Deck 17: Transcriptional Regulation in Eukaryotes

Question 1

What is the general position of the consensus sequence called the GC box? What is its sequence?

A)attenuator; GGGCGG
B)promoter; GGGCGG
C)terminator; CAAT
D)promoter; CAAT
E)terminator; GGGCGG

Answer 1

promoter; GGGCGG

Question 2

Gene regulation in eukaryotes is more complicated than bacterial gene regulation.Which of the following describes a gene regulation event that occurs in eukaryotes but not in bacteria?

A)In eukaryotes,mRNA does not need to be modified.
B)In eukaryotes,histones must be added or removed to regulate gene expression.
C)In eukaryotes,transcription and translation occur in the same cellular compartment.
D)In eukaryotes,proteins are post- translationally modified,whereas bacterial proteins are never post- translationally modified.
E)In eukaryotes,mRNA degrades quickly compared to bacterial mRNA that is more stable.

Answer 2

B

Question 3

A regulatory sequence of DNA that is 10,000 base pairs away from the gene it regulates is mutated.The result is that the gene being regulated is now expressed at a higher rate compared to when this regulatory sequence was not mutated.What would this sequence of DNA best be called?

A)activator protein
B)enhancer
C)insulator
D)zinc finger motif
E)silencer

Answer 3

E

Question 4

DNA is methylated on which nucleotides?

A)adenine
B)uracil
C)guanine
D)thymine
E)cytosine

Question 5

Which of the following would be an example of a cis acting eukaryotic gene regulatory element?

A)TATA binding protein
B)enhancer
C)metallothionein
D)RNA polymerase
E)general transcription factors

Question 6

UASs upstream activating sequences)are DNase hypersensitive.This means that__________ .

A)a UAS is constitutively open
B)each UAS is likely to be single stranded
C)any given UAS is composed of a double- stranded site with a bound repressor
D)each UAS has more histone- binding sites than non- UAS sites
E)more than one strand of DNA exists in each UAS

Question 7

In what way do upstream activator sequences UASs ,regulatory sequences in yeast,differ from enhancers and silencers?

A)UASs function only upstream.
B)UASs can function only in the 5'-3' direction.
C)Enhancers function only downstream.
D)UASs function only downstream.
E)UASs function in the middle of transcription units.

Question 8

The nuclear regions that contain RNA polymerase and transcription regulatory molecules that help compartmentalize eukaryotic regulation are called__________ .

A)interchromatin compartments
B)nucleosomes
C)chromosome territories
D)transcription factories
E)histones

Question 9

Which of the following clusters of terms apply when addressing enhancers or silencers as elements associated with eukaryotic genetic regulation?

A)cis- acting,variable orientation,variable position
B)trans- and cis- acting,variable position
C)cis- acting,fixed position,fixed orientation
D)trans- acting,fixed position,fixed orientation
E)cis- acting,variable position,fixed orientation

Question 10

Considering the location of genes in the interphase nucleus,certain chromosomal territories appear to exist.Specifically__________,.

A)large chromosomes are more likely to be located in the center of the nucleus
B)even- numbered chromosomes are located in the interior of the nucleus,whereas odd- numbered chromosomes are located peripherally
C)small chromosomes are more likely to be located in the center of the nucleus
D)gene- poor regions of chromosomes are located outside the nucleus,whereas gene- rich regions are located inside the nucleus
E)each chromosome appears to occupy a discrete domain

Question 11

The GAL gene system in yeast is used to metabolize galactose.In the presence of galactose,the GAL genes are expressed; however,in the absence of galactose,the GAL genes are repressed.A yeast mutant is discovered that continuously expresses the GAL genes in the presence or absence of galactose.Which GAL gene is likely mutated?

A)GAL3
B)GAL4
C)GAL1
D)GAL 10
E)GAL180

Question 12

Two modular elements that appear as consensus sequences upstream from RNA polymerase II transcription start sites are__________ .

A)TATA and CAAT
B)enhancers and telomeres
C)TTAA and CCTT
D)rDNA and nucleolar organizers
E)microsatellites and transposons

Question 13

The pre- initiation complex PIC)contains several proteins.What would be the direct consequence be if PIC failed to form?

A)Translation would not be initiated.
B)Transcription would not be initiated.
C)mRNA splicing would not be initiated.
D)Protein would not fold properly.
E)Replication would not be initiated.

Question 14

Which of the following is true about histone acetyltransferase HAT ?

A)HATs have an overall effect of increasing the positive charges on DNA.
B)HATs will make the chromatin more compacted and less available to transcription regulatory proteins.
C)HATs will remove acetyl groups from histone proteins.
D)HATs are usually linked to increasing gene expression.
E)HATs will add acetyl groups to DNA.

Question 15

Which process seems to be the most similar between eukaryotic and prokaryotic genetic regulations?

A)polyA)tail addition
B)transcriptional regulation
C)RNA splicing regulation
D)intron/exon shuffling
E)5'- capping regulation

Question 16

If a promoter region is mutated in such a way that it can no longer be methylated,what would the most likely effect be?

A)The gene linked to that promoter would be over expressed.
B)The gene linked to the promoter would still be expressed,but the protein should contain different amino acids.
C)The gene linked to the promoter would be expressed at regular levels.
D)The gene linked to that promoter would not undergo replication.
E)The gene linked to the promoter would be under expressed.

Question 17

In a particular organism,there are two similar genes called YFG1 and YFG2.YFG1 is expressed in the liver and not in the pancreas,and YFG2 is expressed in the pancreas but not the liver.Neither YFG1 nor YFG2 is expressed in the heart.Based on these observations,which of the following is most true?

A)Both YFG1 and YFG2 genes isolated from the heart would be DNase I sensitive.
B)The YFG1 gene isolated from the pancreas and the YFG2 gene isolated from the liver would be DNase I sensitive.
C)Both YFG1 and YFG2 genes isolated from any tissue the liver,the pancreas,and the heart would be DNase I sensitive.
D)The YFG1 gene isolated from the liver and YFG2 gene isolated from the pancreas would be DNase I sensitive.
E)Neither YFG1 nor YFG2 isolated from any tissue the liver,the pancreas,and the heart would be DNase I sensitive.

Question 18

What type of DNA sequence a repressor protein be expected to bind?

A)insulator
B)TATA Box
C)silencer
D)GC Box
E)enhancer

Question 19

The ENCODE Project's goal was to identify all functional DNA sequences within the human genome.Which of the following is a finding from ENCODE?

A)ENCODE determined that approximately 25% of the human genome has some sort of biochemical function.
B)ENCODE determined that approximately 15% of the human genome codes for a protein.
C)ENCODE was able to classify that a large part of the human genome is "Junk DNA."
D)ENCODE was able to determine that each enhancer exerts its regulatory function on only a single gene.
E)ENCODE was able to determine that 75% of the genome is transcribed in at least one cell type.

Question 20

Which of the following is a functional domain that is found in eukaryotic transcription factors and bacteria?

A)basic leucine zipper,zinc finger,and helix- turn- helix motifs
B)basic leucine zipper and zinc finger motifs
C)basic leucine zipper motif
D)zinc finger motif
E)helix- turn- helix motif

Question 21

Describe the function and general natures of promoters in eukaryotes.Include the three different parts of the promoter and their positions from the 5' end of a eukaryotic gene.

Question 22

Describe three characteristics of enhancers and silencers.

Question 23

What is meant by the term helix- turn- helix HTH ?

Question 24

Describe the difference between a focused promoter and a dispersed promoter.

Question 25

List at least three levels or types of genetic regulation in eukaryotes.

Question 26

What are zinc finger motifs,and why are they frequently encountered in descriptions of genetic regulation in eukaryotes?

Question 27

Mutations in the promoter region of the fi- globin gene indicate that some areas are more sensitive than others.When mutations occur in consensus sequences modular elements such as GC box,CAAT box,and TATA box),does transcription usually increase or decrease? Explain.

Question 28

Transcription factors are important molecules that regulate gene activity in eukaryotes.What are the two general classes of transcription factors that exist in eukaryotes? Describe where they bind and what their effects are.

Question 29

On a specific chromosome,an enhancer helps activate the expression of Gene A,but not Gene B,which is equally close to the enhancer.A mutant is identified where this enhancer is now activating the expression of both Gene A and Gene B.Explain what has likely been mutated.

Question 30

Enhancers are said to be cis- acting.What is meant by cis- acting,and what are enhancers?

Question 31

Explain why a transcription factor must have at least two functional domains.

Question 32

Describe the ENCODE project and list five of their findings.

Question 33

In what way 5'- azacytidine can influence transcription?

Question 34

Some diseases are linked to the under or over expression of specific genes.A particular cancer is characterized by the overexpression of a gene.Do you predict the histones associated with this gene to be acetylated? Describe why this would lead to increased gene expression and how histone acetyl transfer HAT)and histone deacetylase HDAC)could be involved.

Question 35

Approximately 5% of the cytosine residues are methylated in the genome of any given eukaryote.In what way is DNA methylation related to genetic regulation?

Question 36

Describe how the presence or absence of nucleosomes influences gene transcription.

Question 37

The human metallothionein IIA gene hMTIIA)is transcriptionally regulated through the interplay of regulatory elements and transcription factors.What is the function of this gene,and how is it regulated by environmental circumstances?

Question 38

Explain five ways that eukaryotic gene regulation is more complex than bacterial gene regulation?

Question 39

In what way 5'- azacytidine is used experimentally)in the treatment of sickle- cell anemia?