Endosynthesis is a term that refers to the internal synthesis of complex organic compounds within an organism, often involving the use of simpler molecules and energy sources. This process is typically associated with metabolic pathways that allow organisms to build essential biomolecules, such as proteins, nucleic acids, and carbohydrates, from basic precursors. It plays a crucial role in growth, energy storage, and cellular function. Endosynthesis can be contrasted with exosynthesis, where substances are synthesized outside of a cell or organism.