NA polymerase II (pol II) is only part of a larger apparatus that assembles on t
ID: 58536 • Letter: N
Question
NA polymerase II (pol II) is only part of a larger apparatus that assembles on the promoter. The other two components are the general transcription factors (GTFs) and the mediator. Match the components to their functions.
DNA unwinding
RNA polymerization
promoter recognition
proofreading
response to regulation by specific activators
Pol II and GTFs
pol II
GTFs
GTFs and Mediator
Pol II and Mediator
Mediator
3 points
QUESTION 26
The TATA box
acts to position RNA polymerase II for transcription initiation.
serves as a promoter sequence for genes transcribed by RNA polymerase III.
is located approximately 100 base pairs upstream of the start site for mRNAs.
is present in all eukaryotic genes.
3 points
QUESTION 27
The ______________ swings over the DNA and locks it in the central groove of RNA polymerase in the process of formation of the transcribing complex
The clamp
The wall
The bridge helix
The cleft
3 points
QUESTION 28
The activation domains of transcriptional activators
can be swapped with another activation domain to create a new chimeric transcription factor.
can facilitate transcription by catalyzing RNA polymerization
can bind to DNA.
can interact directly with the promoter.
3 points
QUESTION 29
The mediator complex
can function to maintain nucleosomes at promoter regions in a hypoacetylated state (facilitating nucleosome stability and chromatin condensation).
is a small, a 30-residue long protein that forms a molecular bridge between activation domains of transcription factors and their DNA binding domains.
can form a molecular bridge between activators of transcription and DNA replication machinery.
transduces regulatory signals between activation (and repression) domains of transcription factors bound to distal DNA elements (e.g. enhancers) and RNA polymerase II by binding directly to both.
3 points
QUESTION 30
Transcription factors can do all of the following EXCEPT
Synthesize RNA.
undergo conformational changes which alter activity.
respond to extracellular signals.
exist as heterodimers.
act to repress transcription of transcription factor genes.
3 points
QUESTION 31
A yeast two-hybrid system provides a way to screen a cDNA library for
Temperature sensitive mutations.
Genes encoding for binding partners of a protein of interest.
Alternative exons.
Genes undergoing RNA editing.
3 points
QUESTION 32
Which is the first factor to bind at the promoter of eukaryotic genes?
TFIIB
RNA polymerase
TATA box-binding protein
TFIIA
TFIIH
3 points
QUESTION 33
Which of the following are not found in DNA-binding proteins? (More than one correct answer possible. Mark all that apply).
CpG islands
zinc fingers
homeodomains
leucine zippers
3 points
QUESTION 34
Which of the following best characterizes the function of enhancers in gene regulation?
They are DNA sequences that directly bind RNA polymerase and regulate transcriptional initiation.
They are mRNA sequences that directly bind initiation factors and regulate translational initiation.
They are DNA sequences that directly bind transcription factors and enhance transcriptional elongation.
They are DNA sequences that directly bind TFIID, and regulate transcriptional initiation.
They are DNA sequences that directly bind specific transcription factors and regulate transcriptional initiation.
3 points
QUESTION 35
Which of the following post-transcriptional processes can lead to the production of multiple protein isoforms from a single gene in eukaryotes?
Capping
Alternative splicing
Phosphorylation of the carboxyl terminal domain of RNA pol II.
Rho dependent termination
3 points
QUESTION 36
Which of the following statements concerning the Mediator is correct?
The major mediator subunits can trace their evolutionary origin to bacterial factors.
All of the statements, including this one, are true.
The mediator acts as a bridge between transcription factors binding at distal sites and enhancers on the one hand and the basal transcription initiation machinery including RNA pol II at promoter sites.
Some of the mediator subunits bind to the DNA at distal sites and at enhancers while other subunits simultaneously bind the DNA at promoter proximal sequences.
Most of the yeast Mediator subunits are unique and have no homologs
in cells of higher eukaryotes (e.g. flies and humans).
3 points
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- A. B. C. D. E. F.DNA unwinding
Read Answer Items for Question 25 - A. B. C. D. E. F.RNA polymerization
Read Answer Items for Question 25 - A. B. C. D. E. F.promoter recognition
Read Answer Items for Question 25 - A. B. C. D. E. F.proofreading
Read Answer Items for Question 25 - A. B. C. D. E. F.response to regulation by specific activators
Read Answer Items for Question 25 Answer A.Pol II and GTFs
B.pol II
C.GTFs
D.GTFs and Mediator
E.Pol II and Mediator
F.Mediator
Explanation / Answer
Q 26). The TATA box
a. acts to position RNA polymerase II for transcription initiation.------------> TRUE
b. serves as a promoter sequence for genes transcribed by RNA polymerase III ---------> FALSE
c. is located approximately 100 base pairs upstream of the start site for mRNAs. ----------> FALSE (is located approximately 25 to 30 base pairs upstream of the start site for mRNAs.)
d. is present in all eukaryotic genes. ------------------------------------------------> TRUE
Q 27). a. the clamp
The __clamp____________ swings over the DNA and locks it in the central groove of RNA polymerase in the process of formation of the transcribing complex.
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