Primary metabolites are directly involved in normal growth, development and reproduction, and are essential for these processes. Examples include carbohydrates, proteins, lipids and nucleic acids. Secondary metabolites are not directly involved in these processes but have important ecological functions, such as antibiotics. Secondary metabolites include mycotoxins, antibiotics, alkaloids, amino acids, steroids and vitamins. They are produced late in the growth cycle and provide benefits to the producing organism or disadvantages to surrounding organisms.