Class 12 Chemistry Chapter 10: Biomolecules Notes for NEET & JEE (PDF + MCQs)

 

Class 12 Chemistry Chapter 10: Biomolecules | Complete Notes for NEET & JEE


Introduction

Biomolecules are the essential organic molecules that form the basis of life. They include carbohydrates, proteins, enzymes, nucleic acids, and vitamins. These molecules are responsible for structure, function, and regulation of living organisms.

This chapter is highly important for NEET, JEE Main, JEE Advanced, and Board Examinations due to its conceptual clarity and direct NCERT-based questions.


Why is This Chapter Important for NEET & JEE?

✅ Direct NCERT-based questions

✅ Easy scoring Organic Chemistry chapter

✅ Frequently asked in NEET and JEE

✅ Important for Biology + Chemistry integration

✅ Conceptual + factual questions


Download Study Material

📘 Complete Biomolecules Notes PDF

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What are Biomolecules?

Biomolecules are large and complex organic compounds that occur naturally in living organisms.

Major Types

  • Carbohydrates

  • Proteins

  • Lipids

  • Nucleic acids

  • Vitamins


Carbohydrates

Carbohydrates are polyhydroxy aldehydes or ketones.

Classification

Monosaccharides

Simple sugars.

Examples:

  • Glucose

  • Fructose


Disaccharides

Two monosaccharides joined.

Examples:

  • Sucrose

  • Lactose

  • Maltose


Polysaccharides

Long chains of sugars.

Examples:

  • Starch

  • Cellulose

  • Glycogen


Glucose

Glucose is the most important monosaccharide.

Properties

  • Aldohexose

  • Sweet taste

  • Water soluble


Fructose

Fructose is a ketohexose.

  • Found in fruits

  • Sweeter than glucose


Proteins

Proteins are polymers of amino acids linked by peptide bonds.

Amino Acids

Basic units of proteins.

Peptide Bond

Link between two amino acids.


Structure of Proteins

Primary Structure

Sequence of amino acids.

Secondary Structure

α-helix and β-pleated sheet.

Tertiary Structure

3D folding of protein.

Quaternary Structure

Association of multiple protein units.


Enzymes

Enzymes are biological catalysts.

Properties

  • Highly specific

  • Work at mild conditions

  • Highly efficient


Vitamins

Vitamins are organic compounds required in small amounts for normal metabolism.

Types

Water Soluble

  • Vitamin B complex

  • Vitamin C

Fat Soluble

  • Vitamin A

  • Vitamin D

  • Vitamin E

  • Vitamin K


Nucleic Acids

Nucleic acids are genetic materials.

Types

DNA

Deoxyribonucleic acid

RNA

Ribonucleic acid


Structure of DNA

DNA is a double helix structure composed of nucleotides.

Components of Nucleotide

  • Sugar

  • Phosphate group

  • Nitrogen base


Bases in DNA

  • Adenine (A)

  • Thymine (T)

  • Guanine (G)

  • Cytosine (C)


Complementary Base Pairing

  • A pairs with T

  • G pairs with C


RNA Types

  • mRNA

  • tRNA

  • rRNA


Lipids

Lipids are hydrophobic biomolecules.

Examples:

  • Fats

  • Oils

  • Waxes


Biological Importance

Carbohydrates

  • Energy source

  • Structural materials

Proteins

  • Growth and repair

  • Enzymes

Lipids

  • Energy storage

  • Cell membranes

Nucleic Acids

  • Genetic information


Daily Practice Problems (DPP)

📝 Download Biomolecules DPP

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Important Points for Quick Revision

✔ Glucose is an aldohexose.

✔ Fructose is a ketohexose.

✔ Proteins are made of amino acids.

✔ DNA is a double helix.

✔ Enzymes are biological catalysts.

✔ Vitamins are essential in small quantities.

✔ Starch is plant storage carbohydrate.

✔ Glycogen is animal storage carbohydrate.


NEET & JEE Quick Revision

✔ Monosaccharides = glucose, fructose

✔ Disaccharides = sucrose, lactose

✔ DNA bases = A, T, G, C

✔ RNA bases = A, U, G, C

✔ Protein linkage = peptide bond

✔ Enzymes = biological catalysts

✔ Vitamins deficiency causes diseases


Frequently Asked Questions (FAQs)

Q1. What are biomolecules?

Biomolecules are organic compounds essential for life processes.

Q2. What are the main types of biomolecules?

Carbohydrates, proteins, lipids, nucleic acids, and vitamins.

Q3. What is DNA?

DNA is the genetic material that stores hereditary information.

Q4. Why are enzymes important?

They act as biological catalysts and speed up reactions in living organisms.


Exercise Problems 

📝 Download Biomolecules Exercises


Conclusion

Biomolecules is a highly important and easy-scoring chapter in Class 12 Chemistry. It connects chemistry with biology and is frequently asked in NEET, JEE, and board examinations.

Understanding carbohydrates, proteins, enzymes, nucleic acids, and vitamins is essential for scoring well in competitive exams.

Stay connected with Chemistry Achievers Academy for free notes, DPPs, MCQs, PYQs, formula sheets, and chapter-wise study materials for NEET, JEE, CSIR NET, TN SET, and PG TRB examinations.



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