A series of enzymatic reactions in which more complex molecules are built from simpler ones. Biosynthetic pathways are energy requiring, this energy usually being supplied either as phosphate bond energy by ATP or as reducing power by NADPH. Three stages of biosynthesis can be recognized. The first stage is concerned with the manufacture of simple organic molecules from inorganic molecules like carbon dioxide and water. These few simple molecules are then converted in the second stage to building blocks for the many biological macromolecules. Finally macromolecules are synthesized from their constituent subunits. The major biosynthetic pathways in plants are shown in the diagram.  The main biosynthetic pathways in plants. |
