Which term refers to a group of genes that are regulated together, particularly in prokaryotic organisms?

The term that refers to a group of genes that are regulated together in prokaryotic organisms is known as an operon. An operon is a functional unit of genomic DNA that contains a cluster of genes under the control of a single promoter. These genes are typically involved in a related function and are transcribed together into a single mRNA molecule. This organization allows for coordinated expression, which is particularly advantageous for prokaryotic cells responding to environmental changes.

For example, in the lactose operon found in E. coli, genes necessary for the metabolism of lactose are grouped together and expressed as needed, allowing the bacterium to efficiently utilize resources based on availability. This strategic regulation demonstrates how operons can enhance bacterial adaptability.

The other terms mentioned refer to different genetic concepts. Cluster genes typically don't specify a regulatory mechanism, gene family refers to groups of related genes that may have similar functions but are not necessarily co-regulated, and genetic locus refers to a specific location on a chromosome where a gene is found, not relating specifically to regulatory mechanisms.