40 Questions
At which stage of gene expression can regulation occur such that specific mRNAs in the cytoplasm are selected for translation by ribosomes?
Translational control
What is the paramount level of control for most genes?
Transcriptional control
How many stages are there in the pathway leading from DNA to protein where gene expression can be regulated?
6
What is the term for the process by which gene expression is controlled through the regulation of when and how often a given gene is transcribed?
Transcriptional control
Where in the cell are completed mRNAs localized after being exported from the nucleus?
Cytosol
What is the primary function of the promoter in an eukaryotic gene control region?
To bind general transcription factors
What type of proteins assemble on DNA with eukaryotic transcription regulators?
Co-activators and co-repressors
Which of the following is NOT a component of an eukaryotic gene control region?
Gene coding region
What is the function of cis-regulatory regions in an eukaryotic gene control region?
To bind specific transcription factors
How do eukaryotic transcription regulators typically function?
In groups, assembling on cis-regulatory sequences
What is the primary function of a positive transcription regulator in eukaryotes?
To help RNA polymerase begin transcribing genes
What is a key difference between transcription regulation in eukaryotes and bacteria?
Eukaryotes have more complex chromatin structures
What is the role of cis-regulatory sequences in transcription regulation?
They specify the time and place of gene transcription
What is the effect of an activator protein on transcription initiation?
It increases the rate of transcription initiation by up to 1000-fold
What is a key aspect of gene control in eukaryotes compared to bacteria?
More intermediate transcription factors
What ensures that cells do not synthesize superfluous intermediates during transcription?
Transcription regulators
What type of proteins recognize specific sequences of DNA and determine which genes to transcribe?
Transcription regulators
What is the primary function of transcription regulators?
To recognize specific sequences of DNA
What feature of transcription regulators allows them to bind specific sequences of DNA?
Their ability to recognize specific sequences of DNA
Approximately what percentage of genes in most organisms are devoted to transcription regulators?
10%
What enables transcription regulators to assemble on DNA?
A combination of cis-regulatory sequences
What is the primary function of the Mediator protein complex?
To act as a coactivator, bridging transcription regulators and RNA polymerase
How do transcription factors act in the process of transcription initiation?
By promoting the binding of additional transcription regulators
What is the result of the cooperative assembly of transcription activators and coactivators on DNA?
The promotion of different steps in transcription initiation
What is the role of cis-regulatory regions in an eukaryotic gene control region?
To recruit transcription regulators and coactivators to the promoter
What is the consequence of the binding of the tryptophan repressor to the operator in the promoter?
The RNA polymerase is blocked from binding to the promoter, preventing transcription.
What is the role of activator proteins in gene transcription?
They bind to the cis-regulatory sequence and help RNA polymerase initiate transcription.
What is the term for the clusters of genes transcribed as a single mRNA molecule in bacteria?
Operon
What is the consequence of abundant tryptophan on the tryptophan operon?
The operon is switched off, and the enzymes are no longer necessary.
What type of transcription factor turns genes OFF?
Repressor
What is the primary advantage of combinatorial transcriptional regulation?
It increases the specificity of transcriptional activation.
What is the function of DNA binding domains in transcription factors?
To bind specific sequences in DNA
How do transcription factors NFAT and AP1 interact to regulate the IL-2 gene?
NFAT and AP1 bind to neighboring sites and interact through protein-protein interactions
What is the consequence of cooperative DNA binding by transcription factors?
It results in considerable combinatorial complexity of transcription control
What is the benefit of having multiple transcription factors bind to different sequences?
It allows for the specific regulation of gene expression
How do dimerization domains in transcription factors contribute to transcriptional regulation?
They mediate protein-protein interactions
What is the result of the interaction between NFAT and AP1 in the IL-2 gene control region?
A stable DNA ternary complex is formed, stabilizing transcriptional activation
What is a characteristic of transcriptional regulation in eukaryotes?
It involves the interaction of multiple transcription factors
What is the consequence of having unique transcription activation requirements for each gene?
It increases the specificity of transcriptional activation
What is the benefit of combinatorial transcriptional regulation in terms of gene control?
It increases the specificity of transcriptional activation
Test your knowledge about eukaryotic gene control regions, including promoters, cis-regulatory regions, enhancers, and silencers. Learn how gene expression is regulated in eukaryotic cells.
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