Biomolecules – MCQs (NEET Style)
Q1. Monosaccharides are:
A. Simple sugars
B. Polymers of glucose
C. Proteins
D. Lipids
Q2. Glucose is:
A. Aldose
B. Ketose
C. Disaccharide
D. Polysaccharide
Q3. Fructose is:
A. Aldose
B. Ketose
C. Reducing sugar
D. Polysaccharide
Q4. Maltose is:
A. Reducing sugar
B. Non-reducing sugar
C. Polysaccharide
D. Amino acid
Q5. Sucrose is:
A. Reducing sugar
B. Non-reducing sugar
C. Polysaccharide
D. Monosaccharide
Q6. Starch is composed of:
A. Glucose units
B. Amino acids
C. Nucleotides
D. Fatty acids
Q7. Cellulose is:
A. Storage polysaccharide
B. Structural polysaccharide
C. Reducing sugar
D. Protein
Q8. Benedict’s test detects:
A. Reducing sugars
B. Non-reducing sugars
C. Proteins
D. Lipids
Q9. Molisch’s test detects:
A. Carbohydrates
B. Proteins
C. Lipids
D. Nucleic acids
Q10. Seliwanoff’s test distinguishes:
A. Aldose and ketose
B. Protein and carbohydrate
C. Fat and carbohydrate
D. DNA and RNA
Q11. Proteins are polymers of:
A. Amino acids
B. Nucleotides
C. Monosaccharides
D. Fatty acids
Q12. Peptide bond is:
A. C–N bond
B. C=O bond
C. O–H bond
D. C–C bond
Q13. Biuret test detects:
A. Proteins
B. Amino acids
C. Carbohydrates
D. Lipids
Q14. Ninhydrin test detects:
A. Amino acids
B. Proteins
C. Carbohydrates
D. Lipids
Q15. Xanthoproteic test is for:
A. Aromatic amino acids
B. Aliphatic amino acids
C. Monosaccharides
D. Nucleotides
Q16. Zwitterion form of amino acids occurs at:
A. Isoelectric point
B. Neutral pH
C. Acidic pH
D. Basic pH
Q17. Denaturation of proteins involves:
A. Breaking hydrogen and disulfide bonds
B. Breaking peptide bonds
C. Oxidation of amino acids
D. Hydrolysis
Q18. Essential amino acids:
A. Can’t be synthesized by the body
B. Can be synthesized by the body
C. All amino acids are essential
D. None of the above
Q19. DNA is:
A. Double-stranded
B. Single-stranded
C. Polysaccharide
D. Protein
Q20. RNA is:
A. Single-stranded
B. Double-stranded
C. Polysaccharide
D. Protein
Q21. Nucleotides consist of:
A. Nitrogenous base, pentose sugar, phosphate group
B. Amino acid, sugar, phosphate
C. Fatty acid, sugar, base
D. Glucose, phosphate, amino acid
Q22. Base-pairing in DNA:
A. A–T, G–C
B. A–G, T–C
C. A–C, G–T
D. A–U, G–C
Q23. Which of the following is a pyrimidine?
A. Cytosine
B. Adenine
C. Guanine
D. Uracil
Q24. Which of the following is a purine?
A. Adenine
B. Cytosine
C. Uracil
D. Thymine
Q25. Enzymes are:
A. Biological catalysts
B. Proteins
C. Substrate-specific
D. All of the above
Q26. Lock and key model explains:
A. Enzyme specificity
B. Enzyme inhibition
C. Cofactor binding
D. Protein folding
Q27. Induced fit model explains:
A. Conformational change in enzyme active site
B. Cofactor activity
C. Substrate hydrolysis
D. Product formation
Q28. Coenzymes are:
A. Organic cofactors
B. Inorganic cofactors
C. Enzymes
D. Substrates
Q29. Vitamins are:
A. Organic micronutrients
B. Proteins
C. Polysaccharides
D. Nucleic acids
Q30. Water-soluble vitamins include:
A. B-complex and C
B. A, D, E, K
C. B12 only
D. None
Q31. Fat-soluble vitamins include:
A. A, D, E, K
B. B-complex
C. C
D. None
Q32. Deficiency of Vitamin C leads to:
A. Scurvy
B. Rickets
C. Night blindness
D. Beriberi
Q33. Deficiency of Vitamin D leads to:
A. Rickets
B. Scurvy
C. Night blindness
D. Beriberi
Q34. Hormones are:
A. Chemical messengers
B. Proteins or steroids
C. Secreted by endocrine glands
D. All of the above
Q35. Insulin is:
A. Protein hormone
B. Steroid hormone
C. Amino acid
D. Carbohydrate
Q36. Testosterone is:
A. Steroid hormone
B. Protein hormone
C. Amino acid
D. Nucleotide
Q37. Benedict’s test is positive for:
A. Glucose
B. Sucrose
C. Cellulose
D. Starch
Q38. Molisch test gives:
A. Violet ring with carbohydrates
B. Blue ring with proteins
C. Red precipitate
D. Yellow solution
Q39. Biuret test gives:
A. Violet color for peptide bonds
B. Red color for amino acids
C. Blue color for lipids
D. Green color for carbohydrates
Q40. DNA differs from RNA because:
A. DNA has deoxyribose, RNA has ribose
B. DNA is double-stranded, RNA single-stranded
C. DNA has thymine, RNA has uracil
D. All of the above
Q41. RNA types include:
A. mRNA, tRNA, rRNA
B. DNA only
C. Proteins
D. Lipids
Q42. Primary structure of protein is:
A. Sequence of amino acids
B. Alpha-helix
C. Beta-sheet
D. Tertiary folding
Q43. Secondary structure of protein is:
A. Alpha-helix or beta-sheet
B. Peptide sequence
C. Quaternary structure
D. Denatured protein
Q44. Tertiary structure of protein:
A. 3D folding due to interactions
B. Sequence of amino acids
C. Linear chain
D. None
Q45. Quaternary structure:
A. Association of multiple polypeptide chains
B. Single chain folding
C. Alpha-helix only
D. Beta-sheet only
Q46. Denaturation can be caused by:
A. Heat
B. pH change
C. Organic solvents
D. All of the above
Q47. Nucleic acids function in:
A. Storage and expression of genetic info
B. Protein synthesis
C. Enzyme cofactors
D. Lipid metabolism
Q48. Proteins function in:
A. Enzymes
B. Structural components
C. Hormones
D. All of the above
Q49. Polysaccharides function as:
A. Energy storage (starch, glycogen)
B. Structural (cellulose, chitin)
C. Both A and B
D. None
Q50. Which test distinguishes between aldose and ketose?
A. Seliwanoff’s test
B. Benedict’s test
C. Molisch test
D. Biuret test
Q1. A – Monosaccharides are simple sugars.
Q2. A – Glucose is an aldose (aldehyde sugar).
Q3. B – Fructose is a ketose (ketone sugar).
Q4. A – Maltose is a reducing disaccharide.
Q5. B – Sucrose is a non-reducing disaccharide.
Q6. A – Starch is a polymer of glucose units (storage polysaccharide).
Q7. B – Cellulose is a structural polysaccharide in plants.
Q8. A – Benedict’s test detects reducing sugars.
Q9. A – Molisch’s test detects carbohydrates in general.
Q10. A – Seliwanoff’s test distinguishes aldose and ketose sugars.
Q11. A – Proteins are polymers of amino acids.
Q12. A – Peptide bond is a C–N bond linking amino acids.
Q13. A – Biuret test detects proteins (peptide bonds).
Q14. A – Ninhydrin test detects amino acids (free α-amino group).
Q15. A – Xanthoproteic test is for aromatic amino acids.
Q16. A – Zwitterion form occurs at isoelectric point (neutral net charge).
Q17. A – Denaturation involves breaking hydrogen/disulfide bonds, not peptide bonds.
Q18. A – Essential amino acids cannot be synthesized by the body.
Q19. A – DNA is double-stranded.
Q20. A – RNA is single-stranded.
Q21. A – Nucleotides consist of a nitrogenous base, pentose sugar, and phosphate group.
Q22. A – DNA base pairing: A–T, G–C.
Q23. A – Cytosine is a pyrimidine.
Q24. A – Adenine is a purine.
Q25. D – Enzymes are protein catalysts, substrate-specific.
Q26. A – Lock and key model explains enzyme specificity.
Q27. A – Induced fit model explains conformational change of enzyme.
Q28. A – Coenzymes are organic cofactors.
Q29. A – Vitamins are organic micronutrients.
Q30. A – Water-soluble vitamins include B-complex and C.
Q31. A – Fat-soluble vitamins include A, D, E, K.
Q32. A – Vitamin C deficiency leads to scurvy.
Q33. A – Vitamin D deficiency leads to rickets.
Q34. D – Hormones are chemical messengers; protein or steroid; secreted by endocrine glands.
Q35. A – Insulin is a protein hormone.
Q36. A – Testosterone is a steroid hormone.
Q37. A – Benedict’s test is positive for glucose.
Q38. A – Molisch test gives violet ring with carbohydrates.
Q39. A – Biuret test gives violet color for peptide bonds.
Q40. D – DNA has deoxyribose, double-stranded, thymine; RNA has ribose, single-stranded, uracil.
Q41. A – RNA types: mRNA, tRNA, rRNA.
Q42. A – Primary structure is amino acid sequence.
Q43. A – Secondary structure includes alpha-helix and beta-sheet.
Q44. A – Tertiary structure is 3D folding due to side chain interactions.
Q45. A – Quaternary structure is association of multiple polypeptide chains.
Q46. D – Denaturation can be caused by heat, pH changes, organic solvents.
Q47. A – Nucleic acids function in storage and expression of genetic info, and protein synthesis.
Q48. D – Proteins function as enzymes, structural components, and hormones.
Q49. C – Polysaccharides function as energy storage (starch, glycogen) and structural (cellulose, chitin).
Q50. A – Seliwanoff’s test distinguishes aldose and ketose sugars.