Final answer:
Prokaryotic gene regulation focuses on controlling the expression and the amount of proteins produced through the regulation of transcription into RNA. This control is mainly achieved through operons and regulons, which respond to environmental changes.
Step-by-step explanation:
The main objective of prokaryotic gene regulation is to control which proteins are expressed and in what quantities within the cell. In prokaryotes, such as bacteria, the processes of transcription and translation occur almost simultaneously since these organisms lack a cell nucleus and their DNA is located in the cytoplasm. Consequently, when a protein is no longer required, transcription stops to prevent its further production. The genetic structure that commonly embodies this control is the operon, like the lac operon in Escherichia coli (E. coli), which can rapidly respond to environmental changes due to the close linkage of transcription and translation.
Prokaryotic organisms can efficiently manage gene expression at the transcriptional level, making the most of polycistronic mRNAs that can encode multiple proteins. Additionally, prokaryotic cells have global gene regulation systems known as regulons that enable a coordinated response to environmental signals, allowing multiple operons to be regulated synchronously.