Classification of biomolecules MCQs With Answer is an essential study aid for B.Pharm students preparing for biochemistry and pharmacology exams. This concise, topic-focused introduction covers the classification of biomolecules—carbohydrates, lipids, proteins, nucleic acids, vitamins and coenzymes—highlighting structural features, functional groups, metabolic roles and pharmaceutical relevance. Practicing multiple choice questions sharpens recall of monosaccharide types, amino acid categories, lipid classes, biochemical tests and biomolecule-drug interactions. Each MCQ with answer strengthens conceptual understanding and exam readiness while linking classification principles to drug action and formulation. Use these targeted questions to reinforce lectures, prepare for practical exams and refine problem-solving skills. Now let’s test your knowledge with 50 MCQs on this topic.
Q1. Which of the following is the correct classification of glucose based on functional group and carbon count?
- Ketopentose
- Aldohexose
- Aldopentose
- Ketotriose
Correct Answer: Aldohexose
Q2. Which class of biomolecules primarily stores genetic information?
- Proteins
- Carbohydrates
- Nucleic acids
- Lipids
Correct Answer: Nucleic acids
Q3. Which lipid class contains a glycerol backbone linked to two fatty acids and a phosphate group?
- Triacylglycerol
- Sphingolipid
- Phospholipid
- Steroid
Correct Answer: Phospholipid
Q4. Which amino acid has a side chain with an aromatic ring and is classified as nonpolar?
- Lysine
- Phenylalanine
- Aspartic acid
- Serine
Correct Answer: Phenylalanine
Q5. Which test is commonly used to detect reducing sugars?
- Salkowski test
- Benedict’s test
- Biuret test
- Sudan III test
Correct Answer: Benedict’s test
Q6. Glycosidic bond formation involves which functional group of monosaccharides?
- Carboxyl group
- Hydroxyl group
- Amino group
- Phosphate group
Correct Answer: Hydroxyl group
Q7. Which vitamin is water-soluble and essential as a coenzyme for carboxylation reactions?
- Vitamin A
- Vitamin B7 (Biotin)
- Vitamin D
- Vitamin K
Correct Answer: Vitamin B7 (Biotin)
Q8. Peptide bonds link amino acids through which type of reaction?
- Hydrolysis
- Oxidation
- Condensation (dehydration)
- Isomerization
Correct Answer: Condensation (dehydration)
Q9. Which carbohydrate is a storage polysaccharide in animals?
- Cellulose
- Starch
- Glycogen
- Pectin
Correct Answer: Glycogen
Q10. Which nucleotide base pairing is correct in DNA?
- Adenine pairs with Cytosine
- Guanine pairs with Thymine
- Adenine pairs with Thymine
- Cytosine pairs with Uracil
Correct Answer: Adenine pairs with Thymine
Q11. Which biomolecule class includes prostaglandins and leukotrienes?
- Steroids
- Fatty acid derivatives (eicosanoids)
- Glycoproteins
- Polysaccharides
Correct Answer: Fatty acid derivatives (eicosanoids)
Q12. Which amino acid is uniquely cyclic and often causes kinks in peptide chains?
- Proline
- Methionine
- Glutamine
- Alanine
Correct Answer: Proline
Q13. Which polysaccharide forms plant cell walls and is composed of β-1,4-linked glucose units?
- Starch
- Cellulose
- Glycogen
- Chitin
Correct Answer: Cellulose
Q14. Which functional group is characteristic of fatty acids?
- Amide group
- Hydroxyl group
- Carboxyl group
- Phosphate group
Correct Answer: Carboxyl group
Q15. An essential amino acid is defined as one that:
- Can be synthesized by the human body
- Must be obtained from the diet
- Contains a sulfur atom
- Is only used in the liver
Correct Answer: Must be obtained from the diet
Q16. Which sugar is a component of RNA but not DNA?
- Deoxyribose
- Ribose
- Glucose
- Fructose
Correct Answer: Ribose
Q17. Which lipid is a major component of cell membranes contributing to fluidity and signal transduction?
- Cholesterol
- Triacylglycerol
- Squalene
- Wax
Correct Answer: Cholesterol
Q18. N-linked glycoproteins are attached to which amino acid residue in proteins?
- Serine
- Threonine
- Asparagine
- Tyrosine
Correct Answer: Asparagine
Q19. Which method is most appropriate to quantify proteins by peptide bond reaction?
- Bradford assay
- Benedict’s test
- Bial’s test
- Seliwanoff’s test
Correct Answer: Bradford assay
Q20. Which of the following is a zwitterion at physiological pH?
- Fatty acid
- Triglyceride
- Amino acid
- Monosaccharide
Correct Answer: Amino acid
Q21. Which vitamin acts as an antioxidant and is fat-soluble?
- Vitamin C
- Vitamin E
- Vitamin B12
- Niacin
Correct Answer: Vitamin E
Q22. The primary structure of a protein refers to:
- Three-dimensional folding stabilized by disulfide bonds
- Sequence of amino acids
- Arrangement of alpha helices and beta sheets
- Association of multiple polypeptide subunits
Correct Answer: Sequence of amino acids
Q23. Which carbohydrate linkage is digestible by human amylase?
- β-1,4 glycosidic linkage in cellulose
- α-1,4 glycosidic linkage in starch
- β-1,3 linkage in agarose
- α-1,6 linkage in chitin
Correct Answer: α-1,4 glycosidic linkage in starch
Q24. Which base is unique to RNA?
- Thymine
- Uracil
- Adenine
- Cytosine
Correct Answer: Uracil
Q25. Saponification is a reaction used to hydrolyze which biomolecule?
- Proteins
- Carbohydrates
- Lipids (esters)
- Nucleic acids
Correct Answer: Lipids (esters)
Q26. Which amino acid side chain can form hydrogen bonds and is polar uncharged?
- Leucine
- Arginine
- Serine
- Phenylalanine
Correct Answer: Serine
Q27. Which biochemical test detects peptide bonds specifically?
- Benedict’s test
- Seliwanoff’s test
- Biuret test
- Emulsification test
Correct Answer: Biuret test
Q28. Which of the following is a sphingolipid commonly found in nerve tissue?
- Triglyceride
- Glycosphingolipid (cerebroside)
- Phosphatidylcholine
- Cholesteryl ester
Correct Answer: Glycosphingolipid (cerebroside)
Q29. In enzyme cofactors, NAD+ is derived from which vitamin?
- Vitamin B3 (Niacin)
- Vitamin B1 (Thiamine)
- Vitamin C
- Vitamin A
Correct Answer: Vitamin B3 (Niacin)
Q30. Which statement correctly distinguishes oligosaccharides from polysaccharides?
- Oligosaccharides are long glucose chains; polysaccharides are di- or trisaccharides
- Oligosaccharides consist of 3–10 monosaccharide units; polysaccharides are larger polymers
- Oligosaccharides are proteins bonded to sugars; polysaccharides are lipids
- Oligosaccharides are always branched; polysaccharides are always linear
Correct Answer: Oligosaccharides consist of 3–10 monosaccharide units; polysaccharides are larger polymers
Q31. Which amino acid is the primary site for phosphorylation in signal transduction?
- Glycine
- Tyrosine
- Proline
- Isoleucine
Correct Answer: Tyrosine
Q32. Which structural level of proteins is stabilized mainly by hydrogen bonding between backbone atoms?
- Primary structure
- Secondary structure
- Tertiary structure
- Quaternary structure
Correct Answer: Secondary structure
Q33. Lipoproteins that primarily transport cholesterol from peripheral tissues to the liver are called:
- Chylomicrons
- LDL (low-density lipoprotein)
- HDL (high-density lipoprotein)
- VLDL (very low-density lipoprotein)
Correct Answer: HDL (high-density lipoprotein)
Q34. Which monosaccharide is a ketose sugar?
- Glucose
- Galactose
- Fructose
- Ribose
Correct Answer: Fructose
Q35. Glycation refers to non-enzymatic attachment of sugars to proteins. Which clinical marker reflects long-term glycation?
- Fasting glucose
- HbA1c (glycated hemoglobin)
- Insulin level
- C-peptide
Correct Answer: HbA1c (glycated hemoglobin)
Q36. Which coenzyme carries acyl groups in metabolism and is essential for fatty acid synthesis?
- NADH
- FAD
- Coenzyme A (CoA)
- ATP
Correct Answer: Coenzyme A (CoA)
Q37. Which nucleic acid structural feature explains complementary base pairing stability?
- Hydrophobic interactions only
- Hydrogen bonding between bases
- Disulfide bridge formation
- Peptide bonding
Correct Answer: Hydrogen bonding between bases
Q38. Which amino acid contains a thiol (-SH) group important for disulfide bond formation?
- Alanine
- Cysteine
- Asparagine
- Tyrosine
Correct Answer: Cysteine
Q39. Which type of carbohydrate is chitin composed of?
- Polymer of N-acetylglucosamine (β-1,4)
- Homopolymer of fructose
- Polymer of galactose units
- α-1,6 linked glucose polymer
Correct Answer: Polymer of N-acetylglucosamine (β-1,4)
Q40. Which vitamin deficiency primarily leads to scurvy due to impaired collagen hydroxylation?
- Vitamin B6
- Vitamin C
- Vitamin D
- Vitamin K
Correct Answer: Vitamin C
Q41. Which phospholipid is commonly found on the outer leaflet of cell membranes and plays a role in signaling when externalized?
- Phosphatidylserine
- Phosphatidylcholine
- Phosphatidylethanolamine
- Cardiolipin
Correct Answer: Phosphatidylcholine
Q42. Which sugar alcohol is commonly used as a low-calorie sweetener and derived from glucose?
- Sorbitol
- Maltitol
- Cellobiose
- Raffinose
Correct Answer: Sorbitol
Q43. Which statement best describes an enzyme prosthetic group?
- A loosely bound cofactor that dissociates easily
- A tightly bound non-protein group permanently attached to the enzyme
- A substrate mimic used in inhibition studies
- A peptide extension of the enzyme chain
Correct Answer: A tightly bound non-protein group permanently attached to the enzyme
Q44. Which biochemical class do glycosaminoglycans belong to and where are they primarily located?
- Proteins; mitochondria
- Polysaccharides; extracellular matrix
- Lipids; plasma membrane
- Nucleic acids; nucleus
Correct Answer: Polysaccharides; extracellular matrix
Q45. Which property differentiates saturated from unsaturated fatty acids?
- Presence of peptide bonds
- Number of double bonds in the hydrocarbon chain
- Presence of phosphate group
- Ability to form glycosidic bonds
Correct Answer: Number of double bonds in the hydrocarbon chain
Q46. Which base modification in DNA is commonly used as an epigenetic marker controlling gene expression?
- 5-methylcytosine
- 6-adenine oxide
- Uracil incorporation
- Thymine dimer formation
Correct Answer: 5-methylcytosine
Q47. Which amino acid side chain is positively charged at physiological pH and contributes to ionic interactions?
- Glutamate
- Lysine
- Serine
- Phenylalanine
Correct Answer: Lysine
Q48. Which of the following describes an amphipathic molecule important for micelle formation?
- Triacylglycerol with three fatty acids
- Phospholipid with hydrophilic head and hydrophobic tails
- Polysaccharide with repeating glucose units
- Protein with only hydrophobic residues
Correct Answer: Phospholipid with hydrophilic head and hydrophobic tails
Q49. Which technique separates biomolecules based on charge and can be used for proteins?
- Gel filtration chromatography
- SDS-PAGE
- Ion-exchange chromatography
- Thin-layer chromatography
Correct Answer: Ion-exchange chromatography
Q50. Which biomolecule class includes enzymes that catalyze the transfer of phosphate groups?
- Kinases (proteins)
- Lipases (lipids)
- Glycosidases (carbohydrates)
- Polymerases (nucleic acids)
Correct Answer: Kinases (proteins)
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