Asked by Pouline Juliet on Jul 03, 2024
Verified
Under high tryptophan conditions, tryptophan binds to and activates the repressor protein, thereby blocking transcription of the trp operon. This is an example of:
A) protein degradation
B) negative control of inducible genes
C) negative control of repressible genes
D) positive control of inducible genes
E) positive control of repressible genes
Negative Control
An experiment or part of an experiment where no response is expected, serving to highlight the effect of the experimental treatment.
Repressible Genes
Genes whose expression can be decreased or turned off by the presence of a specific molecule.
Transcription
The process by which genetic information encoded in DNA is copied into messenger RNA (mRNA) for protein synthesis.
- Become familiar with the control of gene activity in prokaryotes, especially the roles of inducible and repressible operons.
- Differentiate between the mechanisms of positive and negative control in the regulation of gene expression.
Verified Answer
VJ
viral jenny5 days ago
Final Answer :
C
Explanation :
This is an example of negative control of repressible genes because the presence of tryptophan (the product of the trp operon) activates the repressor protein, which in turn binds to the operator region of the trp operon, preventing transcription. This is a classic feedback inhibition mechanism where the end product of a pathway inhibits its own synthesis by repressing gene expression.
Learning Objectives
- Become familiar with the control of gene activity in prokaryotes, especially the roles of inducible and repressible operons.
- Differentiate between the mechanisms of positive and negative control in the regulation of gene expression.