1、Unit3.Biochemistry and Human DevelopmentBiochemistry is the application of chemistry to the study of biological processes at the cellular and molecular level. It emerged as a distinct discipline around the beginning of the 20th century when scientists combined chemistry, physiology and biology to in
2、vestigate the chemistry of living systems. In a sense, biochemistry is both a life science and a chemical science. It uses the methods of chemistry, physics; molecular biology and immunology to study the structure and behavior of the complex molecules found in biological material and the ways those
3、molecules interact to form cells, tissues and whole organism. It covers a broad range of cellular functions from gene transcription to the structure and function of macromolecules.生物化学是在细胞和分子水平上运用化学技术研究生物过程的科学。在20世纪初，当科学家联合化学,生理学和生物化学研究的生命系统时，开始出现这门独立学科。在某种意义上说，生物化学既是生命科学又是化学科学，它使用化学、物理学、分子生物学和免疫学方法
4、研究在生物物质中发现的复杂分子结构与行为以及这些分子相互作用构成细胞、组织和整个生物体的方法。它涉及从基因移录到高分子结构和功能的广阔的细胞功能范围。Biochemistry has become the foundation for understanding all biological processes; it has provided explanations for the causes of many diseases in humans, animals, and plants. Our understanding of biochemistry has had and wil
5、l continue to have extensive effects on many aspects of human endeavor. First, biochemistry is an intrinsically beautiful and fascinating body of knowledge. We now know the essence and many of the details the most fundamental processes in biochemistry, such as how a single molecule of DNA replicate
6、to generate two identical copies of itself and how the sequence of the bases in a DNA molecule determines the sequence of amino acids in an encoded protein. Our ability to describe these processes in detailed, mechanistic terms places a firm chemical foundation under other biological sciences. Moreo
7、ver, the realization that we can understand essential life processes, such as the transmission of heredity information as chemical structures and their reactions has significant philosophical implications. What does it mean, biochemically, to be human? What are the biochemical differences between a
8、human being, a chimpanzee, a mouse, a fruit fly? Are we more similar than we are different?生物化学已成为理解所有生物过程的基础;它提供了对人类、动物和植物许多疾病病因的解释。我们对生物化学的理解已经并将继续在人类努力的许多方面有广泛的影响。首先,生物化学在内在上是一个美丽而迷人的知识体系。我们现在已经知道最基本的生物化学过程的本质和很多细节,例如,单分子DNA如何复制生成两个相同的复制体。DNA分子的碱基序列如何决定已编码的蛋白质中的氨基酸序列。我们以机械的术语详细的描述这些生物化学过程的能力，为其他生
9、物科学研究奠定了坚实的化学基础。再者，我们把基础生命过程理解为化学结构和它们产生的反应，比如遗传信息的传递，这种意识具有重要的哲学含义。从生物化学的上来讲，作为人类意味着什么?人类,黑猩猩,一只老鼠,果蝇之间生物化学上有什么不同?我们的相似性是否大于差异性？Second, biochemistry is greatly influencing medicine and other fields. The molecular lesions causing sickle-cell-anemia, cystic fibrosis, hemophilia, and many other geneti
10、c disease have been elucidated at the biochemical level. Some of the molecular events that contribute to cancer development have been identified. An understanding of the underlying defects opens the door to the discovery of effective therapies. Biochemistry makes possible the rational design of new
11、drugs, including specific inhibitors of enzymes requires for the replication of virus such as immunodeficiency virus (HIV). Genetically engineered bacteria or other organisms can be used as “factories” to produce valuable proteins such as insulin and stimulators of blood-cell development.第二,生物化学大大地影
12、响医药和其他领域。引起镰状细胞贫血、囊性纤维化、血友病和许多其他遗传疾病的分子病变已经在生物化学的水平已经被阐述。一些导致癌症发生的分子事物已经被确认。了解潜在的缺陷为发现有效的治疗方法开启了大门。生物化学使得新药的合理设计成为了可能，包括病毒复制所需的酶的特殊抑制剂（如HIV病毒）。基因工程制造的细菌或其他生物可以用来作为制造有价值的蛋白质的工厂，如胰岛素和血细胞生成刺激因子。Biochemistry is also contributing richly to clinical diagnostics. For example, elevated levels of telltale en
13、zymes in the blood reveal whether a patient has recently had a myocardial infarction (heart attack) . DNA probes are coming into play in the precise diagnosis of inherited disorders, infectious diseases, and cancers. Agriculture, too, is benefiting from advances in biochemistry with the development
14、of more effective, environmentally safer herbicides and pesticides and the creation of genetically engineered plants are, for example, more resistant to insects. All of these endeavors are being accelerated by the advances in genomic sequencing.生物化学对临床诊断也有很大的贡献。例如, 血液中出现高浓度的具有诊断作用的酶揭示病人最近是否有过心肌梗死(心脏
15、病)。DNA 探针在遗传病，传染病以及癌症方面发挥精的确诊断作用。应受益于生物化学的发展，农业方面也有实在的进步，例如，产生了对环境无害更加有效的除草剂，杀虫剂和更能抵抗虫害的基因工程植物。所有这些努力因基因组测序的进展而加速。Third, advances in biochemistry are enabling researches to tackle some of the most exciting questions in biology and medicine. How does a fertilized egg give rise to cells as different a
16、s those in muscle, brain and liver? How do the senses work? What are the molecular bases for mental disorders such as Alzheimer disease and schizophrenia? How does the immune system distinguish between self and nonself? What are the molecular mechanisms of shore-term and long-term memory? The answer
17、 to such questions, which once seemed remote, have been partly uncovered and are likely to be more thoroughly revealed in the near future.第三，生物化学的进展正在使研究者们能够处理一些生物和医学上最令人激动的问题。一个受精卵如何会产生与肌肉、大脑和肝脏细胞中不同的细胞？感官是如何工作的？大脑疾病如老年痴呆症和精神分裂症的分子基础是什么？免疫系统如何区分自体和异体的？长期记忆和短期记忆的分子机制是什么？对于这些问题的答案，过去曾经似乎很遥远，现在已经得到部分的解答，并且可能在不久的将来得到更加全面的解答。
