Procaryotes have several strategies to ordinate regulation of transcription of genes in a given metabolic pathway with changing nutrient levels or biosynthetic ne tryptophan levels, Gln levels or ability to use lactose over glucose). For biosynthesis a two component system has evolved to transcription of Gln synthetase in order to make Gln from ammonia. List regulate in order the steps that lead to activation of transcription of Gln synthetase.