生物专业英语第五章基因的化学本质
12第一讲_lecture_2_揭秘遗传物质的化学本质
你已的化合物这些1929基和磷酸四连环，1、核酸的构成核酸1.1戊糖戊糖个氧构成DNA分子脱氧核糖做核糖，这巨大的影已经知道了物呢？些灰白色黏9年菲巴斯酸基团，并真的是这的基本化学酸的基本化糖的环状结成的，而其子中的戊糖糖，而RNA这一微小影响。
了DNA是主黏糊糊的东斯•利文（并提出了四这样么？让学组成单化学单元包结构是由其其第5’位的糖在其2’位A分子中在的差异对主要的遗东西就是我Phoebus A四核苷酸学让我们来先元包括了戊糖其1’, 2’, 3的碳原子则位碳上连接在这一位置对DNA和传物质，那我们的遗传Aaron Lev学说，认为先看看这些糖、碱基3’, 4’位的则位于戊接的是氢置链接的RNA分子那么你知道传物质DNvene）首先为DNA是些组成核和磷酸根的碳原子和戊糖环外侧氢原子，叫的是羟基，子的功能有道到底是NA。
先分析出由等量的酸的基本三个部分和一侧。
叫做叫有着是谁发现了DNA含有的各种碱基本化学单元分。
了这个神奇有的四种碱基所组成的元吧。
奇碱的1.2核酸分核酸碱基包括啶（T）和其中基的6位配对。
AGCT出现在D碱基，称1.3 核酸分磷酸为什么叫分子的另一酸中的碱基括腺嘌呤（尿嘧啶中嘌呤碱基位上的功能T四种碱基DNA中而称为稀有碱分子的最酸根的存在叫做核酸的一个基本基分为碳氮（A）和鸟（U）。
基的9位和能基团和嘧基出现在U只出现碱基，比如最后一个基在使得DN的原因。
组成单元氮双环的嘌嘌呤（G）和嘧啶碱基嘧啶碱基4DNA中，现在RNA分如tRNA中基本化学组A和RNA元是碱基。
嘌呤碱基和两种，而基的1位是位上的功而AGCU分子中。
某中含有的假组成部分是A分子在生和单环结而嘧啶碱是碱基和功能基团可U是构成R某些RNA假尿嘧啶和是磷酸根生理环境下构的嘧啶基包括胞戊糖连接可以形成RNA的碱A分子中还和二氢尿嘧下具有酸啶碱基两大胞嘧啶（C接的位点，成氢键从而基，注意还含有微量嘧啶。
酸的特性，大类，嘌呤）、胸腺嘧而嘌呤碱而实现碱基意，T通常量的其它这也是其呤嘧碱基其2． 核酸你已2.1 核苷与碱基羟基结合成的分子位碳原子酯，核苷根据其连物分别叫酸和三磷量分子AT这张通常以三Table1‐酸的一级结已经知道了与核苷酸基通过与戊合脱去一份子叫做核苷子上的羟基苷加上磷酸连接的磷酸叫做单磷酸磷酸核苷酸TP 就是三张表里列出三磷酸的形1Nucl结构了构成核酸酸戊糖1’位份子水形成苷，磷酸基基缩合形成酸形成的叫酸基团的数酸核苷酸、酸，比如我三磷酸腺苷出了各种主形式存在，eic acid n酸的基本化碳原子上成糖苷键，基与戊糖成5’磷酸叫做核苷酸数目，相应二磷酸核我们体内的苷酸。
第二章 基因与基因组
基因组结构的特征 • 2. 功能相关的基因大多以操纵子形式出
现。如大肠杆菌的乳糖操纵子等。操纵
子是细菌的基因表达和调控的一个完整
单位，包括结构基因、调控基因和被调
控基因产物所识别的DNA调控原件（启
动子等）。
启动子 结构基因
操纵子
大肠杆菌基因组中，绝大多数基因都以操
纵子（operon）方式组合成表达单位。操 纵子含有一组彼此相邻的结构基因，基因 间隔可以只有1-2bp。大肠杆菌总共有600 个操纵子，每个含2个或更多的基因。
DNA双螺旋模型
Watson & Crick建立双螺旋模型主要是受到4个方面的影响： （1）1938年W.T.Astbury & Bell用x衍射技术研 究DNA。1947年拍摄了第一张DNA的衍射照片，并推断DNA分 子的结构是： ① 柱状； ② 多核苷酸是一叠扁平的核苷酸； ③ 核酸残基取向和分子长轴垂直,间距为3.4。
基因是一段DNA序列, DNA是双螺旋高分子.
1869年 J.T.Miescher 发现核素 （muclein）遗传物质必须具备哪些特 点？ 1）在体细胞中含量稳定； 2) 在生殖细胞中含量减半； 3) 能携带遗传信息； 4) 能精确地自我复制； 5) 能发生变异；
1869年，F.Miescher 从脓细胞中提取到 一种富含磷元素的 酸性化合物。
• 1885—1900年间，Kossel、Johnew、Levene证实核酸由 不同的碱基组成。其最简单的单体结构是碱基-核糖-磷 酸构成的核苷酸。1929年又确定了核酸有两种，一种是 脱氧核糖核酸(DNA)，另一种是核糖核酸(RNA)。
1928年，Griffith 肺炎双球菌的转化
• 1944年，Avery在离 体条件下完成转化。
DNA是主要的遗传物质课件高考一轮复习生物PPT
有没有更好的材料、更好的方法能够将DNA和蛋白 质分开，单独去观察它们的作用呢？
1952年，赫尔希和蔡斯以T2噬菌体为实验材料，完成 了另一个更具有说服力的实验.
考点二 噬菌体侵染细菌的实验 【必备知识速填】 1.实验材料——T2噬菌体:
T2噬菌体在大肠杆菌内的增殖过程？
T2噬菌体在大肠杆菌内的增殖过程: (1)模板: 进入细菌体内的噬菌体的DNA。
加热杀死的S型
混合
R型活菌
S型活菌
后代
S型活菌
R型活菌
R型活菌
在第四组实验死亡的小鼠体内仅仅只能分 离出S型活细菌吗？
D N A 是 主要的 遗传物 质课件 高考一 轮复习 生物P PT【PP T实用课 件】
D N A 是 主要的 遗传物 质课件 高考一 轮复习 生物P PT【PP T实用课 件】
2.艾弗里的体外转化实验:
D N A 是 主要的 遗传物 质课件 高考一 轮复习 生物P PT【PP T实用课 件】
D N A 是 主要的 遗传物 质课件 高考一 轮复习 生物P PT【PP T实用课 件】
项目 培养 细菌 实验 原则 实验 结果 实验 结论
联系
D N A 是 主要的 遗传物 质课件 高考一 轮复习 生物P PT【PP T实用课 件】
格里菲思
艾弗里
赫尔希
D N A 是 主要的 遗传物 质课件 高考一 轮复习 生物P PT【PP T实用课 件】
考点一 肺炎双球菌转化实验
【必备知识速填】 1.格里菲思的体内转化实验: (1)实验材料:
菌落 菌体 毒性
S型肺炎双球菌 _光__滑__
有多糖类荚膜 _有__毒__
D N A 是 主要的 遗传物 质课件 高考一 轮复习 生物P PT【PP T实用课 件】
基因的本质和表达知识点答案x
一、知识点归纳1.肺炎双球菌的转化实验:①格里菲思实验：②艾弗里实验R型活细菌分别注不死S型①蛋白质分别与产物R型S型活细菌射到小死亡活细②荚膜多糖R型活R型加热杀死的S型活细菌鼠体内不死菌分③DNA细菌混R型+S型加热杀死的S型细菌和R型活细菌混合死亡离岀④DNA加DNA酶合R型结论：在S型细菌中存在转化因子，可以使R型细菌结论：DNA是遗传物质；蛋白质、多糖等不是遗传转化为S型细菌。
物质。
2.T 2噬菌体侵染细菌的实验：用_35S_标记噬菌体的蛋白质，用 _即_标记噬菌体的DNA实验过程：第一组：含35S的培养基培养得到4含35S的细菌培养得到.蛋白质外壳含35S的噬菌体侵染细菌.上清液的放射性搅拌离心高结论’厂沉淀物放射性忑，_噬菌体外壳」进入宿主J侵染细菌」沉淀物的放射性高，上第二组：含32P的培养基培养得到.含32P的细菌培养得NA , 含32P的噬菌体搅拌、离心---- 清液放射性低_ 结论—噬菌体DNL进入了宿主搅拌的目的是：使_吸附在细菌上的噬菌体与细菌 _分离；离心的目的是：上清液析出噬菌体，沉淀物中留下大肠杆菌②保温时间过长、过短都会使第二组实验上清液的放射性变强的原因：_保温时间过长噬菌体在细菌内增殖后释放子代噬菌体到上清液；保温时间过短部分噬菌体没有侵染到细菌内—③结果和结论：噬菌体侵染细菌过程中，只有32P进入细菌，而35S未进入，说明只有亲代噬菌体的_DNA进入细胞，_蛋白质外壳—仍留在外面，子代噬菌体的各种性状，是通过亲代的_DNL遗传的，—DNA 才是真正的遗传物质。
新的噬菌体中的蛋白质不是从亲代连续下来的，而是在_噬菌体DNA_的作用下合成的，这说明DNA能够自我复制，在亲子代之间能够保持一定的—连续性______ 。
3.生物的遗传物质：①有细胞的生物(原核和真核)都有—DNA和RNA 核酸，但遗传物质仅是_DN$ ；②病毒含_DNA或RNL，其遗传物质是_DNA或RNA ；③针对生物界，绝大多数生物的遗传物质是DNA ，极少数病毒(TMV HIV、流感病毒)的遗传物质为_RN _，所以_DNL是主要的遗传物质4.DNA分子於螺旋—结构(由—沃森、克里克 _提出)的主要特点：a.DNA分子由两条_反向—平行的_脱氧(核糖)核苷酸—长链盘旋成—双螺旋—结构。
高中生物必修二 第三章 基因的本质
高中生物必修二第三章基因的本质一、基因本质的证明过程1、艾弗里的肺炎双球菌的转化实验（1）肺炎双球菌的毒性S型细菌：菌体表面有多糖类的荚膜，形成的菌落表面光滑（smooth），有毒性R型细菌：菌体表面没有荚膜，形成的菌落表面粗糙（rough），无毒性（2）体内转化实验①R型活细菌注射活鼠→小鼠不死亡②S型活细菌注射活鼠→小鼠死亡，从体内分离出S型活细菌③加热后杀死的S型死细菌注射活鼠→小鼠不死亡④加热后杀死的S型死细菌和R型活细菌混合后注射活鼠→小鼠死亡，从体内分离出S型活细菌和R型细菌⑤得到推论：被加热杀死的S型细菌中，含有某种促成这一转化的活性物质——“转化因子”，这种转化因子将无毒的R型活细菌转化为S型活细菌。
（3）体外转化实验①往含有R型活细菌的培养基中加入S型菌的DNA→R型菌和S型菌②往含有R型活细菌的培养基中加入S型菌的蛋白质或荚膜多糖→R型菌③往含有R型活细菌的培养基中加入S型菌的DNA和DNA酶→R型菌④结论：DNA是使R型细菌产生稳定遗传变化的物质，而蛋白质不是。
（即DNA是遗传物质）（4）转化的实质是基因重组而不是基因突变，R型细菌吸收了S型细菌的DNA，整合到R 型细菌的DNA中，使受体细胞获得新的遗传信息，表现出S型细菌的性状。
（5）发生转化的只有少部分R型细菌2、艾弗里的2T 噬菌体侵染大肠杆菌实验（1）2T 噬菌体(高中所学唯一的DNA 病毒)①结构:DNA(含有P)和蛋白质外壳(含有S)②增殖方式:侵染大肠杆菌后，利用大肠杆菌内的物质合成自身组成成分，进行大量增殖，达到一定数量后，大肠杆菌裂解释放大量噬菌体（2）方法:同位素标记法（3）实验过程:注意:①应先在含有放射性同位素S 35或放射性同位素P 32的培养基中培养大肠杆菌，再用该大肠杆菌培养2T 噬菌体，从而得到蛋白质含有S 35或DNA 含有P 32的2T 噬菌体。
②混合后要经过短时间的保温(保证DNA 注入细菌且细菌不能裂解)并不断搅拌(使吸附在细菌上的噬菌体与细菌分离)③搅拌后离心(让上清液中析出重量较轻的T2噬菌体颗粒，沉淀物中留下被感染的大肠杆菌)（4）实验结论:噬菌体侵染细胞时，DNA进入到细菌的细胞中，而蛋白质外壳仍留在外面。
【精品】生物专业英语翻译+蒋悟生+第3版
生物专业英语翻译+蒋悟生+第3版------------------------------------------作者------------------------------------------日期Lesson One（4学时）Inside the Living Cell: Structure andFunction of Internal Cell Parts1.Cytoplasm: The Dynamic, Mobile Factory细胞质：动力工厂Most of the properties we associate with life are properties of the cytoplasm. Much of the mass of a cell consists of this semifluid substance, which is bounded on the outside by the plasma membrane. Organelles are suspended within it, supported by the filamentous network of the cytoskeleton. Dissolved in the cytoplasmic fluid are nutrients, ions, soluble proteins, and other materials needed for cell functioning.生命的大部分特征表现在细胞质的特征上。
细胞质大部分由半流体物质组成，并由细胞膜（原生质膜）包被。
细胞器悬浮在其中，并由丝状的细胞骨架支撑。
细胞质中溶解了大量的营养物质，离子，可溶蛋白以及维持细胞生理需求的其它物质。
2．The Nucleus: Information Central（细胞核：信息中心）The eukaryotic cell nucleus is the largest organelle and houses the genetic material (DNA) on chromosomes. (In prokaryotes the hereditary material is found in the nucleoid.) The nucleus also contains one or two organelles-the nucleoli-that play a role in cell division. A pore-perforated sac called the nuclear envelope separates the nucleus and its contents from the cytoplasm. Small molecules can pass through the nuclear envelope, but larger molecules such as mRNA and ribosomes must enter and exit via the pores.真核细胞的细胞核是最大的细胞器，细胞核对染色体组有保护作用（原核细胞的遗传物质存在于拟核中）。
生物专业英语翻译 蒋悟生 第3版(可编辑)
生物专业英语翻译+蒋悟生+第3版Lesson One4学时Inside the Living Cell Structure andFunction of Internal Cell Parts1Cytoplasm The Dynamic Mobile Factory细胞质动力工厂Most of the properties we associate with life are properties of the cytoplasm Much of the mass of a cell consists of this semifluid substance which is bounded on the outside by the plasma membrane Organelles are suspended within it supported by the filamentous network of the cytoskeleton Dissolved in the cytoplasmic fluid are nutrients ions soluble proteins and other materials needed for cell functioning 生命的大部分特征表现在细胞质的特征上细胞质大部分由半流体物质组成并由细胞膜原生质膜包被细胞器悬浮在其中并由丝状的细胞骨架支撑细胞质中溶解了大量的营养物质离子可溶蛋白以及维持细胞生理需求的其它物质2．The Nucleus Information Central细胞核信息中心The eukaryotic cell nucleus is the largest organelle and houses the genetic material DNA on chromosomes In prokaryotes the hereditary material is found in the nucleoid The nucleus also contains one or two organelles-the nucleoli-that play a role in cell division A pore-perforated sac called the nuclear envelope separates the nucleus and its contents from the cytoplasm Small molecules can pass through the nuclear envelope but larger molecules such as mRNA and ribosomes mustenter and exit via the pores真核细胞的细胞核是最大的细胞器细胞核对染色体组有保护作用原核细胞的遗传物质存在于拟核中细胞核含有一或二个核仁核仁促进细胞分裂核膜贯穿许多小孔小分子可以自由通过核膜而象mRNA和核糖体等大分子必须通过核孔运输3Organelles Specialized Work Units细胞器特殊的功能单位All eukaryotic cells contain most of the various kinds of organelles and each organelle performs a specialized function in the cell Organelles described in this section include ribosomes the endoplasmic reticulum the Golgi complex vacuoles lysosomes mitochondria and the plastids of plant cells所有的真核细胞都含有多种细胞器每个细胞器都有其特定功能本节主要介绍核糖体内质网高尔基体系液泡溶酶体线粒体和植物细胞中的质体The number of ribosomes within a cell may range from a few hundred to many thousands This quantity reflects the fact that ribosomes are the sites at which amino acids are assembled into proteins for export or for use in cell processes A complete ribosome is composed of one larger and one smaller subunit During protein synthesis the two subunits move along a strand of mRNA "reading" the genetic sequence coded in it and translating that sequence into protein Several ribosomes may become attached to a single mRNA strand such a combination is called a polysome Most cellular proteins are manufactured on ribosomes in the cytoplasm Exportable proteins and membrane proteins are usually made in association with the endoplasmic reticulum核糖体的数量变化从几百到几千核糖体是氨基酸组装成蛋白质的重要场所完整的核糖体由大亚基和小亚基组成核糖体沿着mRNA移动并阅读遗传密码翻译成蛋白质一条mRNA上可能有多个核糖体称多聚核糖体大多数细胞蛋白是由细胞质中核糖体生产输出蛋白和膜蛋白通常与内质网有关The endoplasmic reticulum a lacy array of membranous sacs tubules and vesicles may be either rough RER or smooth SER Both types play roles in the synthesis and transport of proteins The RER which is studded with polysomes also seems to be the source of the nuclear envelope after a cell divides内质网带有花边的生物囊有管状泡状之分以及光滑和粗糙面区别两种都与蛋白质的合成和运输有关粗糙内质网上分布许多核糖体也可能提供细胞分裂后所需的细胞膜SER lacks polysomes it is active in the synthesis of fats and steroids and in the oxidation of toxic substances in the cell Both types of endoplasmic reticulum serve as compartments within the cell where specific products can be isolated and subsequently shunted to particular areas in or outside the cell光滑内质网上无核糖体主要作用是脂肪和类固醇的合成以及细胞内有毒物质的氧化两种内质网合成的产物在其中进行分流或运输到细胞外Transport vesicles may carry exportable molecules from the endoplasmic reticulum to another membranous organelle the Golgi complex Within the Golgi complex molecules are modified and packaged for export out of the cell or for delivery else where in the cytoplasm 运输小泡能够将可运输分子从内质网运输到高尔基复合体上在高尔基复合体中修饰包装后输出细胞或传递到细胞质中的其他场所Vacuoles in cells appear to be hollow sacs but are actually filledwith fluid and soluble molecules The most prominent vacuoles appear in plant cells and serve as water reservoirs and storage sites for sugars and other molecules Vacuoles in animal cells carry out phagocytosis the intake of particulate matter and pinocytosis vacuolar drinking 细胞中的液泡好象是中空的但实际上充满了液体和可溶分子最典型的液泡存在于植物细胞中储备水糖以及其它分子动物中的液泡起吞噬和胞饮作用A subset of vacuoles are the organelles known as lysosomes which contain digestive enzymes packaged in lysosomes in the Golgi complex that can break down most biological macromolecules They act to digest food particles and to degrade damaged cell parts溶酶体是液泡亚单位含有消化酶降解大部分生物大分子消化食物微粒和降解损伤的细胞残片Mitochondria are the sites of energy-yielding chemical reactions in all cells In addition plant cells contain plastids that utilize light energy to manufacture carbohydrates in the process of photosynthesis It is on the large surface area provided by the inner cristae of mitochondria that ATP-generating enzymes are located Mitochondria are self-replicating and probably they are the evolutionary descendants of what were once free-living prokaryotes线粒体是细胞中化学产能的场所另外植物细胞中的质体在光合作用中利用光能产生碳水化合物线粒体内嵴上提供了很大的表面积并分布着产ATP酶线粒体自我复制并且可能是自由生活的原核生物在进化中形成的后代There are two types of plastids leucoplasts which lack pigments and serve as storage sites for starch proteins and oils and chromoplasts which contain pigments The most important chromoplasts arechloroplasts-organelles that contain the chlorophyll used in photosynthesis The internal structure of chloroplasts includes stacks of membranes called grana which are embedded in a matrix called the stroma 质体有两种类型白色体缺乏色素是淀粉蛋白质和油的储备场所色质体含有色素叶绿体是最重要的色质体含有与光合作用有关的叶绿素叶绿体的内部结构是由多层膜形成的叶绿体基粒其中包埋在基质中的基粒称子座4The Cytoskeleton细胞骨架All eukaryotic cells have a cytoskeleton which is a convoluted latticework of filaments and tubules that appears to fill all available space in the cell and provides support for various other organelles A large portion of the cytoskeleton consists of threadlike microfilaments composed mainly of the contractile protein actin They are involved in many types of intracellular movements in plant and animal cells A second protein myosin is involve in the contraction of muscle cells Another main structural component of the cytoskeleton consists of microtubules which are composed of the globular protein tubulin and together act as scaffolding that provides a stable cell shape Cytoskeletal intermediate filaments appear to impart tensile strength to the cell cytoplasm Mechanoenzymes such as myosin dynein and kinesin interact with the cytoskeletal filaments and tubules to generate forces that cause movements所有的细胞都有细胞骨架网络结构的纤丝充满了它所能触及的全部空间并且对细胞器提供支持作用细胞骨架大部分由微丝组成微丝主要由可收缩的肌动蛋白组成动植物细胞的许多种类型细胞内运动与肌动蛋白有关第二类蛋白是肌球蛋白它与肌肉细胞的收缩有关细胞骨架的另一个主要结构成分是微管由球状的微管蛋白组成象脚手架一般维持细胞的稳定形态细胞骨架的中间丝提供了细胞质伸缩动力机械酶例如肌球蛋白动力蛋白驱动蛋白与微丝微管相互作用产生动力而引起细胞运动5Cellular Movements细胞运动Although the cytoskeleton provides some stability稳固 to cells its microtubules英[maikrutjubjul] and filaments 丝状物and their associated proteins enable cells to move by creeping 爬行 or gliding 滑动 Such movements require a solid固体的 substrate to which the cell can adhere 附着 and can be guided by the geometry dimitri] 几何形状of the surface Some cells also exhibit [iɡzibit] 展览 chemotaxis kemtksis趋药性 the ability to move toward or away from the source of a diffusing 扩散chemicalCertain eukaryotic cells can swim freely in liquid environments propelled by whiplike cilia [sili]纤毛or flagella 英[fldel鞭毛 Both cilia and flagella have the same internal structure nine doublets pairs of microtubules are arranged in a ring and extend the length of the cilium or flagellum and two more microtubules run down the center of the ring Every cilium or flagellum grows only from the cell surface where a basal body基体is located Movement is based on the activities of tiny dynein 动力蛋白 side arms that extend from one of the microtubules of each doublet成对的东西Nutrients proteins and other materials within most plant cells are moved about via cytoplasmic streaming The process occurs as myosin maiusin肌凝蛋白 proteins attached to organelles 细胞器小器官 push against microfilaments arrayed [rei] 展示throughout the cell Microfilaments and microtubules are responsible for almost all majorcytoplasmic movements During cell division microtubules of the spindle assembled 集合收集from tubutin subunits near organelles called centrioles move the chromosomesLesson Two2学时PhotosynthesisPhotosynthesis occurs only in the chlorophyllchlorophyll叶绿素-containing cells of green plants algae藻 and certain protists 原生生物and bacteria Overall it is a process that converts light energy into chemical energy that is stored in the molecular bonds From the point of view of chemistry and energetics it is the opposite of cellular respiration Whereas 然而 cellular细胞的 respiration 呼吸is highly exergonic吸收能量的and releases energy photosynthesis光合作用requires energy and is highly endergonic光合作用只发生在含有叶绿素的绿色植物细胞海藻某些原生动物和细菌之中总体来说这是一个将光能转化成化学能并将能量贮存在分子键中从化学和动能学角度来看它是细胞呼吸作用的对立面细胞呼吸作用是高度放能的光合作用是需要能量并高吸能的过程Photosynthesis starts with CO2 and H2O as raw materials and proceeds through two sets of partial reactions In the first set called the light-dependent reactions water molecules are split裂开 oxidized 02 is released and ATP and NADPH are formed These reactions must take place in the presence of 在面前light energy In the second set called light-independent reactions CO2 is reduced via the addition of H atoms to carbohydrate These chemical events rely on the electron carrier NADPH and ATP generated by the first set of reactions光合作用以二氧化碳和水为原材料并经历两步化学反应第一步称光反应水分子分解氧分子释放ATP和NADPH形成此反应需要光能的存在第二步称暗反应二氧化碳被还原成碳水化合物这步反应依赖电子载体NADPH以及第一步反应产生的ATPBoth sets of reactions take place in chloroplasts Most of the enzymes and pigments 色素for the lightdependent reactions are embedded 深入的内含的in the thylakoid类囊体 membrane膜隔膜 of chloroplasts 叶绿体The dark reactions take place in the stroma基质两步反应都发生在叶绿体中光反应需要的大部分酶和色素包埋在叶绿体的类囊体膜上暗反应发生在基质中How Light Energy Reaches Photosynthetic Cells光合细胞如何吸收光能的The energy in light photons in the visible part of the spectrum can be captured by biological molecules to do constructive work The pigment chlorophyll in plant cells absorbs photons within a particular absorption spectrums statement of the amount of light absorbed by chlorophyll at different wavelengths When light is absorbed it alters the arrangement of electrons in the absorbing molecule The added energy of the photon boosts the energy condition of the molecule from a stable state to a less-stable excited state During the light-dependent reactions of photosynthesis as the absorbing molecule returns to the ground state the "excess" excitation energy is transmitted to other molecules and stored as chemical energy生物分子能捕获可见光谱中的光能植物细胞中叶绿素在不同光波下吸收部分吸收光谱在吸收分子中光的作用使分子中的电子发生重排光子的能量激活了分子的能量状态使其从稳定态进入不稳定的激活态All photosynthetic organisms contain various classes of chlorophylls and one or more carotenoid accessory pigments that also contribute tophotosynthesis Groups of pigment molecules called antenna complexes are present on thylakoids Light striking any one of the pigment molecules is funneled to a special chlorophyll a molecule termed a reaction-center chlorophyll which directly participates in photosynthesis Most photosynthetic organisms possess two types of reaction-center chlorophylls P680 and P700 each associated with an electron acceptor molecule and an electron donor These aggregations are known respectively as photosystem Ⅰ P700 and photosystem Ⅱ P680所有的光合作用生物含有不同等级的叶绿素和一个或多个类胡萝卜素光合作用的辅助色素称作天线复合体的色素分子群存在于类囊体中激活色素分子的光能进入叶绿素反应中心其直接参与光合作用大部分光反应细胞器拥有两套反应中心P680和P700每个光系统都含有一个电子受体和电子供体这些集合体就是大家熟识的光合系统Ⅰ和光合系统ⅡThe Light-Dependent Reaction Converting Solar Energy into Chemical-Bond Energy光反应光能转化成化学键能The photosystems of the light-dependent reactions are responsible for the packaging of light energy in the chemical compounds ATP and NADPH This packaging takes place through a series of oxidation reduction reactions set in motion when light strikes the P680 reaction center in photosystem Ⅱ In this initial event water molecules are cleaved oxygen is released and electrons are donated These electrons are accepted first by plastoquinone and then by a series of carriers as they descend an electron transport chain For each four electrons that pass down the chain two ATPs are formed The last acceptor in the chain is the P700 reactioncenter of photosystem Ⅰ At this point incoming photons boost the energy of the electrons and they are accepted by ferredoxin Ferredoxin is then reoxidized and the coenzyme NADP is reduced to the NADPH The ATP generated previously and the NADPH then take part in the light independent reactions光反应的光系统将光能转化成化学复合物ATP和NADPH当光激活光系统Ⅱ的光反应中心时通过一系列的氧化还原反应实现能量的传递反应开始时水被分解氧被释放并提供电子电子首先传递给质体醌然后通过一系列载体形成的电子传递链每传递4个电子形成2个ATP最后一个受体存在于光反应系统Ⅰ的反应中心里此处光子激活电子电子传递给铁氧还蛋白铁氧还蛋白再氧化并且辅酶NADP还原成NADPH早期产生的ATP和NADPH进入暗反应The production of ATP from the transport of electrons excited by light energy down an electron transport chain is termed photophosphorylation The one-way flow of electrons through photosystems II and I is called noncyclic photophosphorylation plants also derive additional ATP through cyclic photophosphorylation in which some electrons are shunted back through the electron transport chain between photosystems Ⅱ and Ⅰ由电子传递链偶连产生ATP的过程称为光合磷酸化通过光合系统Ⅱ流经光合系统Ⅰ的电子路径称非循环式光合磷酸化植物通过循环式光合磷酸化获得额外的ATP一些电子在光合系统Ⅰ和Ⅱ之间的电子传递链中回流The Light-Independent Reactions Building Carbohydrates暗反应碳水化合物的形成In the light-independent reactions of photosynthesis which are driven by ATP and NADPH C02 is converted to carbohydrate The reactions are also known as the Calvin-Benson cycle Atmospheric CO2 is fixed as it reactswith ribulose biphosphate RuBP a reaction that is catalyzed by the enzyme ribulose biphosphate carboxylase The reduction Of C02 to carbohydrate fructose diphosphate is completed via several more steps of the cycle Finally RUBP is regenerated so that the cycle may continue 由ATP和NADPH驱动的暗反应中二氧化碳转化成碳水化合物即卡尔文循环二磷酸核酮糖固定二氧化碳由二磷酸核酮糖羧化酶催化Oxygen An Inhibitor of photosynthesis氧光合作用的抑制因子High levels of oxygen in plant cells can disrupt photosynthesis and can also cause photorespiration-an inefficient fun of the dark reactions in which 02 is fixed rather than C02 and no carbohydrate is produced Reprieve from Photorespiration The C4 PathwayMost plants are C3 plants they experience decreased carbohydrate production under hot dry conditions as a result of the effects of photorespiration Among C4 plants however special leaf anatomy and a unique biochemical pathway enable the plant to thrive in and conditions Thus C4 plants lessen photorespiration by carrying out photosynthesis only in cells that are insulated from high levels of CO2 They also possess a novel mechanism for carbon fixation大部分植物是碳3植物在高温干旱条件下由于光呼吸作用而使碳水化合物的合成降低而在大多数的碳4植物中由于叶脉的特殊构造和独特的化学路径使植物依然很茂盛这是碳固定的一个新机制课后作业第一篇阅读材料答案1B2A3A4D5C6cLesson Three2学时Cellular Reproduction Mitosis and MeiosisThe Nucleus and ChromosomesThe cell nucleus is the main repository of genetic information Within the nucleus are the chromosomes tightly coiled strands of DNA and clusters of associated proteins Long stretches of the continuous DNA molecule wind around these clusters of proteins or histones forming beadlike complexes known as nucleosomes More coiling and supercoiling produces a dense chromosome structure Each long strand of DNA combines with histones and nonhistone proteins to make up the substance chromatin 细胞核是贮藏遗传信息的主要场所DNA盘绕成螺旋线以及相关的成簇蛋白质DNA螺旋线缠绕成簇的组蛋白形成珠链状的核小体这些螺旋和超螺旋形成致密的染色体组结构每个长链DNA与组蛋白和非组蛋白一起构成染色质物质A pictorial display of an organisms chromosomes in the coiled condensed state is known as a karyotype Karyotype reveal that in most cells all but sex chromosomes are present as two copies referred to as homologous pairs Non-sex chromosomes are called autosomes Organisms whose cells contain two sets of parental chromosomes are called diploid those with cells containing a single set of parental chromosomes are called haploid染色体致密的超螺旋状态我们称染色体组除了性染色体外大多数细胞的染色体组成对出现称同源染色体对非性染色体称常染色体生物细胞含有两套父母本染色体的称二倍体含有单套染色体的称单倍体The Cell CycleThe cell cycle is a regular sequence in which the cell grows prepares for division and divides to form two daughter cells each of which thenrepeats the cycle Such cycling in effect makes single-celled organisms immortal Many cells in multicellular organisms including animal muscle and nerve cells either slow the cycle or break out of it altogether 在细胞生长过程中细胞循环遵循特定程序分裂准备分裂成2个子细胞子细胞再循环此循环使得单细胞永生多细胞生物中的许多细胞包括动物肌肉和神经细胞要么降低循环速度要么同时分裂The normal cell cycle consists of four phases The first three include G1 the period of normal metabolism S phase during which normal synthesis of biological molecules continues DNA is replicated and histones are synthesized and G2 a brief period of metabolism and additional growth Together the G1 S and G2 phases are called interphase The fourth phase of the cell cycle is M phase the period of mitosis during which the replicated chromosomes condense and move and the cell divides It is believed that properties of the cell cytoplasm control the cell cycle along with external stimulators and inhibitors such as chalones 正常细胞循环由4个时期组成头三期包括G1正常新陈代谢S期正常新陈代谢同时DNA复制组蛋白合成 G2 期短期的新陈代谢和少许生长G1 S 和G2称分裂间期最后是M期有丝分裂期复制的染色体组浓缩移动并细胞分裂据称是染色质控制了细胞循环伴随外部激活因子和抑制因子如抑素Mitosis Partitioning the Hereditary MaterialBiologists divide the mitotic cycle into four phases At the beginning of prophase 前期 the chromosomes each consist of two highly condensed chromatids attached to each other at a centromere As prophase ends and metaphase 中期 begins the condensed 浓缩的 chromosomes become associated with the spindle 纺锤体 Eventually the chromosomes becomearranged in a plane called the metaphase plate at a right angle to the spindle fibers Next during anaphase 后期 the two sister chromatids of each chromosome split and one from each pair is drawn toward each pole of the cell During telophase 末期 nuclear envelopes 包膜 begin to form around each set of chromosomes and division of the cytoplasm takes place 生物学家将有丝分裂划分为4个阶段分裂前期高度浓缩的两个染色单体通过着丝粒连接在一起在分裂前期后期和分裂中期前期浓缩的染色体与纺锤体相连最后以正确的角度排列在赤道板上在分裂后期两个姊妹单体分离分别拽向细胞两极在分裂末期在每套染色体周围形成核膜细胞质发生分裂As mitosis proceeds the spindle microtubules play a crucial role in ensuring that both paired and separated chromatids 染色单体 move in the right directions at the proper times Each half of the spindle forms as microtubules extend from each pole of a dividing cell to the region of the metaphase plate During prophase other microtubules the centromeric 着丝粒fibers extend outward from the spindle poles to structures on the chromosomes called kinetochores着丝粒 During anaphase the fibers begin to shorten and the chromatids begin to move apart在有丝分裂过程中是纺锤体微管确保了染色单体在适当时间以正确方向进行分离纺锤体微管由两极向赤道板延伸在分裂前期其它微管着丝粒纤维延伸到染色体的动粒在分裂后期纤维开始变短染色单体分离The spindle forms differently in plant and animal cells In animals it is associated with centriole 中心粒 while in plant and fungal 真菌cells spindle formation is associated with reions called microtubule organizing centers植物和动物细胞形成的纺锤体不同动物细胞与中心粒相连而在植物和真菌细胞中纺锤体与微管组织中心的离子相连Cytokinesis Partitioning the Cytoplasm胞质分裂细胞质分离The division of the cell cytoplasm at the end of mitosis is called cytokinesis 细胞浆移动 In animal cells it takes place as a ring of actin filaments contracts使缩短合同契约around the cell equator赤道pinching收聚 the cell in two In plant cells which are bounded 有限制的 by a cell wall cytokinesis involves the building of a new cell plate across the dividing cell at its equator Cell wall material is then deposited 存放堆积 in the region of the cell plate在动物细胞中环形肌动蛋白丝延赤道板收缩而使细胞一分为二在植物细胞中在赤道板形成新的细胞板Meiosis The Basis of Sexual ReproductionMeiosis 减数 is a special form of cell division that takes place in the reproductive 生殖 organs that produce sex cells Like mitosis it takes place after DNA replication has occurred and involves two sequential 连续的 nuclear divisions meiosis I and meiosis Ⅱ These divisions result in four daughter cells each with half the number of chromosomes of the parent cell The phenomenon of crossing over during meiosis results in exchanges of genetic information between chromosomes Hence因此 the homologous 同源的 chromosomes distributed 分布 to different progeny 后裔 cells are not identical同样的减数分裂是性细胞分裂的特殊形式如有丝分裂它也是发生在DNA复制后并有连续的两个核分裂产生4个子细胞分别含有亲本一半的染色体数As in mitosis two chromatids exist for each chromosome at thebeginning of prophase 1 During this phase the homologous 同源 chromosomes undergo 经历sy-napsis 联会 or pairing which is brought about by a bridging structure of proteins and RNA called the synaptonemal 联会丝的 complex The homologous pairs stay together when they align on the metaphase 中plate Unlike the anaphase of mitosis however during anaphase I the two chromatids of each chromosome stay joined at the centromere 着丝点 and move together to one of the two poles of the cell It is this event that results in the halving 减半的 of the chromosome number in the four daughter cells that result from meiosis 正如在有丝分裂中一样两个同源染色单体通过蛋白质和RNA桥配对形成联会复合体与有丝分裂不同的是每组染色体的两个染色单体连接在着丝点上并一起移向细胞两极的一级由此而导致4个子细胞染色体数减半During telophase末期 I nuclear envelopes enclose the chromosomes in nuclei and in most species cytokinesis 细胞浆流动 the first nuclear division follows The second nuclear division begins with metaphase Ⅱin which the chromosomes in each daughter cell again align 排列on a metaphase plate The centromeres着丝粒 finally divide and each sister chromatid moves to one of the poles of the spindle The next phase is telophase followed again by cytokinesis The result of the entire process is four haploid cells in which parental chromosomes are randomly distributed第二次核分裂开始于分裂中期子细胞中染色体重新排列在赤道板上着丝粒最终分离每个姊妹染色单体分向两极接着胞质分裂产生4个单倍体父母染色体随机分配Asexual Versus Sexual ReproductionMitosis and meiosis respectively分别 make simple cell division and sexual reproduction possible Each means of passing on hereditary 遗传information has advantages In asexual 无性的 reproduction the parent organism生物体 gives rise to offspring 后代that are genetic clones of the parent The advantages of this type of reproduction are that it preserves the parents successful genetic complement 遗传互补 requires little or no specialization of reproductive organs and is more rapid than sexual reproduction A major disadvantage of the asexual mode is that a single catastrophic灾难的event or disease may destroy an entire population of genetically identical organisms A prime benefit of sexual reproduction is that it provides genetic variability and a ready mechanism 机制 for the elimination of deleterious mutations It also allows "new" gene forms to arise and spread through populations有丝分裂和减数分裂在传递遗传信息过程中各有优势体细胞的繁殖就是父母本的克隆其优势是保留了父母本的成功遗传信息不需要特殊器官比性复制快的多但一个简单灾难性事件或疾病都可能摧毁一个细胞群体性复制的优势是它提供了遗传可变性和现存排除有害突变的机制也可以产生新的基因并在种群中蔓延课后作业第一篇阅读材料答案1C2B3D4B5A6DLesson Four2学时Foundations of GeneticsEarly Theories of inheritaneeEarly ideas of inheritance included Hippocrates theory of pangenesis and August Weismands germ plasm theory Based on experiments with miceWeismann proposed that hereditary information in gametes transmitted traits to progeny Both of these early views incorporated the blending theory they held that heritable traits of the two parents blend so that the distinct characteristics of each are lost in offspring遗传学的早期理论包括泛生说和种质理论基于小鼠实验维丝曼提出遗传信息储存在配子中并将遗传信息传递给后代这两个早期观点合起来形成融合理论子代拥有父母本混合的遗传特征而不完全象亲代Gregor Mendel and the Birth of GeneticsGregor Mendel an Augustinian monk in the monastery at Brunn Austria is known as the "father of genetics" Having been exposed to theories of the particulate nature of matter while a university student and having a background in mathematics Mendel carried out a series of carefully planned experiments that demonstrated the particulate nature of heredity His revolutionary ideas were neither understood nor accepted until many years after Mendel died孟德尔众所周知的遗传学之父是一名修道士当他还是大学生时就提出了物质的粒子属性孟德尔进行了一系列周密安排的实验来证实遗传的颗粒性直到他去世后他的理论才被理解和接受Mendels Classic ExperimentsMendel studied genetics through plant-breeding experiments with the garden pea a plant species that is self-fertilizing and breeds true each offspring is identical to the parent in the trait of interest To test the blending theory he focused his research on seven distinct characters Each of these characters such as seed color and plant height present only two clear-cut possibilities He also recorded the type and number of allprogeny produced from each pair of parent pea plants and followed the results of each cross for two generations孟德尔通过豌豆实验研究遗传学豌豆是自花授粉植物和纯品系为验证融合理论他的研究主要集中在7个特征上例如种子颜色植株高度这些特征只有两个明确的可能性他记录了产生的每一个子代类型和数量在杂交产生子2代For each of the characters he studied Mendel found that one trait was dominant while the other was recessive In the second filial F2 generation the ratio of dominant to recessive was 31 Mendel deduced that this result was possible only if each individual possesses only two hereditary units one from each parent The units Mendel hypothesized are today known as alleles alternative forms of genes Genes are the basic units of heredity An organism that inherits identical alleles for a trait from each parent is said to be homozygous for that trait if different alleles for a trait are inherited the organism is heterozygous for that trait When an organism is heterozygous for a trait the resulting phenotype for that trait expresses only the dominant alleleThus the organisms phenotypeits physical appearance and properties-differs from its genotype which may include both a dominant and a recessive allele A pictorial representation of all possible combinations of a genetic cross is known as a Punnett square对于每个特征而言要么显形要么隐性在子2代中显形与隐性比为3∶1只有在每个个体仅拥有两个研究遗传单元并每个单元来自一个亲代时实验结果才成立此遗传单元就是今天共识的等位基因两个一样的等位基因决定一个特征称纯合相反称杂合当生物是杂合时它的表型由显性基因决定因此生物的表型与基因型是不同的旁纳特方格可以陈列所有可能的遗传组合The results of Mendels experiments on dominant and recessive inheritance let to Mendels first law the law of segregationThis law states that for a given trait an organism inherits one allele from each parent Together these alleles form the allele pair When gametes are formed during meiosis the two alleles become separated halving of chromosome number To gain evidence for his theory Mendel performed test crosses mating plants of unknown genotype to plants that were homozygous recessive for the trait of interest The ratio of dominant phenotypes if any in the progeny makes clear whether the unknown genotype is heterozygous homozygous dominant or homozygous recessive分离定律生物只遗传父母本等位基因对的一个等位基因减数分裂期形成配子时两个等位基因分离为验证此理论他做了测交实验即基因型未知的植物与纯合的隐性基因植物杂交子代显性表型可以明确测得杂合基因或纯合基因的基因型Mendels Ideas and the Law of independent AssortmentMendel also performed dihybrid crosses which enabled him to consider how two traits are inherited relative to one another This work let to the law of independent assortment which states that the alleles of genes governing different characters are inherited independently An apparent exception to Mendels laws is incomplete dominance a phenomenon in which offspring of a cross exhibit a phenotype that is intermediate between those of the parents However incomplete dominance reflects the fact that both alleles for the trait in question exert an effect on the phenotype The alleles themselves remain separate双因子杂合试验两个特征是如何相互影响遗传的试验结果产生独自分配定。
医学遗传学02人类基因
37
人类基因组
• 人类基因组（genome）是人的所有遗传信 人类基因组（ ）
息的总和。 息的总和。它包括两个相对独立而相互关联的 基因组：核基因组与线粒体基因组。通常人类 基因组：核基因组与线粒体基因组。 基因组指的是核基因组。 基因组指的是核基因组。 核基因组
38
第五节 人类基因组计划 (Human genome project，HGP) ，
• 把基因所储存的遗传信息转变为由特定的氨基 酸种类和序列构成的多肽链， 酸种类和序列构成的多肽链，再由多肽链构成 多肽链 蛋白质或酶分子，从而决定生物各种性状（ 蛋白质或酶分子，从而决定生物各种性状（表 型）的过程。 的过程。
28
三、基因表达Gene Expression 基因表达
• 转录（transcription） 转录（ ） DNA-------mRNA • 翻译（translation） 翻译（ ） • mRNA-------蛋白质 蛋白质 场所： 场所：细胞质内的核糖体
只有一个祖先 基因经过重复 和变异所组成 的一组基因。
生物专业英语第五章基因的化学本质
1.Chromosome and DNA
DNA is a Double Helix
5‘-3’
5 4
3
1 2
2.DNA分子双螺旋结构的发现历程
核酸的早期研究
Unit Five
Discovering the Chemical Nature of the Gene
基因化学本质的发现
Contents
• Warming–up • Words and phrases • Text Analysis
Warming–up
1.Structures and properties of DNA 2.Discovery of DNA 3. DNA Replication: An Overview
诺贝尔史上的遗憾， 永远的英伦玫瑰
Franklin的贡献是毋庸置疑的： 分辨出了DNA的两种构型 成功拍摄DNA的X射线衍射照片 Watson在1968年出版的《双螺 旋》 一书中坦承， “Franklin没有直接给我们她的 数据”。而Crick在很多年后也承 认，“她离真相只有两步”。 目前，科技界对Franklin的工作 给予较高评价，对Wilkins是否有 资格分享发现DNA双螺旋结构的 殊荣存在很大争论。
结构学派
• 富兰克林--最早认定DNA具有双 螺旋结构，1952年，通过X射线 衍射拍摄到一张举世闻名的B型
DNA的X射线衍射照片，由此推算
DNA分子呈螺旋状.
• 威尔金斯-- 计算出DNA分子螺 旋的直径与长度。他们二人还对
• DNA分子的结构作出了确切而 关键性的描述：磷酸根在螺旋的 外侧，碱基在螺旋内侧 .
生物专业英语教学大纲
生物专业英语教学大纲《生物专业英语》教学大纲课程编码:090108\090966英文名称:Specialized English in Biology 一、基本信息1.学分与学时学分:2，学时:322.课程类别专业选修课程3.适应专业生物科学专业、生物技术专业，选修4.课程目的(1)生物专业英语是面向生物科学、生物技术高年级本科生开设的限选课程，本课程教学内容主要涉及普通生物、微生物学、遗传学、分子生物学等领域的专业基础知识。
通过本课程，向学生介绍如何撰写科技论文、投稿等方面的知识;扩大专业英语的词汇量，掌握专业英语书刊的阅读技巧、了解文献检索及写作知识。
(2)本课程帮助已有一定英语基础的学生提高其阅读、翻译专业英语的能力。
旨在拓宽学生的专业词汇量和阅读量，力求将英语与专业紧密结合，了解科技论文的文体特点和写作方法，为将来的学术论文的阅读写作和交流打下坚实的基础。
5.建议先修课程大学英语6.教学方法与手段(1)本课程采用自学与讲授相结合，理论与实践相结合的教学方法。
教学中突出以学生作为主体，运用多媒体等教学手段对其进行专业英语的学习指导。
(宋体五号) (2)同时为了提高学生英语听说读写的基础能力，可采取小组讨论式等灵活多样的教学形式，调动其学习积极性。
7.考核及成绩评定考核方式:本课程为考查课，期末开卷考试。
成绩评定:(1)平时成绩占20%，形式有:课堂讨论、课外作业、学生考勤、课堂提问、听课状态 (2)结课考试成绩占80%，形式有:笔试8.课外自学要求(1)学生能够按照要求按时完成作业，积极参加课后辅导答疑。
(2)勤于浏览中国知网，查询学科前沿知识，能够利用所学理论设计实验，达到应用型人才培养的标准。
(3)能够利用数字课程网站和精品课程网站进行自主学习和课后复习。
9.推荐教材和主要参考书目推荐教材:生物专业英语(第二版).蒋悟生主编.高等教育出版社.2000年.参考书目:[1]生物工程、生物技术专业英语(第一版).邬行彦等编.化学工业出版社.2002年. [2]科技英语的特点和应用(第一版). 戴炜华、陈文雄编.上海外语教育出版社.1984年. 二、主要教学内容和教学要求Introduce 第一章Lesson one基本内容:一、生物专业英语的概念。
课程名称生物专业英语
课程名称生物专业英语英文名称Special English for Biology【课程编号】【课程类别】专业选修课【学分数】【适用专业】生物科学【学时数】34 【编写日期】2013.7.31一、教学目标生物专业英语是面向生物科学、技术高年级本科生开设的限选课程，本课程教学内容主要涉及普通生物、微生物学、遗传学、分子生物学等领域的专业基础知识。
通过本课程，向学生介绍如何撰写科技论文、投稿等方面的知识；扩大专业英语的词汇量，掌握专业英语书刊的阅读技巧、了解文献检索及写作知识。
二、教学内容和学时分配Lesson One Inside the living cell:structure and function of internal cell parts 4学时主要内容：1．GlossaryActin, centriole, chemotaxis, chloroplast, chromosome, cilia, cytoplasm, cytoskeleton, dynein, flagella, lysosome, microfilament, microtubule, mitochondrion, myosin, nucleoid, nucleoli, nucleus, phagocytosis, pinocytosis, plastid, polysome, ribosome, stroma, tubulin, vacuole，endoplasmic reticulum, nuclear envelope, golgi complex, basal body2．重点句型分析分析(1)This quantity reflects the fact that ribosomes are the sits at which ammo acids are assembled into proteins for export or for use in cell processes.the genetic(2)During protein synthesis the two subunits move along a strand of mRNA, ”reading” sequence coded in it and translating that sequence into protein.(3)Both types of endoplasmic reticulum serve as compartments within the cell where specific products can be isolated and subsequently shunted to particular areas in or outside the cell.(4)A subset of vacuoles is the organelles known as lysosomes, which contain digestive enzymes(packaged in lysosomes in the golgi complex)that can break down most biological macromolecules.(5)It is on the large surface area provided by the inner cristae of mitochondria that ATP-generatating enzymes are located.3．Exercises4．Symbols Commonly Used教学要求：使学生掌握细胞的组成结构（各种细胞器以及它们在细胞中的位置），以及结构与功能之间的关系。
生物专业英语第三版蒋悟生课文翻译精华整理精编版
生物专业英语第三版蒋悟生课文翻译精华整理精编版MQS system office room 【MQS16H-TTMS2A-MQSS8Q8-MQSH16898】,,supportedbyt..,ions,solubleproteins,andothermaterialsneededforcellfun ctioning.生命的大部分特征表现在细胞质的特征上。
细胞质大部分由半流体物质组成，并由细胞膜包被。
细胞器悬浮在其中，并由丝状的细胞骨架支撑。
细胞质中溶解了大量的营养物质、离子、可溶蛋白以及维持细胞生理需求的其它物质。
Theeukaryoticcellnucleusisthelargestorganelleandhousesthegeneticmateria l(DNA)onchromosomes.(Inprokaryotesthehereditarymaterialisfoundinthenucl eoid.)真核细胞的细胞核是最大的细胞器，为染色体上遗传物质（DNA）提供空间（原核生物遗传物质存在于拟核中）。
细胞核含有一或二个核仁，在细胞分裂中发挥作用。
一个穿孔的囊叫核膜，将细胞核和其中内含物与细胞质分开，小分子物质可以自由通过核膜，但大分子物质如mRNA和核糖体必须通过核孔进出核膜。
Alleukaryoticcellscontainmostofthevariouskindsoforganelles,,theendoplas micreticulum,theGolgicomplex,vacuoles,lysosomes,mitochondria,andtheplas tidsofplantcells.所有的真核细胞都含有多种细胞器，每种细胞器在细胞中行使一项专门功能。
本节主要介绍核糖体、内质网、高尔基体系、液泡、溶酶体、线粒体和植物细胞中的质体。
,"reading";细胞中核糖体的数量变化从几百到几千，核糖体数量如此之多反映了核糖体是氨基酸组装成蛋白质并被运出或在细胞过程中使用的位点这样一个事实。
专题08+基因的本质与表达-【学考复习】2024年福建省高中生物学业水平合格考复习宝典
• 2.艾弗里的体外转化实验 • (1)实验材料：S型和R型细菌、培养基。 • (2)实验目的：探究S型细菌中的转化因子。
R型细菌 S型细菌
• (3)实验过程及结果
含 ①S型细菌的细胞提取物
R 型
②S型细菌的细胞提取物+蛋白酶
细
③S型细菌的细胞提取物+RNA酶
的
培 ④S型细菌的细胞提取物+酯酶
养
2. DNA是主要的遗传物质： 真核生物与原核生物的遗传物质是DNA,病毒的遗传物质是DNA或RNA。 绝大多数生物的遗传物质是DNA，只有极少数生物的遗传物质是RNA， 因而DNA是主要的遗传物质。
• 四、DNA的结构 • 1. DNA双螺旋结构模型的构建者：沃森和克里克 • 2. DNA 双螺旋结构的形成
基
反密码子则起到翻译的作用
• (2)数量关系：
• ①每种氨基酸对应一种或几种密码子(即密码子具有简并现象)，可由 一种或几种tRNA转运;
• ②除终止密码子外，一种密码子只能决定一种氨基酸；
• ③密码子有64种，其中终止密码子有3种(UGA既是终止密码子，又 是硒代半胱氨酸的密码子)。
• 十二、中心法则 • 1.提出者：克里克 • 2.补充后的中心法则
• 2.过程 • (1) 解旋：在解旋酶的作用下，解开双螺旋的两条链 • (2)合成子链 • ①模板：解开的每条母链 • ②原料：游离的4种脱氧核苷酸 • ③酶：DNA聚合酶等 • ④能量：ATP • ⑤原则：碱基互补配对原则 • (3)重新螺旋：每一条新链与其对应的模板链盘绕成双螺旋结构
• 3.特点 • (1)过程： • 边解旋边复制 • (2)方式： • 半保留复制
• 十四、基因的选择性表达与细胞分化 • 1.表达的基因可以分为两类： • 一类是所有细胞中都表达的基因，指导合成的蛋白质是维持细胞基本生
基因的化学本质是DNA
第三章基因的化学本质是DNA第一节遗传物质是DNA（或RNA）第一节遗传物质是DNA（或RNA）上个世纪四十年代以来，随着微生物遗传学的发展，还有生物进化学，生物物理学以及许多新技术不断引入遗传学，促成了一个崭新的领域——分子生物学的发展。
分子生物学已直接或间接证明，DNA是主要的遗传物质，而在那些缺乏DNA的某些病毒中，RNA就是遗传物质。
一DNA作为遗传物质的间接证据1、每个物种中，不同组织的细胞，无论其大小和功能如何，细胞核中的DNA含量都是恒定的。
而且精子和卵子种的DNA含量正好是体细胞中的一半。
多倍体系列的一些物种，细胞中DNA 的含量随染色体倍数的增加也呈倍数性递增。
而细胞中RNA和蛋白质的含量在不同细胞中的变化很大。
2、DNA是所有生物所共有的，从噬菌体（phage），病毒（virus）直到人类的染色体中都含有DNA，而蛋白质则不同，噬菌体和病毒的染色体上不含有的蛋白质不存在于染色体上，而蛋白质只存在于外壳上，细菌的染色体上也没有蛋白质，只有真核生物的染色体上才有蛋白质的存在。
3、DNA在代谢上是稳定的。
细胞内的其他分子，如蛋白质，都是一面迅速合成，一面又不断分解，但是若某个元素被DNA分子所吸收，则在细胞健全生长的条件下，它不会离开DNA。
二、DNA作为遗传物质的直接证据1．细菌的转化：肺炎双球菌特征抗原型（稳定）粗糙型(R) 无荚膜、粗糙菌落、无毒IR、IIR光滑型(S) 有荚膜、光滑菌落、有毒IS、IIS、IIIS⑴．格里费斯(Griffith F.，1928)：肺炎双球菌定向转化试验：①无毒IIR型小鼠成活重现IIR型②有毒IIIS型小鼠死亡重现IIIS型③有毒IIIS型(65℃杀死)小鼠成活无细菌④无毒IIR型有毒IIIS型(65℃杀死)小鼠死亡重现IIIS型结论：在加热杀死的IIIS型肺炎双球菌中有较耐高温的转化物质能够进入IIR型IIR型转变为IIIS型无毒转变为有毒。
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信息学派
• 1951年开始，沃森和克里克先后建立了三个DNA分子模 型。他们要求建立的模型既要满足物理、化学、数学 研究的最新事实，如X射线衍射结果、碱基配对的力学 要求，还要满足生化知识，如酮型、氢键、键角等， 更要使DNA能解释遗传学和代谢理论，这是一种很先进 的思想。 • 1953年2月28日，第一个DNA双螺旋结构的分子模型终 于诞生-第一个模型是一个三链的结构。这是在对实验 数据理解错误的基础上建立的，最终失败。但他们并 不气馁，继续搜集材料，查阅资料。 • 第二个模型是一个双链的螺旋体，糖和磷酸骨架在外， 碱基成对的排列在内，碱基是以同配方式即A与A，C与 C，G与G，T与T配对。由于配对方式的错误，这个模型 同样宣告失败。
Unit Five
Discovering the Chemical Nature of the Gene
基因化学本质的发现
Contents
• Warming–up • Words and phrases • Text Analysis
Warming–up
1.Structures and properties of DNA 2.Discovery of DNA 3. DNA Replication: An Overview
Okazaki fragment ['ɔ:kɑ:'zɑ:ki:] ['frægmənt] n. 冈崎片段
A short sequence of DNA that is the primary product of
DNA polymerase during DNA replication.
Words and phrases
FAD:黄素腺嘌呤二核苷酸
2. cytosine [ 'saitəsi:n ]
n. 胞嘧啶
A single-ring nitrogenous base molecule in DNA and
RNA. It is complementary to guanine（鸟嘌呤）.
3. guanine [ 'gwɑ:ni:n ]
Semi-conservative mechanism
Semi-discontinous replication
Okazaki fragment
1.Chromosome and DNA
DNA is a Double Helix
5‘-3’
5 1
4
2
3
2.DNA分子双螺旋结构的发现历程
核酸的早期研究
DNA是遗传物质
• 1928年，格里菲斯的肺炎双球菌实验核酸是 “转化因子” 20世纪50年代初期，美国科学家艾弗里和赫尔希及其 学生蔡斯，通过实验已经证明DNA是生物体的遗传物质 查加夫（chargaff）碱基比定律 1952年 查加夫应用纸层析及紫外分光光度计对各种生 物DNA的碱基组成进行了定量测定 所有DNA中腺嘌呤与胸腺嘧啶的摩尔含量相等，即A=T； 鸟嘌呤与胞嘧啶的摩尔含量相等，即G=C。 因此，嘌呤的总含量与嘧啶的总含量相等，即 A+G=C+T。
Francis Harry Compton James Dewey Watson Maurice Hugh Frederick Crick (46y) Wilkins(46y) (34y ) Great Britain Great Britain institute of Molecular USA Biology Cambridge, Great Harvard University University of London Britain Cambridge, MA, USA London, Great Britain 1916 1928 1916 -
1953.Watsosn & Crick
• 1953年2月20日，沃森 灵光一现，放弃了碱基 同配方案，沃森和克里 克立即行动，马上在实 验室中联手开始搭建DN A双螺旋模型。 • 采用碱基互补配对方案， 3月18日终于成功地建 立了DNA分子双螺旋结 构模型。 • 因此，沃森和克里克获 得了1962年诺贝尔生理 学或医学奖。
another DNA molecule.
Thumb
Fingers
Palm
DNA polymerase
6. Double helix ['hi:liks] n. 双螺旋
The three-dimensional structure of double-stranded DNA.
dimensional [di'menʃənəl] 尺寸的，维的
The Nobel Prize in Physiology or Medicine 1962 "for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material"
1.adenine [ 'ædəni:n ]
n. 腺嘌呤
A purine(嘌呤) base that is an essential constituent of the nucleic acids and also of such coenzymes as NAD and FAD.
NAD+:烟酰胺腺嘌呤二核苷酸
n. 鸟嘌呤
A double-ring nitrogenous base molecule in DNA and RNA. It is the complementary base of cytosine.
4. thymine [ 'θaimi:n ]
n. 胸腺嘧啶
A single-ring nitrogenous base molecule of DNA but not RNA. It is complementary to adenine.
诺贝尔史上的遗憾， 永远的英伦玫瑰
Franklin的贡献是毋庸置疑的： 分辨出了DNA的两种构型 成功拍摄DNA的X射线衍射照片 Watson在1968年出版的《双螺旋》 一书中坦承， “Franklin没有直接给我们她的 数据”。而Crick在很多年后也承 认，“她离真相只有两步”。 目前，科技界对Franklin的工作 给予较高评价，对Wilkins是否有 资格分享发现DNA双螺旋结构的殊 荣存在很大争论。
Rosalind Franklin (1920-1958)
1953.Watsosn & Crick
Right-handed B- DNA Double helix Model
这个模型得到科学家们的公认， 并用以解释复制、转录等重要的 生命过程。 经深入研究，发现因湿度和碱基 序列等条件不同，DNA双螺旋可 有多种类型，主要分成A、B和Z3 大类。
结构学派
• 富兰克林--最早认定DNA具有双 螺旋结构，1952年，通过X射线 衍射拍摄到一张举世闻名的B型 DNA的X射线衍射照片，由此推算 DNA分子呈螺旋状. • 威尔金斯-- 计算出DNA分子螺旋 的直径与长度。他们二人还对 • DNA分子的结构作出了确切而关 键性的描述：磷酸根在螺旋的外 侧，碱基在螺旋内侧 . • 然而，他们却未能及时地将分析 资料转变为一个合理的结构模型.
嘧啶
胞嘧啶
尿嘧啶
C
U
胸腺嘧啶 T
嘌呤
腺嘌呤Adenine A
鸟嘌呤guanine G
碱基配对
5. DNA polymerase [ 'pɔlimə,reis ]
n. DNA 聚合酶
An enzyme that brings new DNA triphosphate
nucleotides（核苷三磷酸） into position for bonding on
三大学派的代表
生物化学学派 美国加州理工学院 化学家鲍林实验室
结构学派 英国伦敦皇克
生物化学学派
• 鲍林--最早认定DNA分子具有与氨 基酸链类似的螺旋结构的科学家， 而且研究的环境最优越 • 1950年，利用X射线技术研究蛋白 质结构，提出蛋白质是长链分子， 并发现了α螺旋结构。 • 1952年12月，鲍林宣布建立了DNA 分子的结构模型。但他错误地认 为DNA分子是由三股螺旋组成的， 这使他误入歧途，致使研究最终 以失败告终。
7. nucleoside [ 'nju:kliəsaid ]
n. 核苷
A purine（嘌呤）or pyrimidine（嘧啶） base attached
to ribose（核糖） or deoxyribose（脱氧核糖）.
ribose ['raibəus] 核糖
核酸 nucleic acid 核苷酸 nucleotide 核苷 nucleoside 嘌呤碱 purine base 或 嘧啶碱 pyrimidine base （碱基 base） 磷酸 phosphate 核糖 ribose 或 脱氧核糖 deoxyribose （戊糖 amyl sugar）
Okazaki fragment
DNA的半保留复制 （semi-conservative replication）
A G G T A C T G C C A C T G G T C C A T G A C G G T G A C C AT GC GC TA AT CG TA GC CG CG AT CG TA GC GC AT GC GC TA AT CG TA GC CG CG AT CG TA GC GC
A point at which the two strands of a DNA double
helix are unwound and separated during replication.