Biosynthesis is a phenomenon wherein chemical compounds are produced from simpler reagents. Biosynthesis, unlike chemosynthesis, takes place within living organisms and is generally catalyzed by enzymes. The process is a vital part of metabolism. The prerequisites for biosynthesis are: Precursor substances Energy (usually in the form of ATP). Often required components include: Catalysts, usually enzymes Reduction equivalents (in the form of NADH, NADPH, and others). Important and commonly-kn… (More on Biosynthesis)