Some of these are needed as cofactors in essential enzymes, others are used in other important compounds. For example, phosphorus is needed for cell walls, DNA and in the energy carrier ATP and so on. There are additional elements not listed here which are considered minor but most of them nevertheless needed. Amino acids Purines and pyrimidines A number of bacteria and yeasts are not able to synthesize these growth factors themselves and have to rely on others to provide them. For example, lactic acid bacteria have only limited synthetic capabilities and practically require all of these growth factors.
Vitamins regulate reactions that occur in metabolism.
They work together with enzymes in the building or break-down of other compounds. Amino acids are the building blocks of proteins. All living cells require some sort of energy source. Plants get their energy from light sources through photosynthesis and store this energy in the form of chemical compounds. These compounds, for example starches and sugars, are in turn used as energy source by other organisms.