遗传学试卷_英语版答案.docx

6295976420e807ac934f86bbf54dc0f6.pdfEssentials of GeneticsTest Paper(A)闭卷（）开卷（）适用专业：植物科学与技术2003Name： Student Number： Major and Grade： 本试题一共四道大题，共10页，满分100分。考试时间180分钟。总分题号一二三四五六阅卷人题分203610111013核分人得分注：1.答题前，请准确、清楚地填各项，涂改及模糊不清者、试卷作废。2.试卷若有雷同以零分计。3.所有答案均填在试卷上。一选择题（每题1分，共计20分）1 A _ trait is passed from an affected father to all of his daughters and to none of his sons. A. autosomal dominant B. autosomal recessive C. sex-linked dominant D. sex-linked recessive E. Y-linked 2 In the X-Y system, females are referred to as A. homogametic. B. heterogametic. C. polyploids. D. homospecific. E. heterospecific. 3 In Mendels peas, tall is dominant to dwarf and yellow is dominant to green. A pure-breeding tall, yellow plant is crossed to a pure-breeding dwarf, green plant. The resulting offspring are intercrossed to generate an F2 generation. Which of the F2 offspring phenotypes will breed true? A. yellow, tall B. yellow, dwarf C. green, tall D. green, dwarf E. none of the above 4 An individual heterozygous for five different genes can produce how many genetically different gametes? A. 2 B. 4 C. 8 D. 16 E. 32 5 Consider the cross AaBb x AaBb. If the alleles for both genes exhibit complete dominance, what phenotypic ratio is expected in the resulting offspring? A. 1:1:1:1 B. 9:3:3:1 C. 3:6:3:1:2:1 D. 1:2:1:2:4:2:1:2:1 E. the ratio is not predictable 6 Which sequence(序列) correctly describes the order of events in the cell cycle? A. Mitosis - G1 - G2 - S B. S - G1 - G2 - Mitosis C. G1 - G2 - S - Mitosis D. G1 - S - G2 - Mitosis E. G1 - S - Mitosis - S 7 Are the sister chromatids of a chromosome necessarily identical（同一的） at the beginning of metaphase（中期的） of Meiosis I? A. Yes, sister chromatids are always identical structures; if not, they are not chromatids B. Yes, only homologous chromosomes differ from each other C. No, crossing over could generate differences between sister chromatids D. No, there are never similarities between sister chromatids E. Mabe, it varies from cell division to cell division 8 In corn（玉米）, the endosperm（胚乳） of a kernel（果核） is A. haploid. B. diploid. C. triploid. D. polyploid. E. unbalanced. 9 A gametophyte（配子体：产生配子和具单倍数染色体的植物体） is A. diploid. B. haploid. C. triploid. D. polyploid. E. unbalanced. 10 Which evolutionary explanation(s) are proposed to explain the existence of sex?（存在性） A. adjusting to changing environment B. combining beneficial mutations C. removing deleterious(有害的) mutations D. all of the above E. there is no proposed benefit of sexual reproduction11 Traits expressed only in one sex, although the genes are present in both sexes are said to be A. sex-limited. B. sex-influenced. C. sex-conditioned. D. sex-linked. E. holandric. 12 Consider three recessive alleles (a, b, and c) in a hypothetical （假设的）organism. Assume that a female heterozygous for all three traits is testcrossed. Which of the data sets below would indicate（表明） that all three genes are independently assorting? A. a+ b+ c+ = 378; a b c = 375; a+ b c = 370; a b+ c = 372; a+ b+ c = 370; a b c+ = 379; a+ b c+ = 380; a b+ c = 376 B. a+ b+ c+ = 940; a b c = 932; a+ b c = 282; a b+ c = 286; a+ b+ c = 245; a b c+ = 240; a+ b c+ = 40; a b+ c = 35 C. a+ b+ c+ = 940; a b c = 932; a+ b c = 125; a b+ c = 130; a+ b+ c = 938; a b c+ = 943; a+ b c+ = 132; a b+ c = 135 D. a+ b+ c+ = 300; a b c = 900; a+ b c = 300; a b+ c = 300; a+ b+ c = 300; a b c+ = 300; a+ b c+ = 300; a b+ c = 2 E. none of the above 13 Consider three recessive alleles (a, b, and c) in a hypothetical organism. Assume that a female heterozygous for all three traits is testcrossed. Which of the data sets below would indicate that two of the genes are linked and the third is independently assorting? A. a+ b+ c+ = 378; a b c = 375; a+ b c = 370; a b+ c+ = 372; a+ b+ c = 370; a b c+ = 379; a+ b c+ = 380; a b+ c = 376 B. a+ b+ c+ = 940; a b c = 932; a+ b c = 282; a b+ c+ = 286; a+ b+ c = 245; a b c+ = 240; a+ b c+ = 40; a b+ c = 35 C. a+ b+ c+ = 940; a b c = 932; a+ b c = 125; a b+ c+ = 130; a+ b+ c = 938; a b c+ = 943; a+ b c+ = 132; a b+ c = 135 D.a+ b+ c+ = 300; a b c = 900; a+ b c = 300; a b+ c+ = 300; a+ b+ c = 300; a b c+ = 300; a+ b c+ = 300; a b+ c = 2 E. none of the above 14 Given the gene sequence A B C D E F, crossing over should occur（发生） most frequently between A. A - B. B. A - C. C. B - D. D. A - E. E. D - F. 15 The following data were obtained from a transduction experiment: A+B+C+ = 50; A+B+C- = 75; A+B-C+ = 1; A+B-C- = 300 (Total = 426). What is the correct gene order? A. ABC B. ACB C. BAC D. CAB E. cannot be established with a partial data set 16 Strains（菌株） of bacteria（细菌） that have nutritional requirements（营养条件） are called A. heterotrophs. 异养生物B. autotrophs. 自养生物C. auxotrophs. 营养缺陷型D. prototrophs.原养性微生物 E. conditional-lethals. 条件致死17 A person with a missing chromosome number 13 and a missing chromosome 18 is said to have A. trisomy. B. monosomy. C. disomy. D. double monosomy. E. double disomy. 18 A(n) _ often results when chromosomes from two different species double to produce a viable （可养活的）hybriD. （杂种、混血儿）A. somatic doubling 身体加倍B. allopolyploidy 异源多倍体C. autopolyploidy 同源多倍体D. haploidy E. trisomics19 If a nucleic acid is found to contain （包含）20% A and 20% T, what can you conclude （推断）about the percentage（百分率） of G and C bases（根据） present（现在的）? A. 20% C and 2% G B. G+C=A+T therefore G+C=40% C. G+C=1-(A+T) therefore G+C=60% D. G+C=80% E. cannot be determined 20 The sequence（顺序） of the coding strand （编码链：双链DNA中，不能进行转录的那一条DNA链，该链的核苷酸序列与转录生成的RNA的序列一致（在RNA中是以U取代了DNA中的T），又称有义链（sense strand）。）of DNA is the same as the A. template strand. B. mRNA. C. tRNA. D. both of these E. none of these 二名词解释（每题3分，写出中文名称1分，解释含义2分，共计36分）1 haploid or monoploid2 heritability3 heterochromatin or euchromatin4 homologous chromosomes5 independent assortment6 interference 7 transformation or conjugation8 transduction 9 meiosis or mitosis10 imcomplete dominance or codominance11 synapsis12 translocation三 填空题（每空1分，共10分）1 Genetics studies both 遗传 and 变异 of inheritable traits.2 基因座 is the site or position of a particular gene on a chromosome; is any of the alternative forms of given gene. 3 What is the phenotypic rate in F2 population when two pairs of genes interact Complementary effect 9:7 , Additive effect 9：6：1 ,Recessive epistasis 9：3：4 ,Inhibiting effect 13：3 . 4 In diploid organism, chromosomes composition of Nullsomy is 2n and double trisomy is 2n+2 四简答题（共计11分）1what is main standard(标准) to identify (鉴定或识别)chromosomes？（5分）1、 长度2、 着丝粒的有无和位置3、 臂的长短4、 有无随体2 Your have four strains of Drosophila(A-D) that were isolated form different geographic region. You compare the gene sequence and obtain the results:A：m n r q p o s t u v B: m n o p q r s t u vC: m n r q t s u p o v D: m n r q t s o p u v If C is presumed to be the ancestral strain, what order did the other strains arise, and why? (6分).发生了倒位，在联会时，形成倒位圈，干扰了交换，故需要多代选择，直到有出现不出现倒位圈的足够大的群体，进化完成，以后又倒位，再循环，直到出现了新物种五计算题（10分）These gene cn, c and px are linked in the second chromosome of Drosophila. In a cross of cn c px/+ + + female cn c px/cn c px male, the following progeny were counted:cn c px /cn c px: 296cn c + / cn c px: 63cn + + / cn c px: 119cn + px / cn c px: 10+ c px / cn c px:86+ c + cn c px: 15+ + + / cn c px: 329+ + px / cn c px: 82total 1000(1) what is the frequency（频率） of recombination（重组） between cn and c?(2) what is the frequency of recombination between c and px?(3) what is the frequency of recombination between cn and px?(4) Why is the frequency of recombination between cn and px smaller（小于） than the sum of that between cn and c and that between c and px?(因为cn和px间同时发生了双交换，使频率变低)(5) What is the coefficient of coincidence （符合系数）across this region（在这个地区）? What is the value of the interference（干扰值）?(6) Draw a genetic map of the region, showing the locations of cn, c, and px and the map distances between the genes.（1）确定三基因顺序cncpx296亲本型+329cnc+63单交1+px82+cpx86单交2cn+119cn+px10双交+C+15total 1000由亲本型和双交可知 c/+ 处在中间，及cn-c-px确定单交换点：单交1：c-px单交2：cn-c(2)、求值+双交换值双交换值=（10+15）/1000 *100%=2.5%c与px间的交换值=（63+82）