皮皮学,免费搜题
登录
logo - 刷刷题
搜题
【单选题】
A new type of organism discovered in an Arctic tunnel came to life in the lab after being frozen for 32,000 years. The deep-freeze bacteria could point to new methods of cryogenics, and they are the sort of biology scientists say might exist on Mars and other planets and moons. 'The existence of microorganisms in these harsh environments suggests——but does not promise——that we might one day discover similar life forms in the glaciers or permafrost of Mars or in the ice crust and oceans of Jupiter's moon Europa,' said Richard Hoover, an astrobiologist at NASA's Marshall Space Flight Center. Other microbes have been discovered in similar frigid environments, sometimes clinging to pockets of liquid water in ice packs. And some microbes survive in ice as spores, but they need to be cultured to bring them to life. The announcement of the discovery Wednesday comes just a day after a team of European re- searchers said they found blocks of ice just under the surface of Mars near the equator. The Europeans said the ice, between 2 million and 5 million years old, could serve as storehouses for life. The new bacterium thrives under a microscope despite having been thawed from ice dating back some 32,000 years, to the Pleistocene era. Living bacteria are stained green. Hoover said the creatures he has found might be able to survive in their suspended state for millions of years. The discovery opens up a whole new possibility that a future mission to Mars might be able to retrieve any life that's there. 'Ice samples from this [Martian ice] sea could con-rain cryopreserved microorganisms if life ever flourished on the surface of Mars,' Hoover said in a telephone interview. He is particularly excited about the instant revival qualities of the creatures found in Alaska. 'You might actually get them growing in pure culture,' he said of the potential Martian cousins. It would be a 'wonderful way of retrieving intact, viable Martian organisms, if they are there.' Water does not guarantee life, but it is a crucial ingredient. Hoover said the Martian ice blocks are so near the surface that they might partly melt in summer, creating underground pools of water that would allow any microorganisms to grow and reproduce. (Life above ground is considered unlikely due to Mars' dry surface conditions and intense radiation. ) What does the discovery of deep-freeze bacteria mean to us, according to the passage?
A.
We might one day find form. of life on other planets.
B.
Scientists from NASA made a great progress in discovering the microorganisms
C.
To retrieve any life that has died long ago is impossible.
D.
Alaska is a place abundant in microorganisms.
手机使用
分享
复制链接
新浪微博
分享QQ
微信扫一扫
微信内点击右上角“…”即可分享
反馈
参考答案:
举一反三
【单选题】男,55岁。急性心肌梗死4周,今晨再发胸痛,持续8小时不缓解,遂来急诊。查体:血压l00/60mmHg,心率95次/分,心肺检查无异常,心电图:I、aVL导联ST段弓背向上抬高。血清肌钙蛋白升高。该患者胸痛最可能的原因是
A.
心脏破裂
B.
心室膨胀瘤
C.
急性心包炎
D.
再发急性心肌梗死
E.
心绞痛
【单选题】在下列作家中,属于唐代新乐府运动的倡导者和主要代表的是()
A.
刘禹锡
B.
张籍
C.
白居易
D.
韦应物
【单选题】迁延不愈的营养不良患儿,可引起突然死亡的并发症是
A.
贫血
B.
低血糖
C.
干眼症
D.
肾盂肾炎
E.
肺炎
【单选题】氨由肌肉组织通过血液向肝进行转运的机制是
A.
三羧酸循环
B.
鸟氮酸循环
C.
丙氨酸-葡萄糖循环
D.
甲硫氨酸循环
【单选题】白居易和谁是唐代新乐府运动的倡导者
A.
韩愈
B.
柳宗元
C.
元稹
D.
刘禹锡
【单选题】唐代新乐府运动的倡导者和主要代表诗人是( )
A.
李白
B.
杜甫
C.
白居易
D.
骆宾王
【单选题】氨由肌肉组织通过血液向肝进行转运的机制是
A.
三羧酸循环
B.
核蛋白体循环
C.
丙氨酸-葡萄糖循环
D.
甲硫氨酸循环
【简答题】汉译英:请将下文翻译成英语,注意将译文输入下框。 古代中国和古代希腊的哲学家们,不仅生活在不同的地理环境之中,还生活在不同的经济环境之中。中国是一个大陆国家,中华民族历来依靠农业来维持生存,直到今日,中国的农业人口还占总人口的75%到80%。在一个农业国家里,财富的首要基础是土地,因此,在中国历史上,一切社会经济思想以至政府的政策措施都以土地的分配和利用为中心。
【单选题】氨由肌肉组织通过血液向肝进行转运的机制是
A.
三羧酸循环
B.
鸟氨酸循环
C.
丙氨酸一葡萄糖循环
D.
甲硫氨酸循环
【单选题】唐代新乐府运动的倡导者和主要代表诗人是( )
A.
李白
B.
杜甫
C.
白居易
D.
骆宾王
相关题目:
参考解析:
知识点:
题目纠错 0
发布
创建自己的小题库 - 刷刷题