Biology

Mary Ann Clark, Jung Choi, Matthew Douglas

Chapter 16

Gene Expression - all with Video Answers

Educators

JH

+ 3 more educators

Chapter Questions

Problem 1

In $E$. coli, the tro operon is on by default, while the lac operon is off. Why do you think that this is the case?

Shiksha Dutta

Shiksha Dutta

Numerade Educator

Problem 2

In females, one of the two $x$ chromosomes is inactivated during embryonic development because of epigenetic changes to the chromatin. What impact do you think these changes would have on nucleosome packing?

Shiksha Dutta

Numerade Educator

Problem 3

An increase in phosphorylation levels of elF-2 has been observed in patients with neurodegenerative diseases such as Alzheimer's, Parkinson's, and Huntington's. What impact do you think this might have on protein synthesis?

Shiksha Dutta

Numerade Educator

Problem 4

Control of gene expression in eukaryotic cells occurs at which level(s)?
a. only the transcriptional level
b. epigenetic and transcriptional levels
c. epigenetic, transcriptional, and translational levels
d. epigenetic, transcriptional, posttranscriptional, translational, and posttranslational levels

Shiksha Dutta

Numerade Educator

Problem 5

Post-translational control refers to:
a. regulation of gene expression after transcription
b. regulation of gene expression after translation
c. control of epigenetic activation
d. period between transcription and translation

Karann Putrevu

Numerade Educator

Problem 6

How does the regulation of gene expression support continued evolution of more complex organisms?
a. Cells can become specialized within a multicellular organism.
b. Organisms can conserve energy and resources.
c. Cells grow larger to accommodate protein production. B.
d. Both A and

Shiksha Dutta

Numerade Educator

Problem 7

If glucose is absent, but so is lactose, the lac operon will be ______________ .
a. activated
b. repressed
c. activated, but only partially
d. mutated

Shiksha Dutta

Numerade Educator

Problem 8

Prokaryotic cells lack a nucleus. Therefore, the genes in prokaryotic cells are:
a. all expressed, all of the time
b. transcribed and translated almost simultaneously
c. transcriptionally controlled because translation begins before transcription ends
d. b and c are both true

Aria Rotbart

Numerade Educator

Problem 9

The ara operon is an inducible operon that controls the production of the sugar arabinose. When arabinose is present in a bacterium it binds to the protein AraC, and the complex binds to the initiator site to promote transcription. In this scenario, AraC is $\mathrm{a}(\mathrm{n})$ _______________________.
a. activator
b. inducer
c. repressor
d. operator

Shiksha Dutta

Numerade Educator

Problem 10

What are epigenetic modifications?
a. the addition of reversible changes to histone proteins and DNA
b. the removal of nucleosomes from the DNA
c. the addition of more nucleosomes to the DNA
d. mutation of the DNA sequence

Amrita Narasimhan

Amrita Narasimhan

Numerade Educator

Problem 11

Which of the following are true of epigenetic changes?
a. allow DNA to be transcribed
b. move histones to open or close a chromosomal region
c. are temporary
d. all of the above

Shiksha Dutta

Numerade Educator

Problem 12

The binding of _______________________ transcription to start.
a. a protein
b. DNA polymerase
c. RNA polymerase
d. a transcription factor

Shiksha Dutta

Numerade Educator

Problem 13

What will result from the binding of a transcription factor to an enhancer region?
a. decreased transcription of an adjacent gene
b. increased transcription of a distant gene
c. alteration of the translation of an adjacent gene
d. initiation of the recruitment of RNA polymerase

UR

Umar Rashid

Numerade Educator

Problem 14

A scientist compares the promoter regions of two genes. Gene A's core promoter plus proximal promoter elements encompasses $70 \mathrm{bp}$. Gene B's core promoter plus proximal promoter elements encompasses $250 \mathrm{bp} .$ Which of the scientist's hypotheses is most likely to be correct?
a. More transcripts will be made from Gene B.
b. Transcription of Gene $A$ involves fewer transcription factors.
c. Enhancers control Gene B's transcription.
d. Transcription of Gene $A$ is more controlled than transcription of Gene B.

Shiksha Dutta

Numerade Educator

Problem 15

Which of the following are involved in post transcriptional control?
a. control of RNA splicing
b. control of RNA shuttling
c. control of RNA stability
d. all of the above

Eric Goldman

Numerade Educator

Problem 16

Binding of an RNA binding protein will ____________ the stability of the RNA molecule.
a. increase
b. decrease
c. neither increase nor decrease
d. either increase or decrease

Shiksha Dutta

Numerade Educator

Problem 17

An unprocessed pre-mRNA has the following structure.Which of the following is not a possible size (in bp) of the mature mRNA?
a. $205 b p$
b. 180 bp
c. 150 bp
d. 100 bp

Avery Duncan

Numerade Educator

Problem 18

Alternative splicing has been estimated to occur in more than $95 \%$ of multi-exon genes. Which of the following is not an evolutionary advantage of alternative splicing?
a. Alternative splicing increases diversity without increasing genome size.
b. Different gene isoforms can be expressed in different tissues.
c. Alternative splicing creates shorter mRNA transcripts.
d. Different gene isoforms can be expressed during different stages of development.

Shiksha Dutta

Numerade Educator

Problem 19

Post-translational modifications of proteins can affect which of the following?
a. protein function
b. transcriptional regulation
c. chromatin modification
d. all of the above

Shiksha Dutta

Numerade Educator

Problem 20

A scientist mutates elF-2 to eliminate its GTP hydrolysis capability. How would this mutated form of elF-2 alter translation?
a. Initiation factors would not be able to bind to mRNA.
b. The large ribosomal subunit would not be able to interact with mRNA transcripts.
c. tRNAi-Met would not scan mRNA transcripts for the start codon.
d. elf-2 would not be able to interact with the small ribosomal subunit.

Shiksha Dutta

Numerade Educator

Problem 21

Cancer causing genes are called _________ .
a. transformation genes
b. tumor suppressor genes
c. oncogenes
d. mutated genes

Shiksha Dutta

Numerade Educator

Problem 22

Targeted therapies are used in patients with a set gene expression pattern. A targeted therapy that prevents the activation of the estrogen receptor in breast cancer would be beneficial to which type of patient?
a. patients who express the EGFR receptor in normal cells
b. patients with a mutation that inactivates the estrogen receptor
c. patients with lots of the estrogen receptor expressed in their tumor
d. patients that have no estrogen receptor expressed in their tumor

Shiksha Dutta

Numerade Educator

Problem 24

Describe how controlling gene expression will alter the overall protein levels in the cell.

Marina Ramsey

Numerade Educator

Problem 25

Describe how transcription in prokaryotic cells can be altered by external stimulation such as excess lactose in the environment.

Shiksha Dutta

Numerade Educator

Problem 26

Name two differences between prokaryotic and eukaryotic cells and how these differences benefit multicellular organisms.

Shiksha Dutta

Numerade Educator

Problem 26

What is the difference between a repressible and an inducible operon?

JH

Josh Hill

Numerade Educator

Problem 27

In cancer cells, alteration to epigenetic modifications turns off genes that are normally expressed. Hypothetically, how could you reverse this process to turn these genes back on?

Shiksha Dutta

Numerade Educator

Problem 28

A scientific study demonstrated that rat mothering behavior impacts the stress response in their pups. Rats that were born and grew up with attentive mothers showed low activation of stress-response genes later in life, while rats with inattentive mothers had high activation of stress-response genes in the same situation. An additional study that swapped the pups at birth (i.e., rats born to inattentive mothers grew up with attentive mothers and vice versa) showed the same positive effect of attentive mothering. How do genetics and/or epigenetics explain the results of this study?

Shiksha Dutta

Numerade Educator

Problem 29

Some autoimmune diseases show a positive correlation with dramatically decreased expression of histone deacetylase 9 (HDAC9, an enzyme that removes acetyl groups from histones). Why would the decreased expression of HDAC9 cause immune cells to produce inflammatory genes at inappropriate times?

Shiksha Dutta

Numerade Educator

Problem 30

A mutation within the promoter region can alter transcription of a gene. Describe how this can happen.

Shiksha Dutta

Numerade Educator

Problem 31

What could happen if a cell had too much of an activating transcription factor present?

Shiksha Dutta

Numerade Educator

Problem 32

A scientist identifies a potential transcription regulation site 300 bp downstream of a gene and hypothesizes that it is a repressor. What experiment (with results) could he perform to support this hypothesis?

Shiksha Dutta

Numerade Educator

Problem 33

Describe how RBPs can prevent miRNAs from degrading an RNA molecule.

Shiksha Dutta

Numerade Educator

Problem 34

How can external stimuli alter post-transcriptional control of gene expression?

Shiksha Dutta

Numerade Educator

Problem 35

Protein modification can alter gene expression in many ways. Describe how phosphorylation of proteins can alter gene expression.

Shiksha Dutta

Numerade Educator

Problem 36

Alternative forms of a protein can be beneficial or harmful to a cell. What do you think would happen if too much of an alternative protein bound to the $3^{\prime}$ UTR of an RNA and caused it to degrade?

Shiksha Dutta

Numerade Educator

Problem 37

Changes in epigenetic modifications alter the accessibility and transcription of DNA. Describe how environmental stimuli, such as ultraviolet light exposure, could modify gene expression.

Shiksha Dutta

Numerade Educator

Problem 38

A scientist discovers a virus encoding a Protein $X$ that degrades a subunit of the elF4F complex. Knowing that this virus transcribes its own mRNAs in the cytoplasm of human cells, why would Protein X be an effective virulence factor?

Shiksha Dutta

Numerade Educator

Problem 39

New drugs are being developed that decrease DNA methylation and prevent the removal of acetyl groups from histone proteins. Explain how these drugs could affect gene expression to help kill tumor cells.

Shiksha Dutta

Numerade Educator

Problem 40

How can understanding the gene expression pattern in a cancer cell tell you something about that specific form of cancer?

Shiksha Dutta

Numerade Educator