NCERT MCQ Solutions for Class 12 Chemistry Chapter 10 Biomolecules

Carbohydrates is optically active polyhydroxy aldehydes or ketones or compounds which produce such units on hydrolysis.

Monosaccharides are carbohydrates that cannot be hydrolysed further to give simpler units of polyhydroxy aldehyde or ketone.

Glucose is an aldohexose, meaning it has six carbon atoms and an aldehyde group.

Hydrolysis of sucrose yields one molecule of glucose and one molecule of fructose.

Polysaccharides are carbohydrates yielding a large number of monosaccharide units upon hydrolysis (e.g., starch, cellulose).

In sucrose, the reducing groups (aldehydic C₁ of glucose and ketonic C₂ of fructose) are involved in the glycosidic bond, making it a non-reducing sugar. Maltose and lactose are reducing sugars.

The oxide linkage formed between two monosaccharide units (by loss of water) as a glycosidic linkage.

Amylose is a long, unbranched chain of α-D-glucose units held by C₁–C₄ glycosidic linkages and notes it’s the water-soluble component of starch.

Cellulose is a straight-chain polysaccharide composed only of β-D-glucose units joined by C₁–C₄ glycosidic linkages.

All proteins are polymers of α-amino acids, linked by peptide bonds.

Amino acids are connected by peptide bonds, which are amide linkages formed between the –COOH group of one and the –NH₂ group of another.

Essential amino acids are those that cannot be synthesized in the body and must be supplied through the diet.

The formation of a dipolar ion (zwitter ion) in aqueous solution where the carboxyl group loses a proton and the amino group accepts it.

The primary structure is the specific sequence in which amino acids are linked in a polypeptide chain.

α-helix and β-pleated sheet is the two main types of secondary structure, referring to the shape the polypeptide chain adopts due to hydrogen bonding.

Denaturation is the loss of biological activity when physical or chemical changes disrupt hydrogen bonds, unfolding the globules and uncoiling the helixes (destroying secondary and tertiary structures). The primary structure remains intact.

Enzymes is biocatalysts, almost all of which are globular proteins, that help specific reactions occur under mild conditions in the body.

Vitamins are classified based on solubility. A, D, E and K as vitamins soluble in fat and oils.

Nucleic acids are described as long-chain polymers of nucleotides, hence they are also called polynucleotides.

The double helix structure of DNA where hydrogen bonds form between specific base pairs: Adenine (A) pairs with Thymine (T), and Guanine (G) pairs with Cytosine (C).