Smartbook 14 Questions
Which of the following are similarities between eukaryotic and prokaryotic transcriptional regulation?
-Proteins influence the ability of RNA polymerase to bind to the DNA. -Small effector molecules are involved in gene regulation.
How can gene regulation be specific?
-Specific genes are expressed at different developmental stages. -Specific genes are expressed only in certain cells. -Specific genes differ in expression levels from cell to cell.
Which of the following are key differences between eukaryotic and prokaryotic transcriptional regulation?
-The majority of genes are organized individually in eukaryotes, but are organized as operons in prokaryotes. -The complexity of eukaryotic development requires that transcription be more coordinated and integrated than in prokaryotes. -Combinatorial control of gene expression is more common in eukaryotes.
What is an operon?
A cluster of genes under the transcriptional control of a single promoter
How do activators and repressors regulate the function of RNA polymerase in eukaryotes?
Activators and repressors interact with GTFs or mediator proteins.
The process whereby different transcripts are made from a single gene is called _________ __________
Alternative Splicing
Which of the following is a form of gene regulation in which a eukaryotic pre-mRNA can be processed to produce more than one mature RNA?
Alternative Splicing
How does gene regulation help conserve energy for an organism?
By only expressing the gene product when it is needed in the cell.
The lac operon is also under positive control by an activator protein called what?
CAP
Proteins that use energy from ATP hydrolysis to change the locations and compositions of nucleosomes are called ATP____________-_______________dependent - complexes.
Chromatin-remodeling
In vertebrates and flowering plants, many genes contain DNA sequences called ______ near their promoters that remain unmethylated.
CpG islands
How does gene regulation differ between prokaryotes and eukaryotes?
Eukaryotes process mRNA transcripts in ways that prokaryotes do not.
True or false: In multicellular organisms, genes are regulated in the same way to ensure that gene expression levels are constant regardless of cell type or developmental stage.
False
What is the process by which a cell controls the level of expression of a specific gene or set of genes in a biological pathway?
Gene regulation
What is the function of the enzyme histone acetyltransferase?
It attaches acetyl groups to histones, which prevents them from binding tightly to DNA.
In eukaryotes, which steps are required for gene expression?
Making the protein by translation Converting chromatin into an open conformation Modifying RNA and exporting it from the nucleus Transcribing the gene
Which of the following are forms of translation regulation?
RNA-binding proteins control translation of the mRNA Alternative Splicing
What is cell differentiation?
The process by which cells become specialized in different types
What is the function of ATP-dependent chromatin-remodeling complexes?
They cause a change in the locations and/or compositions of nucleosomes
Cell ______ is the process by which cells become specialized into particular types.
differentiation
Some proteins are produced only when needed. This is an example of gene regulation that conserves ____________
energy
The functional product of genes arises from what process?
gene expression.
In E. coli, the genes required to metabolize lactose are expressed:
only when lactose is present
In the lac operon, the _______ is the DNA sequence at which the lac repressor binds.
operator
The lacO site of the lac operon is called the ________ and is the site where the repressor protein binds.
operator
A(n)__________ is a cluster of genes that are part of a single transcription unit that is under the control of a single promoter.
operon
One benefit of regulating RNA processing in eukaryotes is the ability to
produce more than one mRNA from a single gene.
Regulatory transcription factors influence the expression of genes by binding directly to DNA at or near the __________ site and affect the rate of transcription.
promoter
The ___________ is the collection of all proteins that are expressed in a cell.
proteome
The function of the protein encoded by lacI is:
to repress transcription of the lac operon
How can translation be regulated?
By using non-coding RNAs
What are regulatory transcription factors?
Proteins that bind to DNA and affect the transcription of one or more genes
The lac repressor protein prevents the enzyme __________ ____________ from transcribing the genes in the lac operon.
RNA Polymerase
Eukaryotic gene expression can be regulated at which levels?
RNA modification transcription translation
Why are interactions between RNA polymerase II and GTFs important for transcription in eukaryotes?
RNA polymerase II and GTFs must interact for the polymerase to bind properly at the core promoter site of the DNA.
Which of the following are ways of regulating gene expression in BOTH prokaryotes and eukaryotes?
Regulation of transcription Post-translational regulation Regulation of translation
What is the role of repressor proteins in the regulation of transcription?
Repressor proteins bind to DNA and decrease the rate of transcription.
__________ are regulatory transcription factors that bind to DNA and decrease the rate of transcription.
Repressors
What are the two components of the core promoter?
TATA box transcriptional start site
In order for transcription of protein coding genes in eukaryotes to begin, the promoter must have several key features. What are they?
TATA box, regulatory elements, transcriptional start site
What is chromatin?
The complex formed by DNA and its associated proteins
When are the genes involved in lactose metabolism in E. coli expressed and when are they turned off?
The genes for lactose metabolism are expressed when lactose is present but not when it is absent.
What is the CAP site for the lac operon?
The sequence of nucleotides that is recognized by an activator protein
Proteins that use energy from ATP hydrolysis to change the locations and compositions of nucleosomes are called ATP-dependent - complexes.
Tightly packed chromatin is difficult to transcribe. Loosely packed chromatin allows transcription factors and RNA polymerase to access the promoter site and transcription can take place.
What is the difference between levels of transcription of chromatin in the open versus closed conformation?
Transcription is high when in the open conformation and low when in the closed conformation.
The enzyme that attaches acetyl groups to the amino terminal tails of histone proteins is called histone ____________ .
acetyltransferase
When ________ proteins bind to DNA, they increase the rate of transcription.
activator
Both prokaryotes and eukaryotes use _______ proteins to regulate the process of transcription.
activator and repressor
DNA and its associated proteins form a compact structure called:
chromatin
How can faster regulation of gene expression be achieved in eukaryotes? Select all that apply.
controlling the steps in RNA processing controlling the steps after an RNA is made
The process in which the information in a gene is made into a functional gene product, such as an RNA molecule or a protein, is termed gene ______________
expression
The catabolite activator protein (CAP) is involved in ______ control of the lac operon.
positive
The protein encoded by the lacI gene functions to:
prevent transcription of the lac operon
Bacteria and eukaryotes can regulate genes at the level of transcription. In eukaryotes, gene expression is also commonly regulated at the levels of RNA ____________and translation.
processing
Gene ___________ is the ability of cells to control the expression of genes.
regulation
Methylated CpG islands are usually associated with ______ genes, whereas unmethylated CpG islands are usually associated with ______ genes.
repressed ; active
What molecules can influence transcription by binding to enhancers or silencers?
repressors and activators