E. coli can synthesize the amino acid threonine or absorb it from the environment. In the thr operon, the repressor is active when it is bound to threonine. If an E. coli bacterium is in an environment where threonine is absent, will transcription of threonine synthesis genes take place? Why or why not?

Question

Quizplus · Accepted Answer

In the absence of threonine, the repressor protein cannot bind to the operator region of the thr operon, rendering it inactive. This allows RNA polymerase to transcribe the genes necessary for threonine synthesis, enabling the bacterium to produce threonine internally.

E Coli Can Synthesize the Amino Acid Threonine or Absorb