单选题纯化酶制剂时，酶纯度的主要指标是

单选题最直接联系核苷酸合成与糖代谢的物质是

单选题A.柠檬酸循环B.甲硫氨酸循环C.嘌呤核苷酸循环D.乳酸循环

单选题丙二酸对琥珀酸脱氢酶的抑制作用属于

单选题胆汁中含量最多的有机成分是

单选题A．α-酮戊二酸B．5-磷酸核糖C．二磷酸尿苷葡萄糖D．琥珀酰CoA

单选题天然蛋白质中不存在的氨基酸是

单选题果糖双磷酸-1催化下列哪种反应

单选题红细胞中还原型谷胱甘肽不足，而导致溶血，原因是缺乏

单选题A.柠檬酸B.乙酰CoAC.二者都是D.二者均否

单选题对于酶的化学修饰调节不恰当的是

单选题用离子交换树脂纯化蛋白质是根据不同蛋白质的什么性质

单选题A variety of illegal acts committed by people in the course of their employment, for their own personal gain, are collectively known as white-collar crime. Embezzlement, theft and trading securities (1) insider information are common forms of white-collar crime. The majority of cases involve low-level employees who steal because they are under (2) financial stress. Many plan to (3) the money back as soon as possible but may never do so. Their crimes are usually never (4) because the amounts of money are small, and no one notices the (5) . (6) , there are some very large cases of white-collar crime, such as multimillion-dollar stock market or banking seams that take years to discover and are extremely difficult and expensive to (7) . White-collar crime is not (8) to the business sector. Government employment, especially (9) the city level, also provides opportunities to (10) one's pockets. (11) , building inspectors accept bribes and full-time employees receive (12) payments. Although white-collar crime is less (13) than street crime, it involves (14) more money and harm to the public than crimes committed by street criminals. It is (15) that there are more criminals (16) the office suites than in the streets, yet the (17) of white-collar makes it difficult to uncover the offenses and pursue the offenders. As the economy (18) from manufacturing to services and electronic commerce, opportunities for white-collar crime (19) , while the technology needed to stop such crimes will (20) .

单选题下述氨基酸中哪一种是非必需氨基酸

单选题体内氨基酸脱氨基作用产生的氨可参与合成的物质有

单选题对于酶的化学修饰，不正确的是

单选题下列哪种氨摹酸体内不能合成，必须靠食物供给( )(2006年)

单选题家族性高胆固醇血症的原发代谢障碍可能是

单选题下列检测蛋白质的方法中，哪一种取决于完整的肽键( )(1988年)

单选题核酸中核苷酸之间的连接方式是