《基因工程》习题及参考答案.docx

1、基因工程习题及参考答案基因工程习题及参考答案一、习题：1. What are biotechnology and genetic engineering?2. What is a gene?3. What are genetically engineered medicines?4. What do genome research and human genetics deal with?5. What potentials are held out by genetic diagnosis?6. What options are given by gene therapy?7. What i

2、s an embryo - and what is a fetus?8 What is a genetic fingerprint?9 What does the term therapeutic cloning mean?10 What are stem cells?11 What is a transgenic organism?12 What does xenotransplantation mean?13 How will genetic engineering be used in agriculture?14 How are genetically modified organis

3、ms assessed?15 What does the German Embryo Protection Act regulate?16. What is a genome? 17. Is there a risk of bioterrorism? 18. How does genetic engineering affect the environment?19. Are genetically engineered crops good for farmers?20. What is the difference between restriction digestion and res

4、triction mapping?21. Can you combine two different restriction enzymes in the same reaction tubes to digest the DNA molecules?22. Why should we need to generate restriction mapping data?23. How many restriction enzymes available now on the market?24. Why do you consider mutagenesis in vitro as one o

5、f the most critical techniques for us to understand in genetic engineering class?25. How do we choose the methods for DNA modification?26. How do we choose a gene expression system?27. How can we express eukaryotic gene in E.coli?28. What should we consider before we start the recombinant protein ex

6、pression experiment?29. What is the advantage of yeast expression system?30. What is the advantage of insect expression system?31. Why there are so many different types of vectors available for cloning?32. What is the difference between cloning vector and expression vector?33. What is a genetic fing

7、erprint?34. 基因具体分成多少种类？35. 什么叫印记基因？36什么叫遗传漂变？37人类基因组图谱和初步分析结果是在哪一年公布的？38人类基因组共有多少基因?39. 克隆羊成功的技术关键是什么？40. 有人计划将两个不同物种的动植物体细胞进行融合，然后将融合体的核移植到其中一种生物的未受精卵细胞中，进行体细胞克隆。此计划可行吗？为什么？41.切口移位标记探针的主要步骤有哪些？42.用EcoR和Hind 分别切割同一来源的染色体DNA，并进行克隆，在前者的克隆中筛选到A基因，但在后者的克隆中未筛选到A基因，是什么原因？43.在基因工程中，为了在细菌细胞中表达真核细胞的基因产物，为什么通

8、常要用cDNA而不用基因组DNA？为什么要在cDNA前加上细菌的启动子？44.当两种限制性内切酶的作用条件不同时，若要进行双酶切，应采取什么措施？为什么？45.有些噬菌体和质粒常常编码一些抗限制性酶的蛋白以中和宿主的限制系统。除此之外噬菌体和质粒还有哪些可能的方式避免宿主的限制系统？46.为什么大多数内切酶被称为“限制”酶？47.何谓同裂酶？48.什么是限制性物理图谱？49.为什么反转录酶在聚合反应中会出错？50.RNase A和.RNase H在催化活性和应用上有何不同？51.切口移位标记DNA前，用DNase处理DNA时，应注意什么？52.DNA连接酶对DNA的复制是很重要的，但RNA的合

9、成一般却不需要连接酶，为什么？53.RNA聚合酶特异性地转录小分子RNA，但为什么不转录5.8SrRNA?54.用EcoR 切割外源DNA片段时出现了星号活性，可能是什么原因？二、参考答案：1 What are biotechnology and genetic engineering?Biotechnology is a field of bioscience. In very general terms it can be described as the theory of the use of biological systems in research and application

10、s. Biotechnology applications are a rapidly growing sector of the economy. The number of biotech companies in Germany has increased considerably over the past seven years. Genetic engineering includes all biotechnological processes aimed at effecting specific changes in the genetic material of cells

11、. The principle is, in general, the following: sections of DNA (= deoxyribonucleic acid) from outside sources are introduced into a cell in order to bring about defined changes. What is involved in most cases is the synthesis of molecules, the information for which is contained in the introduced DNA

12、. This process has been used to produce new medicines (see genetically engineered medicines). 2 What is a gene?A gene is the smallest unit of genetic material. It describes a specific section of DNA which, as a result of its nucleotide (= DNA component) sequence, determines specific functions, chara

13、cteristics, features, or structures of a cell. The way genes are expressed in each case is dependent on their interaction with other genes and with the environment.The genome is the entirety of genes contained in an organism. The term is synonymous with genetic material. 3 What are genetically engin

14、eered medicines?In the genetic engineering of medicines genes containing the codes of therapeutically valuable substances are transferred to easily cultivated cells. In most cases bacteria are used, more rarely also yeast cells and the cells of mammals. Medicines produced in this way are called reco

15、mbinant medicines. The human insulin introduced (for diabetics) in 1982 was the first recombinant medicine. Since the mid-1990s persons with hemophilia A (the most common form of this blood disease) have been treated to an increasing extent with recombinant factor VIII. Prior to that the only treatm

16、ent available was factor VIII produced from human plasma.4 What do genome research and human genetics deal with?Genome research pursues the objective of identifying the structures and functions of the individual genes in the genome. The object of genome research is the study of the genetic material

17、of all organisms, meaning that the genomes of certain plants, animals, and microorganisms are just as much a subject of study as the human genome. It is an important task of human genome research to identify what genes are involved and in what ways they are involved in causing diseases. This researc

18、h is expected to bring new approaches in the treatment of cardiovascular diseases, cancer, infectious diseases, and diseases of the central nervous system such as Parkinsons disease, multiple sclerosis, or Alzheimers disease. Scientists presented the largely decoded human genome on June 26, 2000. Bo

19、th scientists and government leaders throughout the world noted this as an epoch-making event and an important milestone in the history of mankind. At the same time this has created new challenges for science, government, and ethics. The field of ethics is called upon to show whether and how this kn

20、owledge can be used responsibly in such widely diverse fields as medicine and agriculture.Human genetics is a medical discipline that deals with human heredity, the causes and diagnosis of hereditary diseases, and the search for possible therapies. Diagnostic procedures today include state-of-the-ar

21、t genetic diagnoses in addition to traditional analyses of hereditary mechanisms.5 What potentials are held out by genetic diagnosis?Modern genetic diagnosis methods make it possible to analyze individual structures of the genome and, in doing so, to identify gene defects associated with hereditary

22、diseases such as cystic fibrosis. This would be beneficial to persons who carry the gene and would run the risk of passing it on to their children. It is conceivable that awareness of an inherited predisposition for a disease that emerges later in life would cause the persons in question to take spe

23、cial precautions such as going in for preventive checkups or pursuing a lifestyle aimed at preventing an outbreak of the disease. Gene tests can be used to confirm the diagnosis of suspected diseases. More than that, modern methods (such as gene chips) can be used to help a wide range of people, inc

24、luding those who are not sick, to identify genetic characteristics such as predispositions for certain diseases. Here, entirely new ethical and legal questions are arising for society. In the case of predictive gene tests, i.e. tests used to make forecasts as to risks of hereditary illness, it will

25、be a separate task to determine whether these tests will be of value to individuals and to society as a whole. We need to distinguish between preimplantation genetic diagnosis (PGD), prenatal genetic diagnosis in the context of prenatal care, and postnatal genetic diagnosis.Preimplantation genetic d

26、iagnosis (PGD) is a controversial area of genetic diagnosis. After in vitro fertilization PGD can be used to carry out a gene test on an embryo before it is implanted in the mothers uterus. By this means embryos showing a specific genetic defect can be sorted out. 6 What options are given by gene th

27、erapy?The objective of gene therapy is to treat or prevent diseases, making use of genetic engineering principles. DNA can, for instance, be introduced into blood or liver cells by means of vectors in order to eliminate genetic defects present there. Or cells that have been genetically modified outs

28、ide of the body may be implanted in the patient. A further approach is the injection of so-called naked DNA as a kind of vaccine. Naked DNA makes it possible to synthesize proteins against which the vaccinated person builds up an immune reaction as in the case of a conventional vaccination, except t

29、hat here a much more specifically targeted effect on the immune system is expected. Somatic gene therapy must be distinguished from germ line gene therapy. After germ line gene therapy the effected change in genetic information would be passed on to the offspring of the individual in question. The p

30、rerequisite for this would be manipulation of the genetic material contained in an egg cell or a sperm cell or of the genetic material contained in an embryo in the early stages of development. The German Embryo Protection Act imposes a comprehensive ban on carrying out germ line gene therapy in hum

31、ans.In the case of somatic gene therapy (= therapy of or involving body cells) only body cells (= somatic cells) are the object of change. Since this type of treatment is directed exclusively at somatic cells, it will not have an effect on the genetic material passed on to the patients offspring. Th

32、e predisposition for a given disease will be passed on to the patients children even if gene therapy is successful. It should be noted that at the present time gene therapy is used mostly to treat malignant cancers, and in Germany exclusively in such cases. The cause of the disease is usually not associated with one single gene but rather with a combination of external factors involving several genes. For part of the diseases treated there is no evidence of a genetic predisposition and in the underlying therapeu