Question

select the correct answer.
what is the determining factor for the transcription of structural genes of the trp operon?
a. the quantity of trp repressor protein made by the regulatory gene trpr
b. the ability of rna polymerase to bind to the promoter region
c. the availability of tryptophan in the environment
d. the location of a regulatory gene with reference to the other regions of the operon
e. the activity of the other operons present in bacteria

Explanation:

The trp operon is a repressible operon that controls the synthesis of tryptophan. When tryptophan is abundant in the environment, it binds to the trp repressor protein, activating it to bind the operator and block transcription of the structural genes. When tryptophan is scarce, the repressor is inactive, allowing transcription to proceed. Thus, the availability of environmental tryptophan is the key determining factor for transcription of the operon's structural genes.

Answer:

C. the availability of tryptophan in the environment