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Icy Microbes In ice that has sealed a salty Antarctic 1ake for more than 2，800 years，s

Icy Microbes

In ice that has sealed a salty Antarctic 1ake for more than 2，800 years，scientists have found frozen bacteria and algae that returned to 1ife after thawing．The research may help in the search for life on Mars．which is thought to have subsurface lakes of ice．

A research team led by Peter Doran of the University of minois at Chicago drilled through more than 39 feet ice to collect samples of bacteria and algae． When Doran’s team brought them back and warmed them up a bit，they sprang back to life．

Doran said the microbes have been age-dated at 2，800 years old，but even older microbes may 1ive deeper in the ice sheet sealing the lake， and in the briny water bel0W the ice． That deeper ice and the water itself will be cautiously sampled in a later expedition that will test techniques may one day be used on Mars．

Called Lake Vida，the 4.5-square-kilometer body is one of a series of lakes located in the McMurdo Dry Valleys of Antarctica，some 2，200 kilometers due south of New Zealand．This lake has been known since the 1 950s，hut people ignored it because they thought it was just a big block of ice．While at the site for other research in the l 990s，Doran and his colleagues sent radar signals into the clear ice covering the lake and were surprised to find that 62 feet below there was a pool of liquid water that was about seven times more salty than seawater．

That prompted the researchers to return in 1996 with equipment to drill a hole down to within a few feet of the water laver． At the bottom of this hole，researchers harvested specimens of algae and bacteria．

The searchers will return in 2004 equipped with instruments that are sterilized． They will then drill through the full 62 feet of ice and sample some of the briny water from the lake for analysis．The water specimen will be cultured to see if it contains life． Specimens from the water are expected to be even older than the life forms extracted from the ice covering．

第 9 题 Paragraph 2_________．

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更多“Icy Microbes In ice that has s…”相关的问题

第1题

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A．Kids having certain microbes will have low risk of getting asthmaB．Kids having certain microbes will have high risk of getting asthmaC．Kids having none microbes will have low risk of getting asthmaD．Kids having any microbes will have low risk of getting asthmaE．我不确定

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第2题

ICY是什么（）

A.ICY是一个服装品牌

B.ICY是设计师集合店

C.ICY是一个升级设计师生态的平台

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第3题

ICY的使命和愿景是什么（）

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第4题

He lost his balance and fell over on the icy road, but luckily, he remained safe and sound。

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第5题

Antibiotics are drugs produced by certain microbes. Antibiotic substances are obtained

from bacteria and fungi that live in the air, soil, and water. Most antibiotics are used by physicians to fight various diseases caused by harmful microbes. A few are used to treat certain cancers. Antibiotics are sometimes called" wonder drugs 'because they can cure many diseases that once were often fatal. The number of deaths that are caused by pneumonia and scarlet fever has declined drastically since people began using antibiotics.

2. There are more than 70 clinically useful antibiotics, Antibiotics fight pathogenic microbes and cancer cells by interfering with their normal cell processes. In most cases, this interference can occur in one of three ways: prevention of cell wall formation, disruption of the cell membrane, and disruption of chemical processes.

3. The contents of bacterial cells are enclosed in a membrane that is surrounded by a rigid wall that prevents the cells from splitting open. Penicillins and some other antibiotics destroy pathogenic microbes by hindering the formation of this wall. Human cells do not have nor need rigid cell walls and so are not damaged by these antibiotics.

4. Some antibiotics, including nystatin, disrupt the cell membrane of certain microbes. This membrane controls the movement of materials in and out of the cell. If the membrane is disrupted, vital nutrients may escape from the cell, or poisonous substances may enter and kill the cell. But the membranes of human cells are not affected because these antibiotics disrupt cell membranes that contain elements found only in microbial cells.

5. All cells produce proteins and nucleic acids, which are vital to the life of any organism. Some antibiotics fight disease by interfering with the chemical processes by which these substances are produced. For example, streptomycin prevent certain kinds of microbes from producing proteins, and rifampin interferes with the formation of nucleic acids. Human cells produce proteins and nucleic acids in much the same way that microbial cells do. But these processes differ enough so that some antibiotics interfere with chemical activities in microbial cells but not in human cells.

A. Autibiotics destroy pathosenic microbes by preventing the formation of the walls surrounding the membranes of the microbial cells that prevent the cells from split- ting open.

B. More than 70 clinically useful antibiotics have been in- vented to fight pathogenic microbes and cancer cells by interacting with their normal cell processes.

C. Human cells are not surrounded by a membrane

D. Some antibiotics disrupt the cell membrane of certain microbes, letting vital nutrients to escape form. the cell or poisonous substances to enter and kill the cell.

E. Nystatin is used to disrupt the wall surrounding the membrane.

F. Some antibiotics fight disease by interfering with chemical activities in microbial cells but not in human cells.

Paragraph 2______。

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第6题

The weather wasn't favorble and both teams had to ______ icy rain and a strong wind during

the match.

A．get stuck in

B．contend with

C．take control of

D．pin down

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第7题

如何找到其他财务经理的联系方式（）

A.按以下流程操作：钉钉-通讯录-支持中心-财务部-财务经理

B.在微信群ICY大家庭中找

C.问周围同事

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第8题

The Gene IndustryMajor companies are already in pursuit of commercial applications of the

The Gene Industry

Major companies are already in pursuit of commercial applications of the new biology. They dream of placing enzymes in the automobile to monitor exhaust and send data on pollution to a microprocessor that will then adjust the engine. They speak of what the New York Times calls "metal-hungry microbes that might be used to mine valuable trace metals from ocean water". They have already demanded and won the right to patent new lifeforms.

Nervous critics, including many scientists, worry that there is corporate, national, international, and inter-scientific rivalry in the entire biotechnological field. They create images not of oil spills, but of "microbe spills" that could spread disease and destroy entire populations. The creation and accidental release of extremely poisonous microbes, however, is only one cause for alarm. Completely rational and respectable scientists are talking about possibilities that stagger the imagination.

Should we breed people with cow-like stomachs so they can digest grass and hay, thereby relieving the food problem by modifying us to eat lower down on the food chain？ Should we biologically alter workers to fit the job requirement, for example, creating pilots with faster reaction times or assembly-line workers designed to do our monotonous work for us？ Should we attempt to eliminate "inferior" people and breed a "super-race"？ (Hitler tried this, but without the genetic weaponry that may soon issue from our laboratories.) Should we produce soldiers to do our fighting？ Should we use genetic forecasting to pre-eliminate "unfit" babies？ Should we grow reserve organs for ourselves, each of us having, as it were, a "savings bank" full of spare kidney, lives or hands？

Wild as these notions may sound, every one has its advocates (and opposers) in the scientific community as well as its striking commercial application.-As two critics of genetic engineering, Jeremy Rifkin and Ted Howard, state in their book Who Should Play God'？ "Broad Scale genetic engineering will probably be introduced to America much the same way as assembly lines, automobiles, vaccines, computers and all the other technologies. As each new genetic advance becomes commercially practical, a new consumer need will be exploited and a market for the new technology will be created".

According to the passage, the exhaust from a car engine could probably be checked by ______.

A．using metal-hungry microbes

B．making use of enzymes

C．adjusting the engine

D．patenting new life forms

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第9题

There's（）

A.ice cream man

B.two ice cream men

C.n ice cream man

D.ice cream man

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第10题

I want some__（）

A.ice cream

B.ice creams

C.和B都可以

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