the formation of organic substances from simpler compounds, occurring within living organisms or outside them under the action of biocatalysts—enzymes. Biosynthesis is part of the metabolic process of plants, animals, and microorganisms. Compounds rich in energy serve as the immediate source of energy for biosynthesis, but ultimately (for all organisms except bacteria, which themselves accomplish biosynthesis), that source is the energy of solar radiation accumulated by green plants. Every unicellular organism, as well as every cell of a multicellular organism, synthesizes the substances that constitute it. The type of biosynthesis accomplished in the cell is determined by the hereditary information “coded” in its genetic apparatus. Biosynthesis accomplished outside organisms is used widely as a method (sometimes the only possible one) for commercially obtaining biologically important substances—vitamins, certain hormones, antibiotics, amino acids, proteins, and other compounds.