Genetics Quiz 4: Regulation of Gene Expression PDF

UST / BIOL3321: Genetics My Grade: ____________ / 99 Formative Assessment My Time: ___________ min Quiz 4: Regulation of Gene Expression in Prokaryotes and Eukaryotes...

UST / BIOL3321: Genetics My Grade: ____________ / 99 Formative Assessment My Time: ___________ min Quiz 4: Regulation of Gene Expression in Prokaryotes and Eukaryotes PROKARYOTES: True or False? (3 points each = 63) 1. ___T____ Nucleoid shape is impacted by NAPs, lncRNAs and transcription. 2. ___T____ NAPs have both structural and regulatory functions in the nucleoid as they modify the shape of the chromosome, mediate interactions with ncRNAs, moderate transcription, and aid in xenogenic silencing among other functions. 3. ___F____ DNA methylation occurs primarily at G bases. 4. ___T____ The R-M system is composed of endogenous methylases and endonucleases that together protect the integrity of the bacterial genome but digest foreign DNA. 5. ___T____ Orphan methylases can regulate gene expression, DNA repair, and initiation of DNA replication. 6. ___F____ In bacteria, RNA editing refers to splicing. 7. ___T____ RNA turnover is impacted by abundance and location of RNases, as well as the binding of ncRNAs and other molecules to the mRNA. 8. ___T____ RNA turnover impacts protein availability. 9. ___T____ Translation in bacteria can be regulated by the presence and strength of ribosome binding sites on the mRNA, codon usage bias and post-translational editing. 10. ___T____ In bacteria, small ncRNAs can impact transcription, translation, mRNA stability, virulence and xenogenic silencing. 11. ___T____ Riboswitches and attenuation are examples of cis-encoded ncRNA elements. 12. ___F____ Cis-encoded ncRNA elements are encoded in a different genomic location from the gene they regulate. 13. ___F____ In bacteria, activators are transcription factors that block the RNAP from binding the promoter. 14. ___T____ Repressors can carry out their function by steric hindrance, road block, DNA looping or modulation of the activator. 15. ___T____ Inducible operons are those in which the structural genes are transcribed in the presence of a specific substrate. 16. ___F____ Repressible operons always require the presence of a regulator that is a repressor. 17. ___T____ The lac operon is both under positive and negative control. 18. ___F____ In the presence of lactose and abundant glucose, the structural genes of the lac operon are expressed. 19. ___F____ The trp operon is both inducible and repressible. 20. ___T____ In the presence of tryptophan, the trp operon is repressed because tryptophan activates the repressor, which in turn binds the operator. 21. ___T____ In the trp operon, the 2:3 hairpin is the antiterminator structure and the 3:4 hairpin is the attenuator. EUKARYOTES: True or False? (3 points each = 36) 1. ___F____ The structure of chromatin and the genome has no impact on regulation of gene expression. 2. ___T____ Transcription in the eukaryotic genome is only possible from euchromatic, non-methylated DNA in active TADs located towards the interior of the nucleus. 3. ___F____ DNA methylation occurs primarily at A bases. 4. ___F____ In eukaryotes, the epigenetic profile is defined by methylated DNA only. 5. ___T____ An imprinted locus is one that has differential methylation and therefore, differential gene expression from the maternal/paternal locus. 1 6. ___F____ CpG islands and transposable elements are typically methylated. 7. ___T____ X-inactivation is an epigenetic process that takes place during early embryogenesis to balance expression of X-linked genes. 8. ___T____ Transcription can be regulated by nucleosome positioning, the presence of alternate promoters and terminators, the action of enhancers and the factors they bind, plus the epigenetic landscape of the locus and the action of various ncRNAs. 9. ___T____ Non-coding RNAs can impact transcription by a variety of mechanisms, including anti-sense transcription, recruiting of complexes that alter DNA methylation and/or the epigenetic code. 10. ___T____ An important mechanism that regulates gene expression post-transcriptionally is alternative splicing. 11. ___T____ Base modifications, RNA turnover and RNA editing are all mechanisms that regulate gene expression post-transcriptionally. 12. ___F____ Translation is not regulated in eukaryotes. 2