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Class XII · Chemistry

Biomolecules: NEET MCQ practice

301 practice questions on Biomolecules, each with an explanation. Practise them chapter by chapter in the GyaanLoop app.

301

Practice questions

260

Easy

40

Medium

1

Hard

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What Biomolecules covers

Topics in the NEET (UG) 2026–27 syllabus for this chapter.

  • General introduction and importance of biomolecules
  • Carbohydrates- classification, aldoses and ketoses, monosaccharides and disaccharides
  • Proteins- alpha-amino acids, peptide bond, polypeptides, protein structure, denaturation, enzymes
  • Vitamins- classification and functions
  • Nucleic acids- chemical constitution of DNA and RNA, biological functions
  • Hormones (general introduction)

Sample questions on Biomolecules

Try each one, then open the answer and explanation.

Question 1 · Practice question

Fermentation of Glucose to alcohol undergoes in presence of :

  1. A.ZnO
  2. B.Cr₂O₃
  3. C.Invertase
  4. D.Zymase
Show answer

Answer: D. Zymase

The fermentation of glucose to ethanol is catalyzed by the enzyme zymase, found in yeast. Options A and B are inorganic catalysts used in other industrial processes, while invertase converts sucrose to glucose and fructose but does not produce alcohol.

Question 2 · Practice question

Glycogen is a branched chain polymer of α-D-glucose units in which chain is formed by C1—C4 glycosidic linkage whereas branching occurs by the formation of C1-C6 glycosidic linkage. Structure of glycogen is similar to ______.

  1. A.Amylose
  2. B.Amylopectin
  3. C.Cellulose
  4. D.Glucose
Show answer

Answer: B. Amylopectin

Glycogen is structurally most similar to amylopectin because both are branched polymers of α‑D‑glucose with C1–C4 main chain and C1–C6 branch points, even though glycogen is more highly branched. Amylose is linear, cellulose has β‑linkages and is unbranched, and glucose is a monomer, not a polymer.

Question 3 · Practice question

Which of the following polymer is stored in the liver of animals?

  1. A.Amylose
  2. B.Cellulose
  3. C.Amylopectin
  4. D.Glycogen
Show answer

Answer: D. Glycogen

Glycogen is the storage polysaccharide in animals, mainly in the liver and muscles, released when the body needs glucose. Options like amylose and amylopectin are components of plant starch, and cellulose is a structural polysaccharide in plants, making glycogen the only animal-specific polymer listed.

Question 4 · Practice question

Sucrose (cane sugar) is a disaccharide. One molecule of sucrose on hydrolysis gives _________.

  1. A.2 molecules of glucose
  2. B.2 molecules of glucose + 1 molecule of fructose
  3. C.1 molecule of glucose + 1 molecule of fructose
  4. D.2 molecules of fructose
Show answer

Answer: C. 1 molecule of glucose + 1 molecule of fructose

Sucrose is a disaccharide made of one glucose and one fructose linked together; hydrolysis simply splits it back into these two monomers. Option (a) would describe maltose, (b) is not a common disaccharide, and (d) would describe a fructose-based disaccharide like inulin, not sucrose.

Question 5 · Practice question

Proteins are found to have two different types of secondary structures viz. α-helix and β-pleated sheet structure. α-helix structure of protein is stabilised by :

  1. A.Peptide bonds
  2. B.van der Waals forces
  3. C.Hydrogen bonds
  4. D.Dipole-dipole interactions
Show answer

Answer: C. Hydrogen bonds

The α-helix is stabilised by hydrogen bonds formed between the -C=O group of one peptide bond and the -N-H group of another peptide bond four residues earlier along the chain. Peptide bonds (option A) form the backbone, but do not cause the folding; van der Waals forces and dipole-dipole interactions are weaker and not the primary stabilising force for this specific secondary structure.

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