QuestionsMarch15
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March 15, 2006 Multiple choice questions (numbers in brackets indicate the number of correct answers) Insulators Delimit functional domains Delimit structural domains Stimulate gene expression are usually smaller than 1000 bp overcome positional effects in gene expression Locus control regions Are located close to genes Stimulate gene expression Are usually smaller than 1000 bp Contain Dnase I hypersensitive sites Are present in prokaryotes (2) (2) Nuclear gene expression can be regulated by Histone methylation Histone acetylation Histone remodeling Histone re-arrangement Histone glycosylation Histone deamination (2) Genomic imprinting Activates genes Involves DNA methylation Is only found in mammals Inactivates one of the sex chromosomes Has been found for hundreds of genes Is always maternally inherited (2) DNA-binding proteins Are usually monomeric Interact with DNA by ionic bonds Contain DNA-binding motifs Can regulate gene expression Can be isolated by affinity chromatography (3) Promoters Are DNA sequences Are always in front of genes Consist of consensus sequences Are binding sites for RNA polymerases Are rich in G and C nucleotides Are only found with protein-coding genes Are very similar in prokaryotes and eukaryotes Enhancers Are proteins Are DNA sequences Activate transcription Are located next to a gene Bind to RNA polymerase Transcription termination Occurs at the ends of coding regions Can be induced by specific RNA stem-loops Is similar in prokaryotes and in the nucleus of eukaryotes Can involve the action of several proteins Is always linked to translation Can be regulated (3) Exons Are always found in the same positions in homologous genes Are always flanked by two introns Are protein-coding sequences Outnumber the introns in an RNA Are common in ribosomal RNAs Splicing Removes introns Removes exons Always requires spliceosomes Occurs primarily in the cytoplasm May require more than 100 proteins (2) (3) (2) (2)
