Next: Principles Related to Practical Chemistry
OpenCarbohydrates, proteins, enzymes, vitamins, nucleic acids and hormones.
Carbohydrates, proteins, enzymes, vitamins, nucleic acids and hormones. Almost entirely NCERT-based.
Chemistry · Class 12 · Biomolecules
Biomolecules for JEE
Everything you need for this topic on one page: the ideas, the formulas, the traps, and free lectures that explain it well.
Last updated: 26 October 2026
Key ideas
Biomolecules: what you must understand
- Glucose is an aldohexose; fructose a ketohexose
- Sucrose is non-reducing; maltose and lactose are reducing
- Peptide bonds link amino acids
- DNA has deoxyribose and thymine; RNA has ribose and uracil
Formula sheet
Must-know formulas for Biomolecules
- Sucrose → glucose + fructose (invert sugar)
- Starch = amylose + amylopectin
- Vitamins A, D, E, K are fat-soluble; B and C water-soluble
- Essential amino acids must come from the diet
Print
One-page formula sheet
Printable Biomolecules formula sheet: formulas, key ideas and traps on one page. Save it as a PDF for offline revision.
Avoid
Common mistakes students make
- Calling sucrose reducing
- Mixing vitamin deficiency diseases
- Confusing primary and secondary protein structure
For the exam
How this topic is asked in JEE
Appears in almost every JEE Main shift. Easy marks from NCERT reading. Read the chapter line by line.
NCERT map
Where Biomolecules is in NCERT
Chapter names follow the current rationalised NCERT textbooks. Read these sections before solving PYQs.
| Class | Book | Chapter | Sections JEE asks from |
|---|---|---|---|
| Class 12 | Chemistry Part II | Biomolecules | Carbohydrates; Monosaccharides; Disaccharides; Polysaccharides; Proteins; Enzymes; Vitamins; Nucleic Acids |
JEE Advanced level
A JEE Advanced-level example on Biomolecules
Question. A disaccharide X with molecular formula C₁₂H₂₂O₁₁ is a non-reducing sugar. On acid hydrolysis, X gives equimolar amounts of an aldohexose (A) and a ketohexose (B). Monosaccharide A shows mutarotation and gives a positive Tollens test. If 34.2 g of X undergoes complete hydrolysis, calculate (i) the total mass of monosaccharides formed, and (ii) the moles of silver deposited when all of monosaccharide A reacts with excess Tollens reagent.
Show solution
- X is a non-reducing disaccharide giving glucose (aldohexose A) and fructose (ketohexose B) on hydrolysis, so X is sucrose
- Molar mass of sucrose = 342 g/mol, so moles of X = 34.2/342 = 0.1 mol
- Hydrolysis reaction: C₁₂H₂₂O₁₁ + H₂O → C₆H₁₂O₆ + C₆H₁₂O₆, giving 0.1 mol each of glucose and fructose
- Total mass of monosaccharides = (0.1 × 180) + (0.1 × 180) = 36 g
- In Tollens test, each glucose molecule (with one aldehyde group) reduces 2 Ag⁺ ions to Ag metal
- Moles of Ag deposited = 2 × 0.1 = 0.2 mol
Answer: (i) Total mass of monosaccharides = 36 g; (ii) Moles of Ag deposited = 0.2 mol
This example was solved twice independently and both solutions agree.
Free lectures
Best free lectures for Biomolecules
Full-chapter free lectures picked from YouTube search results by views, from established JEE channels (mostly in Hinglish). Use the subtopic list to jump straight to the part you need (timestamps come from each video's own chapter list). Watch one, then solve PYQs the same day.
- BIOMOLECULES in 1 Shot: All Concepts & PYQs Covered || JEE Main & Advanced — JEE Wallah, 3:14:14
Jump to a subtopic (13)
- 00:00 Introduction
- 04:57 Biomolecules: Carbohydrates
- 18:38 Cyclic structure of glucose
- 28:35 Structure of fructose
- 49:31 Disaccharides and Polysaccharides
- 1:09:18 Reducing & Non-reducing Sugars
- 1:20:45 Chemical reactions of Glucose
- 1:32:14 Amino acids
- 2:12:45 Proteins
- 2:34:11 Denaturation of proteins
- 2:39:44 Nucleic acids
- 3:08:19 Vitamins
- 3:12:03 Thank You Bacchon!
- Biomolecules FULL CHAPTER | Class 12th Organic Chemistry | Lakshya JEE — Lakshya JEE, 2:45:50
Practise
Where to practise for free
- 13 JEE Main 2026 PYQs on Biomolecules, with solutions.
- Read the chapter in NCERT textbooks (official, free), then solve its NCERT Exemplar (official, free) questions.
- Chapter-wise past questions: JEE Main and Advanced PYQs and question bank.
- Timed practice tests: NTA Abhyas practice tests (official, free) and our free mock tests.
- See it move: interactive simulation.
FAQs
Frequently asked questions
Is Biomolecules important for JEE Main 2027?
Appears in almost every JEE Main shift. It is part of the official 'Biomolecules' unit in the JEE Main 2027 syllabus.
What are the most important formulas in Biomolecules?
Sucrose → glucose + fructose (invert sugar); Starch = amylose + amylopectin; Vitamins A, D, E, K are fat-soluble; B and C water-soluble.
How should I study Biomolecules for JEE?
Understand the key ideas from NCERT or one full lecture, learn the formula sheet, then solve 25–30 past JEE questions on the topic. Easy marks from NCERT reading. Read the chapter line by line.