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: Base pairing in DNA follows
A) A–A and G–G
B) A–C and G–T
C) A–T and G–C
D) T–T and C–C
✅ Correct Answer: C
Explanation: DNA strands are held together by A–T and G–C pairings.
Q: The enzyme lipase acts on
A) Protein
B) Lipid
C) DNA
D) Starch
✅ Correct Answer: B
Explanation: Lipase catalyzes the breakdown of lipids into fatty acids and glycerol.
Q: RNA synthesis is catalyzed by
A) RNA polymerase
B) Protease
C) Helicase
D) DNA ligase
✅ Correct Answer: A
Explanation: RNA polymerase reads DNA and synthesizes RNA.
Q: Vitamins required in trace amounts function as
A) Coenzymes
B) Antibodies
C) Hormones
D) Enzymes
✅ Correct Answer: A
Explanation: Many vitamins serve as essential coenzymes in metabolic pathways.
Q: Hydrogen bonding is important in
A) DNA base pairing
B) Primary structure
C) Ionic bonding
D) Peptide bond formation
✅ Correct Answer: A
Explanation: Hydrogen bonds stabilize base pairs in the DNA double helix.
Q: Translation converts mRNA into
A) DNA
B) Protein
C) Glucose
D) Lipid
✅ Correct Answer: B
Explanation: Translation is the process of synthesizing proteins from mRNA.
Q: Enzyme specificity depends on
A) pH
B) Size
C) Temperature
D) Active site shape
✅ Correct Answer: D
Explanation: The enzyme's active site must match the substrate's shape.
Q: Lactose is composed of
A) Fructose and maltose
B) Glucose and galactose
C) Glucose and fructose
D) Glucose and sucrose
✅ Correct Answer: B
Explanation: Lactose is a disaccharide of glucose and galactose.
Q: Biuret test detects
A) Nucleic acids
B) Proteins
C) Lipids
D) Carbohydrates
✅ Correct Answer: B
Explanation: The Biuret reagent turns violet in the presence of proteins.
Q: ATP primarily serves as
A) Hormone
B) Enzyme
C) Energy currency
D) Structural unit
✅ Correct Answer: C
Explanation: ATP provides energy for most biochemical cellular processes.