CLONDON: What could possibly be wrong with plantin...

第1题

Dolly Madison once invited the children of Washington to roll boiled eggs down the hilly l

awn of______.

第2题

Dolly was once an awfully lonely sheep. When the famous cloned （of an exact copy of a plan

Dolly was once an awfully lonely sheep. When the famous cloned (of an exact copy of a plant or animal made by taking a cell from it and developing it artificially) animal made headlinesin 1997, she was the only mammal ever to be manufactured from the cell of an adult donor. Since then, the clone ranks have swelled, with mice and cattle also making their way out of the labs. Last week cloning technology took another step forward when an international biotechnology company announced that it had created a litter of five genetically identical piglets (young pigs), and that it had a pretty good idea of how they could one day be used as organ donors for ailing humans.

The idea of turning pigs into tissue factories has been around for at least 30 years. Pigs breed easily and mature quickly, and their organs are roughly the same size.as those of humans, meaning operations can be performed with a relative snap-out, snap-in simplicity. The problem is, once the donor organ is stitched in place, the body rebels, rejecting it even more violently than it would a human transplant. " A pig heart transplanted in a person would turn black within minutes, " says David Ayares, a research director with PPL Therapeutics, the biotech firm that helped clone Dolly and also produced the piglets.

What causes pig organs to be rejected so quickly is a sugar molecule on the surface of pig cells that identifies the tissue as unmistakably nonhuman. When the immune system spots this marker, it calls out its defenses. PPL scientists recently succeeded in finding the gene responsible for the sugar and knocking it out of the nucleus of a pig cell. Their next step would be to extract that nucleus, insert it into a pig ovum, and then into the womb of a host pig. The sugar free piglet that was eventually born could then be cloned over and over as a source of safe transplant organs. The idea is to arrive at the ideal animal and repeatedly copy it exactly as it is. The cloned piglets PPL introduced to the world last week were created in just this way, though for this first experiment in pig replication the scientists left the sugar genes intact.

Despite this recent success, PPL is not likely to be setting up its organ shop anytime soon. Knocking out the key sugar gene solves only the problem of short-term rejection. Much more has to be done before any solution to long-term rejection can be found. Nonetheless, Ayares is optimistic, insisting that pig organs could be available in as little as five years. For the present, even a little new transplant material is a big improvement over what's available, and for gravely ill patients awaiting a donor, that's no small thing.

What is true about Dolly according to the text？

A．She was a lonely sheep in the first place.

B．She was manufactured out of the lab.

C．She was cloned from the cell of a mature sheep.

D．She was replaced by cloned piglets in terms of importance.

点击查看答案

第3题

Text 3Dolly was once an awfully lonely sheep. When the famous cloned （of an exact copy of

Text 3

Dolly was once an awfully lonely sheep. When the famous cloned (of an exact copy of a plant or animal. made by taking a cell from it and developing it artificially) animal made headlines in 1997, she was the only mammal ever to be manufactured from the cell of an adult donor. Since then, the clone ranks have swelled, with mice and cattle also making their way out of the labs. Last week cloning technology took another step forward when an international biotechnology company an-nounced that it had created a litter of five genetically identical piglets (young pigs) , and that it had a pretty good idea of how they could one day be used: as organ donors for ailing humans.

The idea of turning pigs into tissue factories has been around for at least 30 years. Pigs breed easily and mature quickly, and their organs are roughly the same size as those of humans, meaning operations can be performed with a relative snap-out, snap-in simplicity. The problem is,once the donor organ is stitched in place, the body rebels, rejecting it even more violently than it would a human transplant. "A pig heart transplanted in a person would turn black within minutes," says David Ayares, a research director with PPL Therapeutics,the biotech firm that helped clone Dolly and also produced the piglets.

What causes pig organs to be rejected so quickly is a sugar molecule on the surface of pig cells that identifies the tissue as unmistakably nonhuman. When the immune system spots this marker, it calls out its defenses. PPL scientists recently succeeded in finding the gene responsible for the sugar and knocking it out of the nucleus of a pig cell. Their next step would be to extract that nucleus,insert it into a pig ovum, and then into the womb of a host pig. The sugar free piglet that was eventually born could then be cloned over and over as a source of safe transplant organs. The idea is to arrive at the ideal animal and repeatedly copy it exactly as it is. The cloned piglets PPL introduced to the world last week were created in just this way, though for this first experiment in pig replication the scientists left the sugar genes intact.

Despite this recent success, PPL is not likely to be setting up its organ shop anytime soon.

Knocking out the key sugar gene solves only the problem of short-term rejection. Much more has to be done before any solution to long-term rejection can be found. Nonetheless, Ayares is optimistic, insisting that pig organs could be available in as little as five years. For the present, even a little new transplant material is a big improvement over what's available, and for gravely ill patients awaiting a donor, that's no small thing.

51. What is true about Dolly according to the text？

[A] She was a lonely sheep in the first place.

[B ] She was manufactured out of the lab.

[C] She was cloned from the cell of a mature sheep.

[D] She was replaced by cloned piglets in terms of importance.

点击查看答案

第4题

Gene therapy and gene-based drugs are two ways we could benefit from our growing mastery o

f genetic science. But there will be others as well. Here is one of the remarkable therapies on the cutting edge of genetic research that could make their way into mainstream medicine in the coming years.

While it's true that just about every cell in the body has the instructions to make a complete human, most of those instructions are inactivated, and with good reason: the last thing you want for your brain cells is to start churning out stomach acid or your nose to turn into a kidney. The only time cells truly have the potential to turn into any and all body parts is very early in a pregnancy, when so-called stem cells haven't begun to specialize.

Yet this untapped potential could be a terrific boon to medicine. Most diseases involve the death of healthy cells-brain cells in Alzheimer's, cardiac cells in heart disease, pancreatic cells in diabetes, to name a few. If doctors could isolate stem cells, then direct their growth, they might be able to furnish patients with healthy replacement tissue.

It was incredibly difficult, but last fall scientists at the University of Wisconsin managed to isolate stem ceils and get them to grow into neural, gut, muscle and bone cells. The process still can't be controlled, and may have unforeseen limitations; but if efforts to understand and master stem-cell development prove successful, doctors will have a therapeutic tool of incredible power.

The same applies to cloning, which is really just the other side of the coin; true cloning, as first shown with the sheep Dolly two years ago, involves taking a developed cell and reactivating the genome within, resetting its developmental instructions to a pristine state. Once that happens, the rejuvenated cell can develop into a full-fledged animal, genetically identical to its parent.

For agriculture, in which purely physical characteristics like milk production in a cow or low fat in a hog have real market value, biological carbon copies could become routine within a few years. This past year scientists have done for mice and cows what Ian Wilmut did for Dolly, and other creatures are bound to join the cloned menagerie in the coming year.

Human cloning, on the other hand, may be technically feasible but legally and emotionally more difficult. Still, one day it will happen. The ability to reset body cells to a pristine, undeveloped state could give doctors exactly the same advantages they would get from stem cells., the potential to make healthy body tissues of all sorts, and thus to cure disease. That could prove to be a true "miracle cure."

The writer holds that the potential to make healthy body tissues will ______.

A．aggravate moral issues of human cloning

B．bring great benefits to human beings

C．help scientists decode body instructions

D．involve employing surgical instruments

点击查看答案

第5题

绵羊Dolly克隆成功的重大意义。

点击查看答案

第6题

Gene therapy and gene-based drugs are two ways we could benefit from our growing mastery o

f genetic science. But there will be others as well. Here is one of the remarkable therapies on the cutting edge of genetic research that could make their way into mainstream medicine in the coming years.

While it's true that just about every cell in the body has the instructions to make a complete human, most of those instructions are inactivated, and with good reason r the last thing you want for your brain cells is to start churning out stomach acid or your nose to turn into a kidney. The only time cells truly have the potential to turn into any and all body parts is very early in a pregnancy, When so-called stem cells haven't begun to specialize.

Yet this untapped potential could be a terrific boon to medicine. Most diseases involve the death of healthy cells-brain cells in Alzheimer's, cardiac cells in heart disease, pancreatic cells in diabetes, to name a few ff doctors could isolate stem cells, then direct their growth, they might be able to furnish patients with healthy replacement tissue.

It was incredibly difficult, but last fall scientists at the University of Wisconsin managed to isolate stem cells and get them to grow into neural, gut, muscle and bone cells. The process still can't be controlled, and may have unforeseen limitations; but if efforts to understand and master stem-cell development prove successful, doctors will have a therapeutic tool of incredible power.

The same applies to cloning, which is really just the other side of the coin; true cloning, as first shown with the sheep Dolly two years ago, involves taking a developed cell and reactivating the genome within, resetting its developmental instructions to a pristine state. Once that happens, the rejuvenated cell can develop into a full-fledged animal, genetically identical to its parent.

For agriculture, in which purely physical characteristics like milk production in a cow or low fat in a hog have real market value, biological carbon copies could become routine within a few years. This past year scientists have done for mice and cows what Ian Wilmut did for Dolly, and other creatures are bound to join the cloned menagerie in the coming year.

Human cloning, on the other hand, may be technically feasible but legally and emotionally more difficult. Still, one day it will happen. The ability to reset body cells to a pristine, undeveloped state could give doctors exactly the same advantages they would get from stem cells: the potential to make healthy body tissues of all sorts, and thus to cure disease. That could prove to be a true "miracle cure".

The writer holds that the potential to make healthy body tissues will ______ .

A．aggravate moral issues of human cloning.

B．bring great benefits to human beings.

C．help scientists decode body instructions.

D．involve employing surgical instruments.

点击查看答案

第7题

克隆羊（Dolly)和转基因小鼠成功的关键技术分别是什么，它们的意义何在？

克隆羊(Dolly)和转基因小鼠成功的关键技术分别是什么，它们的意义何在？

点击查看答案

第8题

Gene therapy and gene based drugs are two ways we could benefit from our growing mastery o

f genetic science. But there will be others as well. Here is one of the remarkable therapies on the cutting edge of genetic research that could make their way into mainstream medicine in the coming years.

While it's true that just about every cell in the body has the instructions to make a complete human, most of those instructions are inactivated, and with good reason: the last thing you want for your brain cells is to start churning out stomach acid or your nose to mm into a kidney. The only time cells truly have the potential to turn into any and all body parts is very early in a pregnancy, when so called stem cells haven't begun to specialize.

Yet this untapped potential could be a terrific boon to medicine. Most diseases involve the death of healthy cells—brain cells in Alzheimer's, cardiac cells in heart disease, pancreatic cells in diabetes, to name a few; if doctors could isolate stem cells, then direct their growth, they might be able to furnish patients with healthy replacement tissue.

It was incredibly difficult, but last fall scientists at the University of Wisconsin managed to isolate stem cells and get them to grow into neural, gut, muscle and bone cells. The process still can't be controlled, and may have unforeseen limitations; but if efforts to understand and master stem cell development prove successful, doctors will have a therapeutic tool of incredible power.

The same applies to cloning, which is really just the other side of the coin; true cloning, as first shown with the sheep Dolly two years ago, involves taking a developed cell and reactivating the genome within, resetting its developmental instructions to a pristine state. Once that happens, the rejuvenated cell can develop into a full fledged animal, genetically identical to its parent.

For agriculture, in which purely physical characteristics like milk production in a cow or low fat in a hog have real market value, biological carbon copies could become routine within a few years. This past year scientists have done for mice and cows what Ian Wilmut did for Dolly, and other creatures are bound to join the cloned menagerie in the coming year.

Human cloning, on the other hand, may be technically feasible but legally and emotionally more difficult. Still, one day it will happen. The ability to reset body cells to a pristine, undeveloped state could give doctors exactly the same advantages they would get from stem cells: the potential to make healthy body tissues of all sorts, and thus to cure disease. That could prove to be a true "miracle cure".

The writer holds that the potential to make healthy body tissues will ______.

A．aggravate moral issues of human cloning

B．bring great benefits to human beings

C．help scientists decode body instructions

D．involve employing surgical instruments

点击查看答案

第9题

Whitney Houston's version of this song is a ______of Dolly Parton's version.

A、part

B、repetition

C、cover

点击查看答案

第10题

Before cloning Dolly successfully, the researchers had succeeded in cloning mice once.

点击查看答案

功能	扣减规则
功能	基础费（查看答案）	加收费（AI功能）
文字搜题、查看答案	1/每题	0/每次
语音搜题、查看答案	1/每题	2/每次
单题拍照识别、查看答案	1/每题	2/每次
整页拍照识别、查看答案	1/每题	5/每次