遗传学双语教学试卷2

第一篇：遗传学双语教学试卷2

Genetics Final Examination 2

Define the following terms(5 points each): BLAST OMIM RefSeq

lagging strand

1.(8 points)Define, compare and contrast kinetochore and centromere

Examine this pedigree(which is from your text)

2.(3 points)Is the trait recessive or dominant?

3.(3 points)Is the trait sex-linked?

4.(5 points)Certain people are almost certainly carriers.Indicate these(and only these)by shading on the diagram below:

You are doing research with yeast(S.cerevisiae).Your new gene(yfg3)is 1 cM.away from HIS3.You examine 100 tetrads and observe all 400 spores(this is actually sort of miraculous, since some spores usually die, but it nevertheless occurs).5.(4 points)What is the expected number of tetrads that contain one or more chromosomes with a recombination between YFG3 and HIS3 ?

6.(6 points)Considering all 400 of the haploid progeny without regard to their tetrads of origin, how likely is it that you will observe:

0 recombinant spores 1 recombinant spore 2 or more recombinant spores

A technique developed by Streisinger et al.allows the production of meiotic half-tetrads from zebrafish of virtually any genotype.This is accomplished by using high pressure to block the second meiotic division.Blocking meiosis II leads to two meiotic products instead of four.When these diploid embros are fertilized by UV-inactivated sperm(which contribute no genetic information)they develop as females known as gynogenetic or matroclinous females.7.(5 points)If the mother is heterozygous for a centromeric recessive mutation causing a lack of pigmentation(call it albino), what fraction of the progeny would be homozygous(albino /albino)and show the albino phenotype?

8.(5 points)Another recessive mutation, near the centromere of another chromosome(call this second gene tubby), causes the fish to be fat.If mothers heterozygous for both mutations are “squeezed” to produce matoclinous progeny, what fraction do you expect to show the albino phenotype, the tubby phenotype, both phenotypes and neither phenotype?

9.(5 points)A third mutation, blind, is very far away from the centromere(over 100 cM.)on yet a third chromosome.When fish that are heterozygous for both albino and blind are are “squeezed” to produce matoclinous progeny, what fraction do you expect to show the albino phenotype, the blind phenotype, both phenotypes and neither phenotype?

10.(5 points)In a parallel experiment, you carry out a standard cross.F1 fish that are heterozygous for both albino and blind are are mated among themselves.Now, what fraction of the F2 do you expect to show the albino phenotype, the blind phenotype, both phenotypes and neither phenotype?

11.(4 points)Two wild-type alleles, 1 and 2, are present in a population in Hardy-Weinberg equilibrium.Homozygotes for allele 1 represent 36% of the population.What fraction of the population is heterozygous?

12.(5 points)Here is the sequence of the template strand of a DNA fragment: 5' TCGCATTGCACGGCGACTCAACCATAGTCCCAC 3' Which of the following would be best to use as a primer for DNA synthesis together with the above DNA as a template:

a)5' GGCGTAACGTGCCGCTGAGTTGGTA 3' b)5' AGCGTAACGTGCCGCTGAGTTGGTG 3' c)5' GTGGGACTATGGTTGAGTCGCCGTA 3' d)5' ATGGGACTATGGTTGAGTCGCCGTG 3'

13.Label each of the following short protein sequences as a)negatively charged(acidic);b)positively charged(basic);c)hydrophobic or d)hydrophilic but uncharged.(2 points each)QANQST LLWIVL ADEADE RKAHRH

14.(14 points)Label each of the following six statements as 1)true of DNA polymerase, 2)true of RNA polymerase, 3)true of both or 4)true of neither.a)Absolutely requires a primer with a base-paired 3' end.b)Absolutely requires a template.c)Uses UTP as a substrate.d)Uses dCTP as a substrate.e)Can have(usually has)a 3'-5' exonuclease “proofreading” activity.f)Adds nucleotides to the 5' end of a polynucleotide chain in accordance with basepairing to a template strand.g)Adds nucleotides to the 3' end of a polynucleotide chain in accordance with basepairing to a template strand.

第二篇：遗传学双语教学试卷5

Genetics Final Examination 5

1.Define morality.What are two requirements of morality?

2.What is cultural relativism and how does it impact morality?

3.Define cloning.What are the two different methods of animal cloning? Describe each in detail.4.How might the Christian approach to moral decision making handle human cloning and why?

5.Two candidate genes for breast cancer are BRAC1 and BRAC2.Mutations in one of these two genes are found in 90% of tumors from breast and ovarian cancer.Women with heredity mutations in one of these two genes are 30 times more likely to develop breast cancer by age 50, while men have a three time higher risk of developing prostate or colon cancer if they inherit this mutation.Given the following pedigree determine the probability of individual X carrying one of these mutations.6.The government of Iceland has created a database with the entire population’s genetic code.They are looking for ways to cure Osteoarthritis, a crippling bone disease.How would the Utilitarian approach and Categorical Imperative approach decide if creating this database is moral?

7.Explain the Egoism approach.Give an example of how this could be used.8.What are two of the major differences between “genetically modified” and “conventionally breed” crops? Explain each of your answers.9.How does the character introduced into the “genetically modified” crop behave from one generation to another?(i.e.in terms of Mendelian inheritance)

10.Would you eat a GMO? Explain your reasoning.(1).Give three different examples of Genetically Modified Organisms and describe how each modification improves that organism.(2).What are three of the major concerns/questions regarding Genetically Modified Organisms? Provide some detail explanation for each.(3).What is DNA sequencing? Define and simply describe the process.(4).Why was it important to know the entire human genome sequence?(5).Given the following figures fill in the blank boxes:

What is does this diagram depict? Dogma

(6).What is the Utilitarian approach in moral decision making? Provide one good genetic example.(8).Define cloning.What are the two different methods of animal cloning? Describe each in detail?(9).What are the major concerns/questions regarding “Patenting of genes”? Provide some detail explanation for at least two of them.(10).What are the major concerns/questions regarding “Genetic Testing”? Provide some detail explanation for at least two of them.11.What are the major concerns/questions regarding “Frozen embryos”? Provide some detail explanation for at least two of them.(1).Name and explain in detail three major differences between “Genetically Modified” and “conventionally breed” crops?

(2).How would the “Christian” and “Utilitarian” approaches to moral decision making handle the issue of “Frozen embryos”? What are the differences and similarities? Explain your answer in detail.(3).The government of Iceland has created a database with the entire population’s genetic code.They are looking for ways to cure Osteoarthritis, a crippling bone disease.How would the Utilitarian and Categorical Imperative approaches decide if creating this database is moral?(4).What is cultural relativism and how does it impact morality?(5).Given the following figures fill in the blank boxes:

(6).What are three advantages and disadvantages of producing GMO crops? Describe each in detail.(7).What are the major concerns/questions regarding “Genetic Testing”? Provide detailed explanation for at least two of them.(8).What are two major concerns/questions regarding “Patenting of genes”? Provide detailed explanation for at least two of them.(9).How does genetics directly affect you as a person? Give three examples and explain how you approach them with the knowledge you have from this class.(10).From the Presidential speech handout, what were the president’s decision on a)human cloning and b)stem cell research? Provide details on what guided his decision-making.

第三篇：遗传学双语教学试卷 10

Genetics Final Examination 10 1.The eukaryotic and prokaryotic cell, its basic structure and function CH: Biochemically important organic compounds(overview, functions);structure of carbohydrates and lipids  GB: Bacterial genetics

 HE: Methods of study of cells and tissues 

2.Chemical composition of the cell(chemical bonds, molecules macromolecules)CH: Chemical bonds – formation, types, description, examples of the bonds in the structure of biochemically important compounds(e.g.proteins, high energy compounds)

 GB: Biochemical screening, cytogenetic methods

 HE: Histochemistry and cytochemistry, detection methods using antibodies, targeted pharmacotherapy 

3.Catalyzers of reactions taking place within cells

CB: The role of protein kinases in cell signaling

 CH: Enzymes and vitamins – structure, classification and importance of enzymes, the relationship of vitamins to enzymes;enzyme kinetics  GB: Genetic disorders of metabolism – examples of AR heredity  HE: Functional types of epithelial cells 

4.Exertion of energy in cells CH: Free(Gibbs)energy, endergonic and exergonic reactions, chemical equilibrium;high-energy compounds(examples, structure, formation, importance in the metabolism)

 GB: Major modes of nutrition of prokaryotes  HE: Intracellular transport, cilia and flagella 

5.How do cells gain energy from food – I Carbohydrates CH: Transport of glucose into the cell, glycolysis, synthesis and degradation of glycogen, gluconeogenesis

 GB: Diabetes(type II)as an example of polygenic heredity  HE: Brush border, endocytosis, pinocytosis, cell inclusions  I: Phagocytosis as a mechanism of immune reaction 

6.How do cells gain energy from food – II Lipids CH: Blood transport of lipids;beta-oxidation, synthesis of fatty acids, synthesis and degradation of triacylglycerols;ketone bodies  GB: Atherosclerosis as an example of polygenic heredity  HE: Lipocytes of the white and brown fat tissues 

7.Proteins, structure and function(shape and structure of proteins, how do they work)     CB: Proteomics

CH: Proteins – structure, physicochemical properties, functions in the cell GB: Mutations as a cause of genetic diseases and tumors

HE: Cells exporting proteins, types of secretion, glands, histochemistry I: Immunoglobulins, structure and function

8.DNA , replication and reparation CH: Structure of purine and pyrimidine bases;nucleosides and nucleotides  GB: Morphology of chromosomes, karyotype, numerical chromosomal abnormalities

 HE: DNA and chromatin in the light(LM)and electron(EM)microscopy 

9.The nucleus, chromatin, and chromosomes CH: Comparison of the structure of DNA and RNA

 GB: Structural chromosomal abnormalities, chromosomal changes in tumors  HE: Cell nucleus as depicted with LM and EM 

10.From DNA to proteins(from DNA to RNA, from RNA to proteins, RNA and the origin of life)     CB: Transcription, RNA, splicing, alternative splicing, translation, and ribosomes

CH: Amino acidsdefect of phenylalanine hydroxylase, familiar hypercholesterolemia – defect of LDL receptors, hemolytic anemia – defect of glucose-6-phosphate dehydrogenase(describe the metabolic function of the proteins)

 GB: Mendelian principles, gene linkage, gene interactions

 HE: Distribution of genetic information in mitosis and meiosis, the role of maternal and paternal genes in embryogenesis 

36.Ecology(global ecological problems)CH: Lipoproteins – transport and metabolism

 GB: Human ecology, work with laboratory animals  HE: Sampling and processing materials for histology 

37.Molecular biology of viruses(constitution, structure of the genome, interaction with the host cell)GB: Genetics of viruses, prions  HE: EM detection of viruses 

38.Population genetics 39.Detoxification processes, principles of genotoxicology CH: Common reactions of biotransformation of xenobiotics  GB: Methods used in genotoxicology   HE: Detoxification apparatus of the cell

40.Prenatal and postnatal diagnostics of hereditary diseases CB: Molecular diagnostics of hereditary diseases  GB: Genetic counselling

 HE: Development of the amnion and chorion 

第四篇：遗传学双语教学习题

山东农业大学

遗传学双语教学章节习题

Problems and Questions

Contents

Chapter 1 An introduction to Genetics Chapter 2 Cytology for Genetics —— Mitosis and Meiosis Chapter 3 Molecular basis for Genetics Chapter 4 Mendelian Genetics Chapter 5 Linkage and Sex linkage Chapter 6 Chromosome Mutations: Chromosomal Changes, Monosomy, Trisomy, Polyploidy, Structural Changes Chapter 7 Genetics in Bacteria and Bacteriophages Chapter 8 Gene expression and Control Chapter 9 Gene Engineering and Genomics and Proteomics Chapter 10 Gene Mutation Chapter 11 Extranuclear Inheritance and Maternal Effect Chapter 12 Genetics and Development Chapter 13 Quantities Genetics Chapter 14 Population genetics and Evolution

Chapter 1 An introduction to Genetics

1.Distinguish between haploid and diploid in a manner that makes it clear that you know what each is and how the two differ.2.Define the term “gene”.Include in your answer a brief description of the function of a gene.3.Distinguish between transcription and translation in a manner that makes it clear that you know what each is and how the two differ.4.What is a gamete and why is it considered important in the study of genetics? 5.What is a zygote and why is it considered important in the study of genetics?

6.Distinguish between gene and genome in a manner that makes it clear that you know what each is and how the two differ.7.In molecular terms, how would you define mutation?

8.How is the information that specifies the amino acid sequence of a protein passed from one generation to the next?

9.Distinguish between genotype and phenotype in a manner that makes it clear you know what each is and how the two differ.10.What genetic mechanisms make it possible for individuals with different genotypes to exhibit the same phenotype.11.What is a chromosome and how does it differ from a gene?

12.Can a gamete be heterozygous? Explain the reasoning behind your answer.13.A typical organism has far more genes than chromosomes.Will all of the genes exhibit independent assortment? Explain the reasoning behind your answer.Chapter 2 Cellular basis of Genetics

1.Distinguish between mitosis and meiosis in a manner that makes it clear that you know what each is and how they differ.2 2.Compare the length of the meiotic prophase in human males and females.Which more closely resembles mitotic prophase.How do both differ from mitotic prophase?(See page 332 of the textbook if you have difficulty with this question).3.Briefly summarize the major events in a haploid-diploid life cycle.Identify a species with a predominantly haploid life cycle and a species with a predominantly diploid life cycle.4.What abbreviations are used to designate the four parts of the mitotic cell cycle and what does each stand for?

5.Distinguish between karyokinesis and cytokinesis in a manner that makes it clear that you know what each is and how they differ.6.Name and briefly describe the four stages that mitosis is commonly divided into.(Caution, this is not a repeat of question 4).7.Describe two distinctly different processes that occur during meiosis to bring about mixing of the two parental genotypes during formation of gametes.Identify the stage of meiosis at which each occurs as precisely as you can, and briefly describe the mechanisms that are involved.8.Identify the five stages of meiotic prophase and briefly describe each, including important genetic events that are occurring during that phase.9.What role does mitosis play in a sexual life cycle?(Why do sexually reproducing organisms need mitosis at all?)

10.At what stage of meiosis does crossing over(genetic recombination)occur?(see page 331 of textbook if you are uncertain).11.What are chiasmata and what is their genetic significance?

12.At what stage of meiosis is independent assortment of unlinked genes achieved? What is the mechanism that is involved?

13.At what stage during meiosis do the centromeres of the individual sister chromatids separate? 14.At what stage of meiosis is the chromosome number reduced to haploid(bivalents with sister chromatids still paired count as single chromosomes).15.At what stage of meiosis is the DNA content per gamete reduced to haploid?

16.In terms of genetic uniformity of the ultimate products of each process, how do mitosis and meiosis differ?

17.What is a lampbrush chromosome and under what circumstances is it observed?

Briefly define each of the folowing and explain its genetic significance or its significance to the study of genetics.a.Homologous chromosomes.b.Tetrad.c.Synaptonemal complex d.Biparental inheritance.e.Gametophyte.19.What are the consequences of nondisjunction during one or the other of the meiotic divisions? 20.A human female has 23 pairs of chromosomes.Assuming that the members of each pair differ from each other, how many different different gametes does she have the potential ability to generate, based on independent assortment alone?

21.Meiosis in a female generates one ovum and 3 polar bodies, whereas in a male meiosis generates 4 spermatozoa.Does this result in four times as much genetic diversity in male gametes as in female gametes? Explain the reasoning behind your answer.22.The part of the mitotic cell cycle that was originally viewed simply as “interphase” is now viewed quite differently.a.How was interphase defined and what criteria were used to define it?

b.Identify the three parts that interphase is now divided into and explain the original significance of each of the three parts.c.How has modern research changed our view of the first and third segments of “interphase”? 23.Meiosis generates genetic diversity, whereas mitosis maintains genetic constancy.Explain how this is advantageous to the organism.24.There is evidence that transcription continues in oogenesis, even after meiotic prophase has begun.a.What is the evidence for transcription during meiotic prophase? b.Speculate on what biological purpose such transcription serves.Chapter 2 Cellular basis of Genetics(Molecular basis for Genetics)1.Briefly summarize the flow of information from a gene to a final gene product, including the form that the information takes at each step along the way and the names of the major processes that are involved in achieving the flow of information.2.Distinguish between prokaryotic and eukaryotic in a manner that makes it clear that you know what each is and how they differ.4 3.Summarize two different lines of evidence that have demonstrated that DNA is the primary carrier of genetic information.4.Identify the four nitrogenous bases that are used for the coding of genetic information in DNA.How are they related to the bases used for coding genetic informaiton in RNA?

5.What are the chemical differences between DNA and RNA? You should be to identify two that are always true and a third that is usually true.6.What is a phosphodiester link and how does it give polarity to nucleic acids? 7.Identify the base pairs in DNA.Which pairs are more stable and why? 8.What is meant by the term “antiparallel” as it applies to double helical DNA?

9.Distinguish between sense and antisense strands in a manner that makes it clear you know what each is and how they differ.10.What factors determine how rapidly DNA renatures after being denatured?

11.Distinguish between transcription and translation in a manner that makes it clear that you know what each is and how they differ.12.Explain how electrophoresis can be used to separate nucleic acid molecules by size.What role does the gel play in the process?

13.The nucleotide sequence of the sense strand of a double helical DNA molecule is ATGCGTAACTAACCG.a.What nucleotide is at the 5'-end? b.What nucleotide is at the 3'-end?

c.How would you distinguish the 5'-end from the 3'-end if the bases were the same at both ends? d.What is the nucleotide sequence of the complementary strand?(You always start at the 5'-end when describing a nucleotide sequence).e.What will be the nucleotide sequence of the mRNA that is transcribed from this DNA? 14.Ribose and deoxyribose are both 5-carbon sugars.a.What is the difference between ribose and deoxyribose?

b.What is attached to carbon #1 of these sugars when they are in nucleic acids? c.What is attached to carbon #3 of these sugars when they are in nucleic acids? d.What is attached to carbon #5 of these sugars when they are in nucleic acids?

e.Ribothymidine is an unusual nucleoside that can be recovered from certain types of transfer RNA(transfer RNAs contain a variety of modified bases).What is unusual about finding ribothymidine in a nucleic acid? 15.The genome of E.coli is a closed circle of double helical DNA that contains 4,639,221 base pairs(based on sequence analysis-see page 208 of the textbook).Based on your knowledge of the DNA double helix, answer the following.a.What is the thickness on one base pair in double helical DNA?

b.How many complete turns of the double helix are contained in the E.coli genome? c.What is the circumference of the circular genome when it is laid out as a perfect circle? d.What is the diameter of the genome when it is laid out as a perfect circle.e.An E.coli cell is relatively short cylinder only about 2 micrometers in diameter.How can that much DNA fit into it.(Hint, look at figures 7.6 and 7.7).16.What does each of the following abbreviations stand for? a.ATP b.dGTP c.UMP d.RNA e.cAMP f.mRNA g.TDP

17.Explain the importance of the flat planar structure of DNA base pairs to the double helical structure of DNA?

18.Explain why AC and GT base pairs do not normally form.(You will have to go to Example 2.3 on page 31 of the textbook to answer this one--I expect you to read the textbook in addition to the lecture notes!)

19.Distinguish between nucleoside and nucleotide in a manner that makes it clear that you know what each is and how they differ.20.One very promising technique for inhibiting unwanted gene expression is the use of antisense RNA, which has a sequence identical to that of the antisense strand of DNA(except for replacement of T with U).Speculate on how antisense RNA might inhibit functional gene expression, based on what has been presented in the course thus far.(We will examine what actually happens later in the semester).Chapter 3 Mendelian Genetics

1.Describe the genotypic and phenotypic ratios for each of the following(assume the parental generations are true breeding when not stated otherwise): a.The F2 of monohybrid cross with full dominance b.The F2 of monohybrid cross with partial dominance c.The F2 of a monohybrid cross with codominance.d.The F2 of a dihybrid cross with full dominance at each genetic locus and no interactions between alleles at the two loci.e.The F2 of a dihybrid cross with partial dominance at both loci and no interactions between alleles at the two loci.f.The F2 of a dihybrid cross with codominance at both loci and no interactions between alleles at the two loci.2.How would you distinguish between partial dominance and codominance(Be careful, you can get yourself thoroughly confused if you try to carry this too far).3.How would you distinguish between partial dominance and full dominance(again be careful).4.Describe a situation in which full dominance by certain criteria becomes partial dominance when examined by other criteria.5.Briefly describe three different genetic mechanisms that can cause the phenotype of a heterozygote A1A2 to be different from that of either of the corresponding homozygotes.A1 and A2 are alleles at the same genetic locus, but you may designate any type of relationship between the two of them that you wish, as long as it corresponds to something that happens in real life.Cite an example of each of the mechanisms that you propose.(Yes, there really are at least three possibilities!)

6.When two indivduals exhibiting dominant traits associated with homozygous lethality(for example, Manx cats)are crossed, altered Mendelian ratios are observed among the progeny.a.What phenotypic ratio is observed among the immediate progeny of such a cross? b.What mechanism is responsible for the altered phenotypic ratio?

c.Explain why it is not possible to obtain a true-breeding strain of Manx cats.d.What is the rationale for calling such a trait dominant when it is impossible to obtain a true-breeding line in order to do a classical dominant x recessive cross?

e.Explain the potential relationship between dominant lethal alleles and haploinsufficiency.7.Explain how a short deletion can generate phenotypic behavior that appears to be dominant lethal, but actually involves two separate genes.8.Why are dominant lethal alleles rarely observed in nature, as opposed to laboratory or domesticated strains?

9.There are three different alleles at the genetic locus responsible for human ABO blood types.a.What mechanism prevents all three alleles from being expressed in a single individual? b.Would it make any difference if all three alleles were codominant? Explain your answer.c.A woman with blood type A is married to a man with blood type B.Their first child is type O.Describe two distinctly different mechanisms that might allow this to happen.d.If only the ABO locus is involved, what blood types would be expected and in what ratio if the couple in part c have enough additional children to include all possible types.Ignore statistical problems due to small sample size.e.How does the ABO*O allele differ from the ABO*A and ABO*B alleles?

10.How many different genotypes are possible at a locus that has 5 alternative alleles? 11.How many of the genotypes in problem 10 can be observed in any one individual?

12.A man is blood type A and his wife is blood type B.Their first child is a girl with blood type O.a.What are the genotypes of the parents?

b.What was the probability of that child's birth among all of the other possible children that the couple could have had?(Be sure to consider both blood type and gender.)c.What is the probability that the next two children will both be blood type A? d.What is the probability that those two children will be one boy and one girl?

e.The couple ultimately has six children.Knowing that the first is a girl with blood type O, what is the probability that they will have two more girls with blood type O?(Be careful--this question is designed to confuse you!)

f.What is the probability that the fourth child will be a boy with blood type AB and the fifth a girl with blood type B?

13.Explain how a single point mutation can have multiple different phenotypic effects.What name is applied to this phenomenon?

14.Briefly explain how each of the following behaves in genetic analysis, including the mechanisms that are involved when they are known.a.Gain of-function-mutation.b.Leaky mutation

c.Dominant loss-of-function mutation d.Haploinsufficiency e.Codominance

15.In Drosophila genetics, e designates ebony body and L designates lobed eyes.What phenotype would you expect for each of the following.a.e/e+

b.e/e

c.L/+

d.e/e+ L/L+

e.L+/L+

16.Explain why an individual who is FUT1*O/*O and ABO*A/*B fails to exhibit the AB blood type.17.What syndrome would you expect an individual who has the genotype HBB*E7V/*E7V to exhibit.(HBB refers to the hemoblobin beta globin subunit.If you need more information, see textbook pages 159-161 and remember that the N-terminal methionine is removed soon after translation occurs.18.What circumstances would lead to each of the following phenotypic distributions in the F2 generation?.a.9:3:3:1 b.6:3:3:2:1:1 c.4:2:2:2:2:1:1:1:1 d.2:1 e.3:1 19.Briefly define each of the following, including a description of how you would verify that it was occurring:.a.Dominant inhibition of gene expression b.Codominance c.Complementary gene action.d.Duplicate gene action.e.Recessive epistasis.20.White leghorn chickens have normal pigment genes, but are white because of a dominant color inhibiting gene(I).White Plymouth rock chickens are white because they are homozygous for a recessive loss of pigmentation gene(c)that behaves much like the coat color gene(C/c)in mice.The genes are unlinked and neither is sex-linked.A true-breeding white leghorn(II CC)is crossed with a true-breeding white Plymouth Rock chicken(ii cc).a.What is the genotype of the F1 progeny? b.What is the phenotype of the F1 progeny?

c.Draw a Punnett square for the F2 whose individual squares are large enough to enter both the genotype and the phenotype of all possible combinations.Insert the genotypes and the phenotypes into the squares.d.What is the phenotypic ratio of the F2 progeny of the original cross?

21.What circumstances would lead to each of the following phenotypic distributions in the F2 generation? a.9:3:3:1 b.12:3:1 c.12:4 d.9:7 e.15:1 f.9:6:1 g.9:4:3

22.Explain how two parents who are both afflicted with a particular non-lethal phenotype, such as deafness, can have children who are not afflicted.You may make any assumptions you wish about the mode(s)of inheritance of the phenotype.You should be able to come up with two totally different answers for this question.23.Distinguish between penetrance and expressivity in a manner that demonstrates that you know what both are and how they differ.24.What mechanism is responsible for black ears and a white body coat on a Himalayan rabbit?

25.A true-breeding eyeless fly(ey/ey)is mated with a true-breeding brown eyed fly(bw/bw).Assume that both mutations are recessive and are located on different autosomes and that both have 100% penetrance(which is not always true for eyeless in real life).a.What will be the phenotype of the F1 progeny? b.What will be the phenotypic distribution when the F1 progeny are test corssed? c.What will be the phenotypic distribution of the F2 progeny of the original cross? d.What fraction of the brown-eyed F2 flies are heterozygous for the eyeless allele? e.What fraction of the wild-type F2 flies are heterozygous for the eyeless allele?

Chapter 4 Linkage and Sex linkage Lecture 30: Linkage, gene order, chromosomal maps

1.For all parts of this question, assume that both parts of the double crossover involve the same two strands of the tetrad.a.What is meant by the term double crossover?

b.How many linked genes must be analyzed to observe a double cross-over? c.What is the effect of a double crossover on the linkage pattern of the genes that are used to observe it?

d.How do you compensate for the effects of double crossovers when calculating map distance between the two outside markers? e.Explain why it is not possible to demonstrate double crossover when using only two markers.2.Describe the steps that must be taken to identify the middle gene in a three point cross.3.A female Drosophila heterozygous for linked autosomal genes, a, b, and c is crossed with a male that is homozygous recessive for all three genes.The female progeny exhibit the following phenotypes.+++, 340;abc, 350;++c, 45, ab+, 55;+b+, 95;a+c, 105;a++, 4;+bc, 6.Total flies counted = 1000.10 a.Which is the middle gene?

b.What is the corrected map distance between the two outside genes?

c.Why would a two point cross between the two outside genes not yield the same value as the corrected map distance?

d.What is the interference value for the double crossover?

e.Would it have made a difference in the original cross if the genes had been sex linked and the male was hemizygous for all three recessive alleles.Explain your answer.f.Could you use a wild type male in question e? Explain your answer.g.How would the observed results have differed if the male parent had been heterozygous and the female parent homozygous recessive?

4.You are working with three autosomal genes in Drosophila whose possible linkage is not known.A three point cross of a female heterozygous for all three genes with a male that is homozygous recessive for all three yields roughly equal numbers of all of the possible phenotypes.a.What alternative interpretations of the data are possible?

b.What additional experiments would be needed to distinguish among the possibilities? c.Would your answer to part b be the same if you were studying mutations in mice?

d.If you conclude in parts b or c that two of the genes are in fact linked, how would you determine the map distance between them.5.How many different alleles can exist at a given genetic locus? Can three different alleles at the same locus be used to perform a three point cross? Explain your answer.6.Three genetic loci, A/a, B/b, and C/c are all on the same autosome, with B located between A and C.The measured distance from A to B in a two point cross is 10 map units and the measured distance from B to C is 8 map units.The observed interference in a three point cross is 0.5.a.What would be the expected frequency of double crossovers if there were no interference? b.What will be the observed frequency of double crossovers?

c.What will be the frequency of each of the reciprocal double crossover phenotypes?

d.What will be the frequency of each of the reciprocal single crossover phenotypes(a total of four phenotypes).e.What will be the frequency of each of the parental phenotypes? 7.Mutations a and b each cause distinctly different phenotypes.A female Drosophila that is heterozygous at both loci has a wild-type pheontype.When she is test crossed, four types of progeny are produced(wild type, phenotype a, phenotype b, and phenotypes a and b)in numbers that are close enough to equal so that a chi-square test does not reject the null hypothesis for a 1:1:1:1 ratio.There is no difference in phenotype between male and female progeny.When a male of the same initial genotype is test crossed, only two types of progeny are obtained, phenotype a and phenotype b.a.How do you explain the apparent discrepancy between the results of these two test crosses? b.What conclusions can you reach about sex linkage of the two loci? c.What are the phenotypes of the true-breeding parents that were used to produce the original heterozygous females and males used in these two test crosses? d.How would the results have differed for a test cross of the female if both loci had been sex-linked? e.Explain how a double recessive male could be obtained for the test cross in part d(sex linked alleles).8.In test crosses of double heterozygotes, genes A and B yield ambiguous recombination frequencies that suggest possible linkage but do not statistically rule out possible independent assortment.A series of two point crosses(single crossovers)yields the following information: Gene C is 20 map units from Gene A.Gene D is 23 map units from gene A.Gene D is 40 map units from gene C.Gene E is 15 map units from gene B.Gene F is 25 map units from gene B.Gene F is 38 map units from gene E.Gene D is 10 map units from gene F Construct a map showing the relative positions and approximate map distances of all of these genes.a.What is the approximate distance in map units from gene A to gene B? b.How do you explain the ambiguous data obtained in a two point cross of genes A and B.c.Explain how the use of 3 point crosses might have simplified the process of developing your map.Sex Determination, Sex-Linked Inheritance

1.How do the XX/XY sex determination mechanisms differ between humans and Drosophila? How are they similar?

2.Do males of all species have Y chromosomes? Explain your answer.3.Briefly define each of the following and explain its significance to the study of genetics.a.Autosome.b.Homogametic.c.Heterogametic.d.SRY(Sry)e.Sxl

f.Mullerian inhibiting factor g.Hemizygous

4.The human gene that codes for the testosterone receptor is carried on the human X chromosome.a.What biological role does the testosterone receptor play?

b.What are the developmental consequences in an XY human who is hemizygous for a defective testosterone receptor gene?

c.Why is one unlikely to encounter human females who are homozygous for defective testosterone receptors? d.What aspects of normal female development are absent in individuals with testicular feminization and why?

e.Why is it not possible to reverse testicular feminization with testosterone injections? 5.What is a gynandromorph and how is it formed?

6.What is the difference between an X chromosome and a Z chromosome?

7.Can the gene that codes for the testosterone receptor be described as a sex-determining gene? Defend your answer.8.Why is the designation sex lethal(Sxl)not an accurate description of the role of the gene or of its loss of function mutation?

9.Distinguish between monoecious and dioecious in a manner that makes it clear you know what each is and how they differ.10.How does the pattern of inheritance of sex-linked genes differ from that of autosomal genes: a.for recessive alleles? b.for dominant alleles?

11.a and b are two genes located close together on the X chromosome in Drosophila, such that crossing over between them is a rare event that can be ignored for purposes of this problem.Assume that in both cases, wild-type is fully dominant.A female with the genotype aab+b+ is mated with a male of the genotype a+b.a.What will be the genotype and phenotype of male F1 progeny?

b.What will be the genotype and phenotype of the female F1 progeny? c.What will be the genotype and phenotype of male F2 progeny?

d.What will be the genotype and phenotype of the female F2 progeny?

12.Same problem as 4, except assume that a and b are located so far apart on the X chromosome that there is enough crossing over so that they appear to assort independently.However, crossing over does not occur in male Drosophila(and could not in this case anyhow, since there is only one X chromosome).Identify as many classes of progeny as you need to answer the question fully.13.Starting with a white-eyed male Drosophila and a wild-type female, describe the series of crosses that you would have to do to generate a true-breeding population.The white-eyed locus is on the X chromosome.14.You have collected a number of male Drosophila that exhibit numerous different mutant phenotypes.You also have access to a colony of wild-type Drosophila.Summarize the tests you would have to perform to verify that you had a mutant from each of the following categories in your collection.Assume that in every case the mutant flies carry only as many mutant alleles as they need to exhibit the phenotype.a.Sex-linked recessive.b.Sex-linked dominant.c.Autosomal recessive.d.Autosomal dominant that is not lethal when homozygous.e.Autosomal dominant that is lethal when homozygous.Linkage: recombination, map distance

1.Do genes that are carried on the same chromosome always demonstrate linkage? Explain your answer.2.What is a map unit? If two genes are 5 map units apart, what is their recombination frequency? 3.Can alleles of two unlinked genes affect the same phenotypic trait? Explain how you arrived at your answer.4.Can alleles be linked? Explain your answer.5.What is the minimum amount of information that must be provided to describe a diploid genotype? Can you infer anything about linkage from that information? Explain your answer.6.Why is a test cross usually used in preference to production of an F2 generation to measure linkage?

Compensation, Sex-Limited, Sex-Influenced Inheritance

1.What is the Lyon hypothesis and how has its validity been demonstrated?

2.Describe the relationship among the following: Barr body, heterochromatin, late replication, dosage compensation, mosaicism.3.Describe the major differences between dosage compensation in Drosophila and humans.4.Describe three different types of human sex chromosome trisomy.What is the sex in each case? What are the major phenotypic traits in each case? Describe the genetic mechanisms that are responsible for the trisomy in each case.5.Turner syndrome is the only viable human monosomy?

a.How does Turner syndrome arise?

b.Speculate on why individuals with Turner syndrome are viable when all other human monosomies are lethal.14 c.In view of your answer to part b, why do individuals with Turner syndrome enhibit any phenotypicdifferences from normal individuals.6.What is a Barr body and what is its significance?

7.What mechanism makes human aneuploidies that involve sex chromosomes more viable than human aneuploidies that involve autosomes?

8.Propose a possible genetic explanation for each of the following(hint, check pages 424-426 and 539 in the textbook):

A.A human male with two X chromosomes and no Y chromosome.B.A human female with normal testosterone receptors, who has one X and one Y chromosome.C.A female Drosophila with a Y chromosome.D.A male Drosophila with no Y chromosome.E.A human female with three X chromosomes

F.A human male with one X and two Y chromosomes

9.Describe two techniques that have greatly facilitated human karyotypic analysis.10.Describe the aneuploidy that you might expect to find in a male calico cat.11.What would your tentative diagnosis be in each of the following cases: A.A human female with no Barr bodies.B.A human female with one Barr body C.A human female with two Barr bodies, D.A human male with no Barr bodies.E.A human male with one Barr body.12.Briefly define each of the following and explain its significance to the study of genetics.a.Autosome.b.Homogametic.c.Heterogametic.d.Hemizygous e.Sex-limited f.Sex-influenced

13.How will the following differ in a ZZ/ZW system, compared to an XX/XY system? a.Which will be the homogametic sex in each?

b.Which sex will exhibit hemizygous expression of recessive genes in each?

c.Would you expect large numbers of essential genes to be carried on the W chromosome? Relate your answer to the Y chromosome.15 d.If a male is heterozygous for a Z-linked trait, how will it be expressed in his female progeny.e.Describe a comparable phenomenon in an XX/XY system.14.Distinguish among traits that are sex-linked, sex-limited, and sex-influenced.15.Explain how the use of attached X stocks of Drosophila allows direct trnasmission of X-linked mutations from father to son.Chapter 5 Chromosome Mutations: Chromosomal Changes, Monosomy, Trisomy，Polyploidy, Structural Changes

1.Distinguish between the following pairs in a manner that makes it clear that you know what each is and how they differ.a.Euploid and aneuploid b.Triploidy and trisomy

c.Autopolyploid and allopolyploid d.Hybrid and allopolyploid.e.Diploid and amphidiploid f.Homologous and homeologous.2.Why are allotetraploids more likely to be fully fertile than autotetraploids?

3.Describe a process for the experimental generation of a fertile allotetraploid from a sterile cross-species hybrid.4.Does the chromosome number of an allotetraploid have to be an even multiple of four? Explain your answer.Would your answer be different for an autotetraploid?

5.What is the agricultural significance of allopolyploids?(You should be able to think of more than one answer).6.Describe two distinctly different reasons why triploid plants may be preferred for certain agricultural crops.7.A fertile allopolyploid plant with a chromosome number of 38 is crossed with one of its parent species.Do you expect the progeny to be fertile? Explain your answer.8.Does the formation of an allotetraploid between two plant species insure that the most desirable properties of both will be found in the allotetraploid? Explain the reasoning behind your answer.9.What approach would you use to attempt to construct an allotetraploid from two plant species that are not capable of cross pollination? Describe the steps that are involved.16 10.How does a diploid banana differ from commercially sold bananas? 11.What problems stand in the way of fertility of triploid plants?

12.What features make polytene chromosomes particularly useful for the detection of altered chromosomal structure?

13.Where other than a polytene chromosome could one look to verify the existence of a chromosomal inversion or partial duplication? 14.Define the following terms a.Dicentric chromosome b.Tandem duplication c.Pseudodominance d.Paracentric inversion e.Unequal crossing over.15.Deletions, duplications and inversions all cause the formation of loops in polytene chromosomes.How would you distinguish among these three possibilities cytologically? What genetic traits would you look for to support your conclusions?

16.Describe the mechanisms that lead to the production of Doublebar progeny from crosses of males that are hemizygous for Bar eye with females that are homozygous for Bar eye.17.An inversion loop is more likely to cause severe problems during meiosis than a deletion loop.Explain the difference.18.Under what conditions is a duplication of genetic material not abnormal?

19.What special property distinguishes a deletion mutation from a typical missense point mutation(one that codes for the wrong amino acid)?

20.Explain how a deletion mutation can cause partial hemizygosity.21.What type of chromosomal change is particularly likely to result in a dominant phenotype with lethality in the homozygous state.What mechanism is likely to be involved in the lethality.22.Are all seedless fruits triploid? Explain your answer.Chapter 6 Genetics in Bacteria and Bacteriophages 1.Describe four distinctly different ways in which genes can be transferred into a bacterial cell.2.What is the shape of the linkage map of E.coli? How has this been shown? 3.What is the difference between an F+ strain and an Hfr strain? Which is the most useful in bacterial genetic analysis and why?

4.What units are normally used to measure map distances in E.coli ? What is the basis for use of this particular type of unit?

5.What is a merozygote and what is its value in genetic research?

6.What type of bacterial mating system is used to generate stable partially diploid cells? 7.How does genetic transduction differ from transformation?

8.What was the nature of the first experimental evidence showing that DNA was capable of carrying genetic information?

9.What is an auxotrophic mutation? What term is used to describe the corresponding non-mutant state?

10.Explain how the inability to utilize a particular substrate can be used as a genetic marker in bacteria.11.The E.coli genome has been completely sequenced.a.How large is the genome of E.coli?

b.How many times as large is the human genome compared to that of E.coli.(The human haploid genome contains about 3.0 x 109 base pairs).c.How many potential protein-coding genes are contained in the E.coli genome(see table 7.3).d.If the human genome contained a comparable density of genes per amount of DNA, how many genes would be in the human genome?

e.A recent(1999)news report suggested that the number of human genes could be as large as 140,000(significantly higher than previous estimates of less than 100,000).What can you conclude about the density of genes in human DNA relative to that in E.coli DNA?

12.Describe a selective medium scheme for isolation of each of the following types of mutations.a.a leucine auxotroph

b.a strain unable to utilize lactose

c.a strain that is resistant to ampicillin(an antibiotic)

d.a strain that is resistant to infection by a specific type of bacteriophage.e.A cell from a strain auxotrophic for leucine that had been transformed to prototrophy with purified DNA from a proptotrophic strain.13.In many cases, Hfr conjugation can transfer several bacterial genes to a recipient cell without the recipient cell becoming an Hfr cell.Explain how this can happen.18 14.Explain how merozygotes can be used for complementation studies.Be sure that your answer makes it clear that you understand what complementation is.15.Distinguish between lytic and lysogenic bacteriophage infections in a manner that makes it clear that you understand what each is and how they differ.16.Distinguish between specialized transduction and generalized transduction in a manner that makes it clear you know what each is and how they differ.17.What is the smallest known genome size for a free-living organism? How many protien coding units does it contain?

18.Distinguish between virulent and temperate bacteriophages in a manner that makes it clear that you know what each is and how they differ.19.Explain how different genotypes can cause bacterial cells to exhibit similar phenotypes.20.You have a collection of mutant strains of E.coli that are auxotrophic for histidine.After you complete an experiment demonstrating the histidine requirements of these strains, you leave the petri dish cultures on the laboratory bench for a few days.When you return, you discover that there is now growth in the histidine-free control dish for one of the strains, but not for the others.How would you explain this observation?

Chapter 7 Gene expression and Control Genetic Fine Structure: Tetrad Analysis, Complementation, Cistrons

1.Briefly describe two experimental systems in which all of the products of a single meiosis can be recovered.How are such systems used in genetic analysis?

2.Explain how the centromere is used as a genetic marker when analyzing patterns of crossing over in Neurospora

3.What are the major differences in life cycles between the two types of yeast that are widely used in genetic research?

4.What is meant by the term “tetrad” and why is tetrad analysis of importance in genetic research? 5.Distinguish between ordered and unordered ascospores and explain how each can be used in genetic research.6.Explain how a single crossover can generate either a 2:2:2:2 pattern or a 2:4:2 pattern in the ascospores of Neurospora.7.Briefly describe the life cycle of Saccharomyces cerevisiae and explain how it can be used for tetrad analysis.8.Why is a tetratype with four different types of spores a more common occurence than a non-parental ditype, which has only two different types of spores?

9.What are the advantages of doing tetrad analysis with Neurospora ? What are the limitations of such studies?

10.What special values does tetrad analysis bring to genetics.What can be done with it that cannot readily be done with Drosophila or peas?

11.Describe the process of formation of a plaque by bacteriophage.12.How is genetic linkage studied in bacteriophage?

13.What properties make bacteriophage such a powerful tool for recombinational analysis? 14.Describe the phenomenon of complementation as it occurs among various rII mutations in bacteriophage T4.15.Explain why complementation studies cannot be done with dominant mutaitons.16.Bacteriophage mutations A and B do not complement each other when tested in a recombination-deficient strain of bacteria.However in strains that support recombination, there is occasional restoration of function.Explain how this can happen.(You will need to do some reasonable extrapolation beyond what has actually been presented to answer this.)

17.How can complementation studies be done in various types of organisms that normally have only a single haploid genome.(You should be able to come up with several examples from different organisms).18.What is meant by the term cistron? What is the origin of the term?

19.Does complementation between two mutant strains prove that both mutations have occurred within the same biochemical pathway? Explain your answer, including any restrictions you have placed on definitions of terms that you use.20.How can you distinguish whether restoration of function by coinfection with two mutant bacteriophage is due to complentation or recombination?

21.What would you do to analyze the frequency of recombination between two mutant strains of bacteriophage that complement each other?(This calls for some projection beyond what has been covered in class, but should be possible to answer based on what you have been told about complementation and about recombination).22.Cite an example of complementation in a diploid organism.What F2 phenotypic ratio is expected when mutant strains that exhibit complementation are crossed?

23.Can recombination occur within the coding unit for a single protein? Cite evidence to justify your answer.24.Can complementation occur within the coding unit for a single protein? Cite evidence to justify your answer.25.Explain how deletion mapping can be used for preliminary placement of previously unstudied mutations within a particular portion of a cistron.26.Briefly summarize the process of gene conversion, including how the Holliday model of genetic recombination explains its occurence.27.Briefly describe each of the following, including where it is likely to be observed: a.Sister chromatid exchange b.Mitotic crossover

c.Complementary gene action d.Complementation e.Non-parental ditype

Prokaryotic gene expression: lac operon

1.Draw a diagram showing the arrangement of the genetic sites that are involved in the lac operon and briefly summarize the role of each site.2.Starting with lactose in the extracellular environment, describe all of the steps that must occur to induce enhanced expression of the genes in the lac operon.3.What effect will each of the following have on induction of the lac operon by lactose in a medium that lacks glucose?

a.A mutation that inactivates beta-galactosidase.b.A mutation that inactivates galactoside permease.c.A mutation that makes the lac repressor protein incapable of binding to the lac operator site.d.A mutation that makes the lac operator site incapable of binding the lac repressor protein.e.A mutation that makes the lac repressor protein incapable of binding allolactose.4.What advantage is provided to E.coli by the presence of two separate regulatory mechanisms for the lac operon, with one responsive to glucose and the other responsive to lactose? 5.What is meant by a polycistronic transcript, and how is it related to the lac operon?

6.What is the normal function of the operator site and what is the effect of loss of that function?

7.What is the catabolite activator protein(CAP)and how does it affect gene expression at the lac operon?

8.What are the minimum set of components that must be present to have an operon? 9.What is a merozygote and how is it used to analyze the control mechanisms of an operon? 10.What is meant by cis and trans when these terms are used to describe regulatory mechanisms within an operon.Give an example of a mutation that is cis-dominant and one that has dominant effects both cis and trans.11.Describe two different roles of beta-galactosidase and explain the importance of each in the overall function of the lac operon.12.Explain how the presence of glucose in the external environment represses transcription of genes in the lac operon.13.What is the advantage of using an artificial inducer, such as IPTG, to study the regulation of the lac operon?

14.An engineered F' plasmid carrys a lac operon that is fully functional and intact except that each of its 3 enzymes have been mutated in ways that allow them to be distinguished from host enzymes, but do not affect their enzymatic activity.What will be the effect of adding that plasmid to each of the following mutant strains of E.coli ? Include in your answers a description of the properties of the mutant strain without the plasmid and a description of the ways in which those properties are changed by addition of the plasmid.a.An operator constituitive(Oc)strain whose operator is incapable of binding the repressor protein.b.A strain with a non-functional repressor protein(I-)that is incapable of binding the operator.c.A strain with a mutation that renders beta-galactosidease nonfunctional(lac Z-).d.A strain with a mutation that renders the lactose permease nonfunctional(lac Y-)

e.A strain with a mutation in the repressor protein that renders it incapable of binding allolactose or IPTG, without altering any of its other funcitons.15.Is the Lac I gene that codes for the lactose repressor protein considered to be part of the lactose operon? Explain your answer.Tryptophan operon, tryptophan attenuator，1.Distinguish between induction and repression in a manner that makes it clear that you know what each is and how they differ.(Be careful, this is a tricky question that needs to be approached at multiple levels).2.Describe two distinctly different ways in which the trp operon is controlled by the overall availability of tryptophan.22 3.How does the interaction between the repressor protein and the operator site differ between the lac operon and the trp operon? What role does the ligand that binds to the repressor protein play in each case?

4.Describe the mechanism responsible for shutdown of the trp operon when a plentiful supply of free tryptophan is available.5.Describe the mechanism by which the leader-attenuator region fine tunes the extent of transcription of the structural genes in the trp operon when the availability of tryptophan is marginal.6.The leader-attenuation system utilizes a conditional transcription termination signal.Explain how that signal is activated and deactivated.7.Leader-attenuator mechanisms have been found to control operons coding for enzymes involved in the synthesis of a number of different amino acids in various bacterial species, sometimes as the only regulatory mechanism.What do you consider to be the most likely reason for failure to find similar regulatory mechanisms controlling rates of synthesis of other types of biologically important molecules, such as vitamins and nucleic acid bases?(This requires analysis beyond the level of information that has been presented in class, but will be very obvious once you realize what the correct answer is.)

8.Would it be possible to reverse positions, placing the leader/attenuator sequence upstream from the promoter/operator sequence of the trp operon? Explain the reasoning behind your answer.9.Some operons are controlled only by a leader/attenuator mechanism.Does this indicate that the trp operon in E.coli could function normally with the promoter/operator sequence completely removed? Explain the reasoning behind your answer and think carefully about what you are saying..10.What effects on control of the trp operon would you expect from a frameshift mutation resulting from addition of one base in each of the following locations? In each case, would you expect the mutant strain to be able to multiply in a medium that did not contain tryptophan, and would you expect the operon to be turned off in the presence of an adequate amount of tryptophan? a.Near the 5'-end of the coding sequence for the trp repressor protein.b.Near the 5'-end of the coding sequence for the trp attenuator peptide.The codon for tryptophan is UGG, and the complete coding sequence for the attenuator peptide, including the UGA stop codon is 5'-AUGAAAGCAAUUUUCGUACUGAAAGGUUGGUGGCGCACUUCCUGA-3'(Consider this one carefully--it could get complicated!).c.Near the 3'-end of the coding sequence for the trp attenuator peptide(beyond the trp codons).(This one could also get complicated).d.Near the 5'-end of the trp E gene(the first structural gene in the operon).23 e.How would the answer to part b differ if the mutation were a missense mutation in the second codon of the attenuator peptide?

11.A strain of bacteria is auxotrophic because of a missence mutation in the trpE gene(the first one in the operon).Explain the reasoning behind your answers to each of the following questions.a.What effect would this have on the the ability of the strain to grow in a medium containing tryptophan?

b.What effect would this have on the the ability of the strain to grow in a medium lacking tryptophan?

c.Would you expect the trpA gene to be transcribed in this strain when tryptophan is absent from the culture medium?

d.Would you expect the trpA gene to be trainscribed in this strain when the culture medium contains tryptophan?

e.Would you expect the trpE gene product to be translated in a medium lacking tryptophan?(Be careful, this one is tricky).12.As illustrated in figure 8.14, The trpA and trpB gene products are needed only for the final step in tryptophan synthesis in E.coli, namely conversion of indole-3-glycerol phosphate(InGP)to tryptophan.The other three genes in the trp operon are involved in steps leading to the synthesis of InGP.Explain the reasoning behind your answers to each of the following quesitons.a.In a wild-type(non-mutant)strain, what effect would you expect the presence of InGP in a culture medium that contained no added tryptophan to have on transcription of the trp operon

b.Would you expect a strain with a loss-of-function mutation in trpE to be able to grow in a medium that contains InGP but no tryptophan?

c.What would be the transcriptional state of the trp operon in question b?

d.Would you expect a strain with a loss-of-function mutation in trpA to be able to grow in a medium that contains InGP but no tryptophan?

e.What would be the transcriptional state of the trp operon in question d?

13.The gene coding for the tryptophan repressor protein is at a remote location relative to the tryptophan operon.What effect would complete deletion of the repressor gene have on the response of the operon to varying levels of tryptophan in the environment?

14.What effect would an operator constituitive mutation(unable to bind the repressor protein)have on the response of the tryptophan operon to varying levels of tryptophan in the environment?

15.What effect would you expect complete deletion of the leader-attenuator sequence from the tryptophan operon to have on its response to varying levels of tryptophan? Eukaryotic transcriptional control

A few questions covering earlier lectures have been included here to review the background needed for this lecture.1.Dinstinguish among the three types of eukaryotic RNA polymerases in terms of the function of each.2.What are the major differences in organization between prokaryotic and eukaryotic genes.3.Summarize the modifications that must be made in a transcript produced by RNA polymerase II before it can be translated.4.Explain why more complex controls over gene expression are needed in multicellular eukaryotic organisms than in prokaryotic organisms.5.What are the features that distinguish enhancer sequences from functional parts of the basic promoter, such as the CAAT box and the TATA box?

6.How is a distant enhancer site believed to activate transcription?(What mechanism allows it to exert its effect over a considerable distance?)

7.Identify the three different domains that a protein must possess as a minimum to function as a ligand-responsive transcription factor(for example, a steroid hormone receptor).What role is played by each of these domains?

8.Describe the regulatory mechanisms that allow the budding yeast, Saccharomyces cerevisiae to turn on genes for galactose utilization when galactose is available.9.The GAL4 binding site in yeast is commonly referred to as an upstream activating sequence(UAS).Does it satisfy all of the criteria of an enhancer site? Explain your answer.10.Describe the sequence of events that results in expression of the genes that are needed for galactose utilization in yeast.Be sure to identify the regulatory protein that galactose interacts with and the way in which it triggers the gene expression process.11.What are three major types of transcription factors(classified in terms of their DNA-binding domains)?

12.What two types of domains must a protein possess to be a transcription factor? Discuss the relative specificity of each.25 13.What role does the GAL80 protein play in the control of galactose utilization genes in budding yeast?

14.What effect would you expect from a mutation in the GAL4 protein that rendered it incapable of binding to the GAL80 protein?

15.What effect would you expect from a mutation in the GAL80 protein that rendered it incapable of binding galactose?

16.Dnguish between each of the following pairs in a manner that makes it clear you know what each is and how they differ.a.Activator and coactivator

b.Enhancer and upstream activating sequence

c.Hormone response element and steroid hormone receptor d.General transcription factor and activator e.Cytosine and 5-methyl cytosine

17.The frequency of CG sequences in eukaryotic genomes is lower than expected based on the CG content of the DNA of each species and an assumption of random occurrence of all possible dinucleotide sequences.a.Describe a modification of CG base pairs that occurs more frequently in inactive parts of the genome than in actively transcribed genes.b.Describe a mutational process that could preferentially convert CG sequences to other sequences in the genetically inactive portion of the genome.(You may need to go back to lecture 6 for the answer).c.How would you explain the failure of DNA repair mechanisms to reverse the preferential loss of CG sequences?

d.How is the DNA modification from part a retained when DNA replicates?

e.What is the evidence that the modification in part a acts indirectly to inhibit transcription of inactive genes(see boxed example 8.4 if you are having trouble with this one).18.Activation factors and basal transcription factors such as the TATA binding protein are able to recognize specific nucleotide sequences within double stranded DNA.(You may want to look at figure 2.11 while answering this set of questions--note that the top of each base pair as drawn corresponds to the major groove).a.Explain how protein molecules, which tend to be bulky molecules, are able to detect differences in nucleotide sequence in various regions of a double-stranded DNA molecule.b.What features of an AT base pair are seen in the major groove? c.What features of a GC base pair are seen in the major groove?

d.An AA sequence or an AT sequence would result in the same two base pairs being next to each other in the double helical DNA.How do you think a DNA binding domain is able to distinguish between the two?(This will require a bit of speculation).e.What mechanism is commonly employed by transcription factors and activator proteins to read palindromic sequences, such as typical hormone response elements?

Chapter 8 Gene Engineering and Genomics and Proteomics Restriction endonucleases, vectors, Recombinant DNA

You will need to use the table of restriction endonuclease cut sites in the lecture 14 notes to answer some of these questions.You do not need to memorize the cut site sequences for the examination.1.Restriction endonucleases are widely used in recombinant DNA research.a.Distinguish between exonuclease and endonuclease in a manner that makes it clear you understand what each is and how they differ.b.What are the characteristic features of a target site for cutting by a restriction endonuclease? c.What range of frequencies of cutting is encountered with the various restriction nucleases that are currently in widespread use?

d.What is the size of the restriction endonuclease recognition site that is most useful for routine gene cloning operations? Explain the reasoning behind your answer.e.What is a sticky end and why is it considered useful in gene cloning?

2.The frequency with which a particular restriction endonuclease can be expected to cut a random DNA is influenced by the overall base composition of the DNA.a.What effect does the overall base composition of a DNA sample have on the average fragment length obtained with a restriction endonuclease?

b.Will the effect in part a be the same for every restriction endonuclease? Explain the reasoning behing your answer

c.The cut site for Eco RI is G|AATTC.What average fragment lengths do you expect to be produced from DNA with each of the following fractions of GC base pairs? 1/4, 1/3, 1/2, 2/3, 3/4 d.Describe a situation in which the shortest restriction fragments would be obtained with a DNA that was 50% A+T.e.Would you expect Sma I(CCC|GGG)to be able to cut DNA that is 50% AT? Explain your answer.f.Among the enzymes on the list in lecture 15 that have cut sites consisting of 6 nucleotide pairs, which would you expect to yield the largest DNA fragments from a GC-rich DNA and why? 3.Distinguish between 5'-overhangs and 3'-overhangs and describe a hypothetical(or real)example of each.4.What role do restriction endonucleases play in nature?(What were they good for before molecular biologists discovered how useful they can be in recombinant DNA studies?)

5.Do different restriction endonucleases ever generate sticky ends that are the same? Explain your answer.6.Eco RI cuts its GAATTC target site between G and A.A hypothetical enzyme Hyp I cuts the same sequence between T and C.Both enzymes yield sticky ends with the sequence 5'AATT3'.a.What problems would be encountered trying to rejoin the ends of DNA fragments cut with these two enzymes? Use a diagram to explain your answer.b.Can you think of any clever methods to overcome the problems described in your answer to part a? Using the same enzyme to cut both fragments is not an available option.c.Identify an actual pair of enzymes from the list in the lecture 14 notes that have a relationship to each other comparable to the relationship between Eco RI and Hyp I described in part a.7.What prevents restriction endonucleases from destroying the genomic DNA of the bacteria that produce them?

8.A DNA fragment prepared with Bgl II was successfully cloned into a vector that had been cut with Bam H1.a.What property of these two enzymes made it possible to perform this cloning without problems.b.It was subsequently discovered that neither of the original enzymes would release the cloned DNA from the vector.Explain why this occurred.c.Would it be possible to use Mbo I to release the DNA from the vector? Explain what problems might be encountered.d.If the Bam HI site were located in the middle of a multicloning site(polylinker), would you expect to be able to release the cloned insert with a different restriction endonuclease than those used in cloning? Explain your answer?

e.What procedure could you use to release the cloned insert in part d? What additional problem(s)would you then have to overcome?

9.What is a vector?(Be careful not to define vectors too narrowly).10.What is the value of using plasmids that carry antibiotic resistance genes as vectors?

11.What is the value of inserting a cloned DNA sequence into the middle of an antibiotic resistance gene?

12.Replica plating was an extremely valuable technique in early gene cloning studies, but is no longer as widely used.a.Describe the processes involved in replica plating.b.Explain the value of replica plating in the early studies.c.What has been done to eliminate the need for replica plating?

13.What is the rationale for the inclusion of multiple cloning sites in modern cloning vectors.Include in your answer a description of what multiple cloning sites are.14.Describe a cloning technique in which both the cloning vector and the bacterial strain that it is infected into have been engineered to work together to facilitate the process of screening.15.What is the rationale for using two different restriction endonucleases to prepare a DNA fragment for cloning.(You should be able to think of at least two different answers.)

16.You are trying to clone a gene by ligating Eco RI fragments into a plasmid vector.You get some successful clones, but sequencing studies reveal that you have only half of the coding sequence because there is an Eco RI restriction site in the middle of the gene.What would you do to obtain a full length clone of the gene?

17.You are trying to clone a gene, but have been unsuccessful in finding any restriction endonucleases that do not have cut sites within the gene.What alternatives are available to you? 18.Describe the selective steps that you would use to identify bacteria containing pBR322 plasmids carrying cloned DNA inserts that were originally ligated into plasmids that had been linearized with Bam HI

19.How would your answer to question 18 differ if the cloning had been done with Pst I? 20.Explain how it was possible to insert a polylinker into the 5'-end of the beta-galactosidase gene without losing biological function.Also explain why biological function is lost when a DNA fragment is ligated into a cut polylinker site.21.Why would you normally not use restriction endonucleases with four or eight nucleotide cut sites for cloning into plasmids?

22.Identify two different pairs of isoschizomers in the list of restriction endonucleases in the lecture 14 notes.In each case, how do the actual cuts differ from each other.23.Explain the value of having two different kinds of selection engineered into a plasmid for DNA cloning.What role is played by each?

24.You have a preparation containing DNA fragments prepared by digestion with Not I.Assuming the original DNA is 50% GT, how many pieces would you expect the average fragment in that preparation to be cut into by Eco RI? By Alu I?

Vectors for large inserts, cDNA, libraries, probes, expression vectors

1.What are the advantages of using each of the following vectors as alternatives to plasmids? a.Lambda-phage(Charon)vector.b.Cosmid

c.M13 viral vector

d.Yeast artificial chromosome.e.Bacterial artificial chromosome.2.How can site-directed mutagenesis be achieved in a cloned cDNA sequence? Include in your answer a description of the type of vector that you would have to use and the way in which you would transfer the cDNA clone from its original vector to the vector used for site-directed mutagenesis.3.Site-directed mutagenesis has become a valuable tool in molecular biology.a.Use the table of codons in figure 4.4 or inside the front cover of the textbook to generate a DNA code for a protein with the following partial sequence: Met-His-Leu-Val-Pro-Gly-Val-trp-Ile-.......b.Describe in detail how you would use site directed mutagenesis to change the proline to serine.4.Expression vectors are widely used in recombinant DNA technology.a.What is an expression vector? Include in your answer the special properties that a vector must have to function as an expression vector.b.Describe as many different reasons as you can why it may be useful to clone a gene or a cDNA into an expression vector.c.What are the potential advantages of using an expression vector with a strong constituitive promoter?

d.What are the potential disadvantages of using an expression vector with a strong constituitive promoter?

e.How can the disadvantages that you described in question 2 be avoided? 5.What is a genomic library and what is its value?

6.cDNA clones are widely used in recombinant DNA studies.a.What does the term “cDNA” stand for? b.How is cDNA prepared?

c.What features of cDNA make it a useful research tool?

d.What are the limitations that restrict the usefulness of cDNA clones?

e.Would you expect an eukaryotic cDNA to work well in a prokaryotic expression vector? Explain the reasoning behind your answer.7.You have a polyclonal antibody to a protein.You would like to clone the coding sequence for the protein.How would you go about it?

8.Explain the rationale for using IPTG rather than lactose or allo-lactose to induce expression of genes cloned downstream from the lac promoter/operator sequence.9.You have the cloned cDNA for a protein.Describe the procedures you would use to isolate a clone that contains the genomic sequence from a genomic library contained in lambda phage vectors.10.Do you expect cDNA preparations to contain cut sites for restiction endonucleases? Explain your answer.30 11.An unaltered vector and the same vector containing a cloned cDNA are denatured in the same solution, allowed to anneal slowly, and prepared for electron microscopy.What would you expect to see with the electron microscope?

12.What is a degenerate probe and what is it used for? In designing such a probe, what problems are likely to be encountered and how can they best be overcome.13.You know the amino acid sequence of a protein.Starting with a preparation of messenger RNA from a tissue that makes large amounts of the protein, how would you go about isolating a cloned cDNA that contains the nucleotide coding sequence for that protein? You should be able to think of two quite different approaches to this question.14.Why is it sometimes desirable to reduce the stringency of probe hybridization reactions? 15.What is meant by the term “restriction map”? What is the value of using partial digests in such mapping?(You may need to go back to lecture 14 for this and the next question)16.What is the advantage of preparing a restriction map with more than one restriction endonuclease?

17.You have used a CDNA to isolate a series of clones of various sizes from a genomic library that was prepared by incomplete digestion with Eco RI.Explain how you might use restriction mapping to determine patterns of overlapping among these clones and to assemble a set that collectively contain the complete genomic sequence including the introns that were spliced out of the mRNA used to prepare the cDNA.Also explain how you could identify presumptive promoter sequences located immediately upstream from the start of transcription.This question will require you to do some projection beyond specific details that we have covered in class, but should be fully answerable with the information that has been presented to you at various times during the semester.18.Using the table of codons in the textbook, identify all possible amino acid sequences whose genomic coding sequences could generate a cut site for EcoRI(G|AATTC).(Be sure to examine all possible reading frames and exclude all nucleotide sequences that could not be found in the coding sequences for proteins.)

19.In an organism whose DNA is 50% AT, how long would a protein have to be to have a 50% chance of containing a cut site for EcoRI within its coding sequence? 20.Vectors derived from bacteriophage lambda have become quite popular.a.Describe the modifications that are made in bacteriophage lambda to generate a typical vector(such as the Charon vectors)

b.Explain how blue-white selection is used to identify lambda vectors that contain cloned inserts.c.What determines the size range of inserts that can be cloned in a lambda phage vector?

d.What is done to prevent lambda phage vectors from entering into a lysogenic relationship with their host bacterial cells.e.What special modification is likely to be needed in order to clone a typical cDNA in a lambda

phage vector?(You have not been given an answer for this question, but you should be able to figure it out, based on what you are supposed to know about cDNAs and lambda phage vectors).PCR, Southern, Northern, Western blots

1.The polymerase chain reaction(PCR)is a widely used technique in molecular genetics.a.What special property must be possessed by the DNA polymerase used in PCR, and why is this so important for doing PCR?

b.Explain the use of primers in PCR, including why two different primers must be used.c.What relationship must exist between the two primers used in PCR?

d.Summarize all of the components that must be present in a PCR reaction mixture.e.Summarize the overall process that makes possible extensive amplification of specific DNA sequences with minimal effort through the use of PCR.2.One of the ways of determining whether a sequence has been successfully amplified by PCR is to do electrophoresis and look for a band of DNA of sharply defined size.Explain how such a band arises during PCR.3.Why is it not necessary to add new DNA polymerase and primers for each new cycle of PCR? 4.You have a cDNA of unknown sequence in a plasmid vector.How could you do a PCR amplification of the cDNA without first determining its end sequences?

5.What types of precautions must be taken when doing PCR to be certain that the desired results are obtained?

6.What aspects of PCR make it particularly useful in forensic investigations? How do the same properties make PCR particularly susceptible to challenge by defense lawyers?

7.Distinguish between Southern and Northern blots in a manner that makes it clear you know what each is and how they differ.8.How does a Western blot differ from both of the above? When is a Western blot used in perference to a Northern or Southern blot?

9.You have a cloned cDNA for a protein.You want to find a restriction endonuclease that can be used to isolate the genomic coding sequence in a single DNA fragment.Describe the procedures you would use to identify an appropriate restriction endonuclease.(Assume that you are dealing with an eukaryotic gene that contains introns of unknown sequence).10.You have a full length cDNA that codes for an eukaryotic protein.The cDNA was cloned using Pst I.When you do a genomic Southern blot with Eco RI, you detect three bands of distinctly different sizes that hybridize with the cDNA probe.32 a.What are two very different possible interpretations of the data?

b.Describe the additional experiments that would be needed to distinguish clearly between the two possibilities.(Be aware that there are multiple possible ways of approaching this problem, and list as many as you can).11.Why is it generally desirable to use a relatively small probe when doing a Southern blot.What situations may make the use of a larger probe desirable?

12.Summarize the major steps that are involved in Southern blotting.13.Describe a procedure that could be used to determine which tissues in a rat express the highest levels of a particular gene.What is the procedure called? What is the origin of the name? 14.Explain how it is possible to separate proteins by size alone, by isoelectric point alone, or by a combination of isoelectric point and size.15.What result would you expect to see if you probed a Southern blot of a PCR product derived from genomic DNA separately with each of its primers? How might the results differ if different restriction endonucleases were used on the PCR product prior to running the Southern blot(this calls for some speculation--explain any assumptions that you have made in arriving at your answer.16.What is a dot blot and when would you be most likely to use it?

17.You have a full-length genomic clone for an eukaryotic gene.You isolate and purify the cloned insert and use it as the starting point for a Southern blot of the clone.Using a cDNA for the gene as a probe, you detect five bands on the Southern blot.However, when you label the cloned genomic sequence and use it as a probe, you see two additional bands.a.Propose an explanation for the additional bands.b.You isolate the restriction fragment that is responsible for one of the additional bands and use it as a probe for a Southern blot prepared the same way as the first one.How many bands do you expect to see? Explain the reasoning behind your answer.c.You purify the cDNA for the gene and do a Southern blot of it using the same restriction endonuclease that was used for the genomic Southern blot.When you probe that Southern blot with the full length cDNA, you only find three bands.Propose an explanation for the reduced number of bands.d.You purify one of the bands from part c and use it as a probe on the genomic Southern blot.How many bands do you expect to detect? Explain the reasoning behind your answer.e.You use the probe from part d on a Southern blot of the cDNA prepared with a different restriction endonuclease.What possible range of results might you see? DNA sequencing

1.Explain the role played by electrophoresis in determining DNA sequences.2.What type of reagent is used to achieve selective chain termination in DNA sequencing studies?

3.DNA sequencing is frequently done with single-stranded DNA as the starting material.a.What are the potential advantages of using single-stranded DNA?

b.Is the use of single-stranded DNA strictly necessary? Explain the reasoning behind your answer.c.What additional step would be needed to start with double-stranded DNA?(You have not been given an exact answer, but you should be able to figure out what must be done.)

d.Would it be possible to do sequencing by adding dideoxyribonucleotide triphosphate chain terminators to a PCR reaction? Explain your answer.e.Would it be possible to use a single PCR primer as a sequencing primer? Explain your answer and discuss any special problems that might be encountered.4.Why is it important to use a polymerase that lacks 5' to 3' exonuclease activity(such as the Klenow fragment of DNA polymerase I)when doing DNA sequencing?

5.You have a series of partial and full length cDNA and genomic clones in vectors that contain polylinker sites.Describe the primers that you would need to determine the entire sequence of the cloned insert and possible alternative strategies that you might use to obtain the complete sequence in each of the following cases.a.The total length of the insert is 350 base pairs.b.600 base pairs.c.1000 base pairs.d.10,000 base pairs.6.Why is it necessary to use four parallel electrophoretic lanes when determining DNA sequence by “standard” methods? How have newer methods eliminated this requirement? 7.Explain how dideoxyribonucleotide triphosphates terminate chain growth.8.What prevents all growing chains from being terminated at the same length?

9.What is an open reading frame and why is its identification important during DNA sequencing? 10.Sanger's early analysis of DNA sequence in the single stranded DNA bacteriophage phi-X174 revealed overlapping open reading frames.What is the significance of this discovery?

11.You are sequencing the cDNA that codes for a particular enzyme in mice.As a check on the accuracy of your procedures, you do sequence analysis on two separate clones both prepared from the mRNA of the same mouse.The two sequences correspond exactly, except at one nucleotide about halfway through the coding sequence, where you obtain a C in one of the samples and a T in the other.a.How would you interpret the data?

b.You transfer both clones to an expression vector, and they both produce equally functional enzyme.What is the most likely explanation for how this can happen?

c.Would you expect to see any differences in the amino acid sequences of the two enzymes? Explain your answer.d.In part b, one of the expression vectors fails to produce a functional enzyme.How would this affect your answers to parts b and c?

e.You have a pair of unique sequence oligonucleotide primers that allow you to use PCR to amplify a sequence 150 nucleotides long that contains the C versus T site, using genomic DNA from the same mouse as your starting material.You then do sequencing on the PCR product, using the primer that hybridizes to the antisense strand as your sequencing primer.What do you expect to see on your sequencing gel at the C versus T site?(Note that this question requires a knowledge of PCR from Lecture 17.It also requires you to extrapolate beyone what you have been told).12.You are sequencing using the sense strand of a cDNA that has been cloned into an M13 viral vector as the template.How does the data that you read from your sequencing gel need to be modified to obtain the correct sequence for the sense strand of the cDNA? What term is used to describe the sequence that you have read from your gel?

13.Why does the sequence you read from the gel in Sanger dideoxy sequencing not begin with the sequence of the primer that you used?

14.What are the advantages of using fluorescent labels rather than radioactive labels for sequencing?

15.When sequencing with a primer for a vector with a multi-cloning site, you encounter the sequence GAATTC at the start of the cloned sequence that you are expecting.Explain how this might happen.16.The RNA coding sequence for the tryptophan operon attenuator peptide(lecture 12)is 5'-AUGAAAGCAAUUUUCGUACUGAAAGGUUGGUGGCGCACUUCCUGA-3'.a.Sketch a sequencing gel showing the sequence that would be obtained if you used the antisense strand of the DNA as the template and a primer that hybridized to the DNA just beyond the end of the coding sequence.b.Same as a, except using the sense strand of the DNA as the template.c.Same as a, except containing a frameshift mutation that causes the formation of a stop codon(UGA)near the middle of the sequence.The stop codon is to be formed by frame-shifting, and not by the direct insertion or deletion of a base at the site of the stop codon.Chapter 9 Gene Mutation DNA repair

1.Thymine dimers are one of the frequent targets of DNA repair systems.a.What is a thymine dimer.b.How are thymine dimers formed?

c.Why is it important to remove thymine dimers from DNA

d.Describe a method that eliminates thymine dimers without removing and replacing DNA sequences.e.Describe as many different mechanisms as you can for removal of thymine dimers from DNA.2.What is excision repair and how does it work? 3.What is mismatch repair and how does it work?

4.What mechanisms are used to distinguish newly made DNA strands from their template strands to be certain that error correction is done on the new strand and not on the template strand when a mismatch is detected?

5.What is the genetic defect involved in the human genetic disease Xeroderma pigmentosum? What limitations does it place on the lives of individuals who have it?

6.How do mutations induced by X rays and ultraviolet radiation tend to differ from each other? 7.Compare the mechanisms used to overcome ultraviolet light-induced damage to DNA in photoreactivation, as opposed to excision repair.8.How is damage to DNA that has been caused by alkylating agents repaired? What is the repair process called? What is the first intermediate step in the repair process?(Hint: you may need to go back to the previous lecture to find the nature of the damage done by alkylating agents)9.Describe the mechanisms that are involved in postreplicative(recombinational)repair.10.What is error-prone repair and under what conditions is it invoked? How can the existence of an error-prone repair system be justified(beyond the fact that it has been observed to occur)? 11.Describe the roles played by the RecA protein in various cellular responses to DNA damage.12.What special mechanisms exist for selective repair of the antisense strands of actively transcribed genes.Why is a comparable level of repair not expected for the sense strands? 13.Describe the last line of defense that a bacterial cell has against ultraviolet damage that is not detected and repaired as soon as it occurs.14.What genetic defect has been associated with Cockayne syndrome in humans.15.Starting with a wild type bacterial cell, what mutations would you select for in order to obtain a 36 strain that could be used to test for mutagens with maximum sensitivity.Chapter 10 Extranuclear Inheritance and Maternal Effect

Extranuclear Inheritance, Maternal Effect

1.What is the effect of a mutation in the bicoid gene in Drosophila?

2)Describe the pattern of inheritance of direction of coiling of the shell of the pond snail Limnea peregra.3.Briefly describe two distinctly different examples of maternal inheritance.4.What is a petite mutation in yeast? What metabolic defect is responsible for the peitite phenotype? 5.Describe three different inheritance patterns of petite mutations in yeast, and explain how each is achieved.6.Distinguish between a neutral petite(rho0)and a suppressive petitite(rho-)in a manner that makes it clear that you know what each is and how they differ.7.How does the pattern of inheritance of genes on the mitochondrial genome differ from that of dominant sex linked genes? Identify a specific pattern that would distinguish between the two.8.What properties make mitochondrial genes particularly useful in the study of short-term evolutionary changes in populations?

9.What conclusions have been drawn from studies on human mitochondrial gene sequences? What problems have caused these conclusions to be viewed somewhat cautiously?

10.What is meant by the term “bottleneck” as it is used in genetics? What are some of the likely causes of bottlenecks? What evidence suggests that a bottleneck may have occurred in human evolution?

11.What properties of modern mitochondria suggest that they may have originated as prokaryotic endosymbionts?

12.Explain the dependence of modern aerobic life forms on mitochondria.13.Describe three distinctly different ways in which uniparental mitochondrial inheritance can be achieved.Based on lectures from earlier in the semester, describe two other ways in which some of the inheritance received by specific individuals can be uniparental.37 14.Paternal imprinting and mitochondrial inheritance will both cause maternally-derived genes to be expressed exclusively in the immediate progeny of a mating.How would you distinguish between the two types of inheritance?

15.What is the presumed evolutionary origin of the genome found in chloroplasts.16.How is a defective chloroplast genome likely to be manifested phenotypically in a higher plant? 17.What is the basis for claiming that cells in higher plants have three separate but interacting genomes?

18.Describe the role played by kappa particles in Paramecium.19.Explain why most cells in budding yeast are homoplasmic even when originally derived from a heteroplasmic cross.20.What reasons may be responsible for the fact that such a high percentage of the genes in a typical mitochondrion code for RNA sequences that are not translated?

Chapter 11 Genetics and Development 1.What characteristics of homeotic gene?

2.Distinguish the role of nuclei cytoplasm in organism development? 3.Explain ABC model in flower development? 4.What is totipotency.Chapter 12 Quantities Genetics Because of time limitations, only questions 1 through 7 were covered in enough detail to be included in the final examination.1.What characteristics of wheat make it particularly useful in studies on quantitative genetics? 2.Distinguish between additive alleles and those that exhibit dominance, and explain how allelic interaction determines phenotype in each case.3.Explain how five different shades of color can be achieved with just two alleles each at two loci.38 4.What characteristics must be possessed by a set of genetic loci in order for the principles of quantitative genetics to be applied to them?

5.How would you determine the theoretical number of different phenotypes and their phenotypic ratios for n different additive genetic loci?

6.What factors usually limit the number of different phenotypes that can be distinguished in polygenic inheritance?

7.What prevents application of the concepts of quantitative genetics to the study of traits that are controlled by dominant and recessive alleles?

Items below this line will not be included on the final examination.8.Describe the difference between discontinuous and continuous variation.9.Distinguish among mean, median, and mode in a manner that makes it clear you know what each is and how they differ.10.How does a distribution with low variance differ from one with high variance? 11.What is the difference between a skewed distribution and a normal distribution? 12.What is meant by the concept of heritability when it is applied to a phenotypic trait that is influenced by polygenic inheritance?

13.Briefly define each of the following and explain its significance.a.Transgressive segregant b.Bimodal distribution c.Hybrid vigor d.Inbreeding depression e.Quantitative trait locus

14.Describe possible patterns of interaction between genotype and environment.15.What factors tend to limit the amount of phenotypic change that can be achieved by selection? 16.What factors do you think are causing average human height to be taller now than a few hundred years ago?(This calls for speculation on your part based on what you should have learned about continuous variation.Also, several different factors may be implicated.)

Chapter 13 Population genetics and Evolution

Population Genetics I

1.What is the basic difference in approach between the Mendelian genetic studies discussed earlier in the semester and the population genetic studies discussed in the current lecture? 2.Write the basic Hardy-Weinberg equations for distribution of alleles in a population and distribution of genotypes in a population, and show how the two are related.3.How can the relationship between allelic frequency and genotypic frequency be depicted visually? Draw an appropriate figure.4.What conditions must be met in order for the Hardy Weinberg relationship to be applicable.5.A rare recessive disease has a frequency of occurrence of X among the children of unrelated parents.a.What is the allelic frequency of the allele that is homozygous in diseased individuals? b.What is the frequency of heterozygous carriers of the disease in the general population? c.What is the frequency of individuals who are neither afflicted nor carriers?

6.What pattern of change of allelic frequencies over time is expected in a large population with random mating and no selective advantage of any of the genotypes?

7.Explain the meaning of the symbols H, P, and Q, and relate each to allelic frequencies p and q.8.Use a diagram to demonstrate how inbreeding leads to loss of heterozygosity.9.What is meant by the term homozygosity by descent?

10.Define the inbreeding coefficient(F)in terms of loss of heterozygosity.11.Use specific equations to show how the frequencies of homozygous genotypes(P and Q)are affected by the inbreeding coefficient.12.What would the inbreeding coefficient be in each of the following cases? a.For the children of a first cousin marriage(parents have the same grandparents).b.For the children of a second cousin marriage(parents have the same great-grandparents)c.For childdren of a marriage in which a grandson of a couple married a great-granddaughter.Assume that the grandson and great-granddaughter were descended from different children of the original couple.(Hint: construct the entire pedigree and determine the dilution of original parental alleles at each reproductive step, taking into account that there is one more generation on one side

than on the other.Don't forget that there are four parental alleles.)(Alternatively, this is a good place to use path distances.)

d.Brother-sister matings of laboratory mice.e.The offspring of the mating of a male laboratory rat with his female progeny(construct a pedigree and determine the dilution of alleles as in question c).13.Alleles A and B are codominant.Calculate the relative frequencies of the three possible phenotypes for each of the following frequencies of A.(Assume that A and B are the only alternatives).a.A = 0.5 b.A = 0.2 c.A = 0.1 d.A = 0.01 e.A = 0.001

14.Allele a is recessive to allele A.Calculate the relative phenotypic frequencies in each of the following situations.(Assume that A and a are the only alternatives).a.a = 0.5 b.a = 0.2 c.a = 0.1 d.a = 0.01 e.a = 0.001

15.What is the highest frequency of heterozygosity that can exist is a population that is in Hardy-Weinberg equilibrium.What are the allelic frequencies that yield the highest fraction of heterozygosity.Hint: If you are not particularly skilled in mathematics, the best approach to this one is trial and error, coupled with a little bit of intuition.(Alternatively, see figure 24.5 in Klug and Cummings, Concepts of Genetics, 5th Edition, Norlin reserve)

16.What changes occur in the Hardy-Weinberg equilibrium when the alleles that are being examined are carried on the X-chromosome?

17.Describe as many different ways as you can in which typical human mating patterns are likely to cause deviations from an idealized Hardy-Weinberg equilibrium.In each case, describe the type of deviation that is expected.18.What aspects of the life cycle of garden peas made it particularly easy for Mendel to obtain true-breeding strains with which to do his experiments?

19.You are working with two independently assorting loci A/a and B/b in garden peas.You deliberately cross true breeding AB peas with true-breeding ab peas.You then grow several generations allowing only self-fertilization, with sufficiently large samples so there is no selection

against rare genotypes.What distribution of genotypes and phenotypes do you expect to emerge? Exact calculations may get too complicated, but you should be able tocome up with some good generalizations.20.You are working with two genetic loci A/a and B/b that are about 10 map units apart on the same chromosome in garden peas.You deliberately do a dihybrid cross of two pure-breeding strains with the recessive alleles in coupling.You then grow several generations allowing only self-fertilization, always working with sufficiently large samples so there is no selection agains rare genotypes.What general patterns of genotypes and phenotypes would you expect to emerge?(You may find it helpful to consult table 15.1b).This is too complex for exact calculations, but you should be able to come up with some reasonable approximations.Also, be sure to take into account the cumulative effects of continued crossing over in successive generations.(Yes, this does call for a lot of speculation!)21.What tentative conclusion would you reach about a population that exhibited a high degree of polymorphism(the presence of alternative alleles at a high percentage of its genetic loci), but a very low level of heterozygosity in its

Population Genetics II

1.What possible explanations can be offered for loss of heterozygosity in certain populations found in the wild?

2.What criteria must be met for a genetic locus to be considered monomorphic? Polymorphic? 3.What is meant by the term “bottleneck” as it is used in genetics?

4.The Northern elephant seal has made a substantial recovery from near extinction.Why are geneticists still worried about its future?

5.Why is a high level of polymorphism in a population considered desirable?

6.What driving forces have caused the allelic frequency of HbS, which causes sickle cell anemia when it is homozygous, to become elevated in Central African populations? 7.What is the relationship between relative fitness and selection coefficient?

8.What is heterozygous advantage and what impact does it have on the population that emerges from an extended selective process?

9.In a population in which there is heterozygous advantage, what determines which of the two alleles that are involved reaches the highest equilibrium frequency?(You may have to make a 42 common-sense extension from what has been presented to answer this one.Think in terms of the relative s values for the two homozygotes.).10.Why does an allele that provides resistance to an adverse environmental condition not always become fully established and essentially monomorphic in a population?

11.Explain how a balance between selection and mutation can establish a constant allelic frequency for a recessive lethal trait.12.Describe two different ways in which reduction of a population to a small size can permanently alter the genetic composition of the progeny of that population, even if their number later increases.13.What are the mechanisms responsible for genetic drift, and how do they differ from founder effects?

14.Explain how an environmental change can alter selection.Illustrate with a real-life example.15.Why is it valuable to have a high degree of heterozygosity in a population?

16.Explain why selection is not very effective in the complete removal from a population of an allele that is deleterious only when in the homozygous recessive state.17.Explain how a disease epidemic can alter the balance of alleles that have nothing to do with resistance to that disease.18.Explain how a pericentric inversion might give rise to disruptive selection, and how such selection might be the first step toward formation of separate species.19.Describe a situation in which selection may not efficiently remove a dominant lethal allele from a population(hint: remember to use the normal definition of a “dominant lethal” allele--it does not mean dominant lethality or it would not exist in the population to start with).population? necessary?

18.What is an embryonal stem cell(ES cell)and what is its special value in genetic research? 19.Describe two different approaches that are being taking toward the use of biotechnology in vaccine production.20.Distinguish between transfection and transformation in a manner that makes it clear you know what each is and how they differ.参考书目：

[1] 《遗传学》第三版 朱军 中国农业出版

[2] 《遗传学》第二版 刘祖洞

上海复旦大学 高等教育出版社 [3] 《遗传学》第一版 刘庆昌 科学出版社

[4] 《Principles of Genetics》Second Edition D.Peter Snustad

University of Minnesota, Michael J.Simmons, University of Minnesota,John Wiley & Sons, Inc.[5]《Essentials of Genetics》Fourth Edition,William S.Klug

The College of New Jersey, Michael R.Cummings

University of lllinois at Chicago高等教育出版社

第五篇：双语教学 省2

“双语教学”优化课堂教学效果

念祖国

彝族有自己的语言和文字。彝语是彝族使用的语言，属藏缅语彝语支，分东部、东南部、南部、北部和中部6大方言。方言土语多，各方言或内部土语之间很难用彝语互相交际。彝族六大方言在云南境内均有分布，方言间差别大，加之云南彝族在境内聚居或杂居情况不同，聚居区内的彝族主要使用本民族语言进行交际，在聚居区边缘带的彝族主要使用本族语外，与周边民族交际时使用周边民族语进行交际；杂聚区的彝族在家庭内部使用本族语交际，与杂居民族交际时则使用与之交往的民族语或汉语；居住在城区的彝族主要使用汉语交际，家庭内主要以彝语或汉语交际。然而由于彝语方言众多，差别较大，各方言之间难以用彝语进行交际，汉语就成了彝民必备的第二语言。

我国是一个统一的多民族国家，几千年来，各民族相互往来，共同生活，形成了双语产生的客观条件和环境。恰当地处理好各民族间的双语关系，不仅有利于我国民族地区科学文化的发展、民族素质的提高和经济的繁荣更有利于各民族的团结和国家的长期稳定与发展。然而由于一直以来由于教学用语和学生的语言基础的衔接问题上严重脱节，致使彝区教育质量不高，导致事倍功半的教学效果。我省部分彝区根据从实际出发，积极稳妥、分类指导，循序渐进和讲求实效的原则，开设“双语教学班” 对巩固学生人数，开发儿童智力，提高彝族人民的科学文化水平等方面起到了良好的作用，并取得了令人鼓舞的成绩。总结出了“母语起步，汉语会话过渡，双语并重，逐步靠近全国统一教学大纲要求”的教学指导思想。我国彝区的这种社会语言使用状况决定了在处理彝族地区双语教学模式过程中，不能采取仅用汉语教学的单一的教学体制。加之彝族地区的社会状况，经济发展和地理环境等方面存在的差异或不平衡因素的影响，应根据不同地区的实际情况和特点，因地制宜，分类指导，实施相互联系，又互有区别的双语教育模式。由于双语教育本身所固有的客观性、复杂性、长期性等特点，决定了双语教学是一项仍需不断实践，摸索和改进的社会系统工程。本文拟对我国彝族地区的彝汉双语教育和发展问题作一些探讨。

一、结合彝族山区的实际，正确处理好彝汉双语教学是提高彝族山区教育质量的有效途径。

山区彝族人民群众不愿让子女上学，原因是多方面的，但最重要的一点是群众对教育目的不够明确。“读书为当干部，读书为当工人，找碗饭吃”的这种认识观念在凉山各地彝族地区相当普遍，如今由于国家不可能办更多的大、中专学校，因而升学的毕竟是少部分，大多数不可能升入大中专，要回到农业生产战线，迟点劳动还不如早点劳动。所以，彝族地区很多人看到年复一年的毕业升学率不高就失去信心，不愿意送子女上学，这在当今时代下的乡镇仍然表现更为突出。家长提心吊胆怀疑自己子女的前程是否光明，到头来能上大中专的是少数，多数人升不了学，这些落榜者走上社会后，由于缺乏技术技能，发挥不了应有的作用。结果是，因教育质量的低劣，难以取信于民，教育事业自然会随之而得不到社会的理解和人民群众的支持。几十年来的实践证明，在正确处理彝汉双语文的过程中，发现彝文教学能够激发学生的学习兴趣和积极性，用彝语文教学，学生学得快，记得牢，容易理解，能促进汉语文的教学，显著地提高了教育教学质量。

二、注意激活学生的课堂思维。

首先，在课堂上通过各种有意义的生活情景、社会情景、问题情景的创设，使学生兴奋和活跃起来，激活学生原先的经验，激起认知冲突，变被动的大脑活动为积极主动的思维，有效地促进新的学习信息与已有经验的耦合。当 激起了学生的求知欲后，倡导“合作交流”改变“一问一答”，让学生通过发现式学习自己去探索新知。而在这种数学学习活动中，学生各自的思维方式、智力活动是不一样的。因此，让学生经历合作和交流，感受不同的思维方式和思维过程，学生的思维会互补、会开阔，最后集思广益，学生获得概念会更清晰，结论会更准确。学生的思维由此被真正激活。然后进入“问题解决”这一环节，学生便能得心应手地把课堂学习成果应用于生活实际。因为学生在强烈的认知冲突与合作交流中获得了学习体验，在解决问题中，学生还将不断地强化和拓展学习体验。我常常引导学生质疑，鼓励学生进行有效的、民主的对话，在沙龙式的课堂思辨中擦出创新的火花，在有价值的课堂论辩中使学生成为有自己思想的学生，从而形成新的思维成果。童学习双语使同一形象与两种语言序列发生联系，加速了儿童对语言和语义的分离，对儿童概念的形成和思维能力特别是发散性思维能力的提高起促进作用。实验表明，学习双语的儿童，往往在思维的流畅性、灵活性、创造性和新颖性方面优于学习单语的儿童。

三、“双语”促进儿童语言的发展

汉语学习向儿童展示了另一套与母语不同的语言符号系统，一方面可以促进儿童对语言多样性的理解，丰富儿童的多种语言经验，另一方面还可以促进儿童语言能力的发展。

首先，汉语语言学习可以使儿童对两种语言之间的差异产生敏感。英语和汉语不属同一语系，各自有相对独立的语音系统和语法系统，随着学习的深入，他们会逐渐意识到两种语言之间的差异，在学习和运用不同语言时能够及时调整自己的学习策略。对语言之间差异产生敏感的直接结果是儿童开始将语言看作他们头脑中已经拥有的诸多系统中的一个特殊系统，从而提高了他们的语言操作能力，也提高了他们的语言学习能力。

其次，汉语语言的学习和掌握有利于儿童言语交际能力的提高。学习并掌握 汉语语言使儿童获得更多的机会参与以语言为交际手段的交际活动，从而提高了他们对交往情景和交往对象的敏感性。最后，早期儿童学习汉语语言，使他们更容易获得纯正、地道的 汉语语言发音。

再次，“双语”有利于儿童社会化的发展。影响儿童社会化发展的因素有社会环境、生物学因素和心理工具等，其中心理工具主要是指语言。学习并掌握汉语语言使儿童有可能与不同语言群体的成员进行交往，可以在一个多文化环境中认识世界的同时，更好地认识自己，评价自己，从而提高自我认知和自我评价的能力。

四、彝语营造氛围，激发学习兴趣。在课堂中注意保持平等、和谐的师生关系是形成良好课堂教学气氛的基础。学生对教师的人格态度、专业水平、教学教法、甚至对某一问题的看法，都会自觉不自觉的进行评价，作出“信任”或“不信任”的判断，“亲近”或“不亲近”的情感反应；甚至于把对教师的好恶迁移到教师所授的课程上来。作为双语教师，首先就要用彝语和学生交流使之产生亲近感，然后摆正心态，不能鄙视少数民族学生，客观公正的评价学生。在教学中，教师应关爱每个学生的全面发展，尊重每个学生的人格平等，不要因为学生的成绩优劣、性别、出身等的不同而产生亲疏和偏向。提问题或组织课堂教学活动，机会要尽量均等，尤其要注意多给那些自卑感强的后进生，使其有表现自我的机会，以增强他们学习的自信心。上课时，教师要环视每个学生，不要只看学习好的学生，而使其他学生感到冷落，或者只看学习差的学生，让他们感到不自在而产生紧张情绪，要及时利用各种教学表情和动作向学生传输信息

学生的兴趣是在求知需要的基础上，在学习活动中体验到成功的喜悦而逐步形成的，它是推动学生学习的有效动力，是学习动机中最现实，最活跃的心理因素。教师只要能把握好节奏，就能使学生产生浓厚兴趣。教学节奏通常指两个方面：一是指紧张度，二是指难度。一堂课的安排与设计，既要做到疏密相间，张弛结合，又要做到难易适中。该快的地方快，该慢的地方慢，该详的地方详，该略的地方略。叶圣陶先生曾说过：“学生自己想得通的，说得清楚的，自然不必教。想不通的，说不清楚的，这就碰了壁了，其时学生心头的苦闷多么厉害，要求解决的欲望多么迫切。这种情况下，受教师的教，真好比久旱逢雨，庄稼就会蓬蓬勃勃地滋长。”教师此时的“教”，说得确切一点，就是启发，必须掌握好。对于问题要化难为易，化大为小，要使学生在思考、行动的过程中体验到成功的喜悦感，进而产生更浓厚的兴趣，使课堂气氛呈现一种积极、兴奋的状态。同时，赞许学生积极提出自己的见解和观点，在课堂上学生提出一些不完全正确的猜想，或者是一种应急性回答，或者设想解决问题的多种方法、构思以前出现的一些新奇观象等。由于长期受传统“应试教育”的束缚，一些教师不愿活跃课堂气氛，不敢活跃课堂气氛，也不知怎样活跃课堂气氛，惟恐一发而不可收，于是课堂上老是一个人滔滔不绝的讲，下面的学生静如一潭死水，被动的接受知识。偶而有学生对某个问题举手发表一些个人看法，他不能接受，把学生的这种直觉思维视为“异端”，大声喝斥，要么说学生是“胡思乱想”，或者给其扣上一个“扰乱正常教学秩序”的大帽子„„好端端的一个直觉思维就这样被一棒子打死，长此以往这种“千篇一律，万生一面”的“同化”教育模式，不知扼杀了多少学生的思维天才。素质教育作为一种高质量的教育，教师应树立和谐教育意识，即教学过程中做到：师生加强合作、同思考、共探索、鼓励辩论、关系和谐。在上每一节课，每一篇课文都要鼓励学生发表自己的观点和见解，让他们知道他们的观点也是有价值的，有意义的。通常情况下，学生们的观点更能激发他们学习的兴趣，这种情况下教师最好只做个牵线人，这样课堂气氛会更活跃些。只有调动好课堂气氛，才能激发学生学习语文的兴趣，使他们积极、主动地学习语文。值得一提的是，在努力活跃课堂气氛的同时，还要注意维持课堂纪律，避免因个别学生违纪而影响了教学效果。而且教师在上课前应有良好稳定的情绪，尽快进入讲课的角色，才能形成轻松活跃的气氛。总之，激活课堂气氛的方法多种多样，其目的只有一个，那就是激发学生对所学知识的学习兴趣，拓展学生的思维空间，培养学生的实践能力和创新能力，充分调动学生学习的积极性和主动性，从而达到乐学的境界，提高学生的综合水平。

四、教学中重视汉语交际活动，培养学生的交际能力，提高课堂效果

新课程把教学过程看成是师生交往、积极互动、共同发展的过程。把教学本质定位为交注，这是对教学过程的正本清源：它是对“把教学品德过程”这一传统观点的重大突破：在课堂交际活动中，教师的任务是创设情景，而真正的交际活动应当由学生完成。当教师组织交际活动时，可以多组同时进行，然后再由一组或几组上讲台表演；要注意引导学生克服对教师的依赖心理，大胆活动。交际活动中，教师蓄力于引导，变“死学”为‘活学’，即将教师传授知识的过程转化为学生探究知识的过程，使教师在帮助学生实现理论知识内化的同时，把凝聚在知识中的智力活动方式转化为自己的认识能力，善于引导学生主体的积极行为。教师的教学应处于“道而弗牵，开而弗达”的境界，有意识地发挥学生参与教学过程的主体性，帮助学生正确使用词语是提高他们口语能力的一个关键方面。

总之，双语教学的实施给彝区带来了生机，带来了希望。对促进彝区的教育发展，人民素质的提高、经济的繁荣、乃至意识观念的转变等方面都起到了不可替代的积极作用。因此，在发展彝族地区双语教育问题上，只要实事求是，放开手脚，坚定不移地引进机制和改革创新经验，取长补短，逐步解决和完善彝汉双语教育中母语教学与汉语教学的衔接问题，教学目标的确定、教学大纳和教材的设计及从理论与实践的结合上研究如何充分发挥彝语教学的优势，提高教学质量等问题，我国彝族地区的彝汉双语文教学将会开创出具有彝区特色的双语教育新局面。