The trp and lac operons are regulated in various ways. How do bacteria regulate transcription of these operons?
Sort the statements into the appropriate bins depending on whether or not each operon would be transcribed under the stated conditions.

a. operon is not transcribed:
trp operon: tryptophan present
lac operon: lactose absent

b. operon is transcribed, but not sped up through positive control:
trp operon: tryptophan absent
lac operon: lactose present, glucose present

c. operon is transcribed quickly through positive control:
lac operon: lactose present, glucose absent