biomolecule

Definition: A biomolecule is any organic molecule that is produced by a living organism, including large polymeric molecules such as proteins, polysaccharides, and nucleic acids as well as small molecules such as primary metabolites, secondary metabolites, and natural products.

As organic molecules, biomolecules consist primarily of carbon and hydrogen, nitrogen, and oxygen, and, to a smaller extent, phosphorus and sulfur. Other elements sometimes are incorporated but are much less common.

Biomolecules are necessary for the existence of all known forms of life. For example, humans possess skin and hair.

The main component of hair is keratin, an agglomeration of proteins which are themselves polymers built from amino acids. Amino acids are some of the most important building blocks used, in nature, to construct larger molecules.

Another type of building block is the nucleotides, each of which consists of three components: either a purine or pyrimidine base, a pentose sugar and a phosphate group. These nucleotides, mainly, form the nucleic acids.

Besides the polymeric biomolecules, numerous small organic molecules are absorbed or synthesised by living systems. Many biomolecules may be useful or important drugs.

Types of biological molecules (biomolecules)

 Proteins and aminoacids
 carbohydrates
 lipids
 nuclei acids

Most of the structures that make up animals, plants and microbes are made from three basic classes of molecule: amino acids, carbohydrates and lipids (often called fats).

As these molecules are vital for life, metabolism focuses on making these molecules, in the construction of cells and tissues, or breaking them down and using them as a source of energy, in the digestion and use of food.

Many important biochemicals can be joined together to make polymers such as DNA and proteins. These macromolecules are essential parts of all living organisms. Some of the most common biological polymers are listed in the table below.

See also

 inorganic elements
 molecules
 molecular pathology

• molecular lesions

 molecular medicine