Biosyntesen

Biosynthesis, or biosyntesen in Danish and Norwegian, is the cellular process by which living organisms build complex organic molecules from simpler precursors. It is the opposite of catabolic pathways and provides the macromolecules needed for growth, repair, and storage. Most biosynthetic processes are anabolic, requiring energy and reducing power, typically in the form of ATP and NADPH. Enzymes catalyze each step and regulate flux through pathways through feedback inhibition, allosteric control, and gene expression.

Key products include proteins from amino acids, nucleotides for genetic material, lipids for membranes, and carbohydrates for energy storage and structure. In plants and photosynthetic organisms, biosynthesis often uses carbon fixed from CO2 and energy from light through photosynthesis. In animals and microorganisms, carbon sources come from diet or environment, with central pathways such as glycolysis, the citric acid cycle, and the pentose phosphate pathway supplying precursors.

Biosynthesis is organized into primary metabolism, which produces essential biomolecules, and secondary metabolism, which produces specialized compounds such as vitamins, pigments, alkaloids, and antibiotics. Pathways can be linear, branched, or cyclical, and are tightly regulated to match cellular needs and environmental conditions. Industrial and medical relevance includes the microbial production of amino acids, vitamins, plastics precursors, and pharmaceuticals, often enhanced by metabolic engineering and synthetic biology. Understanding biosynthesis illuminates how organisms synthesize the molecular components of life and adapt to changing environments.