What is the determining factor for the transcription of structural genes of the trp operon?

1. the quantity of trp repressor protein made by the regulatory gene trp.

2. the ability of RNA polymerase to bind to the promoter region

3. the availability of tryptophan in the environment

4. the location of a regulatory gene with reference to the other regions of the operon

5. the activity of the other operon present in the bacteria

Question

Elliot Andrews

Biology

28 November, 06:54

What is the determining factor for the transcription of structural genes of the trp operon?

1. the quantity of trp repressor protein made by the regulatory gene trp.

2. the ability of RNA polymerase to bind to the promoter region

3. the availability of tryptophan in the environment

4. the location of a regulatory gene with reference to the other regions of the operon

5. the activity of the other operon present in the bacteria

+2

Answers (1)

Know the Answer?

Helena Huff · Answer 1

When tryptophan is available in the environment, it is taken up by the bacteria. Within the cell, tryptophan binds to the inactive trp repressor protein and activates it. This activated complex of repressor protein and tryptophan then binds to the operator of the trp operon and blocks it. Now RNA polymerase cannot bind to the promoter to begin transcription. Therefore, the trp operon is repressed. so the answer is number 1