Bios 220 Exam 3 PDF

Name___________________________________ TA ________________ Bios 220 exam 3 Part I: Matching (2 points each/16 total points) _____ paternally imprinted gene A. required for telomerase activity _____ snRNAs...

Name___________________________________ TA ________________ Bios 220 exam 3 Part I: Matching (2 points each/16 total points) _____ paternally imprinted gene A. required for telomerase activity _____ snRNAs B. conserved nucleotide in introns that forms a covalent bond with the 5' nucleotide in the intron _____ poly-A polymerase C. enhancer binding protein _____ histone methylation D. dosage compensation mechanism in mammals E. functional RNAs that can repress translation of certain _____ miRNAs mRNAs _____ sigma factor F. not expressed from the chromosome provided from the mother, but expressed from a chromosome from the father G. expressed from the chromosome provided from the _____ branch point mother, but not expressed from a chromosome from the father _____X-chromosome inactivation H. associated with actively expressed genes I. epigenetic mark that can be found in chromatin of expressed or repressed genes J. processing factor that adds the poly-A sequence to the 3'- end of prokaryotic mRNAs K. conserved nucleotide located at the 5'-end of introns L. RNAs that position the spliceosome during eukaryotic RNA processing M. functional RNA that brings amino acids to the ribosome N. processing factor that adds the poly-A sequence to the 3'- end of eukaryotic mRNAs For instructor use only section 1 O. recognizes conserved promoter sequences and positions RNA polymerase holoenzyme at the transcriptional start site section 2 P. adds the 5'-Cap to certain mRNAs section 3.1 section 3.2 section 3.3 total page 1 This study source was downloaded by 100000894752802 from CourseHero.com on 12-08-2024 19:29:07 GMT -06:00 https://www.coursehero.com/file/110139463/Exam-3-try-1-genepdf/  Name___________________________________ TA ________________ Bios 220 exam 3 Part 2: Multiple choice (2 point each/20 total points) Circle the letter indicating the best correct answer Which of the following statements are true for DNA molecules but not true for RNA molecules? A. can form double helical structures through base-pair complementarity between two strands in a parallel orientation B. can form double helical structures through base-pair complementarity between two strands in an anti-parallel orientation C. contains ribose sugars D. contains adenine nucleotides E. contains thymine nucleotides In a chromosome, which of the following is true? A. The RNAs of all genes are synthesized 5' to 3' off the same DNA strand. B. The RNAs of all genes are synthesized 3' to 5' off the same DNA strand. C. The RNAs of different genes can be transcribed off either strand, and some are synthesized in the 5' to 3' direction and some are synthesized in the 3' to 5' direction. D. The RNAs of different genes can be transcribed off either DNA strand, but they are always synthesized 5' to 3'. E. The RNAs of different genes can be transcribed off either DNA strand, but they are always synthesized 3' to 5'. In prokaryotes, the cis-acting sequences required for RNA polymerase holoenzyme binding include: A. an upstream enhancer B. the -35 and -10 regions C. the TATA box D. the GC-rich box and the CCAAT box E. the AAUAAA sequence The arabinose operon in E. coli is regulated by the trans-acting factor AraC in response to the presence or absence of sugar arabinose. AraC functions as ____________________. A. an activator when arabinose is present and a repressor when arabinose is absent B. a repressor when arabinose is present and an activator when arabinose is absent C. an attenuator when arabinose is present D. an activator when arabinose is absent E. a repressor when glucose is present Why is transcriptional attenuation a prokaryote-specific mechanism for regulating gene transcription? A. prokaryotic genes do not contain introns B. eukaryotic ribosomes bind the 5'-Cap C. prokaryotic mRNAs can be translated while they are being transcribed D. prokaryotes have s single form of RNA polymerase E. cis-acting regulatory sequences are more complex in eukaryotes than in prokaryotes page 2 This study source was downloaded by 100000894752802 from CourseHero.com on 12-08-2024 19:29:07 GMT -06:00 https://www.coursehero.com/file/110139463/Exam-3-try-1-genepdf/  Name___________________________________ TA ________________ Bios 220 exam 3 Phosphorylation of the C-terminal domain of RNA polymerase II is required for __________________. A. recognition of the TATA box B. formation of the preinitiation complex C. transcriptional elongation D. transcriptional termination E. transcript polyadenylation Transcriptional termination in E. coli depends on _________________ in the mRNA 3’-UTR. A. an AAUAAA sequence B. binding of rho factor to sequences C. formation of a stable hairpin D. A or B E. B or C Transcriptional termination in human cells depends on _________________ in the mRNA 3’-UTR A. an AAUAAA sequence B. binding of rho factor to sequences C. formation of a stable hairpin D. A or B E. B or C Use this information for the next two multiple choice questions: You are working with Marshal Nirenberg to determine the genetic code. He asks you to synthesize short RNAs to use in in vitro translation assays. What components would you include in these in vitro RNA synthesis reactions? A. rNTPs and primase B. rNTPs and RNA polymerase C. rNTPs and poly-A polymerase D. rNTPs and polynucleotide phosphorylase E. rNTPs and telomerase You synthesize an RNA in a reaction containing a 2:1 ratio of CTP and UTP (2C:1U). The codons for proline are CCU, CCC, CCA, and CCG. What proportion of triplets will encode proline? A. 4/3 B. 2/3 C. 4/9 D. 1/3 E. 32/729 page 3 This study source was downloaded by 100000894752802 from CourseHero.com on 12-08-2024 19:29:07 GMT -06:00 https://www.coursehero.com/file/110139463/Exam-3-try-1-genepdf/  Name___________________________________ TA ________________ Bios 220 exam 3 Part 3: Short answer (64 total points for this section) Question 3.1: (28 points total) Below are the chemical structures for the amino acids methionine and valine. Circle the side chain (R group) on each of these amino acids, and clearly indicate: 1) the amino group, 2) the carboxylic acid group, and 3) the alpha-carbon. (8 points) Draw the structure of a Methionine-Valine di-peptide that would form during translation, and clearly indicate the peptide bond between these amino acids. (Met is first, Val is second in your drawing). (6 points) Continued on the next page page 4 This study source was downloaded by 100000894752802 from CourseHero.com on 12-08-2024 19:29:07 GMT -06:00 https://www.coursehero.com/file/110139463/Exam-3-try-1-genepdf/  Name___________________________________ TA ________________ Bios 220 exam 3 Question 3.1 (continued): Below (left) is a schematic diagram of a tRNAMet bound to an AUG codon in an mRNA that encodes Methionine. Indicate on the diagram where a Methionine amino acid would be attached in the charged Met-tRNAMet. (3 points) Write the sequence of the anti-codon that recognizes the AUG codon indicating the 5' to 3' polarity. (3 points) There are two different tRNAs that can recognize Valine codons in mRNAs, and they have anti-codons 3'-CAU-5' and 3'-CAG-5'. Using the wobble rules shown above, write all the possible codons that each of these tRNAs can recognize indicating the 5' to 3' polarity in the anti-codon and codon(s) they recognize. (8 points) page 5 This study source was downloaded by 100000894752802 from CourseHero.com on 12-08-2024 19:29:07 GMT -06:00 https://www.coursehero.com/file/110139463/Exam-3-try-1-genepdf/  Name___________________________________ TA ________________ Bios 220 exam 3 Question 3.2: (22 points total) You are working on the E. coli lac operon regulation for your Bios 399 project, and you advisor gives you three mutant strains that exhibit improper regulation of lac operon. Mutant 1 expresses the lacZ, Y and A genes constitutively at high levels in both the presence and absence of lactose. Mutant 2 fails to express these genes in either the presence or absence of lactose. Mutant 3 fails to express the lacZ, Y and A genes in the absence of lactose, but expresses low levels of these genes in the presence of lactose Your advisor tells you that each of these are independently isolated single gene mutants, but she does not know which genes could be affected. Based on your understanding of the lac operon from Bios 220, she asks you to predict what possible mutations could lead to these phenotypes. Use check marks to indicate in the table below which type of mutation(s) could lead to the phenotypes you observe in Mutant 1, Mutant 2, and Mutant 3. (12 points) Note: The cyaA gene encodes adenylate cyclase, and the crp gene encodes the Catabolite Activator Protein (CAP). Mutant 1 Mutant 2 Mutant 3 Mutant 1 Mutant 2 Mutant 3 lacI- _____ _____ _____ lacOC _____ _____ _____ lacZ- _____ _____ _____ lacIS _____ _____ _____ lacY- _____ _____ _____ lacP- _____ _____ _____ lacA- _____ _____ _____ crp- _____ _____ _____ cyaA- _____ _____ _____ Use '+' and '-' to indicate whether ß-galactosidase and permease will be expressed in the following partial diploids in the absence (-) or presence (+) of the inducer IPTG. (10 points) ß-galactosidase (lacZ) permease (lacY) - inducer + inducer - inducer + inducer I+ P+ O+ Z+ Y-/I+ P+ O+ Z- Y+ I- P+ O+ Z+ Y-/ I+ P+ OC Z- Y+ I+ P+ O+ Z+ Y+/IS P+ O+ Z+ Y+ I- P+ OC Z+ Y-/IS P+ O+ Z- Y+ I- P- OC Z+ Y-/IS P+ O+ Z- Y+ page 6 This study source was downloaded by 100000894752802 from CourseHero.com on 12-08-2024 19:29:07 GMT -06:00 https://www.coursehero.com/file/110139463/Exam-3-try-1-genepdf/  Name___________________________________ TA ________________ Bios 220 exam 3 Question 3.3: (14 points total) For growth in the presence of the sugar galactose, the yeast S. cerevisiae depends on the GAL7 and GAL10 genes that encode proteins necessary to metabolize galactose. These genes are coordinately regulated through the action of the GAL3, GAL4, and GAL80 regulatory proteins in response to galactose in the medium. GAL4 is the key transcriptional activator that binds UAS sequences upstream of the GAL7 and 10 genes Use '+' and '-' to Indicate in the following table whether the GAL1, 2, 7 and 10 genes will be expressed in the absence and in the presence of galactose in the listed strains. All genes not listed are wild type, and the GAL7(UAS∆) mutant has a deletion of the UAS upstream of the GAL7 gene. (9 points) no galactose plus galactose GAL7 GAL10 GAL7 GAL10 wild type GAL4- GAL80- GAL80super repressor GAL3- GAL4- ; GAL3- double mutant GAL7- GAL7(UAS∆) GAL80- ; GAL7(UAS∆) double mutant The GAL4 transcriptional activator is described as a "modular protein". Briefly explain what this means. (5 points) page 7 This study source was downloaded by 100000894752802 from CourseHero.com on 12-08-2024 19:29:07 GMT -06:00 https://www.coursehero.com/file/110139463/Exam-3-try-1-genepdf/ Powered by TCPDF (www.tcpdf.org)