Exam 15: Regulation of Gene Expression

Monod discovered that if tryptophan is present in relatively high quantities in the growth medium, the enzymes necessary for its synthesis are repressed. How does this occur?

The lac operon consists of three structural genes as well as the adjacent region of DNA known as the regulator.

Which term would be applied to a regulatory condition that occurs when protein is associated with a particular section of DNA and greatly reduces transcription?

Describe how nucleosomes may influence gene transcription.

Attenuation is known to occur in the lac operon.

Regarding the lactose utilization system in E. coli, a constitutive mutant is one in which the three enzymes are produced regardless of the presence or absence of lactose.

When referring to attenuation in regulation of the trp operon, it would be safe to say that when there are high levels of tryptophan available to the organism, _.

Two modular elements that appear as consensus sequences upstream from RNA polymerase II transcription start sites are _.

What is the function of RNA interference?

What experimental results would indicate that the mutation lacIs is dominant to lacI+?

Attenuation involves the termination of mRNA synthesis.

In what way is chromosomal organization within the nucleus of an interphase cell thought to be related to gene activity?

Mutagenic studies of the promoter region of the fi -globin gene indicate that some areas are more likely than mutations in other areas to affect transcription rates. When mutations occur in consensus sequences (modular elements such as GC box, CAAT box, TATA box), does transcription increase or decrease?

In the eukaryotic promoters that have it, the CAAT box appears to be critical to the promoter's ability to facilitate transcription.

Within the control region of the trp operon is a section of DNA that is sensitive to levels of tryptophan in the system. What is the name of this region?

In what ways are eukaryotic transcription factors thought to function?

Regarding the trp operon, trpR - maps to a considerable distance from the structural genes. The mutation either inhibits the interaction with tryptophan or inhibits repressor formation entirely. In the presence of tryptophan in the medium, would you expect the trp operon to be transcriptionally active? Explain.

Regarding regulation of the trp operon, what might one appropriately call the amino acid tryptophan?

Genetic regulation in eukaryotes can take place at a variety of levels from transcriptional to posttranslational. At what level is genetic regulation considered most likely in prokaryotes?

Which term refers to a contiguous genetic complex that is under coordinated control?