Biochemistry MCQs
Biochemistry MCQs cover enzymes, metabolism, vitamins, nucleic acids, and clinical correlations. Perfect for MDCAT, USMLE, FCPS, and competitive exams, these quizzes strengthen molecular biology concepts and link biochemical processes to human health and disease.
Q: Hemoglobin binds with
A) Glucose
B) Iron
C) Calcium
D) Oxygen
✅ Correct Answer: D
Explanation: Hemoglobin carries oxygen from lungs to tissues.
Q: An enzyme becomes inactive at
A) Extreme pH
B) Normal pressure
C) Low temperature
D) Optimum pH
✅ Correct Answer: A
Explanation: Extreme pH levels alter enzyme structure, reducing activity.
Q: Enzymes are mostly composed of
A) Carbohydrates
B) Lipids
C) Proteins
D) Nucleic acids
✅ Correct Answer: C
Explanation: Enzymes are biological catalysts made of proteins.
Q: Coenzymes are often derived from
A) Vitamins
B) Lipids
C) Proteins
D) Sugars
✅ Correct Answer: A
Explanation: Many coenzymes are vitamin-based molecules that assist enzymes.
Q: Catalase breaks down
A) Urea
B) Glucose
C) Hydrogen peroxide
D) Starch
✅ Correct Answer: C
Explanation: Catalase decomposes hydrogen peroxide into water and oxygen.