Deck 17: Regulation of Gene Expression in Eukaryotes

Question 1

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

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

Answer 1

B

Question 2

Describe the general structure of a transcription factor.

Answer 2

Transcription factors are modular proteins with at least two functional domains: one binds to DNA in promoters and enhancers,and another activates transcription.

Question 3

DNA methylation may be a significant mode of genetic regulation in eukaryotes.Methylation refers to ________.

A) altering RNA polymerase activity by DNA modifications
B) changes in DNA-DNA hydrogen binding
C) altering translational activity especially of highly methylated tRNAs
D) alteration of DNA polymerase activity by addition of methyl groups to glycine
E) residues F) addition of methyl groups to the cytosine of CG doublets

Answer 3

E

Question 4

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

Question 5

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

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

Question 6

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

Question 7

Describe three characteristics of enhancers and silencers.

Question 8

UASs (upstream activating sequences)are DNase hypersensitive.This means that ________.

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

Question 9

The two major components of the immune system are humoral and cellular immunity.The humoral component ________.

A) is involved in the production of antibodies
B) allows the T cells to produce antigens that then stimulate antibody production
C) plays a major role in the production of antigens
D) suppresses the production of T cells
E) is responsible for allowing horizontal gene transfer

Question 10

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

Question 11

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

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

Question 12

Describe how nucleosomes may influence gene transcription.

Question 13

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

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

Question 14

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

Question 15

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

A) transcriptional regulation
B) RNA splicing regulation
C) intron/exon shuffling
D) 5′-capping regulation
E) poly(A) tail addition

Question 16

Channels between chromosomes in the interphase nucleus are called ________.

A) extrachromosomal elements
B) localized zones
C) nonlocalized zones
D) interchromosomal compartments
E) subchromosomal territories

Question 17

In what way can 5′-azacytidine influence transcription?

Question 18

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

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

Question 19

Because of the imprecision of molecular joining,recombination between LV and J regions shows considerable variation.Which additional circumstance contributes to this variation?

A) transmutation
B) hypermutation
C) transfection
D) conjugation
E) transduction

Question 20

Transcription factors appear to be important molecules relating to the regulation of gene activity.Two general classes of transcription factors exist in eukaryotes.Briefly describe each.

Question 21

In some cases,genes undergo amplification (local,multiple duplications)when additional gene products are in high demand.Would you consider gene amplification as a form of genetic regulation in eukaryotes? Explain your answer.

Question 22

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 23

In general,one could say that fewer levels of regulation are possible in prokaryotes than in eukaryotes.

Question 24

The CAAT (CAAT box)sequence appears to be critical to the ability of many eukaryotic promoters to facilitate transcription.

Question 25

What evidence indicates that steroid hormones exert their influence at the level of DNA?

Question 26

In what way is gene rearrangement related to gene regulation? Give an example.

Question 27

When transcription factors interact with DNA,is the resulting genetic control typically positive or negative?

Question 28

List three major structural classifications of DNA-binding domains that are found in eukaryotic transcription factors.

Question 29

Describe the function and general nature of promoters in eukaryotes.

Question 30

Transcription in eukaryotes is generally influenced by enhancers just as in prokaryotes.

Question 31

Regulation of RNA transport through the nuclear membrane is as common in prokaryotes as in eukaryotes.

Question 32

Mutations in the promoter region of the β-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,TATA box),does transcription usually increase or decrease?

Question 33

What are the approximate positions of consensus sequences (modular elements)at the 5′ end of eukaryotic genes?

Question 34

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

Question 35

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

Question 36

In what ways are eukaryotic transcription factors thought to function?

Question 37

Name three consensus sequences or modular DNA sequences that exist upstream from the coding regions of some eukaryotic genes.

Question 38

List three general pathways in which eukaryotic mRNA is typically degraded in eukaryotes.

Question 39

Provide a general set of statements that describes an enhancer.

Question 40

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 41

An upstream activator sequence (UAS)can function at variable distances and in either orientation.However,it differs from an enhancer in that it cannot function downstream of the transcription starting point.

Question 42

Alternative RNA processing generates different mRNAs,which can direct the synthesis of different polypeptides.

Question 43

One of the earliest steps in the RNAi pathway involves the association of siRNA or miRNA molecules with an enzyme complex composed mainly of reverse transcriptase.

Question 44

The term spliceopathy would be a reasonable term to signify a genetic condition caused by a defect in the regulation of RNA splicing.

Question 45

Alternative RNA processing can result in different mRNAs that start with different exons.

Question 46

Transcription factors are proteins with at least two functional domains-one that binds to DNA and one that binds to RNA polymerase or to other transcription factors.