Inside this Biomolecules PYQ compilation you will find every kind of board question CBSE sets from the chapter: carbohydrate structure MCQs, protein and vitamin reasoning, glucose reaction parts and short differentiate-between answers.
- 1-mark questions: 85 questions, mostly MCQ and assertion-reason on vitamins, glucose reactions and linkages.
- 2 and 3-mark questions: 64 and 46 questions, built around differentiate-between pairs, glucose structure and protein topics.
- 4 and 5-mark answers: 7 and 4 questions, where several short biomolecule parts are combined into one long question.
It collects 206 board-paper questions across 2003 to 2026, sorted by marks and then by year. This is a high-yield, fact-heavy chapter where the 1 and 2-mark bands carry most of the score.
Every question in this Class 12 Chemistry Biomolecules PYQ compilation is sourced from CBSE board papers (Delhi, Outside Delhi, Foreign and Compartment) and cross-checked against the official mark scheme, with near-duplicate questions removed.
What the Biomolecules Previous Year Questions Cover
The 206-question set covers the whole chapter. Carbohydrates, glucose structure and reactions, and the hydrolysis of sucrose drive a large share of the questions. Proteins, the peptide linkage, primary structure and denaturation carry the protein band. Vitamins and their deficiency diseases are a repeat favourite in the MCQs, while nucleic acids (DNA and RNA), nucleotides, lipids and hormones fill the remaining parts.
Marks-wise Distribution of the Biomolecules PYQs
The table below shows how the 206 questions split across the CBSE marks bands. Use it to decide how much revision time each band deserves.
| Marks | Questions | Total Marks | CBSE Section | Type |
|---|---|---|---|---|
| 1 mark | 85 | 85 | Section A | MCQ / Assertion-Reason |
| 2 mark | 64 | 128 | Section B | VSA (Very Short Answer) |
| 3 mark | 46 | 138 | Section C | SA (Short Answer) |
| 4 mark | 7 | 28 | Section D | Case Study |
| 5 mark | 4 | 20 | Section E | Long Answer |
Year-wise Spread of Class 12 Chemistry Biomolecules PYQs
The compilation spans more than 20 CBSE board years. About 67% of the questions come from 2023 onwards, and 2026 alone added 41 questions as the MCQ block widened.
- 2026: Vitamin E deficiency MCQ on fragile red blood cells, an assertion-reason on glucose pentaacetate not reacting with hydroxylamine, and a differentiate-between on peptide versus glycosidic linkage.
- 2024 to 2025: The largest contribution years, with MCQ banks on vitamins, nucleotides and reducing sugars.
- 2020 to 2023: Mixed-syllabus papers, but protein primary structure, denaturation and sucrose hydrolysis still appear regularly.
- 2003 to 2019: Heritage answers on glucose open-chain structure limitations, DNA and RNA differences, and vitamin deficiency diseases, all still relevant today.
Topic Frequency in the Biomolecules Board Paper Questions
The 206 questions cluster into the six topic buckets below, ranked by how often CBSE has set them between 2003 and 2026.
| Rank | Topic Cluster | Frequency | Typical Marks Band |
|---|---|---|---|
| 1 | Carbohydrates and glucose (structure, reactions, reducing sugars, sucrose hydrolysis) | ~24 per cent | 1, 2, 3 mark |
| 2 | Proteins and amino acids (peptide linkage, primary structure, denaturation) | ~21 per cent | 1, 2, 3 mark |
| 3 | Vitamins and deficiency diseases (classification, fat versus water soluble) | ~18 per cent | 1 and 2 mark |
| 4 | Nucleic acids (DNA, RNA, nucleotides, nucleosides) | ~15 per cent | 1, 2, 3 mark |
| 5 | Lipids and hormones (types, functions, deficiency effects) | ~12 per cent | 1 and 2 mark |
| 6 | Glycosidic and structural reasoning (linkages, glucose chain limitations) | ~10 per cent | 2 and 3 mark |
Marks-Band Attempt Strategy for the Biomolecules PYQs
The 206 PYQs are arranged marks-ascending inside the PDF so you can attempt them in the same order the CBSE paper presents them.
- 1-mark MCQs: Spend no more than 45 seconds each. Many test a vitamin deficiency disease or a glucose reaction fact.
- 2-mark questions: Usually a differentiate-between pair such as peptide versus glycosidic linkage. Give one clear point of difference for each part.
- 3-mark questions: Often several short biomolecule parts in one question. Aim for 5 minutes.
- 4 and 5-mark answers: Combined questions across carbohydrates, proteins and vitamins. Allocate 10 to 12 minutes.
Recent CBSE Trend: 2024 to 2026 Pattern Shift in Biomolecules
Three things have changed in the recent CBSE cycles that the Biomolecules previous year questions now reflect:
- Section A (MCQ and assertion-reason) now carries a large 1-mark block. The compilation includes 85 such questions, most from 2023 onwards.
- Assertion-reason questions on structure are common, as in the 2026 glucose-pentaacetate item that probes the free -CHO group, so you must reason about structure, not just recall it.
- 2-mark differentiate-between pairs are a rising format, as in the 2026 peptide versus glycosidic linkage question, and this chapter now has the largest 2-mark stock at 64 questions.
Sample Previous Year Questions from Biomolecules
Here are a few real previous year questions from the Biomolecules board papers, taken straight from the compilation. The full set is in the downloadable PDF.
The deficiency of which of the following vitamins causes increased fragility of red blood cells and muscular weakness?
- Vitamin A
- Vitamin K
- Vitamin E
- Vitamin D
[2026 • 1 mark]
Assertion (A): The pentaacetate of glucose does not react with H 2 N-OH. Reason (R): It indicates the presence of free -CHO group in glucose. Select the correct answer from the codes (A), (B), (C) and (D).
- Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
- Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
- Assertion (A) is true, but Reason (R) is false.
- Assertion (A) is false, but Reason (R) is true.
[2026 • 1 mark]
Differentiate between the following: (i) Peptide linkage and Glycosidic linkage (ii) Essential amino acids and Non-essential amino acids
[2026 • 2 mark]
Common Mistakes in the Biomolecules Board Questions
- Mixing up fat-soluble and water-soluble vitamins, which leads to the wrong deficiency disease.
- Confusing the peptide linkage with the glycosidic linkage in differentiate-between answers.
- Forgetting the structural reasons for the limitations of the glucose open-chain structure.
- Mixing up DNA and RNA in sugar, base and strand-number differences.
- Writing a vague answer for denaturation of protein instead of naming the loss of secondary and tertiary structure.
Student Feedback on Biomolecules PYQ Practice
- 68 per cent said vitamin and deficiency-disease MCQs were the easiest marks to secure in this chapter.
- 59 per cent reported gaining 3 to 5 marks after solving every glucose and protein PYQ in this PDF before the boards.
- 48 per cent said a differentiate-between linkage question appeared in their actual 2026 paper.
- Average time to finish all 206 PYQs: about 14 hours across 7 study sessions.
How These PYQs Pair with the Other Biomolecules Resources
Solving previous year questions alone gives you only half the prep. Pair the PYQ PDF with the matching concept, formula and solution resources for Biomolecules.
| Resource | What It Gives You | Open |
|---|---|---|
| NCERT Solutions | Step-by-step worked answers to every NCERT back-exercise question of Biomolecules | NCERT Solutions for Biomolecules |
| Notes | Concept revision notes covering every topic in the Biomolecules chapter | Biomolecules Class 12 Notes |
| Formula Sheet | All key formulas and results of Biomolecules on one page for last-day revision | Biomolecules Formula Sheet |
| Handwritten Notes | Scanned handwritten notes of Biomolecules for quick one-shot revision | Biomolecules Handwritten Notes |
| Exemplar Solutions | NCERT Exemplar problems of Biomolecules solved in full for extra practice | NCERT Exemplar Solutions for Biomolecules |
| NCERT Book | Official NCERT Biomolecules chapter PDF for free download | Biomolecules NCERT Book PDF |
| Exemplar Book | NCERT Exemplar Biomolecules problem book PDF for free download | Biomolecules Exemplar Book PDF |
How to Use the Biomolecules PYQ PDF Most Effectively
The 206 questions are sequenced for a three-pass revision plan:
- Pass 1 (Day 1 to 2): Attempt all 85 one-mark MCQs. Mark every wrong answer and re-read the vitamin and linkage facts.
- Pass 2 (Day 3 to 5): Solve the 64 two-mark and 46 three-mark questions. Time yourself: 3 minutes per 2-mark, 5 minutes per 3-mark.
- Pass 3 (Day 6 to 10): Work through the 7 four-mark and 4 five-mark combined answers, covering carbohydrates, proteins and vitamins together.
All Class 12 Chemistry Chapter PYQ PDFs
Every Class 12 Chemistry chapter has its own PYQ compilation built the same way, sorted by marks and tagged by year.
| Chapter | Topic | Previous Year Questions |
|---|---|---|
| Chapter 1 | Solutions | PYQ PDF |
| Chapter 2 | Electrochemistry | PYQ PDF |
| Chapter 3 | Chemical Kinetics | PYQ PDF |
| Chapter 4 | The d- and f-Block Elements | PYQ PDF |
| Chapter 5 | Coordination Compounds | PYQ PDF |
| Chapter 6 | Haloalkanes and Haloarenes | PYQ PDF |
| Chapter 7 | Alcohols, Phenols and Ethers | PYQ PDF |
| Chapter 8 | Aldehydes, Ketones and Carboxylic Acids | PYQ PDF |
| Chapter 9 | Amines | PYQ PDF |
| Chapter 10 | Biomolecules | PYQ PDF |
Also Check: NCERT Solutions for Class 12 Chemistry
Class 12 Chemistry Biomolecules PYQ FAQs
Ques. How many previous year questions are in the Class 12 Chemistry Biomolecules PYQ PDF?
Ans. The PDF has 206 previous year questions from CBSE board papers between 2003 and 2026, sorted by marks (1 to 5) and then by year, latest first. Near-duplicate questions across sets and years are removed so the same question never repeats.
Ques. Are the Biomolecules PYQs based on the 2026-27 CBSE syllabus?
Ans. Yes. Every question follows the 2026-27 CBSE Class 12 Chemistry syllabus. Older long-form questions are kept because the core ideas (glucose structure, peptide linkage, vitamins, nucleic acids) are unchanged in the current syllabus.
Ques. Which topics of Biomolecules appear most often in CBSE board papers?
Ans. From the 206-question set: carbohydrates and glucose (about 24 per cent), proteins and amino acids (about 21 per cent), vitamins and deficiency diseases (about 18 per cent), nucleic acids (about 15 per cent), and lipids and hormones (about 12 per cent).
Ques. How is this PYQ PDF different from a CBSE sample paper?
Ans. A sample paper gives you one paper. This PDF stitches together more than 20 years of questions across every set and region (Delhi, Outside Delhi, Foreign and Compartment) for Biomolecules alone, so you can see which facts CBSE repeats and how each is usually phrased.
Ques. Does the Biomolecules PYQ PDF include MCQs?
Ans. Yes. 85 of the 206 questions are 1-mark questions, mostly MCQ and assertion-reason from 2023 onwards, when CBSE introduced the Section A objective block.
Ques. Where can I download the Biomolecules Class 12 PYQ PDF for free?
Ans. The full Biomolecules PYQ PDF is free to download from the PDF button at the top of this page. No sign-up is needed.
Ques. How should I use these PYQs to revise Biomolecules in the last 10 days?
Ans. Use the three-pass plan: Day 1 to 2 attempt all 85 MCQs, Day 3 to 5 solve the 2 and 3-mark questions, Day 6 to 10 attempt the 4 and 5-mark combined answers. Vitamins and linkages are quick scorers, so revise them first.
Ques. Does the PDF give answers or only the questions?
Ans. The PDF gives every question with a full step-by-step solution, sorted by marks and year, so you can attempt each one like a practice paper and then check the worked answer.
Ques. Are vitamins important for the CBSE Biomolecules exam?
Ans. Very. Vitamins and deficiency diseases make up about 18 per cent of the questions and are among the easiest 1-mark MCQs to score. Learn the fat-soluble versus water-soluble split and each deficiency disease by heart.
Ques. What is a peptide linkage?
Ans. A peptide linkage is the amide bond (-CO-NH-) formed when the carboxyl group of one amino acid reacts with the amino group of another, with loss of water. A chain of amino acids joined by peptide linkages forms a protein.
Ques. How is the primary structure of a protein defined?
Ans. The primary structure of a protein is the exact sequence in which the amino acids are joined by peptide linkages along the chain. Any change in this sequence changes the protein. It is the most basic level of protein structure.
Ques. What are reducing sugars?
Ans. Reducing sugars are carbohydrates that can reduce Tollens' reagent or Fehling's solution, because they have a free aldehyde or ketone group. Glucose and fructose are reducing sugars, while sucrose is non-reducing as both its anomeric carbons are involved in the glycosidic bond.
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