CARDIOVASCULAR REVISION

​CVS REVISION

By Roohi Sakina

Multiple Choice

1.A 55-year-old man has muscle weakness and difficulty with fine movements. Tests show reduced levels of a neurotransmitter at the neuromuscular junction.

 

Which process is directly responsible for its synthesis?

• A. Choline uptake into the neuron and combination with acetyl-CoA by choline acetyltransferase

• B. Conversion of tyrosine to L-DOPA

• C. Conversion of tryptophan to serotonin

• 1.A 55-year-old man has muscle weakness and difficulty with fine movements. Tests show reduced levels of a neurotransmitter at the neuromuscular junction.

  Which process is directly responsible for its synthesis?

  D. Synthesis of glutamate from α-ketoglutarate

Multiple Choice

2. A 48-year-old woman presents with muscle fatigue and drooping eyelids. A drug is given to block the enzyme that breaks down a key neurotransmitter at the neuromuscular junction, improving her symptoms.

Which enzyme is responsible for the degradation of this neurotransmitter?

• A. Monoamine oxidase
  
  
  

• B. Acetylcholinesterase

• C. Catechol-O-methyltransferase

• D. Glutamate decarboxylase

Multiple Choice

3. A 35-year-old man presents with sudden onset of fever, headache, and neck stiffness. Lumbar puncture is performed, and cerebrospinal fluid (CSF) is sent for analysis to help identify the underlying cause.

 

Which CSF parameter is most useful in differentiating bacterial from viral meningitis?

• A. Glucose

• B. Protein

• C. Cell count

• D. Lactate

Multiple Choice

4. A 34-year-old pregnant woman undergoes a screening test at 16 weeks of gestation to assess the risk of fetal chromosomal abnormalities.

 

Which of the following maternal serum parameters is most commonly used in this screening?

 

• A. AFP

• B. Beta-hCG

• C. Unconjugated estriol

• D. Inhibin-A

Multiple Choice

5.A 50-year-old man presents with metabolic acidosis. His kidneys respond to help restore normal blood pH.

 

Which renal process primarily helps correct this acid-base imbalance?

 

• A. Excretion of H⁺

• B. Reabsorption of Na⁺

• C. Secretion of K⁺

• D. Excretion of titratable acids

Multiple Choice

6.A 45-year-old man presents with rapid breathing and fatigue. Laboratory results show:

 

Na⁺ = 140 mEq/L

K⁺ = 4 mEq/L

Cl⁻ = 100 mEq/L

HCO₃⁻ = 16 mEq/L

 

Which of the following best describes the type of metabolic acidosis in this patient?

 

 

• A. Normal anion gap (hyperchloremic) metabolic acidosis

• B. High anion gap metabolic acidosis

• C. Respiratory acidosis

• D. Metabolic alkalosis

Multiple Choice

7.A 50-year-old man presents with fatigue and swelling in his legs. The physician orders laboratory tests to assess kidney function.

 

Which of the following is the most commonly used parameter to evaluate renal function?

 

• A. Blood urea nitrogen (BUN)

• B. Serum creatinine

• C. Urine osmolality

• D. Urinary sodium

Multiple Choice

8. A 28-year-old woman presents with irregular menstrual cycles. Laboratory tests reveal a deficiency in enzymes required for the synthesis of ovarian sex steroids.

 

Which of the following is the immediate precursor for the biosynthesis of estrogen and testosterone?

 

• A. Cholesterol

• B. Pregnenolone

• C. Progesterone

• D. Androstenedione

Multiple Choice

9. A 50-year-old man presents with increased thirst and frequent urination. The physician orders a test to assess his blood glucose level.

 

Which of the following parameters is most commonly measured to diagnose hyperglycemia?

 

 

• A. Fasting plasma glucose

• B. HbA1c

• C. Random plasma glucose

• D. Oral glucose tolerance test (OGTT)

Multiple Choice

10. A 35-year-old woman presents with fatigue, weight gain, and cold intolerance. Laboratory tests show low T₃ and T₄ with elevated TSH.

 

Which of the following best describes her condition?

 

• A. Primary hypothyroidism

• B. Secondary hyperthyroidism

• C. Euthyroid

• D. Tertiary hypothyroidism

Multiple Choice

11. A 30-year-old man experiences hypoglycemia after skipping breakfast. His pancreas responds by releasing a hormone to restore blood glucose levels.

 

Which of the following correctly describes the hormone involved?

 

 

• A. Insulin – decreases blood glucose, two-chain polypeptide with disulfide bonds

• B. Insulin – increases blood glucose, single-chain polypeptide

• C. Glucagon – increases blood glucose, single-chain polypeptide

• D. Glucagon – decreases blood glucose, two-chain polypeptide

Multiple Choice

12. A 50-year-old man presents with neurological symptoms and lactic acidosis. His physician suspects a deficiency in a vitamin that is a coenzyme for the reaction:

 

Pyruvate → Acetyl-CoA (catalyzed by pyruvate dehydrogenase).

 

Which of the following coenzymes is derived from the deficient vitamin?

 

A. Thiamine pyrophosphate (TPP)

B. Flavin adenine dinucleotide (FAD)

C. Nicotinamide adenine dinucleotide (NAD⁺)

D. Coenzyme A (CoA)

 

• A. Thiamine pyrophosphate (TPP)

• B. Flavin adenine dinucleotide (FAD)

• C. Nicotinamide adenine dinucleotide (NAD⁺)

• D. Coenzyme A (CoA)

Multiple Choice

13. A 10-year-old boy shows stunted growth and frequent infections. His diet mainly consists of polished rice and lacks diversity.

 

Which deficiency in his diet is most likely responsible?

 

 

• A. Carbohydrates

• B. Proteins

• C. Fats

• D. Water

Multiple Choice

14. A 2-year-old child presents with developmental delay, vomiting, and a characteristic maple syrup odor in urine. Laboratory tests reveal elevated branched-chain amino acids.

 

Which inborn error of protein metabolism is most likely?

 

 

• A. Phenylketonuria

• B. Maple syrup urine disease

• C. Homocystinuria

• D. Alkaptonuria

Multiple Choice

15. A 50-year-old man presents with polyuria, polydipsia, and unexplained weight loss. Laboratory tests show fasting plasma glucose of 160 mg/dL, HbA1c of 8%, and glycosuria.

 

Which of the following biochemical abnormalities is most characteristic of diabetes mellitus?

 

• A. Increased insulin secretion

• B. Decreased blood glucose

• C. Impaired glucose uptake by tissues

• D. Increased glycogen synthesis

Multiple Choice

16. A 45-year-old man with delayed wound healing and frequent infections is found to have impaired glucose tolerance. Laboratory tests show normal insulin levels, but his pancreatic β-cells are not functioning optimally.

Which mineral deficiency is most likely impairing his insulin synthesis and function?

• A. Iron
  

• B. Zinc
  

• C. Magnesium
  

• D. Chromium

Multiple Choice

17.A 35-year-old man presents with impaired wound healing and mild glucose intolerance. One of his key enzymes in carbohydrate metabolism, alcohol dehydrogenase, requires a metal cofactor for proper function:

 

Reaction: Ethanol → Acetaldehyde (catalyzed by alcohol dehydrogenase)

 

Which mineral deficiency is most likely affecting this enzyme’s activity?

 

 

• A. Iron

• B. Zinc

• C. Magnesium

• D. Copper

Multiple Choice

18.A 6-year-old boy presents with developmental delay, anemia, and pale hair. One of his enzymes, cytochrome c oxidase, requires a metal cofactor for electron transport in mitochondria:

Reaction: Cytochrome c (reduced) → Cytochrome c (oxidized) (catalyzed by cytochrome c oxidase)

Which mineral deficiency is most likely affecting this enzyme’s activity?

• A. Zinc
  

• B. Copper
  

• C. Iron
  

• D. Selenium

Multiple Choice

19.A 2-month-old infant presents with bruising and prolonged bleeding after minor trauma. History reveals the baby did not receive vitamin supplementation after birth. Laboratory tests show prolonged prothrombin time (PT).

Which vitamin deficiency is most likely responsible?

• A. Vitamin A
  

• B. Vitamin D
  

• C. Vitamin E
  

• D. Vitamin K

Multiple Choice

20.A 6-month-old infant presents with muscle weakness, poor reflexes, and hemolytic anemia. Laboratory tests reveal increased oxidative stress markers.

 

Which fat-soluble vitamin deficiency is most likely responsible?

 

 

• A. Vitamin A

• B. Vitamin D

• C. Vitamin E

• D. Vitamin K

Multiple Choice

21. A 28-year-old woman undergoes an oral glucose tolerance test (OGTT). Her laboratory results are:

 

Fasting plasma glucose: 90 mg/dL

2-hour post-glucose load: 95 mg/dL

Urine glucose: positive

 

Which of the following best explains her condition?

 

• A. Normal glucose tolerance

• B. Type 2 diabetes mellitus

• C. Renal glycosuria

• D. Impaired glucose tolerance

   

Multiple Choice

22. A 6-year-old boy presents with hyperpigmentation, hypotension, and hyponatremia. Laboratory tests reveal low cortisol and aldosterone, with elevated ACTH.

Which enzyme deficiency is most likely responsible for his condition?

• A. 11β-hydroxylase
  

• B. 21-hydroxylase
  

• C. 17α-hydroxylase
  

• D. 3β-hydroxysteroid dehydrogenase

Multiple Choice

23. A 35-year-old man skips breakfast and begins to feel weak and dizzy. His blood glucose is measured at 60 mg/dL. The pancreas responds to restore normal glucose levels.

Which of the following best describes the primary hormonal response to this condition?

 

 

• A. Insulin secretion increases → glucose uptake by tissues
  

• B. Glucagon secretion increases → glycogenolysis and gluconeogenesis
  

• C. Insulin secretion increases → glycogen breakdown
  

• D. Glucagon secretion decreases → gluconeogenesis inhibition

Multiple Choice

24. A 30-year-old man is found after several days of food deprivation. Laboratory tests show low insulin, high glucagon, increased ketone bodies, and elevated free fatty acids.

 

Which of the following metabolic adaptations is most characteristic of prolonged starvation?

 

 

• A. Increased glycolysis in muscle

• B. Increased gluconeogenesis and ketogenesis

• C. Increased glycogen synthesis in liver

• D. Increased insulin secretion

Multiple Choice

25. A couple comes for genetic counseling. Their first child has phenylketonuria (PKU), caused by a single nucleotide change leading to a dysfunctional enzyme.

 

Which type of mutation is most likely responsible for this condition?

 

• A. Missense mutation

• B. Nonsense mutation

• C. Frameshift mutation

• D. Silent mutation

Multiple Choice

26. A 25-year-old man is being treated with a drug that inhibits RNA polymerase II. Laboratory tests show decreased synthesis of mRNA in his cells.

 

Which step of gene expression is directly affected by this drug?

 

• A. Transcription

• B. Translation

• C. Post-translational modification

• D. DNA replication

Multiple Choice

27. A 30-year-old man is treated with an antibiotic that binds to the 30S ribosomal subunit, inhibiting protein synthesis in bacteria.

 

Which step of gene expression is directly affected by this drug?

 

• A. Transcription

• B. Translation

• C. RNA splicing

• D. DNA replication

Multiple Choice

28. A 28-year-old patient is being treated with a drug that inhibits DNA polymerase activity. Laboratory tests show impaired DNA synthesis in his rapidly dividing cells.

Which step of gene expression or cell function is directly affected by this drug?

• A. Transcription
  

• B. Translation
  

• C. DNA replication
  

• D. RNA splicing

Multiple Choice

29. A 7-year-old girl develops freckles and skin blisters on sun-exposed areas. She has an increased risk of skin cancer. The underlying problem is a defect in repairing UV-induced DNA damage.

 

Which DNA repair mechanism is most likely defective?

 

• A. Base excision repair

• B. Nucleotide excision repair

• C. Mismatch repair

• D. Non-homologous end joining

Multiple Choice

30. A researcher wants to detect and quantify specific RNA molecules expressed in a cell after introducing a recombinant gene.

Which technique should the researcher use?

• A. Western blotting
  

• B. Southern blotting
  

• C. Northern blotting
  

• D. Eastern blotting

Multiple Choice

31. A 50-year-old man presents with sudden severe pain and swelling in his big toe. Laboratory tests reveal hyperuricemia and uric acid crystals in synovial fluid.

Which class of biomolecules is primarily responsible for the accumulation of uric acid in this condition?

• A. Purines
  

• B. Pyrimidines
  

• C. Carbohydrates
  

• D. Amino acids

Multiple Choice

32. A 35-year-old woman presents with symptoms of hyperthyroidism. Her physician explains that thyroid hormones act by binding to intracellular receptors and regulating gene transcription.

 

Which type of hormone signaling does this represent?

 

• A. Peptide hormones via membrane receptors

• B. Steroid and thyroid hormones via intracellular receptors

• C. Catecholamines via G-protein coupled receptors

• D. Insulin via tyrosine kinase receptors

Multiple Choice

33. A 3-week-old newborn presents with jaundice. Laboratory tests reveal elevated unconjugated bilirubin, normal liver enzymes, and no hemolysis.

Which condition is most consistent with defective bilirubin metabolism?

• A. Gilbert syndrome
  

• B. Crigler-Najjar syndrome
  

• C. Dubin-Johnson syndrome
  

• D. Rotor syndrome

Multiple Choice

34. A 6-year-old boy presents with vomiting, lethargy, and confusion. Laboratory tests reveal hyperammonemia and normal liver enzymes. The physician suspects a defect in the urea cycle.

Which of the following pathways is primarily responsible for detoxifying ammonia in the body?

• A. Glutaminase pathway
  

• B. Urea cycle
  

• C. Glycolysis
  

• D. Beta-oxidation

Multiple Choice

35. A 25-year-old man complains of bloating and diarrhea after consuming milk. Laboratory tests suggest a deficiency in an enzyme that hydrolyzes disaccharides at the brush border.

Which enzyme deficiency is most likely responsible?

• A. Maltase
  

• B. Lactase
  

• C. Sucrase
  

• D. Amylase

Multiple Choice

36. A 30-year-old man with chronic pancreatitis develops steatorrhea and weight loss. Laboratory tests reveal decreased activity of pancreatic proteases.

Which of the following enzymes is directly responsible for breaking down dietary proteins into absorbable peptides?

• A. Pepsin
  

• B. Trypsin
  

• C. Lipase
  

• D. Amylase

Multiple Choice

37. A 40-year-old woman has fatty stools after cholecystectomy. Laboratory studies show impaired micelle formation due to lack of bile.

Which process is essential for intestinal absorption of fats?

• A. Emulsification and micelle formation
  

• B. Peptide bond hydrolysis
  

• C. Starch hydrolysis
  

• D. Active transport of amino acids

Multiple Choice

38. A 45-year-old woman presents with right upper quadrant pain after a fatty meal. Ultrasound shows gallstones. Laboratory tests reveal normal liver enzymes.

Which of the following biochemical abnormalities is most commonly associated with gallstone formation?

• A. Increased cholesterol in bile
  

• B. Increased bile acid synthesis
  

• C. Increased lecithin in bile
  

• D. Decreased bilirubin in bile

Multiple Choice

39. 50-year-old man presents with epigastric pain, steatorrhea, and weight loss. Laboratory tests show elevated pancreatic enzymes in the blood.

Which enzyme is most commonly measured to assess exocrine pancreatic function?

• A. Amylase
  

• B. Lipase
  

• C. Trypsin
  

• D. Chymotrypsin

Multiple Choice

40. A 2-year-old child presents with severe wasting, loss of subcutaneous fat, and muscle atrophy, but without edema. His diet has been very low in calories for several months.

Which form of malnutrition is most consistent with this presentation?

 

• A.      Kwashiorkor
  

• B. Marasmus
  

• C. Scurvy
  

• D. Rickets