Control of the trp operon relies on which of the following: a. High levels of tryptophan causing a pause (but not termination) in transcription b. Low levels of tryptophan causing a pause (but not termination) in transcription c. Allolactose binding to the inhibitor to prevent it from binding to the promoter d. Tryptophan binding to the inhibitor to prevent it from binding to the promoter

The DNA sequence before the protein coding region that determines when a gene is used is called the A regulatory protein that binds DNA to determine whether or not a gene is transcribed is called a Two proteins that make up part of the bacterial flagellum are jointly regulated and transcribed together in a(n) A operon is normally transcribed unless it is blocked by a repressor. A(n) operon is normally blocked by a repressor, until it is removed to allow transcription.

Explain how the trp operon is regulated by trp repressor and by attenuation.

When iron is scarce, some bacteria can stop synthesis of all enzymes that require iron (Fe3+), such as superoxide dismutase (SOD). Which of the following accurately describes a mechanism for this regulation? Mark all that apply. A. Regulation occurs by an inducible operon B. When absent, the lack of iron causes the repressor to deactivate and block the promoter region for these genes C. Regulation occurs by a repressible operon D. When present, iron binds and activates the repressor protein

In the lac operon, the lac genes are transcribed in the presence of lactose because   a RNA polymerase binds to the operator b The repressor can not bind the promoter c Production of the repressor protein is inducible d The inducer binds to the repressor e The inducer binds to the operator

ate) DEFINE what is an Operon, and compare and contrast regulation of the LAC Operon and the TRP Operon. When is each turned ON or OFF? A. DRAW each operon in the PRESENCE of its own ligands (signal molecules). B. What controls the activity of the regulatory proteins involved? · Be sure to describe and show both POSITIVE and NEGATIVE regulation where appropriate. C. Explain HOW each type of control system is appropriate for an operon encoding either catabolic or anabolic enzymes.

Given the Table below concerning the lac operon, match the letter with what would be occurring for each scenario. Repressor is bound to the operator, cAMP complex is bound and transcription is prevented.   Allolactose is bound to the repressor, cAMP complex is bound, and transcription is prevalent.                                    Allolactose is bound to the repressor, cAMP complex is not assembled, and transcription is slow                        Repressor is bound to the operator, cAMP complex is not assembled, and transcription is prevented.

Which of the following statements about trp operon regulation is TRUE? A. Low trp levels result in trp repressor binding. O B. High trp levels result in transcriptional antitermination. C. Low trp levels cause the ribosome to fall off at the trp codons in the upstream ORF. O D. High trp levels cause the ribosome to fall off at the trp codons in the upstream ORF. O E. Low trp levels result in transcriptional antitermination. QUESTION 34 Consider the following partial diploid for the lac operon system. lacl+ O+ lac Z+Y-A- lacls O+ 1. 2. lac Z-Y+ A+ In this configuration, which of the following statements is TRUE? A. With no lac present, ZYA will all be expressed. B. with lac present none of the genes (ZYA) will be expressed. O C. With no lac present, only YA will be expressed. D. None of these answers is correct. E. With no lac present, only Z will be expressed.

After treating cells in tissue culture with an HDAC inhibitor, which of the following is the most likely outcome? A. Repression of transcription B. Promoter methylation C. Enhanced splicing D. Activation of transcription E. Depends on the cell type

Which of the following statements is true regarding transcriptional attenuation of the trp operon? a. The leader peptide encodes a protein that binds to the operator site b. Translation of the leader peptide stalls when tryptophan levels are high c. Stalling of the ribosome in region 1 of the leader peptide inhibits formation of the transcriptional terminator sequence d. This kind of mechanism can only occur in prokaryotes e. Both c. and d. are true