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practice test 3 - 0 BiOL 230 Genetics Test 3 name team name...

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Unformatted text preview: 0 BiOL 230 Genetics Test 3 name: team name When you finish, please sign the pledge (but only if it is truel): - t "On my honor, I pledge that I have neither given nor received any aid on this exam, and I will not/did not discuss it, directly or indirectly, with any other student until after 1:00 PM today. I understand that to do so would constitute a violation of the Xavier University policy on academic honesty and could result in a O on this test.” Basic uestions oints multi Ie choice2 ts each 1. Which of the following features is common to both DNA replication and transcription? A. Nucleotides are added to the 5' end of the newly synthesized strand. (51 A sugar-phosphate bond is formed between the 3' hydroxyl and the 5' phosphate. C. Deoxyribonucleotides are incorporated into the growing sequence. D. Both RNA and DNA polymerases require oligonucleotide priming. 2. Which of the following features of a protein structure is most directly determined by the genetic code? (7%.; its amino acid sequence C. its subunit composition (quaternary structure) B. its overall 3—D shape D. whether it plays a catalytic or structural role 3. The excision of the introns and the joining of the exons is accomplished by . spliceosomes B. ribosomes C. RNA polymerase D. mismatch repair ‘4: Transfer RNA participates in protein synthesis by . :1 A. "carrying an amino acid so that it will be lined up in the proper order and orientation “B. transferring genetic instructions from nucleus to cytoplasm C. containing codons D. specifying the amino acid sequence of a particular protein E. all of the above 5. 0n the blot below, sketch the expected appearance of the Muskie transcript given the following description. (6. pts) A researcher is interested in the effects of mutations upon the expression of the Muskie gene in eukaryotes. The transcribed region of the gene is 1500 bp long and contains one intron that is 500 bp long. r i’ .J ' "“ ' L— C)i«"' Mature mRNA from the following individual diploid organisms was run on the gel, the gel was blotted, and the blot was probed with a section of the Muskie gene that includes an exon: a. a normal individual (done as an example) b. an individual that is homozygous for a 3 bp deletion that removed the AG from the splice acceptor site at the intron- exon boundary. c. an individual that is heterozygous with one wild type allele and one allele as described in b. d. an individual that is homozygous for a substitution mutation that causes an early stop codon in the second exon. \900 standard a b c d 2000 hp 1500 bp 1000 bp ‘ 500 bp 6. The following diagram shows one protein-coding gene, and specifies the positions of its translational start and stop signals. (Solid line = transcribed section.) (8 pts) a. Which strand is the template for transcription? A. upper (from this perspective) B. lower (from this perspective) Now yourjob is to sketch the items below alongside the given gene. b. Using a straight line, sketch the corresponding mRNA aligned with the gene. Be sure to label the ends. c. Using a zigzag line, sketch the corresponding polypeptide. Be sure to label the ends. “i d. On the gene diagram itself, label the promoter region. ‘ a L . a. s l “S w a "/ ;/\/\/\/\/Vi/ .’ - ‘ ' 5 ’i/L/‘l/‘x/ \A); J) S ' U 6:: a M l : 3, / ’~\ wm_ _______________________ .. 7. This question is from MCAT Question A Daym: The Lac operon contains three genes; Lac A, Lac Z, and Lao Y. A promoter lies upstream of the three genes. When IPTG, an inducer of the lac operon, indirectly exposes the promoter, which of the operon genes will be transcribed? A. none; only genes immediately adjacent to the promoter will be transcribed B. the first gene in the operon; all genes are controlled by their own individual promoters If; none; promoters do not control the transcription of genes on operons', only standalone genes all; all genes within a single operon are transcribed as a unit, as initiated by a single promoter §. Which of the following are involved in regulating the expression of the lac operon in E. coli? Choose all that apply. ""ATProduct of the lac! gene - 79w- ®cAMP-CRP complex = naval-LA C. Methylation of the operator D. Alternative splicing of polycistronic RNA E. Attenuation ./ :. — I; u 14.41.- ‘ 5-4,: 9. lnducers are small molecules that stimulate mRNA synthesis by binding to which of the followin ? A. Corepressor B. Attenuator C. Promoter D. Operator @Repressor lupui; 1'. L.- 10. In the partial diploids listed here, indicate whether overall b-galactosidase activity is constitutive, inducible, or uninducible (F‘ indicates plasmid). plasmid [chromosome + + + + . //>fi\" a. F'/ 0 EH 0 Z A. constitutive Bmducible b. F' ro*._7/ ro*z* Q? constitutive B. inducible ’ g L' » {3.19;}; h ,SD 5' -'- 33%;. c. F' l*o*g/ ro°z A. constitutive B. inducible d. F’ l*o*2*/rocz+ @constitutive B. inducible lib/L OA ‘vh‘W/Jy‘Lubf ' . ‘- 031%." 11. Aneuploidy is " . A. a chromosome number that is more than twice the haploid number. :;'B_.‘;the addition or lack of a particular Chr°m°s°me' C. a chromosomenumber that is a normal mu iple of the haploid number. It“ -‘ ‘ 7‘1. -.r_:i‘-."!r l. E UDlot-DI sf. : fit-H4 ,1 f“ ... Li‘zh3 aqua-:9 Ll” \ C. uninducible C. uninducible 'l/ J‘ka S; QC) uninducible 1" P3". .1 v- y:}-?_',." C. uninducible 2.7 The two loci A and B are normally 30 map units apart on a given chromosome. Sally finds a weird fly for which linkage crosses only yield an RF of 20 map units. What’s the matter with this weird fly? A. It has a translocation involving the A and B chromosomes. » . I r ‘ ‘ b'.:‘ B. It has a deletion of 1/3 of the A and B genes. ©lt has an inversion of 1/3 of the distance between genes A and B. D. it has a duplication of 2/3 of the chromosome between genes A and B. v " '1?" .L LIZI"I'1I.';€-V:.'<i:v.‘ly‘-‘P'l>; ,r‘l . '— x L. -1‘--1 ‘7 > Gift? ‘ fiat: i- i‘ f l ,' [Q';I‘~ui..i{\,; j.) E; who; ,mor: 13. Which of the following \represents a translocation involving a chromosome with a normal gene order ABCDEF? C. ABEDCF A. ABCEF @ABKLM D. ABBCDEF 14. Sally has four strains of Drosophila that carry deletions on the same chromosome. The deletion strains “uncover” genes k - ras indicated in the following table. In this table, D1 through D4 denote deletions, and a through e denote recessive alleles of different genes. A “—” sign indicates that the recessive is uncovered by a deletion and a “E” sign indicates that it is not uncovered. Deduce the order of the genes. g h d e t I I D1 El + — + — — {DH D2 — — B] + — + D3 + + — — + + D4 + _ + + _ + + (3 ptS) 15. Cri-du-chat (cat cry) syndrome is caused by a deletion on chromosome 5. Affected children have a cat-like, high- pitched cry during infancy, mental retardation and physical abnormalities. About 1 in 20,000 to 50,000 babies is born with this disorder. (4 PtS) Below are the steps for using PCR to establish a diagnosis of Cri-du-chat syndrome in new patients. Put them in the correct order by writing numbers 1 - 6 in the blanks (1 = first step, 2 = second step, etc). _1 prepare DNA from the patient samples (cheek cells or blood) 5' observe the presence or absence of bands on the gel _L(_ mix DNA with primers plus taq polymerase plus nucleotides 2 run reactions in thermal cycler (changes temperature in cycles) 5 run the PCR products on a gel _1_ get primers complementary to the appropriate region of chromosome 5 “MW .- Challenging Questions 115 pts) Draw appropriate conclusions. 16. Consider the qu operon and the expression of the genes for luciferase and other enzymes involved in bioluminescence. Luciferase expression is regulated by a mechanism that senses the relative number of Vibn'o bacteria in the environment; the cells secrete a molecule called VAI that interacts with the LuxR (regulatory) protein. The LuxR regulatory protein has two binding sites, one for VAI and also a DNA—binding site that recognizes luxP. When LuxR protein is bound to luxP, transcription of luxC—G increases greatly. In this way, the bacteria emit light only when the population reaches a certain density, measured experimentally as 1010 to 1011 cells per milliliter. (1 0 pts) The Lnx Operon RNA LuxR luxR luxO luxP luwCDJBIAJEIG l Promoter m 1 mRNA mlENA I) + v ribosomes l nbosomes 1 synthesis at lucitemse - a. Is the qu operon under positive or negative regulation? 2 r b. In this example, is VAI binding to the regulatory protein making the regulatory protein GET ON or GET OFF the promoter? C c. In this example, is VAI working as a co—repressor or a co—activator? .. 13,“ Li,“ ’¢._ ._ . j ' i \f‘ CO ’ My? . . d. Now consider mutants in bioluminescence. The quR gene encodes the regulatory protein, quP is the promoter, and quA encodes one subunit of luciferase. Predict if the following mutants will emit light when grown in media with and withoutVAl. «,2: e v' . rhi- will emit light in high VAl conc. "yes" “no” will emit light in low VAI conc. ll es" “no” 1']. Interferon is a protein that is produced and secreted by virus—infected cells as a warning to neighboring cells. In neighboring cells, receiving the interferon signal triggers defense mechanisms. In this way, interferon is described as interfering with viral replication in the neighboring cells, hence the name. In humans, interferon is encoded by an intronjes‘sgene. The complete gene is contained on a single Bam HI restriction fragment and can be identified on a Southern blot by hybridization to a specific interferon cDNA probe (labeled with 2P). Physicians want you to determine the cause of unknown immune deficiencies in several patients, and have sent you tissue samples from patients and unaffected people so that you can examine them for the a-interferon gene and its expression. Autoradiograms (X-ray films) for Southern and Northern blots and Western blots are shown below. The protein bands are detected by antibodies that recognize interferon protein. Individuals 1 and 2 are normal for immune capacity (“n”); individuals 3, 4 and 5 have immune deficiencies (“d”). (5 pts) Autoradiograms ’ , VJIS‘JIL": t; r Z~ V Edythern blots— "Cm- Northern blots Protein blots 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 n d d d n d d d . n n d d d v.3“ "Where in the gene is the mutation?” Propose a mutation (type, location) for the patients indicated and briefly explain. / Patient 3: Q, _, («LN fad-L‘er— ‘ ‘ z " D f L; $3") “I. -, \ ~'_‘- rt , r ‘ " .w )9.» r L Ktnh , Hm ) ,_. Nu my '5" Patient 4: r. . " i3 Skaagyrw‘30 59,, 6:”: ‘ s: I l C k r: ‘t "- I. b v , .b kg 4:) S 3 ’1 > ‘ ‘Lf“—’,:'§|r_: -- A ’ m {tuna h b a“; c‘ ( 1 Patient 5: L 0 v I ,- ~.:. ' u . 8:11—37 E x r In .‘kw‘i a ‘- -r ‘ I I l!.:1'~v'-‘ ' ' (‘3‘;v'"“ g ' s. (3&2er 2/ ) 0-7;“ T" ‘ Which person appears to be heterozygous for an interferon deficiency? 7,, ...
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  • Fall '12
  • DorothyB.Engle
  • Genetics

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