homeostasis
In prokaryotes, a combination of activators and repressors determines whether a gene is transcribed. As you know, prokaryotic organisms are fairly simple organisms with much less DNA. Prokaryotic genes are arranged in operons , a region of DNA with a promoter, an operator , and one or more genes that encode proteins needed to perform a certain task. To maintain homeostasis and survive , the organism must quickly adapt changing environmental conditions. The regulation of transcription plays a key role in this process.