Chapter 37 Gene Expression in Eukaryotes
Matching Questions
Use the following to answer questions 1–10:
Choose the correct answer from the list below. Not all of the answers will be used.
a) enhancers
b) bromodomain
c) regulated
d) chromatin-remodeling engine
e) ligand
f) coactivators
g) agonists
h) histone acetylase
i) citrate
j) TATA box
k) histone deacetylase
l) zinc finger
1.
A(n) ______________ is a region of a protein that regulates transcription by interacting with the
acetylated lysine of histones.
2.
______________ is a complex that can shift the position of nucleosomes along a DNA strand.
Ans:
d
Section: 37.4
3.
The molecule ______________ shuttles acetyl groups into the nucleus for use by histone-
modifying enzymes.
Ans:
Section: 37.4
4.
Molecules that bind to a receptor and trigger a signaling pathway are called ______________.
Ans:
g
Section: 37.3
5.
______________ is a DNA-binding domain involving eight cysteine residues.
Section: 37.3
6.
Binding sites in DNA for specific regulatory proteins are called ______________.
Ans:
Section: 37.2
7.
Proteins that act in a coordinated manner with hormone receptors to mediate gene expression are
called ______________.
Ans:
Ans:
b
Section: 37.4
Chapter 37 Gene Expression in Eukaryotes
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8.
The enzyme that removes the acetyl group for a lysine of a histone is called ______________.
9.
______________ is a general term for molecules that bind to receptors.
Ans:
Section: 37.3
10.
In eukaryotes, transcription is initiated by the binding of the transcription factor to the
______________.
Ans:
Section: 37.2
Fill–in-the-Blank Questions
11.
The nuclear membrane is important in gene expression because it separates the process of _____
from that of _____.
Ans: transcription; translation Section: Introduction
12.
_____ genes are continuously expressed rather than regulated.
Ans: Constitutive Section: 37.2
13.
Eukaryotic RNA polymerases differ in their sensitivity to the mushroom toxin _____.
14.
RNA polymerase I is located in the _____.
Ans: nucleolus Section: 37.1
15.
The carboxyl-terminal domain of RNA polymerase II is phosphorylated on _____ residues.
Ans: serine Section: 37.1
16.
The repeating unit formed by the DNA wrapping around the histone core is called a(n) _____.
Ans: nucleosome Section: 37.4
17.
_____ receptors differ from cell surface receptors in that they are soluble cytoplasmic proteins.
Ans: Nuclear hormone Section: 37.3
18.
Nuclear hormone receptors bind to specific DNA sites known as ________________.
Ans: response elements Section: 37.3
19.
When a steroid hormone receptor binds ligand, it does not change the binding of a receptor to
DNA but to the _____.
Ans: coactivator Section: 37.3
20.
A molecule that binds to a nuclear hormone receptor but does not trigger a response is called
a(n) _____.
Ans:
k
Section: 37.4
Chapter 37 Gene Expression in Eukaryotes
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Multiple-Choice Questions
21.
Differential gene expression is caused by
A)
control of translation.
B)
control of mRNA processing.
C)
control of transcription.
D)
control of replication.
E)
None of the above.
22.
When phosphorylated, the carboxyl-terminal domain of RNA polymerase II
A)
is insensitive to α-amanitin.
B)
enhances transcription.
C)
recruits other factors.
D)
A and C.
E)
B and C.
Ans: E Section: 37.1
23.
What do many DNA binding proteins contain that is involved in chromatin remodeling?
A)
a helix-turn-helix motif
B)
an acetyl–lysine binding domain
C)
a zinc-finger motif
D)
All of the above.
E)
None of the above.
Ans: B Section: 37.4
24.
In eukaryotes, DNA-binding proteins bind to DNA by which of the following DNA-binding
structures?
A)
the zinc-finger domain
B)
the cAMP binding
C)
closed loops called lariats
D)
A and B
E)
A, B, and C
Ans: A Section: 37.3
25.
A common selective estrogen receptor modulator used in breast cancer therapy is
A)
tamoxifen.
B)
α-amanitin.
C)
acetyl–lysine binding protein (ALBP).
D)
All of the above.
E)
None of the above.
Ans: A Section: 37.3
26.
Pluripotent cells
A)
are stem cells.
B)
can develop into any adult cell.
C)
can develop into any fetal cell.
D)
All of the above.
E)
None of the above.
Ans: D Section: 37.2
Ans: C Section: Introduction
Chapter 37 Gene Expression in Eukaryotes
4
27.
The interaction of many different protein factors to stimulate or repress transcription is called
A)
combinatorial control.
B)
synergy.
C)
the hypomethylation effect.
D)
All of the above.
E)
None of the above.
28.
Enhancer sites are often located
A)
near the poly(A) tail site.
B)
within introns.
C)
at a distance from the transcription start site.
D)
All of the above.
E)
None of the above.
Ans: C Section: 37.2
29.
Molecules that bind to a receptor and trigger signaling pathways are called
A)
antagonists.
B)
agonists.
C)
IRE-binding proteins.
D)
promoters.
E)
None of the above.
Ans: B Section: 37.3
30.
How do coactivators mediate expression?
A)
by blocking RNA polymerase binding
B)
by loosening the histone complex formation
C)
by inhibiting intron splicing
D)
A and B
E)
B and C
Ans: B Section: 37.3
31.
A key reaction in gene repression is the deacetylation of which amino acids in histones?
A)
serine
B)
threonine
C)
arginine
D)
lysine
E)
All of the above.
Ans: D Section: 37.3
32.
A deletion in which of the following would most likely inhibit cell specific protein synthesis?
A)
enhancer sequence
B)
promoter sequence
C)
initiator element
D)
downstream core element
E)
–35 region
Ans: A Section: 37.1
Ans: A Section: 37.2
Chapter 37 Gene Expression in Eukaryotes
5
33.
Like so many other proteins, the carboxy-terminal domain of RNA polymerase II undergoes
what type of activation to transition from initiation to elongation?
A)
dephosphorylation
B)
phosphorylation
C)
binding of a steroid hormone receptor
D)
binding of a G-protein
E)
acetylation
34.
Why would an inhibitor of RNA polymerase II not cause rapid cell death even if every molecule
of RNA polymerase II was inhibited?
A)
Phosphorylation protects RNA polymerase II from inhibitor binding.
B)
As long as TFIID can bind, then RNA polymerase II can stay bound and continue to
transcribe proteins.
C)
There would still be many functional mRNAs and viable proteins to continue cellular
functions.
D)
TBP binding to the TATA box protects degradation of RNA polymerase II.
E)
Downstream core promoter elements initiate RNA polymerase activation.
Ans: C Section: 37.2
35.
Why is the action of nuclear receptors so different from G-protein-coupled receptors?
A)
G-protein-coupled receptors act on cytosolic proteins, not nuclear proteins.
B)
Nuclear receptors activate transcription factors via methylation reactions, not
phosphorylations.
C)
G-protein-coupled receptors activate or inhibit enzymes, not transcription.
D)
Nuclear receptors bind steroids, which can cross the cellular membrane; thus, specificity
of action resides in the cytoplasm.
E)
G-protein-coupled receptors bind carbohydrate moieties, whereas nuclear receptors bind
prostaglandin hormones.
Ans: Section: 37.
36.
What steroid-hormone receptors make good targets for drugs?
A)
Anabolic steroids stimulate the expression of genes that enhance the development of lean
muscle mass.
B)
Raloxifene blocks estrogen-mediated pathways needed for cancer growth.
C)
Tamoxifen is used in the treatment and prevention of breast cancer.
D)
Estradiol triggers signaling pathways and is said to have agonist properties.
E)
All of the above.
Ans: E Section: 37.4
Short-Answer Questions
37.
What additional complexities exist between gene expression in eukaryotes but not in
prokaryotes?
mRNA is more extensive. Additionally, transcription and translation take place in
different cellular compartments.
Ans: B Section: 37.2
Chapter 37 Gene Expression in Eukaryotes
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38.
Why must gene regulation be more complicated in eukaryotic cells when compared to
prokaryotic cells?
39.
Briefly describe the path of a steroid hormone in gene regulation.
expression (with the assistance of other proteins).
Section: 37.3
40.
How does a coactivator function in gene expression?
lead to the modification of chromatin structure.
Section: 37.3
41.
Why are steroid hormone receptors excellent drug therapy targets?
triggering the exact same reaction as the native hormone does.
Section: 37.3
42.
How does binding of thyroid hormone to its nuclear hormone receptor promote transcription?
to bind.
Section: 37.3
43.
By what mechanism does histone acetylation prepare the DNA for transcription?
histone and lysine together. The DNA is then available for transcription.
Section: 37.4
44.
What is the role of a mediator in transcription?
transcription.
Section: 37.2
45.
Which two characteristics differentiate promoters from enhancers?
promoter.
Section: 37.2
Finally, there are many more genes spread across eukaryotic genomes.
Section: Introduction
Chapter 37 Gene Expression in Eukaryotes
7
46.
What are the steps in modifying gene expression by hormones such as estrogen?
47.
What benefit does combinatorial control give to multicellular organisms?
Ans:
Combinatorial control means that the combination of proteins present can alter gene
regulation. Thus, different tissues can express genes differently in time and development.
Section: 37.2
48.
What are induced pluripotent stem cells?
which, when introduced into mature fibroblast skin cells, will cause them to return to a
pluripotent stem cell state. Thus, pluripotency has been induced.
Section: 37.2
49.
What are the three most common cis-acting elements for genes transcribed by RNA polymerase
II?
between positions −24 and −32. Two other common regulatory sequences are the CAAT
Section: 37.2
50.
Explain why different RNA polymerases transcribe specific genes and only those genes.
example, RNA polymerase II recognizes promoter sites upstream of the gene transcribed,
whereas RNA polymerase III promoters consist of conserved sequences within the gene.
response elements. Upon binding, a conformational change occurs, allowing for
recruitment of coactivator molecules required for gene expression.
Section: 37.3