K1.01 Biochemistry Questions 2015
1. Carnitine was recommended to a sportsman to improve performance. What process is primarily activated by carnitine?
- Transport of fatty acids to the mitochondria ✓
- Synthesis of steroid hormones
- Synthesis of ketone bodies
- Synthesis of lipids
- Tissue respiration
2. A patient presents with yellow skin, dark urine, and dark-yellow feces. Which substance is most likely elevated in the blood serum?
- Biliverdin
- Unconjugated bilirubin
- Mesobilirubin
- Conjugated bilirubin ✓
- Verdoglobin
3. A patient has elevated blood pyruvate levels, most of which is excreted in the urine. What type of avitaminosis is likely present?
- Avitaminosis B3
- Avitaminosis B6
- Avitaminosis E
- Avitaminosis B2
- Avitaminosis B1 ✓
4. A patient presents with symmetrical dermatitis on sun-exposed areas. He consumes mostly cereals with little meat, milk, and eggs. Which vitamin deficiency is most likely?
- Folic acid
- Calciferol
- Nicotinamide ✓
- Biotin
- Tocopherol
5. A 20-year-old patient complains of general weakness, dizziness, and fatigue. Hb = 80 g/L. Microscopic examination shows abnormally shaped erythrocytes. What is the most likely cause?
- Hepatocellular jaundice
- Acute intermittent porphyria
- Sickle-cell anemia ✓
- Obstructive jaundice
- Addison’s disease
6. Diabetes mellitus causes ketosis due to increased fatty acid oxidation. What acid-base imbalance results from excess ketone bodies in blood?
- Metabolic acidosis ✓
- Metabolic alkalosis
- No change
- Respiratory acidosis
- Respiratory alkalosis
7. A diabetic patient loses consciousness and experiences convulsions after insulin injection. What is the most likely blood glucose concentration?
- 1.5 mmol/L ✓
- 8.0 mmol/L
- 10.0 mmol/L
- 3.3 mmol/L
- 5.5 mmol/L
8. In biliary tract obstruction, blood coagulation is impaired and bleeding is common. Which vitamin’s absorption is reduced?
- Vitamin D
- Vitamin K ✓
- Vitamin E
- Vitamin A
- Vitamin C
9. After intense muscular work, a worker shows reduced blood buffer capacity. Which acidic substance likely entered the blood in excess?
- Lactate ✓
- Pyruvate
- 1,3-bisphosphoglycerate
- 3-phosphoglycerate
10. A patient has frequent internal and mucosal hemorrhages. Collagen analysis shows proline and lysine are present but not hydroxylated. Which vitamin deficiency is responsible?
- Vitamin E
- Vitamin D
- Vitamin K
- Vitamin A
- Vitamin C ✓
11. A patient has been diagnosed with alkaptonuria. Choose an enzyme whose deficiency can be the reason for this pathology:
- Pyruvate dehydrogenase
- Glutamate dehydrogenase
- Phenylalanine hydroxylase
- Homogentisic acid oxidase ✓
- Dioxyphenylalanine decarboxylase
12. While examining a child, the doctor revealed roughness on the cheeks, diarrhea, and dysfunction of the nervous system. What lack of which food components caused this condition?
- Nicotinic acid, tryptophan ✓
- Lysine, ascorbic acid
- Methionine, lipoic acid
- Threonine, pantothenic acid
- Phenylalanine, pangamic acid
13. An 18-year-old patient has enlarged, painless inguinal lymph nodes, thickened on palpation. In the genital mucous membrane, there is a small ulcer with thickened edges and a “lacquer” bottom of a greyish color. What is the most probable diagnosis?
- Lepra
- Tuberculosis
- Trophic ulcer
- Syphilis ✓
- Gonorrhea
14. A 4-year-old child with signs of prolonged protein malnutrition was admitted to the hospital. The signs included growth inhibition, anemia, edema, and mental deficiency. What is the cause of the edema development?
- Reduced synthesis of hemoglobin
- Reduced synthesis of globulins
- Reduced synthesis of lipoproteins
- Reduced synthesis of albumins ✓
- Reduced synthesis of glycoproteins
15. A patient with complaints of permanent thirst presents with hyperglycemia, polyuria, and increased concentration of 17-ketosteroids in the urine. What disease is most likely?
- Insulin-dependent diabetes mellitus
- Myxedema
- Type I glycogenosis
- Addison’s disease
- Steroid diabetes ✓
16. Donor skin transplantation was performed on a patient with extensive burns. On the 8th day, the graft became swollen and changed color; on the 11th day, graft rejection began. What cells are involved in this process?
- Basophils
- Erythrocytes
- T-lymphocytes ✓
- Eosinophils
- B-lymphocytes
17. In patients with bile duct obstruction, fibrillation is inhibited, and bleeding occurs due to the low absorption of a particular vitamin. What vitamin is deficient?
- K ✓
- A
- Carotene
- D
- E
18. During a hypersensitivity test, a patient received a subcutaneous injection of an antigen, which caused reddening of the skin, edema, and pain due to histamine action. Which biogenic amine is generated as a result of histidine amino acid transformation?
- Deaminization
- Methylation
- Decarboxylation ✓
- Isomerization
- Phosphorylation
19. An increased amount of free fatty acids is observed in the blood of patients with diabetes mellitus. What could cause this?
- Activation of ketone body utilization
- Activation of apolipoprotein synthesis
- Storage of palmitoyl-CoA
- Decreased activity of phosphatidylcholine-cholesterol-acyltransferase in plasma
- Increased activity of triglyceride lipase in adipocytes ✓
20. An experiment showed that UV-radiated cells from patients with xeroderma pigmentosum restore the native DNA structure more slowly than cells from healthy individuals due to a defect in the repair enzyme. Which enzyme helps in this process?
- Primase
- RNA ligase
- Endonuclease ✓
- DNA polymerase III
- DNA gyrase
21. Surgical removal of a part of the stomach resulted in disturbed absorption of vitamin B₁₂, which is excreted with feces. The patient was diagnosed with anemia. What factor is necessary for the absorption of this vitamin?
- Hydrochloric acid
- Gastromucoprotein ✓
- Pepsin
- Gastrin
- Folic acid
22. A 38-year-old patient suffers from rheumatism in its active phase. What laboratory characteristic of blood serum is of diagnostic importance in case of this pathology?
- C-reactive protein ✓
- Creatinine
- Uric acid
- Transferrin
- Urea
23. In case of enterobiasis, acrihine – the structural analogue of vitamin B₂ – is administered. The synthesis disorder of which enzymes does this medicine cause in microorganisms?
- Peptidases
- Cytochrome oxidases
- NAD-dependent dehydrogenases
- Aminotransferases
- FAD-dependent dehydrogenases ✓
24. A 48-year-old patient complained about intense pain, slight swelling, and reddening of the skin over the joints, with a temperature rise up to 38°C. Blood analysis revealed a high concentration of urates. This condition might be caused by disturbed metabolism of:
- Collagen
- Cholesterol
- Pyrimidines
- Carbohydrates
- Purines ✓
25. Pathological changes in the liver and brain were revealed in a 27-year-old patient. The copper concentration is abruptly decreased in blood plasma and increased in the urine. Wilson’s disease was diagnosed. The activity of what enzyme in the blood serum should be examined to prove the diagnosis?
- Leucinaminopeptidase
- Carbonic anhydrase
- Xanthine oxidase
- Alcohol dehydrogenase
- Ceruloplasmin ✓
26. A patient with continuous bronchopneumonia was admitted to the therapeutic department. Antibiotic therapy didn’t give much effect. What medication for improving the immune state should be added to the complex treatment of this patient?
- Analgin
- Timaline ✓
- Benadryl
- Sulfocamphocaine
- Paracetamol
27. Increased production of thyroid hormones T₃ and T₄, weight loss, tachycardia, psychic excitement, and so on are present in thyrotoxicosis. How do thyroid hormones affect energy metabolism in the mitochondria of cells?
- Disconnect oxidation and oxidative phosphorylation
- Activate the phosphorylation of substances
- Stop the phosphorylation of substances
- Stop the respiratory chain
- Activate oxidative phosphorylation ✓
28. To prevent postoperative bleeding, a 6-year-old child was administered vicasol, a synthetic analogue of vitamin K. Name the post-translational changes of blood coagulation factors that will be activated by vicasol:
- Polymerization
- Partial proteolysis
- Phosphorylation of serine residues
- Carboxylation of glutamic acid ✓
- Glycosylation
29. Depressions and emotional insanities result from the deficit of noradrenaline, serotonin, and other biogenic amines in the brain. Their concentration in the synapses can be increased by means of antidepressants that inhibit the following enzyme:
- Monoamine oxidase ✓
- D-amino-acid oxidase
- L-amino-acid oxidase
- Phenylalanine-4-monooxygenase
- Diamine oxidase
30. A 13-year-old boy complains of general weakness, dizziness, and tiredness. He is mentally retarded. Increased levels of valine, isoleucine, and leucine are found in the blood and urine. Urine has a specific smell. What is the diagnosis?
- Addison’s disease
- Tyrosinosis
- Maple syrup urine disease ✓
- Graves’ disease
- Histidinemia
31. A patient diagnosed with carcinoid of the bowels was admitted to the hospital. Analysis revealed high production of serotonin. It is known that this substance is formed from the tryptophan amino acid. What biochemical mechanism underlies this process?
- Microsomal oxidation
- Decarboxylation ✓
- Desamination
- Transamination
- Formation of paired compounds
Explanation: Serotonin is synthesized from tryptophan via a decarboxylation reaction, where the amino acid decarboxylase enzyme removes a carboxyl group.
32. A 46-year-old female patient has a continuous history of progressive muscular (Duchenne’s) dystrophy. Which blood enzyme changes will be of diagnostic value in this case?
- Lactate dehydrogenase
- Glutamate dehydrogenase
- Adenylate cyclase
- Creatine phosphokinase ✓
- Pyruvate dehydrogenase
Explanation: Duchenne muscular dystrophy results in muscle breakdown, causing elevated levels of creatine phosphokinase (CPK) in the blood.
33. The buffer capacity of blood was decreased in the worker due to exhausting muscular work. Entry of what acid substance to the blood can this state be explained?
- 1,3-bisphosphoglycerate
- Pyruvate
- Lactate ✓
- 3-phosphoglycerate
- α-ketoglutarate
Explanation: During intense muscular work, lactate is produced due to anaerobic metabolism and can lower the blood’s buffering capacity, contributing to acidosis.
34. In clinical practice, tuberculosis is treated with isoniazid preparation – an antituberculous agent able to penetrate into the tuberculosis bacillus. Tuberculostatic effect is induced by the interference with replication processes and oxidation-reduction reactions due to the buildup of pseudo-coenzyme:
- CoQ
- NAD ✓
- FMN
- TDP
- FAD
Explanation: Isoniazid disrupts the synthesis of mycolic acids in Mycobacterium tuberculosis by inhibiting NAD (nicotinamide adenine dinucleotide) production, a key component in cell wall synthesis.
35. A 35-year-old man under treatment for pulmonary tuberculosis has acute onset of right big toe pain, swelling, and low-grade fever. Gouty arthritis was diagnosed, and high serum uric acid levels were found. Which of the following antituberculosis drugs are known for causing high uric acid levels?
- Cycloserine
- Thiacetazone
- Pyrazinamide ✓
- Rifampicin
- Aminosalicylic acid
Explanation: Pyrazinamide is known to increase serum uric acid levels, which can lead to gout, a common side effect of this tuberculosis medication.
36. A patient was delivered to the hospital by an emergency team. Objectively: grave condition, unconscious, adynamy. Cutaneous surfaces are dry, eyes are sunken, face is cyanotic. There is tachycardia and a smell of acetone from the mouth. Analysis results: blood glucose – 20.1 micromole/l (standard is 3.3-5.5 micromole/l), urine glucose – 3.5% (standard is 0). What is the most probable diagnosis?
- Hypoglycemic coma
- Acute alcoholic intoxication
- Acute heart failure
- Hyperglycemic coma ✓
- Anaphylactic shock
Explanation: The symptoms and the elevated blood glucose, along with the acetone breath, suggest diabetic ketoacidosis (hyperglycemic coma).
37. A patient with serious damage to muscular tissue was admitted to the traumatological department. What biochemical urine index will be increased in this case?
- Mineral salts
- Common lipids
- Creatinine ✓
- Glucose
- Uric acid
Explanation: Muscle damage leads to the release of creatinine into the bloodstream and its excretion in the urine, making it a key indicator of muscle injury.
38. A 4-year-old boy has had recent severe viral hepatitis. Now, there are such clinical presentations as vomiting, loss of consciousness, and convulsions. Blood analysis revealed hyperammonemia. Disturbance of which biochemical process was disturbed, causing such pathological conditions in the patient?
- Disturbed neutralization of ammonia in the liver ✓
- Disturbed neutralization of biogenic amines
- Increased putrefaction of proteins in the bowels
- Inhibition of transamination enzymes
- Activation of amino acid decarboxylation
Explanation: The liver’s inability to process ammonia due to hepatitis results in hyperammonemia, which can cause neurological symptoms.
39. Vitamin A, together with specific cytoreceptor,s penetrates through the nuclear membranes, inducing transcription processes that stimulate the growth and differentiation of cells. This biological function is realized by the following form of vitamin A:
- Trans-retinal
- Cis-retinal
- Trans-retinoic acid ✓
- Retinol
- Carotene
Explanation: Trans-retinoic acid is the active form of vitamin A that regulates gene expression for the growth and differentiation of cells.
40. A 1.5-year-old child presents with both mental and physical lag, depigmentation of skin and hair, and decreased catecholamine concentration in the blood. When a few drops of a 5% solution of trichloroacetic acid were added to the child’s urine, it turned olive green. Such alterations are typical for the following pathology of the amino acid metabolism:
- Tyrosinosis
- Xanthinuria
- Alkaptonuria ✓
- Albinism
- Phenylketonuria
Explanation: Alkaptonuria is characterized by the accumulation of homogentisic acid, which causes the urine to turn dark upon exposure to air, a key diagnostic feature.
41. A newborn child has convulsions that have been observed after the prescription of vitamin B6. The most probable cause of this effect is that vitamin B6 is a component of the following enzyme:
- Glutamate decarboxylase ✓
- Pyruvate dehydrogenase
- Netoglubarate dehydromine
- Aminolevulinate synthase
- Glycogen phosphorylase
Explanation: Vitamin B6 is a cofactor for glutamic acid decarboxylase, which is involved in the conversion of glutamate to GABA. A deficiency or excess can cause neurological symptoms like convulsions.
42. It was found out that some compounds, for instance, fungal toxins and some antibiotic,s can inhibit the activity of RNA-polymerase. What process will be disturbed in a cell in case of inhibition of this enzyme?
- Transcription ✓
- Replication
- Processing
- Reparation
- Translation
Explanation: RNA polymerase is responsible for transcription, the process by which messenger RNA is synthesized from DNA, so its inhibition would disrupt transcription.
43. A 9-month-old infant is fed with artificial formulas with an unbalanced vitamin B6 concentration. The infant presents with pellagra dermatitis, convulsions, and anemia. Convulsion development might be caused by the disturbed formation of:
- DOPA
- Dopamine
- Serotonin
- GABA ✓
- Histamine
Explanation: Vitamin B6 is involved in the synthesis of GABA, a neurotransmitter, and its deficiency can lead to convulsions.
44. A 49-year-old driver complains about unbearable constricting pain behind the breastbone radiating to the neck. The pain arose 2 hours ago. Objectively: the patient’s condition is grave, he is pale, heart tones are decreased. Laboratory studies revealed high activity of creatine kinase and LDH1. What disease are these symptoms typical of?
- Acute pancreatitis
- Stenocardia
- Diabetes mellitus
- Cholelithiasis
- Acute myocardial infarction ✓
Explanation: The symptoms and elevated levels of creatine kinase and LDH1 (lactate dehydrogenase) suggest a heart attack (acute myocardial infarction).
45. A patient complained about dizziness, memory impairment, and periodic convulsions. It was revealed that these changes were caused by a product of the decarboxylation of glutamic acid. Name this product:
- ATP
- TDP
- Pyridoxal phosphate
- THFA
- GABA ✓
Explanation: The decarboxylation of glutamic acid produces GABA, a neurotransmitter, which is involved in regulating neuronal activity.
46. Utilization of arachidonic acid via the cyclooxygenase pathway results in the formation of some bioactive substances. Name them:
- Somatomedins
- Prostaglandins ✓
- Insulin-like growth factors
- Biogenic amines
- Thyroxine
Explanation: Arachidonic acid is converted to prostaglandins via the cyclooxygenase pathway, which plays a role in inflammation and other processes.
47. Methotrexate (a structural analogue of folic acid, which is a competitive inhibitor of dihydrofolate reductase) is prescribed for the treatment of malignant tumors. On which level does methotrexate inhibit the synthesis of nucleic acids?
- Replication
- Mononucleotide synthesis ✓
- Transcription
- Reparation
- Processing
Explanation: Methotrexate inhibits dihydrofolate reductase, which is involved in the synthesis of purines and pyrimidines, affecting mononucleotide synthesis.
48. A patient has an increased pyruvate concentration in blood. A large amount of it is excreted with the urine. What vitamin is lacking in this patient?
- B3
- B1 ✓
- E
- B6
- B2
Explanation: A deficiency in vitamin B1 (thiamine) can cause impaired pyruvate metabolism, leading to its accumulation in blood and urine.
49. The blood of a 12-year-old boy presents a low concentration of uric acid and accumulation of xanthine and hypoxanthine. This child has a genetic defect of the following enzyme:
- Xanthine oxidase ✓
- Arginase
- Urease
- Glycerylkinase
- Ornithine carbamoyltransferase
Explanation: A deficiency in xanthine oxidase leads to a buildup of xanthine and hypoxanthine and a decrease in uric acid.
50. A woman with blood type O (I) has given birth to a child with blood type AB. What antigen is present in the child’s erythrocytes, which is absent in the mother’s erythrocytes?
- Anti-A
- Anti-B
- Anti-D
- A antigen ✓
- B antigen
Explanation: The A and B antigens are inherited from both parents. The mother’s blood type O means she has neither A nor B antigens, while the child’s AB blood type indicates the presence of both antigens.
51. Characteristic sign of glycogenosis is muscle pain during physical work. Blood examination reveals usually hypoglycemia. This pathology is caused by congenital deficiency of the following enzyme:
- Lysosomal glycosidase
- Alpha amylase
- Glucose 6-phosphate dehydrogenase
- Gamma amylase
- Glycogen phosphorylase ✓
52. Examination of a patient suffering from chronic hepatitis revealed a significant decrease in the synthesis and secretion of bile acids. What process will be mainly disturbed in the patient’s bowels?
- Glycerin absorption
- Fat emulsification ✓
- Protein digestion
- Carbohydrate digestion
- Amino acid absorption
Explanation: Bile acids are crucial for the emulsification of fats, which increases the surface area for lipase action.
53. Galactosemia is revealed in the child. Concentration of glucose in the blood is not considerably changed. Deficiency of what enzyme caused this illness?
- Phosphoglucomutase
- Amylo-1,6-glucosidase
- Galactose-1-phosphate uridyltransferase ✓
- Hexokinase
- Galactokinase
Explanation: Classic galactosemia results from a deficiency in galactose-1-phosphate uridyltransferase, leading to toxic buildup of galactose metabolites.
54. A patient complains about dyspnea provoked by physical activity. Clinical examination revealed anemia and presence of the paraprotein in the zone of gamma-globulins. To confirm the myeloma diagnosis it is necessary to determine the following index in the patient’s urine:
- Haemoglobin
- Bence Jones protein ✓
- Bilirubin
- Ceruloplasmin
- Antitrypsin
Explanation: Bence Jones proteins are free immunoglobulin light chains found in the urine of multiple myeloma patients.
55. A child is languid, apathetic. Liver is enlarged and liver biopsy revealed a significant excess of glycogen. Glucose concentration in the blood stream is below normal. What is the cause of low glucose concentration?
- Low (absent) activity of glucose 6-phosphatase ✓
- High activity of glycogen synthetase
- Deficit of a gene that is responsible for synthesis of glucose 1-phosphaturidine transferase
- Low (absent) activity of glycogen phosphorylase in liver
- Low (absent) activity of hexokinase
Explanation: Von Gierke disease (Type I glycogen storage disease) is caused by glucose-6-phosphatase deficiency.
56. A 46 year old patient applied to a doctor complaining about joint pain that becomes stronger the day before weather changes. Blood examination revealed strengthened concentration of uric acid. The most probable cause of the disease is the intensified disintegration of the following substance:
- Cytidine monophosphate
- Thymidine monophosphate
- Uridine triphosphate
- Uridine monophosphate
- Adenosine monophosphate ✓
Explanation: Uric acid is the final product of purine (adenine, guanine) metabolism. AMP breakdown contributes significantly.
57. A 52 year-old patient with bronchial asthma was treated with glucocorticoids. Fever reaction appeared as a result of postinjective abscess. The patient had subfebrile temperature, which didn’t correspond to latitude and severity of inflammatory process. Why did patient have low fever reaction?
- Thermoregulation center inhibition
- Violation of heat loss through lungs
- Inflammatory barrier formation in injection place
- Violation of heat-producing mechanisms
- Inhibited endogen pyrogens production ✓
Explanation: Glucocorticoids suppress IL-1, IL-6, and TNF-α, leading to decreased endogenous pyrogen production.
58. In course of histidine catabolism a biogenic amine is formed that has powerful vasodilatating effect. Name it:
- Dopamine
- Histamine ✓
- Serotonin
- Dioxyphenylalanine
- Noradrenalin
Explanation: Histamine is derived from histidine via decarboxylation and causes vasodilation.
59. A 65 year old man suffering from gout complains of kidney pain. Ultrasound examination revealed renal calculi. The most probable cause of calculi formation is the strengthened concentration of the following substance:
- Cystine
- Uric acid ✓
- Bilirubin
- Urea
- Cholesterol
Explanation: Uric acid stones are common in gout due to hyperuricemia.
60. Pharmacological effects of antidepressants are connected with inhibition of an enzyme catalyzing biogenic amines noradrenaline and serotonine in the mitochondrions of cerebral neurons. What enzyme participates in this process?
- Decarboxylase
- Peptidase
- Lyase
- Transaminase
- Monoamine oxidase ✓
Explanation: Monoamine oxidase (MAO) degrades serotonin and norepinephrine. MAO inhibitors are used as antidepressants.
61. Autopsy of a 12-year-old girl revealed: multiple cutaneous hemorrhages (mostly into the skin of buttocks, lower extremities), serous and mucous membrane hemorrhages, cerebral hemorrhages. Adrenal glands show focal necrosis and massive hemorrhages; kidneys show necrotic nephrosis, suppurative arthritis, iridocyclitis, vasculitis. What is the most probable diagnosis?
- Epidemic typhus
- Radiation sickness
- Periarteritis nodosa
- Systemic lupus erythematosus
- Meningococcemia ✓
Explanation: Waterhouse–Friderichsen syndrome (massive adrenal hemorrhage) is a complication of meningococcemia.
62. RNA-polymerase B(II) is blocked due to amanitine poisoning (poison of death-cup). It disturbs:
- Reverse transcription
- Maturation of m-RNA
- Synthesis of t-RNA
- Primers synthesis
- Synthesis of m-RNA ✓
Explanation: Amanitin from Amanita phalloides inhibits RNA polymerase II, blocking mRNA synthesis.
63. Examination of a 27-year-old patient revealed pathological changes in liver and brain. Blood plasma analysis revealed an abrupt decrease in the copper concentration, urine analysis revealed an increased copper concentration. The patient was diagnosed with Wilson’s degeneration. To confirm the diagnosis it is necessary to study the activity of the following enzyme in blood serum:
- Xanthine oxidase
- Carbonic anhydrase
- Leucine aminopeptidase
- Alcohol dehydrogenase
- Ceruloplasmin ✓
Explanation: Ceruloplasmin is a copper-carrying protein, low in Wilson disease.
64. After a serious viral infection a 3-year-old child has repeated vomiting, loss of consciousness, convulsions. Examination revealed hyperammonemia. What may have caused changes of biochemical blood indices of this child?
- Activated processes of amino acids decarboxylation
- Disorder of biogenic amines neutralization
- Disorder of ammonia neutralization in ornithinic cycle ✓
- Increased putrefaction of proteins in intestines
- Inhibited activity of transamination enzymes
Explanation: Urea cycle disorder (e.g., ornithine transcarbamylase deficiency) results in hyperammonemia.
65. A newborn child suffers from milk curdling in stomach, this means that soluble milk proteins (caseins) transform to insoluble proteins (paracaseins) by means of calcium ions and a certain enzyme. What enzyme takes part in this process?
- Secretin
- Renin ✓
- Gastrin
- Pepsin
- Lipase
Explanation: Rennin (or chymosin) curdles milk by converting casein to paracasein in infants.
66. A woman who has been keeping to a clean-rice diet for a long time was diagnosed with polyneuritis (beriberi). What vitamin deficit results in development of this disease?
- Pyridoxine
- Ascorbic acid
- Folic acid
- Thiamine ✓
- Riboflavin
Explanation: Thiamine (Vitamin B1) deficiency causes beriberi, common in diets lacking whole grains.
67. A 6-year-old child was delivered to a hospital. Examination revealed that the child couldn’t fix his eyes, didn’t keep his eyes on toys, eye ground had the cherry-red spot sign. Laboratory analyses showed that brain, liver and spleen had high rate of ganglioside glycometide. What congenital disease is the child ill with?
- Wilson’s syndrome
- Turner’s syndrome
- Niemann-Pick disease
- Tay-Sachs disease ✓
- MacArdle disease
Explanation: Tay-Sachs disease is due to hexosaminidase A deficiency, leading to ganglioside accumulation and cherry-red macula.
68. Profuse foam appeared when dentist put hydrogen peroxide on the mucous of the oral cavity. What enzyme caused such activity?
- Cholinesterase
- Glucose-6-phosphatdehydrogenase
- Catalase ✓
- Acetyltransferase
- Methemoglobinreductase
Explanation: Catalase breaks down hydrogen peroxide to water and oxygen, causing foaming.
69. Objective examination of a patient revealed: slender figure, big skull, highly developed frontal region of face, short extremities. What constitutional type is it characteristic for?
- Mixed
- Respiratory
- Muscular
- Digestive
- Cerebral ✓
Explanation: These are features of the cerebral (asthenic) constitutional body type.
70. Ammonia is a very toxic substance, especially for nervous system. What substance takes the most active part in ammonia detoxication in brain tissues?
- Lysine
- Proline
- Histidine
- Glutamic acid ✓
- Alanine
Explanation: Glutamic acid combines with ammonia to form glutamine, aiding detoxification in the CNS.
71. A 3-year-old child with stomatitis, gingivitis, and dermatitis was found to have an inherited disturbance of neutral amino acid transport in the bowels. These symptoms are due to deficiency of which vitamin?
- Biotin
- Cobalamin
- Vitamin A
- Pantothenic acid
- Niacin ✓
Explanation: Niacin deficiency causes pellagra, which includes dermatitis, diarrhea, and dementia. Hartnup disease disrupts tryptophan absorption, reducing niacin synthesis.
72. A 30-year-old nursing woman consumes 1000 mg calcium, 1300 mg phosphorus, and 20 mg iron daily. What mineral adjustment is needed?
- To increase calcium content
- To increase phosphorus content
- To reduce fluorine content
- To increase iron content ✓
- To reduce iron content
Explanation: Lactating women need increased iron (27 mg/day). Her current intake (20 mg) is insufficient to meet increased maternal and infant demands.
73. After being fed carbon-labeled glucose for a week, what compound in an experimental animal is likely to be labeled?
- Methionine
- Vitamin A
- Choline
- Palmitic acid ✓
- Arachidonic acid
Explanation: Excess glucose is converted into fatty acids like palmitic acid through lipogenesis. The carbon label gets incorporated into the fatty acid chain.
74. A patient who had a gallbladder removed has impaired calcium absorption. Which vitamin can stimulate this process?
- D3 ✓
- PP
- B12
- K
- C
Explanation: Vitamin D3 (cholecalciferol) enhances intestinal calcium absorption by upregulating calcium-binding proteins in enterocytes.
75. Albinos lack sun tanning ability and get sunburns. This is due to a metabolic defect in which amino acid?
- Methionine
- Glutamic acid
- Tryptophan
- Histidine
- Phenylalanine ✓
Explanation: In albinism, defective tyrosinase prevents phenylalanine from converting to melanin, which protects skin from UV radiation.
76. A 10-year-old girl has frequent infections and spotty hemorrhages where clothes rub. What vitamin deficiency is present?
- B6
- C ✓
- A
- B1
- B2
Explanation: Vitamin C is essential for collagen synthesis. Its deficiency causes capillary fragility and bleeding under the skin—scurvy.
77. An 11-month-old has leg osteoectasia and delayed skull mineralization. What vitamin is likely deficient?
- Pantothenic acid
- Cholecalciferol ✓
- Thiamin
- Bioflavonoids
- Riboflavin
Explanation: Cholecalciferol (Vitamin D3) deficiency causes rickets in children, leading to poor bone mineralization and deformities.
78. A child presents with rickets. Which compound deficiency is most likely responsible?
- Biotin
- Naphtaquinone
- Tocopherol
- Retinol
- 1,25[OH]-dihydroxycholecalciferol ✓
Explanation: 1,25-dihydroxycholecalciferol is the active form of vitamin D, essential for calcium and phosphate metabolism in bone growth.
79. Which arthropod is the primary vector of epidemic typhus?
- Spiders
- Cockroaches
- Bed-bugs
- Houseflies
- Lice ✓
Explanation: Epidemic typhus is caused by Rickettsia prowazekii, transmitted by lice, especially in overcrowded, unhygienic conditions.
80. A diabetic patient needs retrospective glucose monitoring. Which plasma protein provides this information?
- Albumin
- Fibrinogen
- C-reactive protein
- Ceruloplasmin
- Glycated hemoglobin ✓
Explanation: Glycated hemoglobin (HbA1c) reflects average blood glucose over the past 8 weeks and is used for long-term glycemic control.
81. A newborn has dyspepsia after milk feeding that improves with glucose solution. What enzyme is deficient?
- Amylase
- Invertase
- Maltase
- Lactase ✓
- Isomaltase
Explanation: Lactase breaks down lactose into glucose and galactose. Deficiency leads to lactose intolerance, causing digestive upset.
82. A stroke patient with high kinin levels is treated with contrical. What proteinase does this drug inhibit?
- Collagenase
- Trypsin
- Kallikrein ✓
- Chemotrypsin
- Pepsin
Explanation: Contrical inhibits kallikrein, which generates kinins (e.g., bradykinin) that increase vascular permeability and inflammation.
83. Hydroxylation reactions require a proton donor. Which vitamin performs this role?
- Vitamin P
- Vitamin C ✓
- Vitamin E
- Vitamin B6
- Vitamin A
Explanation: Vitamin C acts as a reducing agent in hydroxylation of proline and lysine during collagen synthesis and in detoxification.
84. A woman with a collagen disorder has elevated levels of which metabolite in urine?
- Urea
- Oxyproline ✓
- Creatinine
- Urobilinogen
- Indican
Explanation: Hydroxyproline (oxyproline) is a collagen breakdown product. Its urinary excretion increases with collagen degradation.
85. A pellagra patient has a maize-based diet low in meat. What nutrient in maize is deficient, leading to the condition?
- Proline
- Tyrosine
- Histidine
- Tryptophan ✓
- Alanine
Explanation: Maize is low in tryptophan, a precursor of niacin. Deficiency leads to pellagra (dermatitis, diarrhea, dementia).
86. Leukocytes digest staphylococci in a culture. What is this cellular process called?
- Facilitated diffusion
- Phagocytosis ✓
- Pinocytosis
- Osmosis
- Diffusion
Explanation: Phagocytosis involves engulfing pathogens into vesicles for digestion. It’s a key innate immune response by neutrophils.
87. A patient with bronchial asthma died from an asthmatic attack. What type of hypersensitivity caused this?
- Granulomatosis
- Cytotoxic reaction
- Reagin reaction ✓
- Cytolysis determined by lymphocytes
- Immunocomplex reaction
Explanation: Type I hypersensitivity (reagin reaction) involves IgE-mediated mast cell degranulation, leading to bronchospasm and eosinophilia.
88. A patient suspected of muscular dystrophy undergoes a urine test. What finding supports the diagnosis?
- Porphyrin
- Myoglobin ✓
- Calmodulin
- Collagen
- Kreatine
Explanation: Myoglobin in urine indicates muscle breakdown, common in muscular dystrophies due to degeneration of skeletal muscle fibers.
89. Vitamin B1 deficiency disturbs oxidative decarboxylation of α-ketoglutarate. Which coenzyme is directly affected?
- Nicotinamide adenine dinucleotide (NAD)
- Flavine adenine dinucleotide (FAD)
- Coenzyme A
- Lipoic acid
- Thiamine pyrophosphate ✓
Explanation: Thiamine (B1) is a precursor of thiamine pyrophosphate, essential for decarboxylation of α-ketoacids in the Krebs cycle.
90. A 65-year-old gout patient has kidney stones. These are due to accumulation of which metabolic product?
- Decay of purine nucleotides ✓
- Protein catabolism
- Ornithine cycle
- Restoration of cysteine
- Heme decay
Explanation: Gout leads to uric acid overproduction from purine metabolism, resulting in crystal deposition and renal stone formation.
91. An oncological patient was prescribed methotrexate. With the lapse of time target cells of the tumour lost susceptibility to this drug. There is change of gene expression of the following enzyme:
1 Deaminase
2 Dehydrofolate reductase ✓
3 Folate oxidase
4 Thiaminase
5 Folate decarboxylase
Explanation: Methotrexate inhibits dihydrofolate reductase. Tumors become resistant by increasing expression or mutating DHFR.
92. A 1-year-old child with muscle symptoms was found to have carnitine deficiency. What process is disrupted?
1 Transporting of fatty acids to mitochondria ✓
2 Regulation of Ca²⁺ level in mitochondria
3 Substrate phosphorylation
4 Lactic acid utilization
5 Actin and myosin synthesis
Explanation: Carnitine transports long-chain fatty acids into mitochondria for β-oxidation.
93. A patient with bladder cancer has increased serotonin and hydroxyanthranilic acid. Which amino acid is in excess?
1 Tryptophan ✓
2 Alanine
3 Histidine
4 Methionine
5 Tyrosine
Explanation: Tryptophan is a precursor of serotonin.
94. After a fatty meal, a patient develops steatorrhea and high cholesterol. What is deficient?
1 Triglycerides
2 Fatty acids
3 Bile acids ✓
4 Chylomicrons
5 Phospholipids
Explanation: Bile acids emulsify fats for absorption; their deficiency causes steatorrhea.
95. Diabetic patients without insulin develop acidosis due to increased:
1 Cholesterol
2 Unsaturated fatty acids
3 Triacylglycerols
4 Fatty acids
5 Ketone bodies ✓
Explanation: Uncontrolled diabetes leads to ketogenesis → metabolic acidosis.
96. In rheumatoid arthritis, which blood parameter helps confirm diagnosis?
1 Acid phosphatase
2 Lipoproteids
3 General cholesterol
4 Additive glycosaminoglycans ✓
5 R-glycosidase
Explanation: Glycosaminoglycans increase due to cartilage breakdown.
97. A man from South America has sleeping sickness. What is the route of transmission?
1 With contaminated fruits and vegetables
2 Through dirty hands
3 As a result of mosquito’s bites
4 After contact with sick dogs
5 As a result of bug’s bites ✓
Explanation: Trypanosoma cruzi (Chagas disease) is transmitted by Reduviid bugs.
98. A patient with fatal asthma had many degranulating mast cells and eosinophils. What is the mechanism?
1 Atopy ✓
2 Cytotoxic, cytolytic action of antibodies
3 Cellular cytolysis
4 Granulomatosis
5 Immunocomplex mechanism
Explanation: Bronchial asthma is a Type I hypersensitivity reaction (Atopy).
99. A family shows hypertrichosis in all males, inherited from father to son. Type of inheritance?
1 Autosome-recessive
2 Y-linked chromosome ✓
3 X-linked recessive chromosome
4 Autosome-dominant
5 X-linked dominant chromosome
Explanation: Y-linked traits pass from father to son only.
100. A child with frequent infections, eczema, and food reactions likely has which diathesis?
1 Hemorrhagic
2 Exudative-catarrhal ✓
3 Arthritism
4 Lymphohypoplastic
5 Asthenic
Explanation: Exudative-catarrhal diathesis presents with allergies, eczema, and infections.
101. Glutamate decarboxylation produces which CNS inhibitory neurotransmitter?
1 Glutathione
2 Asparagine
3 Histamine
4 GABA ✓
5 Serotonin
Explanation: Glutamate → GABA via glutamate decarboxylase.
102. Blood flow restoration stops lactate buildup and slows glucose use due to:
1 Lipolysis
2 Anaerobic glycolysis
3 Aerobic glycolysis ✓
4 Gluconeogenesis
5 Glycogen biosynthesis
Explanation: Oxygen allows aerobic metabolism → less lactate.
103. Collagenosis shows increase of which urine compound?
1 Glucose
2 Mineral salts
3 Hydroxyproline ✓
4 Ammonium salts
5 Arginine
Explanation: Hydroxyproline is a marker of collagen breakdown.
104. Disulfiram inhibits aldehyde dehydrogenase. Accumulation of which metabolite causes alcohol aversion?
1 Propionic aldehyde
2 Acetaldehyde ✓
3 Ethanol
4 Malonyl aldehyde
5 Methanol
Explanation: Acetaldehyde causes flushing, nausea – deters alcohol intake.
105. A man with a fat-free but protein- and carb-rich diet has dermatitis, poor healing, vision loss. Cause?
1 Lack of vitamins PP, H
2 Lack of linoleic acid, vitamins A, D, E, K ✓
3 Low caloric value of diet
4 Lack of palmitic acid
5 Lack of oleic acid
Explanation: Essential fatty acids and fat-soluble vitamins are absent.
106. Low albumin levels cause edema due to impaired:
1 Maintaining the blood sedimentation system
2 Maintaining the body temperature
3 Maintaining the pH level
4 Maintaining the oncotic blood pressure ✓
Explanation: Albumin maintains colloid osmotic pressure.
107. A food dye is metabolized only via microsomal oxidation. Key enzyme?
1 Cytochrome A
2 Cytochrome B
3 Cytochrome C
4 Cytochrome P-450 ✓
5 Cytochrome oxidase
Explanation: Phase I detoxification involves cytochrome P450 enzymes.
108. Scurvy disrupts collagen maturation due to impaired:
1 Removal of C-terminal peptide
2 Detaching of N-terminal peptide
3 Formation of polypeptide chains
4 Hydroxylation of proline ✓
5 Glycosylation of hydroxylysine residues
Explanation: Vitamin C is needed for proline hydroxylation in collagen.
109. Carnitine helps with fat oxidation by:
1 Activation of intracellular lipolysis
2 Transport of FFA from cytosol to mitochondria ✓
3 Transport of FFA from fat depots to tissues
4 Participating in FFA beta-oxidation reaction
5 FFA activation
Explanation: Carnitine shuttles fatty acids into mitochondria for oxidation.
110. ATP synthesis is completely blocked. What happens to membrane potential?
1 It will be slightly increased
2 It will be considerably increased
3 It will disappear ✓
4 First it will increase, then decrease
5 First it will decrease, then increase
Explanation: Na⁺/K⁺-ATPase fails → ion gradients collapse → potential disappears.
111. A patient presents with fatty liver infiltration and impaired phospholipid metabolism. Which of the following compounds promotes methylation during phospholipid synthesis?
1 Glucose
2 Citrate
3 Methionine ✓
4 Ascorbic acid
5 Glycerin
Explanation: Methionine provides methyl groups (via S-adenosylmethionine) for phosphatidylcholine synthesis.
112. Autopsy of a 46-year-old man revealed fibrinous colitis with brown-green patches, hemorrhages in the rectum and sigmoid colon, and S. sonnei bacteria in the colon contents. What is the most probable diagnosis?
1 Dysentery ✓
2 Cholera
3 Salmonellosis
4 Yersiniosis
5 Crohn’s disease
Explanation: Shigella sonnei causes bacillary dysentery, presenting with bloody-mucous diarrhea and fibrinous inflammation.
113. A 50-year-old patient presents with weakness, appetite loss, cardiac arrhythmia, muscle hypotonia, flaccid paralysis, and decreased bowel peristalsis. What is the most likely cause?
1 Hypoproteinemia
2 Hyperkaliemia
3 Hypophosphatemia
4 Hypokaliemia ✓
5 Hyponatremia
Explanation: Low potassium (hypokalemia) leads to muscular and cardiac dysfunction.
114. A fasting blood glucose is 5.65 mmol/L. One hour after a glucose load: 8.55 mmol/L; two hours later: 4.95 mmol/L. These findings are typical of:
1 Patient with insulin-dependent diabetes mellitus
2 Patient with non-insulin dependent diabetes mellitus
3 Patient with hidden diabetes mellitus
4 Healthy person ✓
5 Patient with thyrotoxicosis
Explanation: Normal glucose tolerance returns to baseline within 2 hours.
115. A patient with frequent internal and mucosal hemorrhages shows defective hydroxylation of proline and lysine in collagen. What vitamin deficiency is responsible?
1 Vitamin A
2 Vitamin K
3 Vitamin C ✓
4 Thiamine
5 Vitamin E
Explanation: Vitamin C is essential for proline and lysine hydroxylation during collagen synthesis.
116. During prolonged fasting, muscle proteins are broken down into amino acids. These are primarily used in:
1 Gluconeogenesis in liver ✓
2 Synthesis of higher fatty acids
3 Glycogenolysis
4 Gluconeogenesis in muscles
5 Decarboxylation
Explanation: Amino acids are converted into glucose in the liver during fasting.
117. An athlete takes a carnitine supplement to improve performance. Which process is most enhanced by carnitine?
1 Amino acids transporting
2 Glucose transporting
3 Calcium ions transporting
4 Fatty acids transporting ✓
5 Vitamin K transporting
Explanation: Carnitine facilitates mitochondrial transport of fatty acids for β-oxidation.
118. Researchers isolated five isoenzymes of lactate dehydrogenase from human serum. Which property proves they are isoenzymes of the same enzyme?
1 The same electrophoretic mobility
2 The same physicochemical properties
3 Catalyzation of the same reaction ✓
4 Tissue localization
5 The same molecular weight
Explanation: Isoenzymes catalyze the same reaction but differ in structure or tissue location.
119. Untrained individuals often experience muscle pain after intense exercise due to lactate buildup. What process is responsible?
1 Lipogenesis
2 Gluconeogenesis
3 Glycolysis ✓
4 Pentose phosphate pathway
5 Glycogenesis
Explanation: Anaerobic glycolysis produces lactate, especially during intense activity.
120. A newborn’s diapers have dark staining due to homogentisic acid accumulation. This indicates a metabolic defect in:
1 Methionine
2 Cholesterol
3 Tyrosine ✓
4 Galactose
5 Tryptophan
Explanation: Alkaptonuria is a disorder of tyrosine metabolism leading to homogentisic acid buildup.
121. A patient presents with elevated levels of lactate dehydrogenase isoenzymes LDH1 and LDH2, along with increased activity of aspartate aminotransferase and creatine phosphokinase. These findings are most suggestive of pathology in which organ?
- Skeletal muscles (dystrophy, atrophy)
- Kidneys and adrenal glands
- Heart muscle (early-stage myocardial infarction) ✓
- Connective tissue
- Liver and kidneys
Explanation: LDH1 and LDH2 are cardiac-specific isoenzymes. Elevated AST and CK also suggest myocardial injury, particularly in early myocardial infarction.
122. A 42-year-old man with gout has elevated uric acid levels. He is prescribed allopurinol to reduce serum urate levels. Allopurinol competitively inhibits which of the following enzymes?
- Adenine phosphoribosyltransferase
- Adenosine deaminase
- Xanthine oxidase ✓
- Hypoxanthine phosphoribosyltransferase
- Guanine deaminase
Explanation: Allopurinol is a structural analog of hypoxanthine and acts as a competitive inhibitor of xanthine oxidase, preventing conversion to uric acid.
123. A chronic alcoholic patient treated with diuretics presents with muscle weakness, cardiac abnormalities, and hypotension. Which electrolyte is most likely depleted?
- Calcium
- Sodium
- Chloride
- Potassium ✓
- Phosphates
Explanation: Diuretics, especially loop and thiazide types, cause potassium loss, leading to hypokalemia — characterized by muscle weakness and cardiac disturbances.
124. A 62-year-old woman develops cataracts as a complication of diabetes mellitus. Which protein modification is most likely involved in the formation of diabetic cataracts?
- Phosphorylation
- ADP-ribosylation
- Limited proteolysis
- Methylation
- Glycosylation ✓
Explanation: Non-enzymatic glycosylation of lens proteins leads to aggregation and opacity in diabetic cataract formation.
125. A patient with hepatic encephalopathy shows a correlation between mental symptoms and absorption of certain intestinal products. Which of the following intestinally-derived compounds most likely contributes to endotoxemia in this case?
- Butyrate
- Acetoacetate
- Indole ✓
- Ornithine
- Biotin
Explanation: Indole is a toxic metabolite produced from tryptophan in the gut, absorbed into the bloodstream, and poorly detoxified in liver failure, contributing to hepatic encephalopathy.
126.
In an experiment, the cell membrane of an excitable cell became more permeable to potassium ions. What is the most likely effect on the membrane’s electrical potential?
- Hyperpolarization ✓
- Depolarization
- Action potential
- Local response
- No change
Explanation: Increased K⁺ permeability allows K⁺ to exit the cell, making the inside more negative — a state known as hyperpolarization.
127.
A 4-year-old child with hereditary kidney disease presents with signs of rickets, despite normal blood levels of vitamin D. What is the most likely cause of the rickets?
- Hyperparathyroidism
- Increased calcium excretion
- Hypoparathyroidism
- Impaired synthesis of calcitriol ✓
- Dietary calcium deficiency
Explanation: In renal rickets (renal osteodystrophy), the kidney fails to convert vitamin D to its active form, calcitriol, leading to impaired calcium absorption.
128. A patient is prescribed pyridoxal phosphate to correct a metabolic disturbance. This compound primarily supports which of the following processes?
- Oxidative decarboxylation of keto acids
- Deamination of purine nucleotides
- Transamination and decarboxylation of amino acids ✓
- Synthesis of purine and pyrimidine bases
- Protein translation
Explanation: Pyridoxal phosphate (active form of vitamin B6) acts as a coenzyme in transamination and decarboxylation reactions involving amino acids.
129. Aspirin has anti-inflammatory effects due to its inhibition of cyclooxygenase. Which of the following mediators is decreased as a result?
- Biogenic amines
- Leukotrienes
- Prostaglandins ✓
- Catecholamines
- Thyroid hormones
Explanation: Aspirin inhibits COX enzymes, thereby decreasing the synthesis of prostaglandins, which are key mediators of inflammation, pain, and fever.
130. During metabolism, reactive oxygen species such as superoxide anions are generated. Which enzyme catalyzes the dismutation of superoxide radicals into less reactive species?
- Peroxidase
- Catalase
- Superoxide dismutase ✓
- Glutathione peroxidase
- Glutathione reductase
Explanation: Superoxide dismutase converts superoxide anion (O₂⁻) to hydrogen peroxide (H₂O₂), which is then broken down by catalase and glutathione peroxidase.
131. The formation of a secondary mediator is obligatory in the membrane-intracellular mechanism of hormone action. Which of the following substances cannot be a secondary mediator?
- CAMP
- Inositol-3,4,5-triphosphate
- Glycerol ✓
- Ca2+
- Diacylglycerol
Explanation: Glycerol is not a secondary mediator in hormone signaling. Secondary mediators like cAMP and Ca2+ play roles in intracellular signaling pathways.
132. A 30-year-old woman has pain, joint swelling, and redness over the joints. The provisional diagnosis is rheumatoid arthritis. Which connective tissue protein is most likely altered in this disease?
- Troponin
- Myosin
- Collagen ✓
- Mucin
- Ovoalbumin
Explanation: Rheumatoid arthritis is commonly associated with alterations in collagen, a key protein in connective tissue. This leads to joint inflammation and damage.
133. A child’s lab results show increased levels of leucine, valine, isoleucine, and their ketoderivatives in blood and urine, with a characteristic maple syrup odor. Which enzyme is deficient?
- Aminotransferase
- Glucose-6-phosphatase
- Dehydrogenase of branched-chain amino acids ✓
- Phosphofructokinase
- Phosphofructomutase
Explanation: Maple syrup urine disease is caused by a deficiency in the branched-chain alpha-keto acid dehydrogenase, leading to the accumulation of branched-chain amino acids.
134. A patient has frequent diarrhea, especially after eating fatty foods, along with weight loss and steatorrhea. What is the most likely cause of these symptoms?
- Lack of pancreatic phospholipase
- Mucous membrane inflammation of small intestine
- Obturation of biliary tracts
- Lack of pancreatic lipase ✓
- Unbalanced diet
Explanation: Pancreatic lipase deficiency leads to poor fat digestion, resulting in steatorrhea and weight loss, especially after fatty meals.
135. A 62-year-old woman presents with chest pain, rib fractures, and suspected myelomatosis. Which laboratory finding is most diagnostically significant?
- Paraproteinemia ✓
- Hyperalbuminemia
- Hypoproteinemia
- Proteinuria
- Hypoglobulinemia
Explanation: Paraproteinemia, the presence of abnormal monoclonal proteins, is characteristic of multiple myeloma and helps in diagnosis.
136. A newborn with reduced sucking ability, vomiting, and hypotonia has elevated citrulline levels in urine and blood. What metabolic pathway is disrupted?
- Glycolysis
- Tricarboxylic acid cycle
- Glyconeogenesis
- Cori cycle
- Ornithine cycle ✓
Explanation: Increased citrulline levels indicate a defect in the urea cycle, particularly in the ornithine cycle, leading to ammonia buildup.
137. A 5-year-old child develops erythema, vesicular rash, and skin itching after sun exposure. Lab tests show low iron and high uroporphyrinogen I in urine. What is the most likely inherited condition?
- Coproporphyria
- Methemoglobinemia
- Hepatic porphyria
- Erythropoietic porphyria ✓
- Intermittent porphyria
Explanation: Erythropoietic porphyria is an inherited disorder of heme synthesis, causing photosensitivity and uroporphyrinogen I buildup.
138. A 2-year-old child with mental and physical retardation presents with vomiting after meals and phenylpyruvic acid in urine. What metabolic abnormality causes this?
- Lipid metabolism
- Amino acid metabolism ✓
- Carbohydrate metabolism
- Phosphoric calcium metabolism
- Water-salt metabolism
Explanation: The presence of phenylpyruvic acid indicates phenylketonuria (PKU), a disorder of amino acid metabolism.
139. A patient with hepatic cirrhosis is being examined. Which substance in the urine can indicate the liver’s antitoxic function?
- Creatinine
- Ammonium salts ✓
- Hippuric acid
- Uric acid
- Amino acids
Explanation: Ammonium salts are excreted when the liver’s ability to detoxify ammonia is impaired, as in cirrhosis.
140. A patient develops increased skin sensitivity to sunlight, and their urine turns dark red. What is the most likely cause?
- Alkaptonuria
- Porphyria ✓
- Hemolytic jaundice
- Albinism
- Pellagra
Explanation: Porphyria is a disorder of heme metabolism that can cause photosensitivity and dark-colored urine.
141. Primary hyperparathyroidism is characterized by osteoporosis, renal lesions, and urolithiasis. What substance makes up the majority of these calculi?
- Cystine
- Calcium phosphate ✓
- Bilirubin
- Uric acid
- Cholesterol
Explanation: Calcium phosphate is commonly found in kidney stones formed in primary hyperparathyroidism due to elevated calcium levels.
142. A patient with diabetes mellitus shows a blood pH of 7.3. Which buffer system is used to diagnose acid-base disturbances in this case?
- Hemoglobin
- Protein
- Phosphate
- Oxyhemoglobin
- Bicarbonate ✓
Explanation: The bicarbonate buffer system is the primary regulator of blood pH and is used in diagnosing acid-base disorders, such as metabolic acidosis in diabetes.
143. An experimental animal on a protein-free diet developed fatty liver infiltration due to methylating agent deficiency. Which metabolite is most affected?
- Cholesterol
- Acetoacetate
- Linoleic acid
- DOPA
- Choline ✓
Explanation: Choline, a methylating agent, is critical for fat metabolism. Its deficiency can cause fatty liver infiltration.
144. A 16-year-old boy developed appendicitis. Which type of immune cells are most likely infiltrating the tissue in this condition?
- Eosinophils
- Lymphocytes
- Basophils
- Neutrophils ✓
- Monocytes
Explanation: Neutrophils are the first responders to infection and inflammation, which is typical in appendicitis.
145. A 44-year-old woman has moon face, hirsutism, hypertension, and obesity around her neck and stomach. What is the main pathogenic cause of her obesity?
- Decreased glucagon production
- Increased insulin production
- Increased mineralocorticoid production
- Decreased thyroid hormone production
- Increased glucocorticoid production ✓
Explanation: Increased glucocorticoid production, often seen in Cushing’s syndrome, causes central obesity, moon face, and other symptoms.
146. An infant has diarrhea with abundant sodium bicarbonate loss. What acid-base disturbance is most likely occurring?
- No disorders of acid-base balance
- Respiratory acidosis
- Metabolic alkalosis ✓
- Respiratory alkalosis
- Metabolic acidosis
Explanation: Loss of sodium bicarbonate results in metabolic alkalosis, as the body loses bicarbonate, which buffers acid.
147. Blood coagulation factors are modified by vitamin K. Which amino acid is carboxylated in these proteins to increase calcium ion affinity?
- Serine
- Valine
- Phenylalanine
- Arginine
- Glutamic ✓
Explanation: Glutamic acid is carboxylated in vitamin K-dependent proteins, increasing their calcium-binding ability in blood clotting.
148. In aldosteronism, hypertension and edema occur due to sodium retention. Which gland is primarily affected in this condition?
- Ovaries
- Adrenal glands ✓
- Testicles
- Pancreas
- Hypophysis
Explanation: The adrenal glands produce aldosterone, and excess secretion can lead to sodium retention, hypertension, and edema.
149. After consuming fatty food, a patient experiences nausea, heartburn, and steatorrhea. What is the likely cause of these symptoms?
- Increased lipase secretion
- Amylase deficiency
- Disturbed trypsin synthesis
- Disturbed phospholipase synthesis
- Bile acid deficiency ✓
Explanation: Bile acid deficiency impairs fat digestion and absorption, causing steatorrhea and digestive discomfort after fatty meals.
150. Urea synthesis is inhibited, causing ammonia accumulation in the blood. Which liver enzyme is most likely deficient?
- Amylase
- Aspartate aminotransferase
- Carbamoyl phosphate synthetase ✓
- Urease
- Pepsin
Explanation: Carbamoyl phosphate synthetase is involved in the urea cycle, and its deficiency leads to ammonia buildup.
Question 151
Pain along large nervous stems and increased amount of pyruvate in the blood were revealed in the patient. Insufficiency of what vitamin can cause such change?
- В2
- РР
- Biotin
- В1 ✓
- Pantothenic acid
Explanation:
- Vitamin B1 (Thiamine) deficiency leads to neurological symptoms (e.g., pain along large nerve stems) and metabolic disturbances, such as elevated pyruvate levels due to impaired pyruvate dehydrogenase activity. This condition is often seen in beriberi or Wernicke-Korsakoff syndrome.
Question 152
A sportsman was recommended to take a medication that contains carnitine in order to improve his results. What process is activated by carnitine the most?
- Synthesis of steroid hormones
- Fatty acids transport to mitochondrions ✓
- Synthesis of ketone bodies
- Tissue respiration
- Synthesis of lipids
Explanation:
- Carnitine facilitates the transport of long-chain fatty acids into mitochondria for oxidation, crucial for energy production, especially during prolonged exercise. It is not directly involved in hormone synthesis or lipid metabolism.
Question 153
A 3-year-old child with fever was given aspirin. It resulted in intensified erythrocyte haemolysis. Hemolytic anemia might have been caused by congenital insufficiency of the following enzyme:
- Glucose 6-phosphatase
- γ-glutamyltransferase
- Glucose 6-phosphate dehydrogenase ✓
- Glycogen phosphorylase
- Glycerol phosphate dehydrogenase
Explanation:
- Glucose 6-phosphate dehydrogenase (G6PD) deficiency leads to hemolytic anemia, particularly after exposure to oxidative stressors, such as infections or medications like aspirin. This condition is more common in males and can cause significant erythrocyte damage.
Question 154
A patient with suspected diphtheria went through bacterioscopic examination. Examination of throat swab revealed rod-shaped bacteria with volutin granules. What etiotropic preparation should be chosen in this case?
- Diphtheria antitoxin ✓
- Antidiphtheric antitoxic serum
- Bacteriophage
- Eubiotic
- Interferon
Explanation:
- The presence of volutin granules and rod-shaped bacteria suggests Corynebacterium diphtheriae. Diphtheria antitoxin is the first-line treatment to neutralize the exotoxin produced by the bacteria.
Question 155
After a sprint an untrained person develops muscle hypoxia. This leads to the accumulation of the following metabolite in muscles:
- Ketone bodies
- Lactate ✓
- Acetyl CoA
- Glucose 6-phosphate
- Oxaloacetate
Explanation:
- In muscle hypoxia, anaerobic metabolism becomes predominant, leading to the accumulation of lactate (lactic acid) as a byproduct of glucose fermentation. This is a normal response to intense exercise, especially in untrained individuals.
Question 156
A male patient has been diagnosed with acute radiation disease. Laboratory examination revealed a considerable reduction of platelet serotonin level. The likely cause of platelet serotonin reduction is the disturbed metabolism of the following substance:
- Histidine
- 5-oxytryptofane
- Tyrosine
- Phenylalanine
- Serine ✓
Explanation:
- Serine is a precursor for tryptophan, which is involved in the synthesis of serotonin in platelets. Radiation damage can affect serotonin levels by disrupting the metabolic pathways.
Question 157
Analysis of amniotic fluid that was obtained as a result of amniocentesis (puncture of amniotic sac) revealed cells the nuclei of which contain sex chromatin (Barr’s body). What can it be evidence of?
- Development of female fetus ✓
- Trisomy
- Genetic disorders of fetus development
- Development of male fetus
- Polyploidy
Explanation:
- Barr’s body is an inactive X chromosome, typically present in female fetuses. Its presence suggests that the fetus is female, as males do not have a second X chromosome.
Question 158
A 46-year-old woman suffering from chololithiasis developed jaundice. Her urine became dark-yellow and feces became colourless. Blood serum will have the highest concentration of the following substance:
- Mesobilirubin
- Unconjugated bilirubin
- Biliverdin
- Urobilinogen
- Conjugated bilirubin ✓
Explanation:
- Conjugated bilirubin accumulates in the bloodstream when there is an obstruction in the bile ducts (as in cholelithiasis). This leads to jaundice, dark urine, and pale stools due to the failure to excrete bilirubin into the intestine.
Question 159
A genetics specialist analyzed the genealogy of a family and found that both males and females may have the illness, not across all the generations, and that healthy parents may have ill children. What is the type of illness inheritance?
- Y-linked
- X-linked recessive
- Autosomal recessive ✓
- X-linked dominant
- Autosomal dominant
Explanation:
- Autosomal recessive inheritance means that the disease is not present in every generation, and healthy parents (carriers) can have affected children. Both males and females can be affected equally.
Question 160
Emotional stress causes activation of hormon-sensitive triglyceride lipase in the adipocytes. What secondary mediator takes part in this process?
- Adenosine monophosphate
- Cyclic adenosine monophosphate ✓
- Cyclic guanosine monophosphate
- Diacylglycerol
- Ions of Са2+
Explanation:
- Cyclic AMP (cAMP) is the secondary messenger involved in the activation of hormone-sensitive lipase in adipocytes, which plays a key role in fat breakdown during stress and other hormonal signals.
Question 161
A child’s blood presents high content of galactose, glucose concentration is low. There are such presentations as cataract, mental deficiency, adipose degeneration of liver. What disease is it?
- Diabetes mellitus
- Lactosemia
- Fructosemia
- Steroid diabetes
- Galactosemia ✓
Explanation:
- Galactosemia is a genetic disorder in which the body cannot metabolize galactose properly, leading to its accumulation and causing symptoms like cataracts, liver damage, and mental deficiency.
Learning Objectives:
- Understand the role of vitamins and enzymes in metabolic disorders (Questions 151, 152, 153).
- Recognize diagnostic clues for infectious diseases and genetic conditions (Questions 154, 159, 157).
- Identify key biochemical markers and their role in diseases (Questions 158, 161, 160).
- Learn the inheritance patterns of genetic disorders and their clinical presentation (Question 159).
2/2
4o mini
You said:
Question 162 to 168 also
ChatGPT said:
Here are the high cognitive questions for Questions 162 to 168, along with options, explanations, and learning objectives:
Question 162
Marked increase of activity of МВ-forms of CPK (creatinephosphokinase) and LDH-1 were revealed on the examination of the patient’s blood. What is the most likely pathology?
- Hepatitis
- Rheumatism
- Cholecystitis
- Myocardial infarction ✓
- Pancreatitis
Explanation:
- CPK-MB and LDH-1 are isoenzymes that are typically elevated in myocardial infarction (heart attack). CPK-MB is more specific to heart muscle, and LDH-1 is elevated in myocardial injury.
Question 163
Myocyte cytoplasm contains a big number of dissolved metabolites of glucose oxidation. Name one of them that turns directly into a lactate:
- Glycerophosphate
- Fructose 6-phosphate
- Pyruvate ✓
- Glucose 6-phosphate
- Oxaloacetate
Explanation:
- Pyruvate is the end product of glucose oxidation in glycolysis and can be converted to lactate under anaerobic conditions in muscles. This process is important during intense exercise when oxygen supply is insufficient.
Question 164
Products of some proteins hydrolysis and modification are the biologically active substances called hormones. Lipotropin, corticotropin, melanotropin, and endorphins are synthesized in the hypophysis of the following protein:
- Neurostromin
- Neuroalbumin
- Neuroglobulin
- Thyreoglobulin
- Proopiomelanocortin (POMC) ✓
Explanation:
- Proopiomelanocortin (POMC) is the precursor protein from which several important hormones like lipotropin, corticotropin (ACTH), melanotropin (MSH), and endorphins are synthesized in the pituitary gland (hypophysis).
Question 165
A 45-year-old woman suffers from Cushing’s syndrome – steroid diabetes. Biochemical examination revealed: hyperglycemia, hypochloremia. Which of the under-mentioned processes is the first to be activated?
- Gluconeogenesis ✓
- Glucose transport to the cell
- Glucose reabsorption
- Glycogenolysis
- Glycolysis
Explanation:
- In Cushing’s syndrome, excess cortisol promotes gluconeogenesis, which increases blood glucose levels and can lead to hyperglycemia. This process involves the production of glucose from non-carbohydrate sources, particularly in the liver.
Question 166
The energy inputs of a healthy man have been measured. In what position was the patient if his energy inputs were less than the main exchange?
- Easy work
- Rest ✓
- Calmness
- Nervous exertion
- Sleep
Explanation:
- When a person is at rest, their energy expenditure is lower than their basal metabolic rate (main exchange). In this state, the body uses energy at a very minimal level for basic functions such as breathing and circulation.
Question 167
12 hours after an acute attack of retrosternal pain a patient presented a jump of aspartate aminotransferase activity in blood serum. What pathology is this deviation typical for?
- Collagenosis
- Viral hepatitis
- Myocardium infarction ✓
- Diabetes mellitus
- Diabetes insipidus
Explanation:
- Aspartate aminotransferase (AST) is an enzyme found in the heart and liver. A significant increase in AST levels, especially after a retrosternal pain attack, is indicative of myocardial infarction (heart attack), as the enzyme is released during heart muscle damage.
Question 168
As a result of posttranslative modifications some proteins taking part in blood coagulation, particularly prothrombin, become capable of calcium binding. The following vitamin takes part in this process:
- B1
- C
- A
- B2
- K ✓
Explanation:
- Vitamin K plays a crucial role in the post-translational modification of prothrombin and other clotting factors. It is required for the gamma-carboxylation of glutamic acid residues, which allows these proteins to bind calcium and participate in the coagulation cascade.