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

单选题关于核苷酸的叙述不正确的是______。

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.

单选题下列克隆载体对外源DNA容载量最大的是( )。

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

单选题下列化合物不属于糖异生的原料的是(　　　)

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

单选题tRNA结构中哪个位点是与特定氨基酸结合的位点

单选题合成脂肪酸不需

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

单选题糖蛋白糖链合成场所为

单选题 信号肽的作用是： A、保护N-端的蛋氨酸残基 B、保护蛋白质不被水解 C、维持蛋白质的空间构象 D、引导多肽链进入内质网 E、传递蛋白质之间的信息

单选题通过鸟氨酸循环生成尿素时，其分子中的两个氮原子一个直接来自游离的氨，另一个直接来源于( )(1998年)

单选题下列哪种因素不会影响真核细胞中mRNA的稳定性______ A.5'端帽子 B.siRNA C.polyA尾 D.去稳定元件 E.miRNA

单选题哪种血浆脂蛋白运输内源性甘油三酯(　　　)

单选题真核生物5S rRNA基因的启动子在转录结构基因的( )。

单选题Scientists have for the first time used cloning to create human embryos that live long enough in a laboratory dish to have their stem cells harvested. The feat could set the stage for physicians to produce cells and tissues, tailored to a patient's genetic identity that can treat a wide variety of human illnesses. The accomplishment also provides a road map for how to clone a person, an even more divisive undertaking. The new work, performed in South Korea, represents "a major advance in stem cell research. It could help spur a medical revolution as important as antibiotics and vaccines", says Robert Lanza of Advanced Cell Technology (ACT), a company in Worcester, Mass., that's also investigating the promising stem cell strategy called therapeutic cloning. "However, now that the methodology is publicly available", Lanza adds, "I think it is absolutely imperative that we pass laws worldwide to prevent the technology from being abused for reproductive-cloning purposes." While some fertility doctors and a religious cult have claimed success at creating a pregnancy via cloning, they've offered no convincing proof. In contrast, the South Korean research is being reported at the meeting of the American Association for the Advancement of Science in Seattle and will appear in an upcoming Science. "This is reality," says stem cell researcher John Gearhart of Johns Hopkins University. "He4'e is a bona fide, refereed journal saying that a human embryo has been cloned and a cell line derived from it." Although ACT has not yet published a report of a cloned human blastocyst, Lanza says that the South Korean success is "consistent with our own results." Therapeutic cloning appeals to Lanza and physicians because cells made this way could have the same DNA as a patient's cells do and thus avoid rejection after they're transplanted. Seeking a compromise that would permit this strategy to be pursued, many scientists have called for legislation that would ban cloning to produce a baby but allow the creation of cloned embryos to generate stem cells for research or therapies. "The debate has been very polarized," notes bio-ethicist Laurie Zoloth of Northwestern University in Evanston.

单选题真核生物DNA复制速度与原核生物相比： A．相同 B．略快 C．快很多 D．慢很多

单选题新生链延伸过程中tRNA的移动路径为______。

单选题类固醇激素生化信息的传递首先需通过______。