学科分类

已选分类 理学生物学生物化学与分子生物学
单选题蛋白X是一种跨膜蛋白,如果通过分子生物学技术截去它的停止转移序列,那么突变的X在细胞中的最后定位是:
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单选题结晶牛胰岛素的人工合成是生命科学上的重要成果,对生命起源问题的哪个阶段提供了有利证据?( )
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单选题胆固醇合成的限速酶是
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单选题下面不属于蛋白质二级结构中存在的构象是
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单选题关于启动子叙述错误的是______ A.原核和真核生物均有 B.调控转录起始 C.与RNA聚合酶结合 D.都不能被转录 E.位于转录起始点附近
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单选题胆汁酸生成过程的限速步骤是
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单选题遗传密码简并性的特点是 A.防止错位突变翻译出不同的氨基酸 B.引起错位突变 C.密码子与反密码子结合 D.氨基酰-tRNA进入线粒体 E.翻译相同的氨基酸
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单选题紫外线照射引起DNA损伤时,细菌DNA修复酶基因表达增强,这种现象被称为( ) A.诱导表达 B.阻遏表达 C.基本的基因表达 D.正反馈 E.负反馈
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单选题以下关于顺式作用元件的叙述哪项是错误的( )。
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单选题下列关于核糖体的叙述正确的是 A.tRNA的三级结构形式 B.参与转录终止,因为翻译紧接着转录之后 C.有转运氨基酸的作用 D.遗传密码的携带者 E.由rRNA和蛋白质构成
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单选题关于核苷酸的叙述不正确的是______。
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单选题More than any other industry, the luxury-goods business needs people to feel good about spending money. So at a recent conference in Moscow, Bernard Arnault, the head of Moet Hennessy Louis Vuitton (LVMH), the world's biggest luxury-goods group, went to great lengths to dismiss investors' fears about the impact on the industry of America's credit crisis, a possible recession and the weak dollar. Indeed, Mr. Arnault said he expects the industry's sales almost to double in the next five years, thanks to strong demand from emerging markets and the creation of new wealth across the globe. After a depressing period at the beginning of the decade when the terrorist attacks in America, the outbreak of SARS and the war in Iraq reduced international travel and people's appetite for frivolous things, the industry has had three excellent years. According to Bain, a consultancy, sales of luxury goods grew by 9% in 2006 to 159 billion ($ 200 billion) and will reach about 170 billion this year, which would double the 1996 figure. Europe remains the biggest market, with about 40% of sales, though the strongest growth is in China, Russia, the Middle East and some Latin American countries. Can the industry really double again in half the time? Analysts at Citigroup say that Christmas will be good this year for luxury-goods firms, but they are more cautious about next year because of worries about falling demand in America. It is tempting to think that luxury goods are isolated from the broader economy, because customers are rich enough to ignore it, says Luca Solca, a luxury-goods analyst. But the industry's expansion into a broader "aspirational" market, by selling to the merely affluent, makes it susceptible. And as luxury firms expand in Asia and the Americas, they will continue to suffer currency woes. Most of the industry's production is in the euro-zone, mainly in France and Italy. Even the optimistic Mr. Arnault complained at his firm's recent annual meeting that the euro had reached "incomprehensible" levels against the dollar and the yen. Luxury companies could shift more of their production to countries with weaker currencies and cheap labor (ie, China), but some customers-especially Asian customers-want the elitism and craftsmanship associated with products manufactured in Europe. At least sales in emerging markets are growing fast. But Melanie Flouquet, a luxury analyst at JPMorgan, an investment bank, says that this growth is not enough to offset a slowdown in America. Chinese and Russian consumers account for around 7% and 4% of global luxury sales respectively, compared with 16-18% for Americans. Even so, European firms are sticking to their plans in New York, America's fashion capital. Gucci will open its biggest shop in February in Trump Tower, a shiny skyscraper on New York's Fifth Avenue. Ermenegildo Zegna will also open a shop on Fifth Avenue next year. And this week Dolce Gabbana re-opened its spruced-up shop on Madison Avenue. Claudia D' Arpizio of Bain thinks luxury makers need to follow Giorgio Armani and segment their customers more carefully with different product lines at different price ranges. She predicts that the industry will see solid growth rates of up to 10% a year in the near term. This means that the industry could double in ten years-by which time China is likely to account for more than a quarter and maybe as much as a third of the world's consumption of luxury goods. Yet Mr. Arnault's rosy prediction seems unlikely to come true. As Americans tighten their purse-strings, over-optimism is a luxury even this industry cannot afford.
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单选题下列克隆载体对外源DNA容载量最大的是( )。
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单选题苹果酸-天冬氨酸穿梭的生理意义是 A.将草酰乙酸带入线粒体彻底氧化 B.维持线粒体内外有机酸的平衡 C.为三羧酸循环提供足够的草酰乙酸 D.将细胞质中NADH上的H带入线粒体 E.将乙酰CoA转移出线粒体
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单选题下列化合物不属于糖异生的原料的是(   )
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单选题下列物质中,氧化磷酸化的解偶联剂是 A.一氧化碳 B.氰化物 C.鱼藤酮 D.二硝基苯酚 E.硫化氢
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单选题tRNA结构中哪个位点是与特定氨基酸结合的位点
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单选题合成脂肪酸不需
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单选题以下不是是SAGE分析软件的是( ) A.SAGE300 B.WEBSAGE C.ATCG D.POWERSAGE E.Clustal
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单选题糖蛋白糖链合成场所为
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