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Biomolecules CBSE Class 12 MCQ & Practice Questions

Practice Biomolecules MCQs for CBSE Class 12 Chemistry with answers, explanations, chapter revision and related ChemNexa mock tests.

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Biomolecules Revision Guide for CBSE Class 12 Chemistry

Biomolecules is part of CBSE Class 12 Chemistry preparation. A strong revision plan should combine concept review with exam-style questions so that definitions, relationships, calculations and exceptions are recalled accurately.

Use the sample MCQs on this page to check understanding, then attempt the related ChemNexa tests for broader practice. When an answer is wrong, review the explanation and return to the underlying concept before attempting another set.

Important Topics

  • Core definitions and principles
  • Important equations or relationships
  • Common applications and examples
  • Frequently confused concepts
  • Exam-style multiple-choice questions
  • Error review and targeted revision

Revision Tip

Create a one-page summary of trends, structures, reactions, exceptions and key terminology for Biomolecules, then test recall with mixed MCQs.

What to practise in Biomolecules

Concept Revision

Revise definitions, principles, equations, trends and core ideas from Biomolecules before attempting MCQs.

Exam-style MCQs

Use chapter-focused multiple-choice practice to improve accuracy, recall and application for CBSE Class 12 Chemistry.

Performance Practice

Attempt ChemNexa tests, review results and return to weak areas for another round of targeted revision.

Top 20 Biomolecules MCQs with Answers

These public questions are selected from the exact Biomolecules chapter, screened for topic relevance and deduplicated so repeated versions of the same MCQ are not shown publicly. Use them for quick revision, then sign in to attempt the complete test experience with more questions, results and performance review.

CBSE Class 12 Chemistry · Biomolecules · Very Very Hard

1. The monomer of proteins is:

  • A. Monosaccharide
  • B. Amino acid
  • C. Nucleotide
  • D. Fatty acid
Answer: B
Explanation: Proteins are polymers of amino acids.

CBSE Class 12 Chemistry · Biomolecules · Very Very Hard

2. Peptide bond is:

  • A. –COO–
  • B. –CONH–
  • C. –O–
  • D. –CHO
Answer: B
Explanation: Condensation between amino acids.

CBSE Class 12 Chemistry · Biomolecules · Very Very Hard

3. Glucose is a:

  • A. Disaccharide
  • B. Monosaccharide
  • C. Polysaccharide
  • D. Oligosaccharide
Answer: B
Explanation: Single sugar unit.

CBSE Class 12 Chemistry · Biomolecules · Very Very Hard

4. Sucrose is composed of:

  • A. Glucose+Glucose
  • B. Glucose+Fructose
  • C. Glucose+Galactose
  • D. Fructose+Fructose
Answer: B
Explanation: Common table sugar.

CBSE Class 12 Chemistry · Biomolecules · Very Very Hard

5. Starch is a polymer of:

  • A. Fructose
  • B. Glucose
  • C. Galactose
  • D. Ribose
Answer: B
Explanation: Amylose/amylopectin.

CBSE Class 12 Chemistry · Biomolecules · Very Very Hard

6. Cellulose contains:

  • A. α-D-glucose
  • B. β-D-glucose
  • C. Fructose
  • D. Ribose
Answer: B
Explanation: β-1,4 linkages.

CBSE Class 12 Chemistry · Biomolecules · Very Very Hard

7. DNA sugar is:

  • A. Ribose
  • B. Deoxyribose
  • C. Glucose
  • D. Fructose
Answer: B
Explanation: DNA contains 2-deoxyribose.

CBSE Class 12 Chemistry · Biomolecules · Very Very Hard

8. RNA sugar is:

  • A. Deoxyribose
  • B. Ribose
  • C. Glucose
  • D. Mannose
Answer: B
Explanation: RNA contains ribose.

CBSE Class 12 Chemistry · Biomolecules · Very Very Hard

9. Base absent in RNA:

  • A. A
  • B. G
  • C. T
  • D. C
Answer: C
Explanation: Uracil replaces thymine.

CBSE Class 12 Chemistry · Biomolecules · Very Very Hard

10. Denaturation affects:

  • A. Primary structure
  • B. Secondary/tertiary structure
  • C. Peptide bonds
  • D. Molecular formula
Answer: B
Explanation: Peptide bonds remain intact.

CBSE Class 12 Chemistry · Biomolecules · Very Very Hard

11. Essential amino acids are:

  • A. Synthesized fully
  • B. Not synthesized adequately
  • C. Only in plants
  • D. Non-protein
Answer: B
Explanation: Must come from diet.

CBSE Class 12 Chemistry · Biomolecules · Very Very Hard

12. Vitamin C is:

  • A. Fat soluble
  • B. Water soluble
  • C. Steroid
  • D. Protein
Answer: B
Explanation: Ascorbic acid.

CBSE Class 12 Chemistry · Biomolecules · Very Very Hard

13. Vitamin D deficiency causes:

  • A. Scurvy
  • B. Rickets
  • C. Night blindness
  • D. Beriberi
Answer: B
Explanation: Bone mineralization defect.

CBSE Class 12 Chemistry · Biomolecules · Very Very Hard

14. Enzymes are mostly:

  • A. Lipids
  • B. Proteins
  • C. Carbohydrates
  • D. Steroids
Answer: B
Explanation: Biological catalysts.

CBSE Class 12 Chemistry · Biomolecules · Very Very Hard

15. Enzyme specificity is due to:

  • A. Shape of active site
  • B. Color
  • C. Size only
  • D. pH only
Answer: A
Explanation: Lock-key/induced fit.

CBSE Class 12 Chemistry · Biomolecules · Very Very Hard

16. Mutarotation is shown by:

  • A. Glucose
  • B. Ethanol
  • C. Acetic acid
  • D. Benzene
Answer: A
Explanation: Open-chain equilibrium.

CBSE Class 12 Chemistry · Biomolecules · Very Very Hard

17. Glycosidic linkage joins:

  • A. Amino acids
  • B. Sugar units
  • C. Nucleotides
  • D. Fatty acids
Answer: B
Explanation: Carbohydrates.

CBSE Class 12 Chemistry · Biomolecules · Very Very Hard

18. DNA is usually:

  • A. Single helix
  • B. Double helix
  • C. Triple helix
  • D. Random
Answer: B
Explanation: Watson-Crick model.

CBSE Class 12 Chemistry · Biomolecules · Very Very Hard

19. Purine bases are:

  • A. C,T
  • B. A,G
  • C. A,C
  • D. G,T
Answer: B
Explanation: Double-ring bases.

CBSE Class 12 Chemistry · Biomolecules · Very Very Hard

20. Pyrimidine bases are:

  • A. A,G
  • B. C,T(U)
  • C. A,T
  • D. G,U
Answer: B
Explanation: Single-ring bases.

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Biomolecules Practice Tests

Biomolecules Frequently Asked Questions

How should I prepare Biomolecules for CBSE Class 12 Chemistry?

Revise the core concepts first, make a short list of important relationships or exceptions, and then solve chapter-focused MCQs while reviewing every error.

How can ChemNexa help with Biomolecules practice?

This page provides public sample questions and links to published ChemNexa tests so you can combine quick revision with structured practice.

What should I do after getting an MCQ wrong?

Identify whether the mistake came from a concept gap, calculation, unit, sign, wording or memory error, review that point, and then attempt a similar question again.

Continue with another chapter to build connected concepts and strengthen your overall Chemistry preparation.

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