Biochemistry MCQs
Biochemistry MCQs play a vital role in preparing students for understanding life at the molecular level. These MCQs include topics such as carbohydrate metabolism, lipid and protein structures, enzymes, vitamins, DNA/RNA, and clinical applications. These quizzes are essential for students appearing in MDCAT, USMLE, FCPS, and other competitive exams. Regular practice enhances understanding of how biochemical processes affect 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.
Q: A zwitterion has
A) Positive charge only
B) No charge
C) Negative charge only
D) Both charges
✅ Correct Answer: D
Explanation: Zwitterions have both positive and negative charges on the same molecule.
Q: DNA replication is
A) Dispersive
B) Non-selective
C) Semi-conservative
D) Conservative
✅ Correct Answer: C
Explanation: Each new DNA molecule contains one original and one new strand.
Q: Pepsin is active in the
A) Liver
B) Stomach
C) Intestine
D) Mouth
✅ Correct Answer: B
Explanation: Pepsin functions in the stomach at acidic pH.
Q: Chylomicrons transport
A) Proteins
B) Nucleic acids
C) Lipids
D) Carbohydrates
✅ Correct Answer: C
Explanation: Chylomicrons carry dietary lipids from the intestine to the bloodstream.
Q: Liver stores excess glucose as
A) Lactose
B) ATP
C) Fructose
D) Glycogen
✅ Correct Answer: D
Explanation: The liver converts and stores excess glucose in the form of glycogen.