and keratin plaques on the temporal half of the 2 days ago. Vital signs are within normal ranges. conjunctiva. Which of the following is most likely Pertinent PE findings include a visibly erythematous 72. deficient? medial big toe, right that is warm and tender to the A. Ascorbic acid touch. Pertinent laboratory findings include B. Retinol hyperuricemia and scleral icterus. C. Zinc The direct sequelae of excess alcohol consumption D. Niacin 66. causes a certain molecule to be excessive, which leads E. Molybdenum to hyperuricemia, and ultimately, the patient’s presentation. This particular molecule consists of which of the following functional groups? I. Phosphate II. Amide III. Anhydride IV. Carboxylic acid TOPNOTCH MEDICAL BOARD PREP BIOCHEMISTRY PRACTICE TEST HANDOUT BY DR. JAMES DANIEL E. OMALIN Page 6 of 17 For inquiries visit www.topnotchboardprep.com.ph or email us at [email protected] This handout is only valid for the March 2023 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly.  TOPNOTCH MEDICAL BOARD PREP BIOCHEMISTRY PRACTICE TEST HANDOUT BY DR. JAMES DANIEL E. OMALIN For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/ This handout is only valid for March 2023 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly. 75/M presents with labs showing a mild increase in 46/M presented to you with paresthesias. One month INR. One week ago, he was prescribed azithromycin prior to consult, he arrived in a military camp and was for community-acquired pneumonia. He has history of provided with three meals per day, clothing, and atrial fibrillation maintained on warfarin and shelter. The doctor in the camp diagnosed him with metoprolol. Which of the following best explains this pulmonary tuberculosis and has been started on anti- 73. patient's laboratory finding? mycobacterial therapy. Physical examination A. Depletion of intestinal flora revealed decreased sensation in a stocking-glove B. Induction of cytochrome p450 80. pattern, tongue erythema, and ulcers on his oral C. Increased non-protein bound warfarin fraction mucosa. What vitamin deficiency is responsible for D. Drug-induced hepatotoxicity this man’s presentation? E. Hepatorenal syndrome A. Vitamin B1 35/F with Crohn disease S/P multiple small bowel B. Vitamin B2 resections presents with hair loss and rash. She also C. Vitamin B3 noticed that food tasted bland recently. PE shows D. Vitamin B5 bullous, erythematous perioral plaques. A deficiency E. Vitamin B6 of which of the following is the most likely cause of this 55/M presents with easy fatigability and prickly 74. patient's condition? sensation on his bilateral feet. Labs confirm an A. Retinoic acid inherited deficiency of methylmalonyl-CoA mutase. B. Niacin Vitamin B12 supplementation has a positive effect for C. Cobalamin this patient. What is the role of vitamin B12 in this D. Zinc 81. case? E. Selenium A. Cofactor for methylmalonyl-CoA mutase 23/M presents with PBS results consistent with B. Competitive inhibitor of methylmalonyl-CoA mutase megaloblastic anemia. Further labs reveal a folic acid C. Feedback inhibitor of methylmalonyl-CoA mutase deficiency. 2 years ago, he had vitamin B12 deficiency. D. Precursor for methylmalonyl-CoA mutase How are these two vitamins related? E. None of the choices A. Deficiency of either vitamin may lead to neuropathy 42/F presents to you with right upper quadrant pain 75. B. Both vitamins are found in green leafy vegetables and fever. A hepatobiliary tree ultrasound confirms C. Both vitamins are supplemented in the first acute cholecystitis. On review of medication, this trimester of pregnancy patient has been on combination statin and D. Vitamin B12 regenerates folic acid in the body cholestyramine therapy to lower her cholesterol E. Deficiency of either vitamin may be caused by levels. Prior to cholecystectomy, this patient would be Crohn disease 82. well advised to be supplemented with which of the 55/F presents with chronic fatigue. CBC: Hgb 88, MCV following? 102. Further labs: Elevated homocysteine, normal A. Vitamin A methylmalonic acid levels. Which of the following is B. Vitamin B deficient in this patient? C. Vitamin C 76. A. Folic acid D. Vitamin K B. Vitamin B12 E. Linolenic acid C. Iron 40/F with notable psychiatric illness presents to you D. A and B only with vomiting and severe headaches. Further history E. All of the choices revealed that she practices bizarre diets. Physical Which of the following is required for the reaction examination revealed xerosis, papilledema, and catalyzed by the enzyme that converts oxaloacetate to hepatosplenomegaly. You ordered a plain cranial CT citrate in the TCA cycle? scan which revealed to be unremarkable. What is the 83. A. Thiamine underlying etiology of this patient’s case? 77. B. Pantothenic acid A. Vitamin B1 deficiency C. Guanosine diphosphate B. Vitamin B3 deficiency D. Niacin C. Vitamin A deficiency E. Riboflavin D. Vitamin A overuse 6/M with cystic fibrosis also suffers from pancreatic E. Vitamin E overuse involvement. Which of the following may happen to 56/M with type 2 diabetes and non-healing wound is this patient? admitted under your service. He is now on day 8 of A. Vitamin B12 deficiency and neuropathy antibiotics. PE: Multiple bruises on his arms. No 78. B. Vitamin K deficiency and osteomalacia history of trauma. PT is elevated at 17 seconds. What C. Vitamin D deficiency and coagulopathy could have caused this patient’s presentation? 84. D. Vitamin A excess and jaundice A. Chronic kidney disease E. Vitamin A deficiency and night blindness B. Hemophilia A A new drug has been researched for the treatment of C. Leukemia systolic heart failure, but phase I clinical trials were D. Thrombocytopenia discontinued because of an adverse event. This E. Vitamin K deficiency adverse event is characterized by the inhibition of 71/F presents to you with history of bleeding gums. gastrointestinal uptake of pantothenic acid. Which of Physical examination revealed gingival bleeding and the following adverse events most likely occurred in perifollicular hemorrhages. Further history revealed 79. patients who participated in the research? that her diet primarily consists of tea and toast. This A. Megaloblastic anemia patient’s presentation is likely caused by enzyme B. Adrenal insufficiency hypoactivity in which of the following cellular 85. C. Cheilosis compartments? D. Seizures A. Nucleus E. Heart failure B. Rough endoplasmic reticulum C. Mitochondria D. Golgi apparatus E. Lysosomes TOPNOTCH MEDICAL BOARD PREP BIOCHEMISTRY PRACTICE TEST HANDOUT BY DR. JAMES DANIEL E. OMALIN Page 7 of 17 For inquiries visit www.topnotchboardprep.com.ph or email us at [email protected] This handout is only valid for the March 2023 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly.  TOPNOTCH MEDICAL BOARD PREP BIOCHEMISTRY PRACTICE TEST HANDOUT BY DR. JAMES DANIEL E. OMALIN For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/ This handout is only valid for March 2023 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly. 65/M presents with chest pain. ECG is consistent with An unvaccinated 4/F presents with fever, malaise, and anterolateral wall STEMI. Emergent PC shows sore throat. PE shows cervical lymphadenopathy and complete occlusion of the left main coronary artery. gray-white membranes over the tonsils and posterior The release of which of the following substances from pharynx. The patient's symptoms are most likely caused platelets is most likely involved in the pathogenesis of by disruption of which of the following steps in protein 86. this patient's angiography findings? 93. synthesis? A. Thromboxane A2 A. Translocation of the ribosome along the mRNA B. Prostaglandin E2 B. Binding of tRNA to the A site C. Adenosine C. Formation of the initiation complex D. Nitric oxide D. Interference of post-translational modifications E. Leukotriene C4 E. DNA intercalation 16/F wants to get leaner by having a fat-free diet for 13/M presents with recurrent headaches. MRI: 2.5 cm several weeks. You requested labs to assess her ability calcified cystic mass in the suprasellar space. Biopsy: to synthesize various lipids. Which of the following Consistent with craniopharyngioma. Further labs will be deficient in her ability to synthesize? reveal increased RNA polymerase I activity. The 87. A. Cholesterol activity of this enzyme is highest in which of the B. Glycolipids 94. following? C. Phospholipids A. Mitochondria D. Prostaglandins B. Rough endoplasmic reticulum E. All of the choices C. Lysosomes 6/M presents with convulsions shortly after drinking a sweet, D. Nucleus viscous fluid in his dad’s garage. The first-line treatment is E. Nucleolus unavailable so you give the second-line treatment. What 34/F presents to you with joints pains and facial r