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

单选题组成人体蛋白质的20种氨基酸，都是

单选题A．时间特异性B．空间特异性C．组成性表达D．透导表达E．阻遏表达

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( )。

单选题真核生物核DNA复制方式是

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We assumed ethics needed the seal of certainty, else it was non-rational. And certainty was to be produced by a deductive model: the correct actions were derivable from classical first principles or a hierarchically ranked pantheon of principles. This model, though, is bankrupt. I suggest we think of ethics as analogous to language usage. There are no univocal rules of grammar and style which uniquely determine the best sentence for a particular situation. Nor is language usage universalizable. Although a sentence or phrase is warranted in one case, it does not mean it is automatically appropriate in like circumstances. Nonetheless, language usage is not subjective. This should not surprise us in the least. All intellectual pursuits are relativistic in just these senses. Political science, psychology, chemistry, and physics are not certain, but they are not subjective either. As I see it, ethical inquiry proceed like this: we are taught moral principles by parents, teachers, and society at large. As we grow older we become exposed to competing views. These may lead us to reevaluate presently held beliefs. Or we may find ourselves inexplicably making certain valuations, possibly because of inherited altruistic tendencies. We may "learn the hard way" that some actions generate unacceptable consequences. Or we may reflect upon our own and others' "theories" or patterns of behavior and decide they are inconsistent. The resulting views are "tested"; we act as we think we should and evaluate the consequences of those actions on ourselves and on others. We thereby correct our mistakes in light of the test of time. Of course people make different moral judgments; of course we cannot resolve these differences by using some algorithm which is itself beyond judgement. We have no vantage point outside human experience where we can judge right and wrong, good and bad. But then we don't have a vantage point from where we can be philosophical relativists either. We are left within the real world, trying to cope with ourselves, with each other, with the world, and with our own fallibility. We do not have all the moral answers; nor do we have an algorithm to discern those answers. Neither do we possess an algorithm for determining correct language usage but that does not make us throw up our hands in despair because we can no longer communicate. If we understand ethics in this way, we can see, I think, the real value of ethical theory. Some people, talk as if ethical theories give us moral prescriptions. They think we should apply ethical principles as we. would a poultice: after diagnosing the ailment, we apply the appropriate dressing. But that is a mistake. No theory provides a set of abstract solutions to apply straightforwardly. Ethical theories are important not because they solve all moral dilemmas but because they help us notice salient features of moral problems and help us understand those problems in context.

单选题下列哪种物质是细胞间信息物质

单选题新生链延伸过程中tRNA的移动路径为______。

单选题蛋白质一级结构的主要化学键是

单选题类固醇激素生化信息的传递首先需通过______。