【多选题】Medical geneticists study DNA and genes for many purposes, including ().
A.
to learn how organisms cause illness
B.
to understand the gene changes that lead to birth defects or genetic illnesses
C.
to change gene structure and thus prevent or cure genetic diseases
D.
to improve the chances of success in organ transplants.
【简答题】The man is the next room. He brought our textbooks yesterday.
【单选题】选择填空。 — How many bookcases ______ there in your study? — There ______ one. [ ]
【简答题】土质路堑开挖,根据挖方数量大小及施工方法的不同,按掘进方向可分为() 掘进 和 () 掘进两种,同时又可在高度上分 () 和 () 等
【单选题】The purpose of the study described in paragraph 2 was to determine
A.
how many hours people can survive without sleep
B.
how people react when their sleep is interrupted
C.
the changes in brain activity that occur during sleep
D.
the effects of sleep deprivation on brain activity
【简答题】下列试剂和酶常用于蛋白质化学的研究中:CNBr、异硫氰酸苯酯、丹黄酰氯、脲、 6mol/L HCl、β-巯基乙醇、水合茚三酮、过甲酸、胰蛋白酶、胰凝乳蛋白酶。其中哪 一个最适合完成以下各项任务? (1)测定小肽的氨基酸序列。 (2)鉴定肽的氨基末端残基。 (3)不含二硫键的蛋白质的可逆变性;如有二硫键存在时还需加什么试剂? (4)在芳香族氨基酸残基羧基侧水解肽键。 (4)在蛋氨酸残基羧基侧水解肽键...
【单选题】推动经济持续健康发展,必须加快转变经济发展方式。转变经济发展方式的主攻方向是( )