The lactose operon is a classic example of gene expression and why we include it in molecular biology

 If any eukaryotes use operons to organize functional sets of genes?

The majority of genes are individually arranged in eukaryotes, but are organized in prokaryotes as operons. Prokaryotic operators are excellent models for learning about gene regulation in general, since eukaryotic genes are not organized into operons. In eukaryotes, there are some gene clusters which function similar to operons. Many of the concepts can be extended to eukaryotic processes and lead to our knowledge of gene changes. An operon is a set of genes all under the same promoter's influence. Many of the genes in the operon are on the same mRNA when an operon is transcribed.

Operons, but not eukaryotes, exist in prokaryotes. Each gene is made from individual mRNAs in eukaryotes and each gene has its own promoter. Under the influence of a single promoter, the operons are prokaryotic arrangements of multiple genes with similar functions. There are genes in the lac operon that E. Coli uses for sugar lactose metabolization. Operation control is important. RNA and protein synthesis requires considerable energy. If they do not need them, cells can not afford to waste energy producing genes. Operons, such as the lac operon, must therefore turn on when the metabolism of lactose is required and turn off when it is not. Therefore eukaryotes do not use operons to organize functional sets of genes