Exam 2 Review pt. 2 Flashcards
An intrinsic (protein independent) transcription terminator region consists of:
a. a stem-loop structure followed by a string of U’s
b. a string of U’s followed by a stem-loop structure
c. a stem-loop structure
d. a string of U’s
e. no defined sequences
a. a stem-loop structure followed by a string of U’s
Which eukaryotic basal transcription factor has a function most similar to the sigma factor of prokaryotes?
A. TFIIA
B. TFIIB
C. TFIID
D. TFIIF
E. TFIIH
C. TFIID
What is a zinc-finger (Zn2+-finger) domain?
A. A protein domain that phosphorylates other proteins
B. A protein domain that interacts with RNA polymerase
C. A protein domain that binds DNA at specific sequences
D. A protein domain that binds the TATA box
E. A protein domain that activates transcription
C. A protein domain that binds DNA at specific sequences
Which statement best describes termination of RNA polymerase II transcription in eukaryotes?
A. Formation of a stem-loop followed by a string of U’s in the transcript causes the polymerase to dissociate from the template.
B. Termination proteins are bound to the DNA at the points where transcription should stop. When RNA polymerase bumps into them, transcription ends.
C. The rho protein catches up to the polymerase, and its helicase activity causes the polymerase to dissociate from the template.
D. Once RNA polymerase passes the poly-A signal sequence, the RNA is cleaved.
E. TFIIH phosphorylates the C-terminal domain of RNA polymerase, causing it to stop transcription.
D. Once RNA polymerase passes the poly-A signal sequence, the RNA is cleaved.
What type of modification is found in RNA polymerase II active in transcription initiation at a eukaryotic promoter?
A. None
B. Phosphorylation
C. Methylation
D. Acetylation
E. Carbonylation
B. Phosphorylation
Which of the following is a common DNA binding domain?
A. Ankyrin repeat
B. Beta-sheet
C. Leucine zipper
D. P-loop
E. Zinc finger
C. Leucine zipper
E. Zinc finger
Riboswitch controls gene expression by modulating:
a. transcription
b. translation
c. either transcription or translation
d. RNA stability
c. either transcription or translation
In the Lac operon, allolactose acts as a(n) ______ when bound to _______
a. repressor; LacZ b. activator; RNA polymerase c. inducer; LacZ d. co-repressor; LacI e. inducer; LacI
e. inducer; LacI
Insulators control gene expression in eukaryotes. Insulators:
a. are boundary elements that function to prevent the enhancer for one gene from activating transcription of another gene
b. require binding of zinc-finger protein CTCF for function
c. can be less than 50 bp in size
d. All of the choices are correct
d. All of the choices are correct
Which of the following statements is NOT true about the glucocorticoid receptor (GR)?
a. GR is an unstable protein and is stabilized by HSP 90 in the cell cytoplasm
b. The hormone enters the cytoplasm and binds GR
c. Hormone bound GR monomer enters the cell nucleus
d. In the nucleus hormone bound GR binds to the target sequence and activate gene expression
c. Hormone bound GR monomer enters the cell nucleus
Which of the following is NOT a function of the RNA-induced silencing complex (RISC)?
a. primary miRNA transcript conversion to precursor miRNA
b. cleavage of precursor miRNA to short duplex miRNAs
c. facilitation of base pairing between mature miRNA and its complementary sequence in an mRNA
d. cleavage of the mRNA transcript targeted by siRNA
a. primary miRNA transcript conversion to precursor miRNA
You have a hypothesis that a genetic disease is the result of a mutation that affects splicing such that an intron gets retained in the final mRNA. Which method would you first use to test your hypothesis?
A. Whole genome sequencing
B. RNA-seq
C. Proteomics
D. Metabolomics
B. RNA-seq
What are CpG islands? How do they affect gene expression?
CpG islands are DNA regions rich in CpG dinucleotides near gene promoters.
They influence gene expression by serving as binding sites for regulatory proteins.
Methylation of CpG islands can silence genes by hindering transcription factor binding, impacting normal development and contributing to diseases like cancer.
What are the roles of RNA polymerase II CTD phosphorylation?
RNA polymerase II CTD phosphorylation regulates transcription initiation, elongation, RNA processing, and termination.
It enables recruitment of processing factors, enhances processivity, and triggers RNA release during transcription
How does attenuation control of trp operon expression differ between E. coli and B. subtilis?
E. coli employs RNA secondary structures in the attenuator region, affected by tryptophan levels, to regulate transcription termination.
In contrast, B. subtilis utilizes the trp RNA-binding attenuation protein (TRAP) to interact with mRNA, modulating transcription based on tryptophan availability.
What enzyme modifies histones leading to less tight binding of nucleosomes to DNA?
histone acetyltransferases (HATs)
which target lysine (K) residues on the N-terminal histone tail.
What prevents MyoD from activating muscle cell genes too early in development
The repressive action of chromatin-remodeling complexes and transcriptional repressors prevents MyoD from activating muscle cell genes too early in development.
Additionally, inhibitory signals from signaling pathways and microRNAs may also contribute to regulating the timing of MyoD activity.
How do transcription factors bound to sequences far away from a transcription initiation site affect transcription?
Transcription factors bound far from initiation sites can affect transcription by inducing DNA looping, regulating enhancer or silencer activity, and mediating long-range chromatin interactions, thereby modulating gene expression.
Which protein processes primary miRNA transcripts to precursor miRNAs?
Drosha
Name one genetic disorder that is caused by a mutation in a transcription activator binding site.
β-thalassemia.
Mutations in the promoter region of the β-globin gene, which disrupt the binding of transcription factors like GATA-1, can lead to reduced or absent expression of the β-globin gene, resulting in β-thalassemia, a type of inherited anemia.
What is the function of the Dicer protein in the RISC complex?
cleaves double-stranded RNA into small RNA duplexes (siRNAs or miRNAs).
These guide RISC to target mRNAs for degradation or translational repression, essential for post-transcriptional gene regulation.
Which RNA - sense RNA, anti-sense RNA or double-stranded RNA - serves as the best inhibitor for gene expression?
Double-stranded RNA (dsRNA) serves as the best inhibitor for gene expression.
dsRNA can trigger RNA interference (RNAi) pathways, leading to the degradation of complementary mRNAs or inhibition of their translation.
This process effectively reduces the expression of the targeted gene.
