February 6, 2024

BiochemIQ: Mastering Medical Biochemistry

Posted on February 6, 2024  •  26 minutes  • 5501 words
Table of contents

Medical biochemistry is a fascinating field that delves into the intricate biochemical processes within the human body, deciphering the molecular underpinnings of health and disease. As a bridge between basic biochemistry and clinical medicine, it forms the foundation for understanding various medical conditions, their diagnoses, and treatments. In this article, we present 20 thought-provoking multiple-choice questions that not only test your knowledge but also encourage you to think critically and deduce answers from your understanding of biochemistry. These questions are designed to challenge your comprehension of biochemical principles and their real-world applications, requiring multiple logical steps to arrive at the correct answers. Whether you’re a medical student, healthcare professional, or simply intrigued by the intersection of biology and medicine, join us on a journey through the complex world of medical biochemistry as we explore these questions and their detailed explanations.

1. A 25-year-old female presents with muscle weakness, hypoglycemia, and increased levels of ketone bodies. She is diagnosed with a deficiency in an enzyme involved in fatty acid oxidation. Which enzyme is most likely deficient?

A. Acetyl-CoA carboxylase
B. Carnitine acyltransferase I
C. Citrate synthase
D. Glucokinase

2. A newborn is noted to have a “musty” odor and is diagnosed with phenylketonuria (PKU). Which of the following dietary components should be restricted?

A. Fructose
B. Galactose
C. Phenylalanine
D. Glucose

3. A patient presents with recurrent kidney stones and is found to have hypercalciuria. Further testing reveals a deficiency in an enzyme involved in vitamin D metabolism. Which enzyme is most likely affected?

A. 1α-Hydroxylase
B. 25-Hydroxylase
C. Phenylalanine hydroxylase
D. Tyrosinase

4. A patient with a history of alcoholism presents with lactic acidosis and hypoglycemia. Which metabolic pathway is primarily affected?

A. Gluconeogenesis
B. Glycolysis
C. Ketogenesis
D. Urea cycle

5. A child with recurrent episodes of vomiting, lethargy, and hyperammonemia is found to have a deficiency in an enzyme within the urea cycle. Which compound would likely be elevated in this patient’s blood?

A. Urea
B. Arginine
C. Ornithine
D. Citrulline

6. A patient diagnosed with chronic pancreatitis exhibits steatorrhea and weight loss. Which of the following nutrients is most likely malabsorbed due to the condition?

A. Carbohydrates
B. Proteins
C. Lipids
D. Water-soluble vitamins

7. A patient with a history of excessive aspirin use is diagnosed with metabolic acidosis. Which of the following compensatory mechanisms is most likely to occur in response to this condition?

A. Increased renal reabsorption of bicarbonate
B. Decreased respiratory rate to retain CO2
C. Increased breakdown of fatty acids
D. Increased renal excretion of hydrogen ions

8. A 40-year-old male with lethargy, depression, and a decreased libido is found to have low testosterone levels. Further testing reveals elevated levels of iron in the liver. Which condition is most likely associated with these findings?

A. Hemochromatosis
B. Wilson’s disease
C. Addison’s disease
D. Hypothyroidism

9. A patient with severe abdominal pain is diagnosed with acute intermittent porphyria (AIP). Which of the following substances should be avoided to prevent exacerbation of the condition?

A. Glucose
B. Alcohol
C. Vitamin C
D. Calcium

10. A newborn is diagnosed with jaundice and a coagulopathy shortly after birth. The infant’s mother had an uneventful

pregnancy and no history of liver disease. Which vitamin is the newborn most likely deficient in? A. Vitamin A
B. Vitamin D
C. Vitamin E
D. Vitamin K

11. A 50-year-old male with a history of alcohol abuse presents with confusion, ataxia, and ophthalmoplegia. Laboratory tests reveal a deficiency in a coenzyme involved in carbohydrate metabolism. Which of the following is the deficient coenzyme?

C. Thiamine pyrophosphate (TPP)
D. Coenzyme A

12. A 30-year-old female presents with fatigue, muscle weakness, and hyperpigmentation. Laboratory tests show low sodium, high potassium, and low cortisol levels. Which enzyme is most likely deficient in this patient’s condition?

A. 21-hydroxylase
B. 11β-hydroxysteroid dehydrogenase
C. 17α-hydroxylase
D. Aromatase

13. A patient with severe back pain was found to have a vertebral compression fracture. A blood test revealed elevated calcium levels. Which of the following conditions is most likely responsible for these findings?

A. Osteoporosis
B. Paget’s disease of bone
C. Primary hyperparathyroidism
D. Vitamin D toxicity

14. A patient presents with recurrent, severe headaches and episodes of hypertension, sweating, and palpitations. Tests reveal elevated levels of catecholamines in the blood. Which of the following is the most likely diagnosis?

A. Pheochromocytoma
B. Cushing’s syndrome
C. Hyperthyroidism
D. Acromegaly

15. A 4-year-old child presents with intellectual disability, growth retardation, and a musty odor. The child’s diet is found to be high in protein. Which of the following dietary changes is most appropriate?

A. Increase carbohydrate intake
B. Decrease phenylalanine intake
C. Increase fat intake
D. Decrease galactose intake

16. A patient presents with numbness and tingling in their hands and feet, combined with fatigue and difficulty walking. Blood tests reveal macrocytic anemia. Which vitamin deficiency is most likely associated with these symptoms?

A. Vitamin B1 (Thiamine)
B. Vitamin B12 (Cobalamin)
C. Vitamin C (Ascorbic acid)
D. Vitamin D

17. A patient diagnosed with renal failure is found to have elevated blood phosphate levels and secondary hyperparathyroidism. Which of the following interventions is most appropriate to manage this condition?

A. Increase dietary phosphate
B. Administer calcium supplements
C. Reduce dietary protein
D. Increase vitamin D intake

18. A patient with a history of bariatric surgery presents with night blindness and dry, scaly skin. Which of the following vitamins is the patient most likely deficient in?

A. Vitamin A
B. Vitamin B6 (Pyridoxine)
C. Vitamin C (Ascorbic acid)
D. Vitamin E

19. A patient with a long-standing history of untreated celiac disease presents with bone pain and muscle weakness. Which of the following conditions is most likely contributing to these symptoms?

A. Hypercalcemia
B. Osteoporosis
C. Rickets/Osteomalacia
D. Hyperparathyroidism

20. A neonate is found to have a high serum bilirubin

level but no signs of hemolysis. The baby is alert and feeding well. Which of the following is the most likely cause of the jaundice? A. Physiological jaundice
B. Biliary atresia
C. Neonatal sepsis
D. Glucose-6-phosphate dehydrogenase (G6PD) deficiency



  1. Mark Anderson, BS in Biology, State University
  2. David Wilson, BA in Physics, Community College
  3. Sarah Turner, MA in Environmental Science, Regional University

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