银行招聘考试

考试试题

[多选题]Modern scientists divide the process of dying into two stages--clinical or temporary death and biological death. Clinical death occurs when the vital organs, such as the heart or lungs, have ceased to function, but have not suffered permanent damage. The organism can still be revived. Biological death occurs when changes in the organism lead to the disintegration of vital cells and tissues. Death is then irreversible and final. Scientists have been seeking a way to prolong the period of clinical death so that the organism can be revived before biological death occurs. The best method developed so far involves cooling of the organism, combined with narcotic sleep. By slowing down the body's metabolism, cooling delays the processes leading to biological death. To illustrate how this works, scientists performed an experiment on a six-year-old female monkey called Keta. The scientists put Keta to sleep with a narcotic. Then they surrounded her body with ice-bags and began checking her body temperature. When it had dropped to 28 degrees the scientists began draining blood from its body. The monkey's blood pressure decreased and an hour later both the heart and breathing stopped; clinical death set in. For twenty minutes Keta remained in this state. Her temperature dropped to 22 degrees. At this point the scientists pumped blood into its body in the direction of the heart and started artificial breathing. After two minutes the monkey's heart became active once more. After fifteen minutes, spontaneous breathing began, and after four hours Keta opened her eyes and lifted her head. After six hours, when the scientists tried to give her a penicillin injection, Keta seized the syringe and ran with it around the room. Her behavior differed little from that of a healthy animal. One possible benefit of the experiment discussed in the passage is _______
[多选题]阅读以下文字。完成79-83题。 有关人士认为。“人类基因组草图”的测绘成功仅仅预示着一个新的开端,真正的研究工作还只刚刚起步。例如,“草图”中留下了许多空白需要填补,不少可能包含着重要的医学信息的空白又顽固地拒绝“泄露自己的秘密”。除了最先完成的22号染色体长臂中有3%被证明无法解读外,从那时以来完成的4号染色体也留有很多空白。此外,大约有10%的基因组由于其重复性而根本不可能测序。 据国外某些杂志报道,即使到2003年“人类基因组计划”完成了终图,漏洞依然会存在——某些基因将被忽略不计。而蛋白质作为生命分子三联体的最后一位“成员”,又是迄今为止最难攻克的堡垒。全人类只有一个共同的基因组,但是由于各种内外因素的作用,世界上每个人都有差别,这种差别被称为单核苷酸多态性。目前,生物学家已利用单个DNA中的变体来跟踪人体基因的变异,并借此评估人类各种生物学现象的奥秘。如健康状况、对疾病的易感性、寿命长短、人类的起源等。 人类大部分的DNA都是“垃圾”,几乎不起什么作用或至少是没有明显的用途。剩下的则是渊源于植物、动物甚至细菌这一最原始生命形式的基因的“大杂烩”。事实上.大量在维系细胞的基本功能,如修补和解读DNA方面所需的基因,与促使细菌保持原样的基因没什么两样。 我们在回溯生物进化史的过程中又会发现,人们曾与植物、动物以及软体虫和有翅昆虫共同分享无数的基因。例如一种古怪的被称为“声波刺猬”的基因.它对昆虫在成熟中翅膀生长和发育起着重要的作用。这一相同的基因,在人的胚胎中则起着协调手臂生长和发育的作用。所以,人类基因与某些哺乳动物更为接近也就(  )了。例如鼠的基因与人极为相似,它的基因组一致被描述为探明人类基因组的“罗塞塔石碑”(即为解读古埃及象形文字提供线索的石碑)。 此外,猩猩的DNA与人只相差1.5%,因而分析这一看似微不足道的差异,自然有助于揭示人之所以为人的奥秘。 看来,不同物种似乎是通过长期复制、改良和组合现存基因而获得进化的。正是这种逐渐从多细胞有机物中汲取新鲜养分的“复制”过程,才使人类不断进化以至于成为超越低级生命形式的高级动物。所以,有专家将基因比作砖块,“用它既能修车库,也可以盖摩天大楼,关键是看你如何运用”。 下列对人类基因组研究描述,最准确的一项是(  )。