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: Primary structure of a protein refers to
A) Folding
B) Hydrogen bonding
C) Sequence of amino acids
D) Subunit interaction
✅ Correct Answer: C
Explanation: Primary structure is the unique sequence of amino acids in a polypeptide chain.
Q: Final electron acceptor in the electron transport chain
A) Oxygen
B) Water
C) Carbon dioxide
D) ATP
✅ Correct Answer: A
Explanation: Oxygen accepts electrons and combines with hydrogen to form water.
Q: Major buffer system in human blood
A) Bicarbonate buffer
B) Protein buffer
C) Ammonia buffer
D) Phosphate buffer
✅ Correct Answer: A
Explanation: The bicarbonate buffer system maintains pH balance in the blood.
Q: Type of bond joining amino acids
A) Disulfide bond
B) Hydrogen bond
C) Ionic bond
D) Peptide bond
✅ Correct Answer: D
Explanation: A peptide bond is formed between amino acids during protein synthesis.
Q: Enzyme catalyzing DNA synthesis
A) DNA polymerase
B) RNA polymerase
C) DNA helicase
D) Ligase
✅ Correct Answer: A
Explanation: DNA polymerase adds nucleotides to the growing DNA strand during replication.
Q: Basic unit of nucleic acids
A) Nucleotide
B) Amino acid
C) Sugar-phosphate
D) Nucleoside
✅ Correct Answer: A
Explanation: A nucleotide consists of a sugar, phosphate, and nitrogenous base and is the building block of DNA and RNA.
Q: Metal ion required for hemoglobin function
A) Copper
B) Magnesium
C) Iron
D) Zinc
✅ Correct Answer: C
Explanation: Iron in the heme group binds oxygen molecules in hemoglobin.
Q: Amino acid with a sulfur-containing side chain
A) Alanine
B) Serine
C) Cysteine
D) Glycine
✅ Correct Answer: C
Explanation: Cysteine contains a thiol group in its side chain, which can form disulfide bonds.
Q: Primary organ for detoxification of drugs
A) Pancreas
B) Liver
C) Spleen
D) Kidney
✅ Correct Answer: B
Explanation: The liver metabolizes and detoxifies harmful substances in the body.
Q: Substrate for the enzyme lactase
A) Sucrose
B) Glucose
C) Lactose
D) Galactose
✅ Correct Answer: C
Explanation: Lactase hydrolyzes lactose into glucose and galactose.