单选题RNA中含稀有碱基最多的是

单选题决定抗体特异性的是( ) A．重链与轻链 B．重链可变区 C．轻链可变区 D．重链和轻链的稳定区 E．重链和轻链的可变区

单选题PCR的产物是( ) A．一段单链DNA B．与循环数呈3的指数倍增长 C．只取决于模板 D．产量与初始模板数有关 E．模板的完全拷贝

单选题大肠杆菌共有几种DNA聚合酶______ A.1 B.2 C.3 D.4 E.5

单选题5-FU的抗肿瘤作用的生化机制为

单选题检测蛋白质-蛋白质相互作用的方法不包括：

单选题生理常温下，脂质双分子层的状态是______。

单选题 DNA helicase的生物学功能是 A、缓解DNA复制时产生的twisting problem B、防止DNA的过度超螺旋 C、解开双螺旋DNA双链的配对 D、促进引物酶的结合。

单选题肝内生成乙酰乙酸的直接前体是

单选题A．溶酶体B．内质网C．线粒体D．细胞液 (2007年)

单选题由于碱基突变使编码Cys的密码子TGC突变为TGA，这种突变称为：

单选题从量上说，餐后肝内葡萄糖去路最多的代谢途径是( )(1990年)

单选题Rarely do major diseases have a single cause. They are usually the result of a complex interaction between many factors, including genetic, environmental and lifestyle components. Many media reports, however, can tead us to believe that if we gave up something that we might otherwise enjoy, we could completely escape that particular affliction. Clearly, this is not the case. Vegetarians die of cancer of the colon (结肠). Teetotallers die of liver complaints, including cirrhosis (硬化). People who never go out in the sun contract skin melanomas (黑素瘤). Always, there are other factors at work than the single element being examined in a scientific study. Quite often the alleged benefits of a particular nutritional element are the result not so much of the element itself but of the lifestyle and general diet of the people who consume it most. People who eat lots of "healthy" foods, including fiber, carrots, broccoli etc. , also tend to drink less alcohol, take more exercise, avoid too many fatty foods and smoke less. Only when a study can rule out all of these other factors and often we do not know what these factors might be can we say that there is a causal link between two things. That is not to say that things like fiber and broccoli have no beneficial effects at all. But those with sedentary lifestyles cannot expect these foods to make them healthy. There is, however, one thing which increases the likelihood of dying relatively young, even when all of the other factors have been taken into account. It is one of the biggest killers even among those who lead lifestyles which, by any criteria, are clearly healthy ones. This single, incontrovertible risk factor is that of being poor. Recent report from the Cancer Research Campaign suggested that 12 700 deaths could have been avoided between 1986 and 1990 if inequalities in cancer care did not exist in England and Wales. Comparing cancer survival rates, the study found that England and Wales fared unfavorably with Europe and the US, but the most affluent regions of these two countries exhibited similar figures to the European average. In an attempt to counter this disparity the government has announced plans for the provision of Health Action Zones which seek to encourage greater cooperation between health and social services, targeting both rural and inner city areas. The emphasis of this new scheme however appears to focus on inadequacies within health education in these areas, rather than attacking the broader issues of social inequality.

单选题下列属于全局比对算法的是( ) A．Needleman-Wunsch B．Smith-Waterman C．PIR D．PAUP E．Pfam

单选题影响Hb与氧结合的因素是______。

单选题关于G蛋白的叙述中，错误的是

单选题不易进行的糖异生反应是

单选题人体内嘌呤核苷酸分解代谢的代表性终产物是

单选题磷酸戊糖途径的重要生理功能不包括

单选题脂肪酸β-氧化过程中脂酰CoA脱氢的受氢体为