What term refers to a cluster of genes controlled by a single promoter in prokaryotic cells?

The term that refers to a cluster of genes controlled by a single promoter in prokaryotic cells is "operons." Operons are fundamental units of gene regulation in bacteria, consisting of a series of related genes that are transcribed together from one promoter. This coordinated expression allows the cell to efficiently regulate the production of proteins that are often involved in a common metabolic pathway or function.

In an operon, the genes are adjacent to each other on the chromosome, and the expression of these genes can be turned on or off in response to environmental conditions, such as the presence or absence of certain substrates or signals. This is essential for prokaryotic cells as it enables them to adapt quickly to changes in their environment by managing resource allocation effectively.

The other terms relate to different aspects of genetics and gene regulation. Enhancers are regulatory sequences that can increase the probability of transcription from a particular gene but are not limited to controlling clusters of genes. Promoters are regions of DNA where transcription of a gene begins, but they do not refer to the cluster of genes themselves. Transposons, or "jumping genes," are segments of DNA that can move around within the genome but do not function as clusters controlled by a single promoter.