Biomolecule
From Halbeeg, the open encyclopedia · Af-Soomaali
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A biomolecule is a molecule produced or used by a living organism to carry out the functions of life. They are found in bacteria, plants, animals, and humans. Most are based on carbon, combined with hydrogen, oxygen, and nitrogen; some also contain phosphorus and sulfur.
Large biomolecules are called macromolecules. Usually they are chains made of small repeating units (monomers) linked together. For example, proteins are built from amino acids, carbohydrates are built from simple sugars, and nucleic acids are built from nucleotides.
Major Classes
The four main classes are: proteins, nucleic acids (DNA and RNA), carbohydrates, and lipids. Proteins perform various functions: structure, transport, and catalysis (as enzymes). Nucleic acids store and transmit genetic information. Carbohydrates provide energy and structure (such as cellulose in plants). Lipids form cell membranes and store energy.
Small Molecules
Beyond the macromolecules, organisms contain small but essential molecules: water, ions, vitamins, hormones, and energy-transfer molecules such as ATP. These small molecules participate in the chemical reactions of the organism (metabolism), which involves the breakdown and synthesis of substances.
Structure and Function
The function of a biomolecule is closely tied to its three-dimensional structure. When a protein loses its structure—due to heat or acidic conditions, for example—it typically ceases to function; this is called denaturation. Similarly, the bonding between two strands of DNA depends on the pairing of nucleotides, which makes it possible to copy genetic information.