Question

An operon encodes enzymes for making an essential amino acid and is regulated like the trp operon. Which of the statements is true?
A: the amino acids inactivates the repressor
B: the amino acids acts as a repressor
C:inductible enzymes are produced
D: the repressor is active in the absence of the amino cids

Answer 1

With repressible systems, the binding of the effector molecule to the repressor greatly increases the affinity of repressor for the operator and the repressor binds and stops transcription. Thus, for the trp operon , the addition of tryptophan (the effector molecule) to the E. coli environment shuts off the system because the repressors binds at the operator.

Answer = B. The amino acid acts as a repressor