Definition of "operon" []

• A unit of genetic material that functions in a coordinated manner by means of an operator, a promoter, and one or more structural genes that are transcribed together. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "In at least one case, IS elements activate an operon during starvation only if the substrate for that operon is present in the environment. (emphasis mine)"
• "It was largely the work of François Jacob and Jacques Monod and led, at the beginning of the 1960s, to the identification of messenger RNA as the mediator between genes and proteins, and to the description of a regulatory model of gene activation, the so called operon-model, in which two classes of genes became distinguished: One class was that of structural genes."
• "Now, an operon is a little segment of DN A in a bacteria which codes for a couple of genes, and genes code for proteins, and the proteins usually have related functions or function as a group, and one of them is called the lac operon which is used to, the proteins of which are necessary for the bacterium Escherichia coli to metabolize a sugar called lactose, which is a milk sugar."