Unit8Cloning.ppt

1、Unit 8 Cloning Text A A Clone is Born,Pre-Reading Task Cultural Notes Language Points Text Organization Language Focus,First Stem Cells Extracted from Cloned Human EmbryoPosted: 02.17.04 Scientists in South Korea have extracted stem cells from a cloned human embryo - a breakthrough that has potentia

2、l for treating various diseases but also ignites fears that rogue scientists will use the technology to clone humans.,Part I: Pre-Reading Task,Other scientists have cloned small numbers of human embryos that lived for a short time, but the South Koreans who announced their work last week in the jour

3、nal Science, apparently succeeded on a scale that far outstripped earlier human cloning efforts.,South Korean researchers make medical history,The researchers began with a group of 16 women who were given hormone treatments to produce large numbers of reproductive egg cells. They eventually obtained

4、 242 eggs from the women. Then the scientists used innovative techniques to strip out the nucleus from each of these egg cells. The nucleus is the portion of the cell containing many of the cells genetic instructions.,The scientists next took body cells from the same women who had donated the egg ce

5、lls. The body cells have two sets of chromosomes, the full genetic blueprint needed to create a human being. The scientists removed these body cells nuclear material and placed it into the egg cells.,The result was 66 cloned eggs, in effect, human embryos, with the exact genetic makeup of the origin

6、al females. The researchers grew 30 of the embryos for a week to the so-called blastocyst stage, when stem cells could be extracted,Stem cell technology could help cure diseases,Embryonic stem cells are unique because they have the potential to develop into any type of tissue or cell in the body. Th

7、e research, called therapeutic cloning, could allow scientists to take a plug of skin or blood sample from a patient and use it to grow tissue, organs or batches of cells. The new cells would have the same genetic makeup as the donor and would therefore lower the risk that the injured or sick person

8、s body would reject the new tissue.,Our approach opens the door for the use of these specially developed cells in transplantation medicine, said Woo Suk Hwang, who led the government-funded study. Researchers also hope the stem cell research will lead to treatments for a range of diseases from Alzhe

9、imers to Parkinsons to diabetes.,Ethical questions,But embryonic stem cell research is controversial because harvesting the cells destroys an embryo that could have grown into a baby if implanted in a womans uterus. President Bush is against making and destroying human embryos. The use of embryos to

10、 clone is wrong. We should not as a society, grow life to destroy it, he said in 2001. The Bush administration policy does not allow the government to fund any research on stem cells taken from embryos destroyed after Aug. 9, 2001. Since the research is expensive, the ban has limited the amount of w

11、ork being done in the United States.,Reproductive vs. therapeutic cloning,Some fear that the South Korean scientific advance will encourage people to create human clones, called reproductive cloning. In reproductive cloning, which has been performed with animals but not people, the embryos are impla

12、nted in the womb and allowed to develop into a fetus. In therapeutic cloning, the embryos are never implanted, but are grown for a few days in the laboratory so that the stem cells can be extracted. The first mammal was cloned in 1996 when Scottish researchers made Dolly the sheep. Dolly died a year

13、 ago of what scientists said was premature aging and complications from cloning. Most scientists believe human reproductive cloning is unethical because any baby created by this method would be prone to severe deformities.,Scientific research in the United States,While many U.S. lawmakers would like

14、 to ban human reproductive cloning, the debate is complicated by the question of whether to allow therapeutic cloning. Conservative lawmakers have attached bans on embryonic stem cell research to all bills regarding reproductive and therapeutic cloning, preventing Congress from coming up with a clea

15、r policy. Some U.S. scientists worry that the lack of government support for all cloning related to humans is already harming the future of American medical research. We will be sitting here with the best scientists in the world watching things on television, Dr. Jose Cibelli, professor of animal bi

16、otechnology at Michigan State University told the New York Times. Cibelli collaborated with the South Korean scientists and is an author of their paper. Several countries in Europe ban all human cloning, including therapeutic cloning.,Reading Comprehension Questions:,1. Explain how the South Korean

17、scientists created the stem cells. 2. Why are embryonic stem cells so interesting to scientists? How can this research be applied to medical treatments? 3. Why is embryonic stem cell research controversial? 4. Why does President Bush want to limit embryonic stem cell research? 5. How is reproductive

18、 cloning different from therapeutic cloning? 6. Why hasnt the United States banned human reproductive cloning?,Keys:,1. Explain how the South Korean scientists created the stem cells.The scientists took body cells from 16 women who were given hormone treatments to produce large numbers of reproducti

19、ve egg cells. The body cells have two sets of chromosomes, the full genetic blueprint needed to create a human being. The scientists removed these body cells nuclear material and placed it into the egg cells. The result was 66 cloned eggs, in effect, human embryos, with the exact genetic makeup of t

20、he original females. The researchers grew 30 of the embryos for a week to the so-called blastocyst stage, when stem cells could be extracted. 2. Why are embryonic stem cells so interesting to scientists? How can this research be applied to medical treatments? Embryonic stem cells are unique because

21、they have the potential to develop into any type of tissue or cell in the body. The research, called therapeutic cloning, could allow scientists to take a plug of skin or blood sample from a patient and use it to grow tissue, organs or batches of cells. The new cells would have the same genetic make

22、up as the donor and would therefore lower the risk that the injured or sick persons body would reject the new tissue. 3. Why is embryonic stem cell research controversial? Embryonic stem cell research is controversial because harvesting the cells destroys an embryo that could have grown into a baby

23、if implanted in a womans uterus.,keys,4. Why does President Bush want to limit embryonic stem cell research? Harvesting the cells destroys an embryo that could have grown into a baby if implanted in a womans uterus. President Bush is against making and destroying human embryos. The use of embryos to

24、 clone is wrong. We should not as a society, grow life to destroy it, he said in 2001.,5. How is reproductive cloning different from therapeutic cloning? In reproductive cloning, which has been performed with animals but not people, the embryos are implanted in the womb and allowed to develop into a

25、 fetus. In therapeutic cloning, the embryos are never implanted, but are grown for a few days in the laboratory so that the stem cells can be extracted. 6. Why hasnt the United States banned human reproductive cloning? While many U.S. lawmakers would like to ban human reproductive cloning, the debat

26、e is complicated by the question of whether to allow therapeutic cloning. Conservative lawmakers have attached bans on embryonic stem cell research to all bills regarding reproductive and therapeutic cloning, preventing Congress from coming up with a clear policy.,Part II Cultural Notes:,1. clone: a

27、 group of organisms or cells that are genetically identical, having been produced from one parent by asexual reproduction. The individual organisms or cells are precise copies of the parent and genetically identical to it. Clones are found naturally among single-celled organisms ( such as bacteria),

28、 a few invertebrates (such as corals), and some asexually reproducing plants ( as in the production of runners by a strawberry plant). In agriculture, plant cloning can be used to advantage, in that individuals with desirable properties, such as pest-resistance or high growth rates, can be replicate

29、d exactly without the unpredictable results associated with sexual reproduction. Artificial cloning of animals and cells can be achieved by teasing apart the cells of the early embryo. Similarly, cells capable of growing into mature plants can be obtained from plant growth-regions (meristems). In ge

30、netic engineering cloning refers to the copying of DNA molecules.,2. genetic engineering: the deliberate modification of the genetic make-up(genome) of an organism by manipulation of its DNA. Genetic engineering techniques include cell fusion and the use of recombinant DNA (r DNA). Since the late 19

31、60s these techniques have held out the most exciting promise for biotechnology. In such a new field controversy inevitably abounds. Worries concerning release of genetically novel bacteria into the environment, or the possible manipulation of human embryos, have led to the setting up in the USA of t

32、he Genetic Manipulation Advisory Group (GMAG). Legislation governing genetic research has also been passed in several other countries.,3. NARCISSUS ( in Greek mythology): a beautiful youth who spurned the love of the nymph Echo and in punishment was made to fall in love with his own reflection; he p

33、ined away gazing at himself in a pool and at his death was changed into the flower bearing his name narcissus.,4. Prometheus: in Greek mythology, a Titan who made the first man from clay and stole fire from the gods to give to mankind. In revenge for the theft, Zeus chained Prometheus to a rock, whe

34、re his liver was eaten every day by an eagle, only to grow again ever night. Herecules eventually rescued him. Prometheus has been seen as a symbol of freedom, rebellion against tyranny, and of creative imagination.,5. Oppenheimer, ( Julius) Robert (1904-1967): US physicist. He was appointed in 1942

35、 as director of the Manhattan Project, the secret project to develop the atomic bomb in the USA during World War II, based at Los Alamos, New Mexico, which in 1945 made the first atomic bomb. In 1953, at the height of the witch-hunting campaign led by the US Senator Joseph McCarthy, Oppenheimer was

36、excluded from sensitive research on the grounds that he had Communist sympathies, but subsequently (1963) he was unreservedly rehabilitated.,6. Hiroshima: Japanese city in southern Honshu. Hitherto largely undamaged by the US bombing campaign, Hiroshima became the target of the first atomic bomb att

37、ack on 6 august 1945, which resulted in the virtual obliteration of the city centre and the deaths of about one-third of the population of 300,000. The attach on Hiroshima, together with that on Ngasaki three days later, helped bring about Japans unconditional surrender and the end of World War II.,

38、7. Nagasaki: Japanese city in Kyushu. On 9 August 1945, three days after the first atomic bomb attack on Hiroshima, Nagasaki became the next target. The hilly terrain protected the population of 230,000 from the full effects of the explosion, but 40,0000 people were killed and tremendous destruction

39、 caused. On the following day Japan offered to surrender and the ceasefire began on 15 August, the official surrender finally being signed on 2 September.,Part III Language Points:,1. clone: any of a group of plants or animals produced from the cells of a single ancestor and therefore exactly the sa

40、me as it is. e.g. Researchers produced clones from adult mice in 1998. Although two clones are identical genetically, they may develop in different ways. e.g. Researchers in Japan have cloned eight calves from the cells of a single adult cow. The idea of cloning extinct life forms still belongs to s

41、cience fiction. Experiments to try to clone human embryos have met with hostility from some sections of the public.,2. give birth to: 1) bear (a bird), bring forth e.g. Although a mother panda often gives birth to two cubs, she usually abandons one of them without attempting to care for it. The rese

42、arch has shown that mothers who smoke give birth more frequently to premature or underweight babies. create, originate e.g. The extraordinary experience gave birth to his latest novel. Einstein gave birth to a whole new way of looking at matter and energy. 3. for all the world: in every respect; exa

43、ctly e.g. I felt for all the world as if I was still a child. He looked for all the world like a country doctor.,4. dot: spread things or people in various separate places over an area e.g. From the top floor we could see the trees dotting the landscape. The sky was dotted with stars. n. a small rou

44、nd mark e.g. He forgot the dot on the letter i and so it looked like an 1. The stars just look like thousands of tiny dots of light. 5. union: a uniting or being united; combination; an organization of workers from a particular profession, an association or club. e.g. Marriage is a socially recogniz

45、ed and approved union between individuals. Labor unions bargained with employers to determine issues such as wages, conditions of work, and worker security.,6. fuse: ( cause to ) join together ( followed by with) e.g. Nearly 50 percent of the cumulus cells that successfully fused with an egg develop

46、ed into an advanced embryo. Genes determine how we develop from the moment the sperm fuses with the egg. 7. gene: a unit in a chromosome which controls inherited characteristics e.g. Genetics is the study of the function and behavior of genes. The human Genome基因组 Project has so far identified nearly

47、 all of the estimated 31,000 genes in the nucleus of a human cell. The DNA is divided into units called genes, just like a long train is divided into separate cars.,8. take up: go and live; move into ( a certain position) e.g. The hunter took up his quarters in a hut. As the crowd grew, riot police

48、took up their positions. UN peacekeeping forces are expected to take up positions along the Afghanistan border. 9. residence: the fact of living in a particular place e.g. He took up his permanent residence in China. Campus residence halls provide common settings for students to form new bonds with

49、peers who share similar experiences. More immigrants were admitted to the United States for permanent residence in recent years.,10. identical: exactly alike or equal; the very same ( followed by to) e.g. The journalist David Rorvik wrote a true story of a billionaires quest to produce a son identic

50、al to himself. Although Euro bills are identical in all countries, each country can issue its own coins. 11. twin: persons who have the same mother and were born on the same day e.g. The two boys looked like twins. He has a twin brother and a younger brother. Unlike my friend, I think there are many

51、 positive aspects to being a twin. 12. beforehand: in advance; earlier e.g. Catherine got married without telling anyone beforehand. Mum had done most of the cooking beforehand, so we werent tied to the kitchen.,13. oppose: express strong disapproval with the aim of preventing or changing a course o

52、f action: resist e.g. My father opposed my wish to become a musician. The local residents strongly opposed the chemical companies dumping their waste in the sea. be opposed to : be against e.g. We are utterly opposed to any form of terrorism. They are strongly opposed to the presence of American tro

53、ops in this region. 14. theoretical: concerned with the theory of a subject; based on theory e.g. Information theory is primarily a theoretical study. With his brilliant theoretical work, Albert Einstein revolutionized 20th century physics. Aristole defined the basic concepts and principles of many

54、of the theoretical sciences, such as logic, biology and physics.,15. in principle: as far as basic principles are concerned e.g. In principle, clones may even be essentially immortal, dying only from disease or the deterioration of the environment. In principle, Quantum theory could be used to predi

55、ct the behavior of any physical, chemical, or biological system. 16. offensive: causing sb. to feel upset, insulted or annoyed e.g. Minority groups are protected from hateful and offensive speech and actions on campus. The document did not appear to contain any offensive statements. 17. compromise:

56、a settlement in which each side gives up some demands e.g. In order to reduce carbon monoxide emissions from motor vehicles but at the same time develop the industry, a compromise was reached. The two countries continued to have difficulties reaching a compromise on a solution to the problem of acid

57、 rain. v. (used in the patterns: compromise with sb. Over sth., compromise on sth.),18. potential: the possibility of sth. Happening or being developed e.g. The potential for abuse of genetic engineering has presented society with many ethical and legal controversies. The best single indicator of a

58、states great-power potential may be its total Gross Domestic Product (GDP). Volcanoes have the potential to create some of the planets most formidable natural disasters. a. that can, but has not yet, come into being; possible e.g. In large cities with a million or more potential customers, there are

59、 much larger clothing stores with many more choices of items and styles. In the article Wilmut discussed potential medical uses for cloning, and ethical issues surrounding cloning technology. Scientists can only speculate on the potential impact of the depletion of the ozone layer.,19. tolerate: allow (