题干

S型肺炎双球菌菌株是人类肺炎和小鼠败血症的病原体,而R型菌株却无致病性。下列有关叙述正确的是(  )

A:S型菌进入人体后可刺激效应B细胞使细胞中某些基因选择性表达

B:S型菌与R型菌的结构不同是由于遗传物质有差异的缘故

C:肺炎双球菌利用人体细胞的核糖体合成蛋白质

D:高温处理过的S型菌蛋白质因变性而不能与双缩脲试剂发生紫色反应

上一题 下一题 0.0难度 选择题 更新时间:2019-10-26 09:47:49

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B

同类题3

阅读下面的文言文,完成下列小题。

    霍彦威,字子重,洺州曲周人也。少遭兵乱,梁将霍存掠得之,养以为子。后事粱太祖,太祖亦爱之,迁邠宁节度使。李茂贞遣梁叛将刘知俊攻邠州,彦威固守逾年,每获知俊兵,必纵还之,知俊德之,后不复攻。徙天平,与晋军相持河上。庄宗灭粱,彦威自陕来朝,庄宗置酒,赐姓名曰李绍真。明年,徙镇武宁,从明宗击契丹,明宗爱其为人,甚亲厚之。其后赵在礼反,彦威别讨赵太于邢州,破之,还以兵属明宗讨在礼。明宗军变,纵火焚营噪呼:“城中之人何罪,戍卒思归而不得耳!天子不垂原宥,志在剿除。今宜与城中合势,击退诸镇之兵。”彦威与安重诲劝明宗许之,乃拥兵入城,彦威独不入。部兵在外者皆溃去,独彦威所将五千人营城西北隅不动。居二日,明宗复出,得彦威兵,乃之魏县。庄宗崩,彦威从明宗入洛阳,首率群臣劝进,内外机事,皆决彦威。彦威素与段凝、温韬有隙,因擅捕凝、韬下狱,将杀之,安重诲日:“主上方平内难,以恩信示人,岂公报仇之时?”彦威乃止。彦威徙镇平卢。朱守殷反,伏诛,彦威遣使者驰骑献两箭为贺,明宗赐两箭以报之。夷狄之法,起兵令众,以传箭为号令,然非下得施于上也。明宗本出夷狄,而彦威武人,君臣皆不知礼,动多此类。然彦威客有淳于晏者,少举明经及第,遭世乱,依彦威。彦威尝战败脱身走麾下兵无从者独晏徒步以一刽从之榛棘间以免彦威高其义所历方镔常辟以自从至其家事无大小皆决于晏彦威以故得少过失。天成三年冬,彦威卒于镇。赠彦威太师,谥曰忠武。

(节选自《新五代史·霍彦威传》)

同类题4

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                                                                                   Growing Up in Australia

    Since 2004, Australia has been holding its largest study of children's health ever. This project, “Growing Up in Australia,” is following two groups of children from early childhood until they become adults. The project is being supported by the Australian government and involves hundreds of researchers visiting the homes of 10,000 children. Researchers hope to find a relationship between the children's future behavior and their health, education, and family environments.

    When the study began, the first group of children was aged 0-1, while the second group was aged 4-5. In order to make sure that children from every kind of environment and background were chosen, the study found volunteers from each area. Some volunteers are in the countryside, while others are in big cities. The volunteers for both groups were chosen from a variety of different social and ethnic (种族) backgrounds.

    The researchers visit the participants' (参与者) homes every two years to gather information. They interview the parents about parenting styles and the child's daily activities. They also take measurements of the children's health and how well the children perform in school. The researchers also collect information such as the income of the child's family, the school the child attends, and the kind of community (社区) in which the child lives. They plan to use the information to improve children's lives.

    Researchers have already begun to publish some interesting results. For instance, after examining information from the second group of children when they were 10-11 years old, researchers found that children who spend a lot of time doing organized activities, such as music lessons or sports, have good control of their emotions and behavior. The study also found that they are able to complete their homework without their parents around. On the other hand, it found that children who watch a lot of television get upset easily and have worse behavior. The Australian government is now using this information to make better educational and health policies for Australian children.