Final answer:
A cluster of genes controlled by a single promoter in prokaryotes is known as an operon, which includes a promoter, operator, and the genes themselves for regulating gene transcription.Option 4 is the correct answer.
Step-by-step explanation:
A cluster of genes whose transcription is controlled by a single promoter and associated regulatory sequences is called an operon. In prokaryotes, structural genes of related function are often organized into operons which include a promoter, an operator, and the genes themselves. The operator is a specific DNA sequence where regulatory proteins bind, influencing the transcription of the genes controlled by the operon. For example, the lac operon in bacteria is responsible for the metabolism of lactose and is regulated by a promoter and operator that control the transcription of the genes involved in this pathway.
An operon in prokaryotes is a cluster of genes regulated as a single unit. Comprising a promoter, operator, and structural genes, the operon controls transcription. The operator, a distinct DNA sequence, interacts with regulatory proteins, modulating the transcription of associated genes. The lac operon, managing lactose metabolism in bacteria, exemplifies this regulatory mechanism.