Ch 10Biomolecules — Class 12 Chemistry, concept-first.

Every living organism grows, maintains itself, and reproduces — yet at bottom it is built from the same non-living atoms and molecules that make up the rest of the physical world.

Carbohydrates form one of the largest groups of naturally occurring organic compounds, and plants are their primary source. Everyday examples include cane sugar, glucose and starch.

Carbohydrates are sorted according to how they behave when hydrolysed — that is, by how many (if any) simpler sugar units they break down into on treatment with acid or water.

Within the monosaccharide group itself, a further split is made along two independent axes: how many carbon atoms the molecule has, and which carbonyl functional group it carries.

Glucose is an aldohexose, and its everyday name in commerce and physiology is dextrose. It occurs freely in nature — sweet fruits, honey and ripe grapes are all rich in it — and also occurs in the com…

Fructose is the second important hexose sugar of the chapter, and it is a ketohexose rather than an aldohexose.

When a disaccharide is hydrolysed — using dilute acid or an appropriate enzyme — it splits into two monosaccharide units, which may be identical or different.

Polysaccharides are built from a very large number of monosaccharide units, all linked together by glycosidic linkages.

Carbohydrates are essential to life in both the plant and animal kingdoms, forming a major portion of the food that living organisms consume.

Proteins are the single most abundant class of biomolecule in any living system. They are found in every tissue and every part of the body, and they underpin both the structure and the function of lif…

An amino acid is any molecule carrying two functional groups at once: a basic amino group () and an acidic carboxyl group ().

Beyond their individual side chains, amino acids can be grouped into three broad categories based on a simple count: how many amino groups versus how many carboxyl groups a given amino acid's structur…

Proteins are polymers of α-amino acids, and the individual amino acid units are joined to each other through a peptide bond (also called a peptide linkage).

A protein that exists in a biological system with its own unique three-dimensional structure and full biological activity is called a native protein.

A living organism survives because thousands of chemical reactions inside it run in a coordinated sequence — digesting food, absorbing the useful molecules, and finally releasing energy from them is o…

Because an enzyme acts as a catalyst and is not itself consumed in the reaction it speeds up, a reaction can be driven to completion using only a tiny quantity of the enzyme relative to the amount of…

Certain organic compounds are needed by the body only in very small quantities, yet their absence has a very specific consequence: a deficiency of one particular vitamin produces one particular diseas…

Vitamins are sorted into two broad groups purely on the basis of one physical property: whether they dissolve in water or in fat.

Every organism resembles its parents and ancestors in many ways — this transmission of inherited characters from one generation to the next is called heredity.

When a nucleic acid (DNA or RNA) is completely hydrolysed, it breaks down into three distinct types of simpler molecules:

The first step in assembling a nucleic acid is attaching a base to the sugar. A base is linked to the position of the pentose sugar through a β-N-glycosidic linkage (the base's nitrogen bonds to the a…

DNA is the chemical basis of heredity — it can be thought of as the cell's permanent reserve of genetic information.

Hormones are molecules that carry signals between cells, allowing one part of the body to instruct another.

- Carbohydrates: Polyhydroxy aldehydes or ketones. Classified as monosaccharides (e.g., glucose ), oligosaccharides (e.g., sucrose), and polysaccharides (e.g., starch, cellulose).

These are the final answers printed at the end of the NCERT chapter. The book gives answers for some intext questions only — every question below links to our complete worked solution.

Higher-order thinking / exemplar-style practice problems.

Sample papers and previous-year board questions for this subject.