final_2006_key

final_2006_key - 1 Name:_ ID:_ BIS 101 - 03 Final June 10,...

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1 Name:________________________________ ID:____________________ BIS 101 - 03 Final June 10, 2006 READ THE FOLLOWING INSTRUCTIONS: Write your name and ID # LEGIBLY on each page of this exam. All work must be done in INK. Show ALL your work. This exam is worth 200 points. You have 110 minutes to complete the exam. ______________________________________________________________ AUTHORIZATION FOR PUBLIC DISTRIBUTION OF GRADED EXAMINATIONS I, _________________________________, ID#__________________________ authorize the University to publicly distribute my graded examination for BIS 101-03. Date_______________ Signed:____________________________________ I, _________________________________, ID#__________________________ hereby certify that I have read and understood all the instructions given on this page. I also hereby agree not to give or take any outside help from other students and/or any written material during this examination. I certify that all the work presented here was executed by me and that I understand that the rules and regulations predicted in the University's Code of Academic Conduct will be applied if necessary. GOOD LUCK!
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2 P a g e : 3 ________ 4 ________ 5 ________ 6 ________ 7 ________ 8 ________ 9 ________ 8________ 9 ________ 10 ________ 11 ________ 12 ________ 13 ________ 14 ________ 15 ________ 16 ________ Total ________ Bonus ________
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3 Name:______________________________ (1) The DNA helices of each of the four chromatids of a meiotic bivalent in a Neurospora crassa heterozygote + b are shown below. The heteroduplex shown below was generated during meiotic DS DNA break repair. The A-T base pair is present in the + allele and the G-C base pair is present in the b allele. (a) Show how a 2 + : 6 b ascus is produced by gene conversion. Draw base pairing after conversion in the blank space in the Figure below. (6 points) Base pairing before conversion Base pairing after conversion Genotypes Genotypes of tetrad cells of ascospores ______________________________________________________________________ + _______ _ _ ____A_______ 5' ____A_______ 5’ + _____ _ _ _ _____ T_______ 3' ___ T_______ 3' + _____ _ _ _ ______A_______ 5' ______G_______ 5' b _____ _ _ _ ______C_______ 3' ______C_______ 3' b b _____ _ _ _ ______G_______ 5' ______G_______ 5' _____ _ _ _ ______C_______ 3' ______C_______ 3' b b _____ _ _ _ ______G_______ 5' ______G_______ 5' b _____ _ _ _ ______C_______ 3' ______C_______ 3' b b b (b) Show how a 3 + : 5 b ascus is produced. (6 points) + _____ _ _ _ ______A_______ 5' ______A_______ 5' + + _____ _ _ _ ______T_______ 3' ______T_______ 3' + _____ _ _ _ ______A______ 5' ______A______ 5' _____ _ _ _ ______C______ 3' ______C______ 3' +/b b ______ _ _ _ _____G______ 5' _____G______ 5' ______ _ _ _ _____C______ 3' _____C______ 3' b b _____ _ _ _ ______G______ 5' ______G______ 5' b _____ _ _ _ ______C______ 3' ______C______ 3' b b b
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4 Name:______________________________ (1) Mr. and Mrs. Simpson have been trying for years to have a child but have been unable to conceive. A test revealed that Mr. Simpson has a markedly reduced sperm count. His chromosomes were studied, and testicular biopsy was done. His chromosomes proved to be normal except for chromosome pair number 12. The G banding of the chromosomes indicated that one chromosome 12 was normal but its homologue had a pericentric inversion . (a) Using an arbitrary gene sequence ABCDE centromere FG , write down a sequence that would be a pericentric inversion. (2 points) AFcentromereEDCBG (b) Draw the pachytene loop chromosome configuration you expect to frequently observe if you would examine Mr. Simpson’s meiocytes under microscope. Indicate the centromeres, and write the appropriate gene sequence into each chromosome. (4 points) (c) Explain by a single sentence the most important genetic reason why the heterozygosity for the pericentric inversion is responsible for Mr. Simpson’s reduced fertility. (4 points) Single crossovers in the inverted region result in 50% of tetrad cells receiving chromosomes with duplications and deletions, which result in defective sperm.
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final_2006_key - 1 Name:_ ID:_ BIS 101 - 03 Final June 10,...

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