biomolecule

A biomolecule is any organic molecule produced by living organisms that participates in biological processes. The major classes are carbohydrates, lipids, proteins, and nucleic acids, which together fulfill structural, catalytic, regulatory, and informational roles. In addition, many small molecules such as vitamins, hormones, and metabolic intermediates function as biomolecules.

Carbohydrates provide energy and structural support. Simple sugars store readily available energy, while polysaccharides such as starch, glycogen, and cellulose serve storage and structural roles in plants and animals. Lipids form membranes, store energy, and act as signaling molecules; major types include triglycerides, phospholipids, and cholesterol-containing sterols. Proteins perform a wide range of functions, including catalysis as enzymes, structural support, transport, and immune defense, and are built from amino acids linked by peptide bonds. Nucleic acids store and transmit genetic information (DNA) and participate in protein synthesis and regulation (RNA).

Biomolecules are organized into monomers and polymers. Monomers include monosaccharides, amino acids, nucleotides, and fatty acids; polymers include polysaccharides, proteins, and nucleic acids. Lipids are often complex assemblies rather than true polymers but can form membrane structures such as phospholipid bilayers.

Common chemical features include carbon-based backbones, hydrogen, oxygen, and nitrogen, with phosphorus and sulfur in specific biomolecules. Many biomolecules are chiral and engage in non-covalent interactions such as hydrogen bonding, ionic interactions, and hydrophobic effects, which shape their structure and function.

Examples illustrating their roles include ATP as the energy currency, enzymes as catalysts, DNA as genetic material, RNA in transcription and translation, and phospholipids forming cell membranes. Biomolecules arise through cellular biosynthesis and underpin metabolism, growth, and reproduction.