Biomolecules, or biological molecules are substances produced by living organisms. Biomolecules have a wide range of sizes and structures and perform a vast array of functions. The four major types of biomolecules are carbohydrates, lipids, nucleic acids and proteins.

Nucleic acids, namely DNA and RNA, have the unique function of storing an organism's genetic code-the sequence of nucleotides that determines the amino acid sequence of proteins, which are of critical importance to life on Earth.

There are 20 different aminoacids that can occur within a protein; the order in which they occur plays a fundamental role in determining protein structure and function. Proteins themselves are major structural elements of cells. They also serve as transporters, moving nutrients and other molecules in and out of cells, and as enzymes and catalysts for the vast majority of chemical reactions that take place in living organisms. Proteins also form antibodies and hormones, and they influence gene activity.

Likewise, carbohydrates, which are made primarily of molecules containing atoms of carbon, hydrogen and oxygen, are essential energy sources and structural components of all life, and they are among the most abundant biomolecules on Earth. They are built from four types of sugar units-monosaccharides, disaccharides, oligosaccharides and polysaccharides.

Lipids, another key biomolecule of living organisms can serve as a source of stored energy or act as chemical messengers. They also form membranes, which separate cells from their environments and compartmentalize the cell interior, giving rise to  organelles, such as the nucleus and the mitochondrion in higher (more complex) organisms.

GALEGO

As biomoléculas, ou moléculas biolóxicas, son substancias producidas polos organismos vivos. As biomoléculas teñen un gran rango de tamaños i estructuras e levan a cabo moitas funcións. Os catro tippos principais de biomoléculas son os carbohidratos, lípidos, ácidos nucleicos e proteínas.

Os ácidos nucleicos, DNA e RNA, teñen a función única de conter o código xenético do organismo- a secuencia de nucleótidos que determinan a secuencia de aminoácidos das proteínas, que son de importancia crítica para a vida na Terra.

Hai 20 aminoácidos diferentes que poden aparecer nunha proteína; a orde na que aparecen xoga un papel fundamental na estrutura e función da proteína. As proteínas son os principais elementos estruturais das células. Tamén serven como transportadores, movendo nutrientes e outras moléculas dentro e fóra das células, e como encimas e catalizadores para a meirande parte das reaccións nos organismos vivos. As proteínas tamén conforman os anticorpos e as hormonas, e influencian a actividade dos xens.

Asemade, os carbohidratos, feitos principalmente de moléculas que conteñen átomos de carbono, hidróxeno e osíxeno, son fontes de enerxía esenciais e compoñentes estruturais de toda a vida, e son as biomoléculas máis abundantes na Terra. Fórmanse a partir de catro tipos de unidades de azucre-monosacáridos, disacáridos, oligosacáridos e polisacáridos.

Os lípidos, outra biomolécula chave dos organismos vivos poden server coma fonte de enerxía cumulada ou actuar como mensaxeiros químicos. Tamén conforman as membranas, que separan as células dos seus medios e compartimentalizan o interior celular, dando lugar a orgánulos, coma o núcleo ou a mitocondria.