首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Imagine an animal that becomes frozen in cold weather. Then, when it gets warmer, the animal simply unfreezes and goes back to i
Imagine an animal that becomes frozen in cold weather. Then, when it gets warmer, the animal simply unfreezes and goes back to i
admin
2015-01-31
32
问题
Imagine an animal that becomes frozen in cold weather. Then, when it gets warmer, the animal simply unfreezes and goes back to its normal life. Although this may sound like something from a science-fiction movie, it is exactly what happens to the wood frog over winter and spring. When winter begins, the frog, which is found throughout much of Canada, buries itself in leaves and dirt. As the ground begins to freeze, so does the frog’ s body.
Normally, if a living creature is frozen, the cells inside its body are destroyed, leading to death. How, then, does the wood frog survive? The secret lies in the fact that although the water between the cells in the frog’ s body becomes frozen, the water inside the cells does not freeze. Before the winter begins, the frog stores starch in its body. As the weather gets colder, the drop in temperature causes the frog’ s body to change this starch into glucose. This glucose, in turn, lowers the temperature at which the liquid inside the frog’s cells freezes. As a result, the cells do not freeze even at very low temperatures, allowing the frog to stay alive. Some wood frogs stay in this frozen state— with their hearts stopped completely—for months without harm.
Now researchers are hoping to adapt the wood frog’ s secret to help them preserve human organs for transplants. Currently, after organs are removed from a donor’ s body, they are packed in a special liquid and kept very cold. However, they cannot be frozen because the ice would damage the cells in the organs. For this reason, the organs must be used quickly. If doctors had a way to preserve organs longer, they would have more time to find the best matches among people waiting for organ transplants.
There is still a lot about the wood frog that scientists do not understand. They still have to work out, for example, exactly how the frog is able to unfreeze itself and what actually restarts the frog’s heart when the weather becomes warmer. What is clear, however, is that lessons learned by studying this tiny creature could be of great benefit to humans in the near future.
What effect does the glucose produced in the wood frog’ s body have?
选项
A、It stops the water in the frog’ s cells from freezing in cold weather.
B、It lowers the temperature in the spaces between the frog’ s cells.
C、It causes the frog’ s cells to produce more starch.
D、It allows the frog’ s cells to produce more water.
答案
A
解析
细节题。短文第二段中间指出This glucose,in turn,lowers the temperatureat which the liquid inside the frog’s cells freezes.意为这种葡萄糖可以降低wood frog细胞液体结冰的温度。由此可知这种葡萄糖使细胞里的水不会结冰,故选A。
转载请注明原文地址:https://kaotiyun.com/show/zjq7777K
0
大学英语四级
相关试题推荐
Two-thirdsofAmericansareoverweightorobese.Developingcountriesarecatchingup.InChinanearly30%ofadultsaretoowid
Thereportsaysthattracesofradiationhavebeenfoundinthepowderedmilk,______(这可能对人们的健康有害).
Whowantstopayfor"D"-qualityplumbing(管道)?Flytheskieswitha"D"-ratedpilot?Settle【C1】______a"D"restaurant?Exa
A、Becausetheywanttoworkformorepeople.B、Becausetheyneedtrainingoverseas.C、Becausethereisanursingshortageworldw
AslongasAmericanslovetodrivefarandfast,electriccarsmayneverbetheperfectanswertothecountry’sgreentransporta
A、HehasbeenworkingforTheArizonaRepublicfornineyears.B、HehasbeenworkingforTheWashingtonPostfornineyears.C、H
A、Theydon’tsellshirtshere.B、Theyshouldwaittilltheclothesareonsale.C、Theclotheshereareveryexpensive.D、Heknow
Alotofpeopleinstinctivelybelieve—withoutreallyknowing—thatpoorreadersarenotespeciallysmart.Anewstudybyres
A、Humanbeingssuddenlyappearbeforethem.B、Someunexpectedanimalsstepintothebush.C、Thereareloudnoisescomingfromma
It’swellknownthatbiganimals,likepolarbears,aresensitivetoclimatechange.TheEarthwarms,polarice【B1】______,andt
随机试题
注意的两个基本特点是()
种植后牙周维护治疗包括
投资于衍生品的QDII应在( )计算并披露净值。
银行业监督管理的具体目标包括()。
企业在谋求公司发展筹集资金的过程中,都会为了降低公司的成本而在利率较低时获得贷款,此时公司可能采取的做法有()。
下列各句中,标点符号使用正确的一项是()。
某公司总裁曾经说过:“当前总裁批评我时,我不喜欢那感觉,因此,我不会批评我的继任者。”
甲、乙、丙三人参加了物理和化学两门考试。三人中,只有一个在考试中发挥正常。考前,甲说:如果我在考试中发挥不正常,我将不能通过物理考试。如果我在考试中发挥正常,我将能通过化学考试。乙说:如果我在考试中发挥不正常,我将不能通过
南方都市报
[*]
最新回复
(
0
)