首页
财务会计
医药卫生
金融经济
考公考编
外语考试
学历提升
职称考试
建筑工程
IT考试
其他
登录
职称考试
共用题干 第三篇Eat More, Weigh Less, Live LongerClever genetic detective work may h...
共用题干 第三篇Eat More, Weigh Less, Live LongerClever genetic detective work may h...
admin
2020-12-24
51
问题
共用题干
第三篇
Eat More, Weigh Less, Live Longer
Clever genetic detective work may have found out the reason why a near-starvation diet
prolonas the life of many animals.
Ronald Kahn at Harvard Medical School in Boston,U.S.,and his colleagues nave
been able to extend the lifespan(寿命)of mice by 18 per cent by blocking the rodent's(啮
齿动物)increase of fat in specific cells.This suggests that thinness一and not necessarily
diet一Iromotes lonq life in"calorie(热量卡)restricted" animals.
"It's very cool work",says aging researche:Cynthia Kenyon of the University ot
California, San Francisc."These mice eat all they want, lose weight and live longer.It's
like heaven."
Calorie restriction dramatically extends the lifespan of organisms as different as worms
and rodents.Whether this works in humans is still unknown,partly because few people are
willina to submit to such a strict diet.
But many researchers hope they will be able to trigger the same effect with a drug once
they understand how less food leads to a longer life.One theory is that eating less reduces
the increase of harmful things that can damage cells.But Kahn's team wondered whether
the animals simply benefit by becoming thin.
To find out, they used biology tricks to disrupt the insulin(胰岛素)receptor (受体)
gene in lab mice一but only in their fat cells."Since insulin is needed to help fat cells store
fat ,these animals were protected against becoming fat,"explains Kahn.
This slight genetic change in a single tissue had dramatic effects.By three months of
age.Kahn's modified mice had up to 70 per cent less body fat than normal control mice,
despite the fact that they ate 55 per cent more food per gram of body weight.
In addition ,their lifespan increased.The average control mouse lived 753 days,while
the thin rodents averaged a lifespan of 887 days.After three years,all the control mice had
died.but one-quarter of the modified rodents were still alive.
"That they ciet these effects by just manipulating the fat cells is controversial,"says
Leonard Guarente of the Massachusetts Institute of Technology,who studies calorie
restriction and aging.
But Guarente says Kahn has yet to prove that the same effect is responsible for
increased lifespan in calorie-restricted animals."It might be the same effect or there might
be two routes to long life,"he points out,"and that would be very interesting."
选项
According to the passage,we do not know whether humans will benefit from taking in fewer calories partly because
A:humans,worms and rodents are different.
B:most people are not willing to be put on a strict diet.
C:the effect is not known.
D:genetic changes in tissues can not be performed on humans.
答案
B
解析
转载请注明原文地址:https://ti.zuoweng.com/ti/GMMQKKKQ
相关试题推荐
共用题干 EconomicReforminChinaMoreUSsinologistshaveexpressedconfidencei...
共用题干 EconomicReforminChinaMoreUSsinologistshaveexpressedconfidencei...
共用题干 EconomicReforminChinaMoreUSsinologistshaveexpressedconfidencei...
共用题干 EconomicReforminChinaMoreUSsinologistshaveexpressedconfidencei...
共用题干 EconomicReforminChinaMoreUSsinologistshaveexpressedconfidencei...
共用题干 EconomicReforminChinaMoreUSsinologistshaveexpressedconfidencei...
共用题干 EconomicReforminChinaMoreUSsinologistshaveexpressedconfidencei...
共用题干 TheJoyofLivingAloneMoreandmoreAmericansarelivingalone.Someli...
共用题干 TheJoyofLivingAloneMoreandmoreAmericansarelivingalone.Someli...
共用题干 TheJoyofLivingAloneMoreandmoreAmericansarelivingalone.Someli...
随机试题
关于通货膨胀率、汇率、黄金价格三者之间的关系,下列说法正确的是( )。 A、
胸痹总属本虚标实之证,其标实常见为下列几项,除外 A.气滞 B.血瘀 C.
复苏中提起下巴的目的是() A.提起舌体 B.改善咽喉成角 C.保护咽部
(36-37题共用题干) 李某,女,72岁。因急性胆囊炎急诊行胆囊切除术,采用
缺陷未消除前,根据缺陷情况,(____)应组织制订预控措施和应急预案
根据以下资料,回答题。 2012年,黄山市全年接待海内外旅游者3641.3万人
某工程双代号网络计划如下图所示,图中已标出各项工作的最早开始时间和最迟开始时间,
《上市公司证券发行管理办法》取消了配股前仅要求最近3年连续盈利的条件。增加为配股
讲授法的优点不包括() A.可以充分发挥教师的主导作用 B.使学生在短时间内获得大量系统的科学知识 C.有利于因材施教 D.有限的教师...
—般来说,老年期退行性变化出现最早的心理过程是()。 (A)感觉 (B)想象 (C)思维 (D)记忆