Chapter 17 Regulation of Gene Expression in Eukaryotes 1) 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 positionB) trans-acting, fixed position, fixed orientationC) cis-acting, fixed position, fixed orientationD) cis-acting, variable position, fixed orientationE) trans- and cis-acting, variable positionAnswer: ASection: 17.42) Two modular elements that appear as consensus sequences upstream from RNA polymerase IItranscription start sites are ________.A) microsatellites and transposonsB) rDNA and nucleolar organizersC) TATA and CAATD) TTAA and CCTTE) enhancers and telomeresAnswer: CSection: 17.43) 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: BSection: 17.74) Which process seems to be the most similar between eukaryotic and prokaryotic genetic regulation?A) transcriptional regulationB) RNA splicing regulationC) intron/exon shufflingD) 5'-capping regulationE) poly(A) tail additionAnswer: ASection: 17.1, 17.31Copyright © 2012 Pearson Education, Inc.5) DNA methylation may be a significant mode of genetic regulation in eukaryotes. Methylation refers to ________.A) altering RNA polymerase activity by DNA modificationsB) changes in DNA-DNA hydrogen bindingC) altering translational activity especially of highly methylated tRNAsD) alteration of DNA polymerase activity by addition of methyl groups to glycine residuesE) addition of methyl groups to the cytosine of CG doubletsAnswer: ESection: 17.36) Considering the location of genes in the interphase nucleus, certain chromosomal territories appear to exist. Specifically, ________.A) each chromosome appears to occupy a discrete domainB) gene-poor regions of chromosomes are located outside the nucleus, whereas gene-rich regionsare located inside the nucleusC) even-numbered chromosomes are located in the interior of the nucleus, whereas odd-numbered chromosomes are located peripherallyD) large chromosomes are more likely to be located in the center of the nucleusE) small chromosomes are more likely to be located in the center of the nucleusAnswer: ASection: 17.37) Channels between chromosomes in the interphase nucleus are called ________.A) extrachromosomal elementsB) localized zonesC) nonlocalized zonesD) interchromosomal compartmentsE) subchromosomal territoriesAnswer: DSection: 17.38) What is the general position of the consensus sequence called the GC box? What is its sequence?A) promoter; CAATB) promoter; GGGCGGC) terminator; CAATD) terminator; GGGCGGE) attenuator; GGGCGGAnswer: BSection: 17.42Copyright © 2012 Pearson Education, Inc.9) UASs (upstream activating sequences) are DNase hypersensitive. This means that ________.A) a UAS is constitutively openB) more than one strand of DNA exists in each UASC) each UAS is likely to be single-strandedD) each UAS has more histone binding sites than non-UAS sitesE) any given UAS is composed of a double-stranded site with a bound repressorAnswer: ASection: 17.710) The two major components of the immune system are humoral and cellular immunity. The humoral component ________.A) is involved in the production of antibodiesB) allows the T cells to produce antigens that then stimulate antibody productionC) plays a major role in the production of antigensD) suppresses the production of T cellsE) is responsible for allowing horizontal gene transferAnswer: ASection: 17.211) Because of the imprecision of molecular joining, recombination between LV and J regions shows considerable variation. Which additional circumstance contributes to this variation?A) transmutationB) hypermutationC) transfectionD) conjugationE) transductionAnswer: BSection: 17.212) Enhancers are said to be cis-acting. What is meant by cis-acting, and what are enhancers?Answer: Cis-acting means that the genes under control must be in the same chromosome as the cis-acting element. Enhancers are sections of DNA that regulate transcription of other sections ofDNA.Section: 17.413) Describe three characteristics of enhancers and silencers.Answer: Position need not be fixed. Orientation may be inverted without significant effect. Theycan regulate other genes when inserted. They can act at a great distance from the promoter.Section: 17.414) 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.Answer: One class assembles at promoter regions adjacent to the site of transcription. The other class binds at more distant regions (enhancers).Section: 17.53Copyright © 2012 Pearson Education, Inc.15) What are zinc fingers, and why are they frequently encountered in descriptions of genetic regulation in eukaryotes?Answer: Zinc fingers consist of amino acid sequences containing two cysteine and two histidine residues at repeating intervals. Interspersed cysteine and histidine residues covalently bind zinc atoms, folding the amino acids into loops (zinc fingers). They are one of the major groups of eukaryotic transcription factors.Section: 17.516) Describe the function and general nature of promoters in eukaryotes.Answer: Promoter regions are necessary for the initiation of transcription. Promoters that interact with RNA polymerase II are usually located within 100 bp upstream of a gene and usually contain a TATA box (-25 to -30) and a CAAT box (-70 to -80).Section: 17.417) What is meant by the term helix-turn-helix (HTH)?Answer: A geometric conformation is formed by two adjacent α helices separated by a "turn" of several amino acids. Such motifs bind to the major grooves of DNA and interact with the DNA backbone.Section: 17.518) What evidence indicates that steroid hormones exert their influence at the level of DNA?Answer: translocation of the hormone-receptor complex from the cytoplasm to the nucleus, increase in the rate of transcriptionSection: 17.519) List at least three levels or types of genetic regulation in eukaryotes.Answer: transcriptional, DNA methylation, posttranscriptional regulation, posttranslational regulationSection: 17.120) In some cases,