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
The term "virus" is derived from the Latin word for poison, or slime. It was originally applied to the noxious stench emanating
The term "virus" is derived from the Latin word for poison, or slime. It was originally applied to the noxious stench emanating
admin
2010-07-06
151
问题
The term "virus" is derived from the Latin word for poison, or slime. It was originally applied to the noxious stench emanating from swamps that was thought to cause a variety of diseases in the centuries before microbes were discovered and specifically linked to illness. But it was not until almost the end of the nineteenth century that a true virus was proven to be the cause of a disease.
The nature of viruses made them impossible to detect for many years, even after bacteria had been discovered and studied. Not only are viruses too small to be seen with a light microscope, they also cannot be detected through their biological activity, except as it occurs in conjunction with other organisms. In fact, viruses show no traces of biological activity by themselves. Unlike bacteria, they are not living agents in the strictest sense. Viruses are very simple pieces of organic material composed only nucleic acid, either DNA or RNA, enclosed in a coat of, protein made up of simple structural units. They are parasites, requiring human, animal or plant cells to live. The virus replicates by attaching to a cell and injecting its nucleic acid; once inside the cell, the DNA or RNA that contains the virus’ genetic information takes over the cell’s biological machinery, and the cell begins to manufacture viral protein rather than its own.
The author implies that bacteria were investigated earlier than viruses because
选项
A、bacteria are easier to detect.
B、bacteria are harder to eradicate.
C、viruses are extremely poisonous.
D、viruses are found only in hot climates.
答案
A
解析
本题考查推理判断。文中讲:与细菌相比,病毒小到用光学显微镜都无法观察,也不能通过其生物活动来探查,所以比较容易观察和检测的细菌先于病毒被发现。故A 是正确答案。
转载请注明原文地址:https://kaotiyun.com/show/WPDd777K
本试题收录于:
公共英语四级笔试题库公共英语(PETS)分类
0
公共英语四级笔试
公共英语(PETS)
相关试题推荐
"Down-to-earth"meanssomeoneorsomethingthatishonest,realisticandeasytodealwith.Itisapleasuretofind【C1】______wh
Millionsofman-hoursarelosttoindustrythroughemployeessufferingbackacheorstraincausedbyoperatingpoorlydesignedma
EmployeesoftheTaffValeRailwayCompanyinSouthWalesgreasedthetracksandcuttelegraphwiresduringabitterstrikein1
Ontheheelsofitsrecentdecisiontocriminalizeconsumerswhoripsongsfromalbumstheyhavepurchasedtotheircomputers(o
EmployeesoftheTaffValeRailwayCompanyinSouthWalesgreasedthetracksandcuttelegraphwiresduringabitterstrikein1
Whatisthefirstjobthemanappliedforrightafterhisuniversitygraduation?Whatisthenewbrandnameforhiscompany?
Whatisthefirstjobthemanappliedforrightafterhisuniversitygraduation?Howlongdoeshistourgenerallylast?
Somecitiesgrowverylargebecauseoftwoimportantreasons.First,theremaybeimportantnaturalresourceslikewood,gas,oi
Inthe1960stheWestCoastbecameanimportantcenterforrockmusic.LosAngelesandSouthernCaliforniaarefamousforsun
Asisthecaseinmanycultures,thedegreetowhichaminoritygroupwasseenasdifferentfromthecharacteristicsofthedomi
随机试题
休克代偿期的临床表现是
不属于硝酸甘油不良反应的是
正常成年人心胸比值一般不超过
乙醚、氯仿、丙酮、阴离子去垢剂及胆汁中去氧胆酸盐等脂溶剂灭活病毒的机制是热力灭活病毒的机制是
根据中国法学的历史,简述法家有关法律的论述并说明其观点对当今中国的法治建设有何影响。
水泥砂浆楼梯面的工程量是按设计图示尺寸以楼梯水平投影面积计算,下列表述中错误的是()。
Nodiscountwillbegranted_youplaceanorderformorethan1000dozen.
影响财政收入规模的因素主要是( )。
一项工程,甲、乙合作12天完成,乙、丙合作9天完成,丙、丁合作12天完成,如果甲、丁合作,则完成这项工程需要的天数是:
Eveninthecurrenteconomicgloom,bankershavebeenreluctanttopartwithonemassiveallowanceoftheirjobs—thelavishbonu
最新回复
(
0
)