Unit 6 · Free note
Lac operon: high vs low vs off
Do not write “the operon turns on.” Name the repressor and CAP, then state high, low, or off transcription.
| Glucose | Lactose | Repressor | CAP | Transcription |
|---|---|---|---|---|
| High | Absent | Bound (off) | Inactive | Off |
| Low | Absent | Bound (off) | Active but blocked | Off |
| High | Present | Off operator | Inactive | Low |
| Low | Present | Off operator | Helps polymerase | High |