Isoprenoid synthesis is the biological process through which organisms produce isoprenoids, a diverse class of organic compounds. These compounds are built from five-carbon units called isoprene, which are linked together in various ways to form larger molecules. Isoprenoids play crucial roles in many biological functions, including cell signaling, photosynthesis, and the formation of essential hormones. The synthesis of isoprenoids occurs via two main pathways: the mevalonate pathway and the methylerythritol phosphate (MEP) pathway. The mevalonate pathway is primarily found in animals and fungi, while the MEP pathway is present in plants and some bacteria. Both pathways ultimately lead to the production of isoprenoid precursors, which are then converted into various isoprenoid compounds.