The E. coli Operons

(a)

(b)

Figure 3-H-4.   E. coli operons.  An operon consists of several genes which are transcribed together.
(a) The lac operon comprises lacA, lacY and lacZ.  The lacI gene is not part of the operon, but encodes a protein which could repress transcription of the lac operon.  
(b) The trp operon consists of trpA, trpB, trpC, trpD, and trpE. 
 (Numbers represent the genome sequence).