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Cystic fibrosis is caused by a gene called CFTR.
A．Right
B．Wrong
C．Not mentioned
答案
更多“Cystic fibrosis is caused by a gene called CFTR.A．RightB．WrongC．Not mentioned”相关的问题
第1题
Cystic fibrosis patients are very susceptible to lung infections and thus die early.
A．Right
B．Wrong
C．Not mentioned
第2题
Other groups that have attempted to correct the genetic defect that causes cystic fibrosis have used viruses as "vectors" (媒介) to carry the healthy gene into target cells. Unfortunately, viruses can also cause inflammation in the lungs, an undesirable side effect in CF patients, whose lungs are already diseased. The new method for introducing corrective genes into the lungs of CF patients promises to be much safer.
Cystic fibrosis is caused by defects in a gene called CFTR, which plays a part in the transport of chloride ions(离子) out of the cells lining the lungs, airways and gut. Defects in this gene mean that patients have difficulty expelling mucus(黏液) and inhaled (吸入) microorganisms from their lungs. As a result, they are very susceptible to lung infections, and usually die at around 30 years old.
As an alternative to the viral vector, the researchers, linked loops (环)of DNA containing healthy copied of the CFTR gene to microscopic liposomes. When the liposomes come in contact with a cell, they fuse(融合) with its outer membrane, and release the DNA into the cell's interior. To test the system, the team sprayed the liposomes into the noses of volunteers with cystic fibrosis. "The cells lining the nose are very similar to those lining the lung," explains David Porteous of the human genetics group in Edinburgh. But the ceils in the nose are easier to monitor, and the risks are lower if any nasal (鼻的)cells are damaged.
In the event(结果,到头来), none of the volunteers suffered any unpleasant side effects. And a single spraying partially corrected the cystic fibrosis defect. The researchers assessed the effectiveness of the treatment by measuring the voltage(电压,伏特) across the layer of cells lining the nose. This voltage is higher in cystic fibrosis sufferers than in healthy people. A single spraying reduced this difference by around 20 per cent. The re-searchers reported that the effect lasted for up to a week.
The British researchers have yet to test their spray in the lungs, but are confident that the liposomes will not cause inflammation. The question, however, is how effective the shuttle system is. In the nose, the researchers had to add more copies of the healthy CFTR gene to match the performance of the adenovirus. This is because adenoviruses carry genes directly to the cell' s nucleus, ensuring that the instructions they carry are read. Genes carried by liposomes are only guaranteed a ride into the cell's cytoplasm, and fewer will find their way to the nucleus. Many will be broken down by the cell's waste disposal system before they get there.
Bob Williamson, who heads the group at St. Mary's Hospital, says this will require much more efficient vectors. "People in 10 to 15 years will laugh at the crudity of the liposomes and viruses that we're using today, " he says. The aim is to make customized vectors which combine the best aspects of both systems, and include other genetic sequences to ensure that the information carried by the healthy CFTR gene is used by the target cells lining the lungs.
Liposomes were tested as a vector for ferrying replacement genes into the lungs of CF patients.
A．Right
B．Wrong
C．Not mentioned
第3题
Many genetic defects, such as the hemophilia of European royalty, can be traced back through the family tree. And a genetic counselor can calculate probable risks for couples even before they have defective children. But faulty genes may also occur without warning by mutation in any generation.
In recent years, researchers have detected a number of disorders caused by an extra chromosome, or lack of part of a chromosome. Mongolism, a form. of retardation accompanied by short stature, a flattened nose and broad hands and feet, is caused by an extra chromosome. The parents of such a child have little increased risk of having another Mongoloid.
There are blood, urine and other tests which show promise in detecting more than 100 genetic diseases, including cystic fibrosis, hemophilia and some forms of muscular dystrophy.
Researchers are also detecting genetic defects even before a child is born. "Intrauterine detection," notes Dr. Henry L. Nadler of Northwestern University Medical School, "brings a new dimension to genetic counseling. The physician may now inform. the parents that they will have either an affected or a normal child. "
The original title of the passage can be best replaced by______.
A．Genes and Diseases
B．Genes and One's Characteristics
C．Genetic Defects and the Family Tree
D．Dominant and Recessive Genes
第4题
根据材料请回答 36～40 题
The genes that help determine a person's individual characteristics -- from the color of his eyes to the score he makes on an IQ test-- are located on chromosomes(染色体)within the cells of his body.Half of a person's chromosomes come from his father, hail from his mother.Many diseases are the result of a .single defective(有缺陷的)gene on one of the chromosomes.Achondroplastic dwarfism (软骨营养障碍性矮小), for example, is caused by a dominant gene ,and any child who inherits it will have the disease.A genetic counselor confronted by a parent with such a disease could warn that half of his children risk the disease.More often, genetic diseases are caused by recessive(隐性的)genes.The most common is cystic fibrosis(囊肿性纤维化), a disorder that affects at least .one in every 1,600 babies and causes their lungs and other body organs to become congested(充赛)with mucus (黏液).Some diseases, such as the blood-clotting(血栓) disorder, hemophilia (血友病), are, sex-linked recessive defects carried On the female X chromosome.
Many genetic defects, such as the hemophilia of European royalty, can be traced back through the family tree.And a genetic counselor can calculate probable risks for couples e-ven before they have defective children.But faulty genes may .also occur without warning by mutation(突变)in any generation.
In recent years, researchers have detected a number of disorders caused by an extra chromosome, or lack of part of a chromosome.Mongolism(先天愚型), a form. of retarda-tion(迟钝) accompanied by ,short stature(身材矮小), a flattened nose and broad hands and feet, is caused by an extra chromosome.The parents of such a child have little risk of hav-ing another Mongoloid(先天愚型患者).
There are blood, urine and other tests which show promise in detecting more than 100genetic diseases, including cystic fibrosis, hemophilia and some forms of muscular dystro-phy(先天愚型患者 ).
Researchers are also detecting genetic defects even before a child is born."Intrauter-ine detection (子宫内检测)," notes Dr.Henry L.Nadler of Northwestern University Medical School, "brings a new dimension to genetic counseling.The physician may now inform. the parents that they will hare either an affected or a normal child."
第 36 题 The original title of the passage can most probably be
A．Genes and Diseases
B．Genes and One's Characteristics
C．Genetic Defects and the Family Tree
D．Dominant and Recessive Genes
第5题
Benji left us about 15 years ago for that great kennel in the sky. But recently I've been thinking about him a lot. Was he really conscious？ Could any animal have consciousness like we do？ Does it matter whether animals are conscious or not？
For many, it is a matter of life and death. On the one hand, animal research has helped prevent some of the most pressing human diseases, including hepatitis B, hepatitis C, "mad cow" disease, malaria, cystic fibrosis and emphysema. On the other hand, this research is performed largely on chimps, our closest nonhuman relatives, with whom we share 98.4% of our genetic material, and great apes, with whom we are similarly biologically close.
Some people feel this connection is strong enough to warrant special treatment. An international group called the Great Ape Project is lobbying the United Nations to adopt a declaration on the rights of great apes modeled on the UN declaration On the Rights of Man. The group believes that apes are "conscious" and so deserve legal protection of their right to life and freedom from imprisonment and torture.
If great apes were shown to have consciousness or something like our own, I would consider it among the scientific discoveries of the century. I would then agree with the Australian philosopher and founder of the animal rights movement, Peter Singer, that per forming medical experiments on chimps would be like experimenting on orphan children. That's a pretty chilling thought, and no amount of' human suffering saved could justify such an action. But before we close down the laboratories and stop searching for a vaccine against AIDS, we had better take a long hard look at the evidence for ape consciousness.
Why does the author bring up the example of Benji？
A．To show that animals have consciousness.
B．To raise the question of animal consciousness.
C．Because Benji was his best friend.
D．To illustrate the differences between dogs and chimps.
第6题
Benji left us about 15 years ago for that great kennel in the sky. But recently I've been thinking about him a lot. Was he really conscious？ Could any animal have consciousness like we do？ Does it matter whether animals are conscious or not？
For many, it is a matter of life and death. On the one hand, animal research has helped prevent some of the most pressing human diseases, including hepatitis B, hepatitis C, "mad cow" disease, malaria, cystic fibrosis and emphysema. On the other hand, this research is performed largely on chimps, our closest nonhuman relatives, with whom we share 98.4% of our genetic material, and great apes, with whom we are similarly biologically close.
Some people feel this connection is strong enough to warrant special treatment. An international group called the Great Ape Project is lobbying the United Nations to adopt a declaration on the rights of great apes modeled on the UN declaration On the Rights of Man. The group believes that apes are "conscious" and so deserve legal protection of their right to life and freedom from imprisonment and torture.
If great apes were shown to have consciousness or something like our own, I would consider it among the scientific discoveries of the century. I would then agree with the Australian philosopher and founder of the animal rights movement, Peter Singer, that performing medical experiments on chimps would be like experimenting on orphan children. That's a pretty chilling thought, and no amount of human suffering saved could justify such an action. But before we close down the laboratories and stop searching for a vaccine against AIDS, we had better take a long hard look at the evidence for ape consciousness.
Why does the author bring up the example of Benji？
A．To show that animals have consciousness.
B．To raise the question of animal consciousness.
C．Because Benji was his best friend.
D．To illustrate the differences between dogs and chimps.
第8题
A.主胰管（main pancreaticduct）
B.副胰管（accessory pancreatic duct）
C.胆囊管（cystic duct）
D.左、右肝管（hepatic duct）
