Overview of Biomolecules

Optically active polyhydroxy aldehydes or ketones or the compounds which yield such units on hydrolysis are called carbohydrates.

Carbohydrates which cannot be hydrolysed to simpler units are called monosaccharides.

Carbohydrates which yield two to ten monosaccharide units on hydrolysis are called oligosaccharides.

Carbohydrates which yield a large number of monosaccharide units on hydrolysis are called polysaccharides.

The linkage formed between two monosaccharide units through an oxygen atom is called glycosidic linkage.

The cyclic hemiacetal forms of a sugar differing in configuration at the anomeric carbon are called anomers.

The sequence of amino acids in a polypeptide chain is called primary structure of protein.

Biological catalysts which increase the rate of biochemical reactions are called enzymes.

Organic compounds required in small amounts in the diet to perform specific biological functions are called vitamins.

The unit formed when a nucleoside is linked to phosphoric acid is called nucleotide.

Long chains of nucleotides joined by phosphodiester linkage are called nucleic acids.

Chemical messengers secreted by endocrine glands and transported through blood are called hormones.

• Proteins are classified into two types based on their molecular shape: fibrous proteins and globular proteins.
• Fibrous proteins consist of parallel polypeptide chains held together by hydrogen and disulphide bonds; they are generally insoluble in water and provide structural support.
• Globular proteins are formed when polypeptide chains coil into a spherical shape; they are usually soluble in water and perform functional roles such as enzymatic and hormonal activities.
• Protein structure is organized into four hierarchical levels: primary, secondary, tertiary, and quaternary, each representing increasing complexity of folding and organization.
• The stability of higher-level protein structures (secondary, tertiary, and quaternary) is maintained by hydrogen bonds, disulphide linkages, van der Waals forces, and electrostatic interactions.