What is an operon? Biology Signal Transduction and Control of Gene Expression Promoters / Operators 1 Answer Kate M. Jun 18, 2015 An operon is a unit of genomic DNA that is controlled by a promoter. Explanation: The operon is made up of one or multiple structural genes, an operator, and a promoter. The operon is transcribed together (or not) as one unit. Click here to learn specifically about the Lac Operon. Answer link Related questions What are operators? What are promoters? How do transcription factors bring about expression of a gene? How does trp operon regulate tryptophan levels? See all questions in Promoters / Operators Impact of this question 4087 views around the world You can reuse this answer Creative Commons License