生物專業(yè)英語(Bioengineering English)(中英文對照)

1、 PAGE 8生物專業(yè)英語（Bioengineering English）Lesson One（4學(xué)時(shí)）Inside the Living Cell: Structure andFunction of Internal Cell PartsCytoplasm: The Dynamic, Mobile Factory細(xì)胞質(zhì)：動(dòng)力工廠生命的大部分特征表現(xiàn)在細(xì)胞質(zhì)的特征上。細(xì)胞質(zhì)大部分由半流體物質(zhì)組成，并由細(xì)胞膜（原生質(zhì)膜）包被。細(xì)胞器懸浮在其中，并由絲狀的細(xì)胞骨架支撐。細(xì)胞質(zhì)中溶解了大量的營養(yǎng)物質(zhì)，離子，可溶蛋白以及維持細(xì)胞生理需求的其它物質(zhì)。The Nucleus: Information Ce

2、ntral（細(xì)胞核：信息中心）真核細(xì)胞的細(xì)胞核是最大的細(xì)胞器，細(xì)胞核對染色體組有保護(hù)作用（原核細(xì)胞的遺傳物質(zhì)存在于擬核中）。細(xì)胞核含有一或二個(gè)核仁，核仁促進(jìn)細(xì)胞分裂。核膜貫穿許多小孔，小分子可以自由通過核膜，而象mRNA和核糖體等大分子必須通過核孔運(yùn)輸。Organelles: Specialized Work Units（細(xì)胞器：特殊的功能單位）所有的真核細(xì)胞都含有多種細(xì)胞器，每個(gè)細(xì)胞器都有其特定功能。本節(jié)主要介紹核糖體， 內(nèi)質(zhì)網(wǎng)，高爾基體系，液泡，溶酶體，線粒體和植物細(xì)胞中的質(zhì)體。核糖體的數(shù)量變化從幾百到幾千，核糖體是氨基酸組裝成蛋白質(zhì)的重要場所。完整的核 糖體由大亞基和小亞基組成。核糖體沿

3、著mRNA移動(dòng)并閱讀遺傳密碼，翻譯成蛋白質(zhì)。一 條mRNA上可能有多個(gè)核糖體，稱多聚核糖體。大多數(shù)細(xì)胞蛋白是由細(xì)胞質(zhì)中核糖體生產(chǎn)。輸出蛋白和膜蛋白通常與內(nèi)質(zhì)網(wǎng)有關(guān)。內(nèi)質(zhì)網(wǎng)，帶有花邊的生物囊，有管狀，泡狀之分，以及光滑和粗糙面區(qū)別。兩種都與蛋白質(zhì)的合成和運(yùn)輸有關(guān)。粗糙內(nèi)質(zhì)網(wǎng)上分布許多核糖體，也可能提供細(xì)胞分裂后所需的細(xì)胞膜。光滑內(nèi)質(zhì)網(wǎng)上無核糖體，主要作用是脂肪和類固醇的合成以及細(xì)胞內(nèi)有毒物質(zhì)的氧化。兩種內(nèi)質(zhì)網(wǎng)合成的產(chǎn)物在其中進(jìn)行分流或運(yùn)輸?shù)郊?xì)胞外。運(yùn)輸小泡能夠?qū)⒖蛇\(yùn)輸分子從內(nèi)質(zhì)網(wǎng)運(yùn)輸?shù)礁郀柣鶑?fù)合體上。在高爾基復(fù)合體中修飾， 包裝后輸出細(xì)胞或傳遞到細(xì)胞質(zhì)中的其他場所。細(xì)胞中的液泡好象是中空的，但實(shí)

4、際上充滿了液體和可溶分子。最典型的液泡存在于植物細(xì)胞中，儲(chǔ)備水，糖以及其它分子。動(dòng)物中的液泡起吞噬和胞飲作用。溶酶體是液泡亞單位，含有消化酶，降解大部分生物大分子。消化食物微粒和降解損傷的細(xì)胞殘片。線粒體是細(xì)胞中化學(xué)產(chǎn)能的場所。另外，植物細(xì)胞中的質(zhì)體在光合作用中利用光能產(chǎn)生碳水化合物，線粒體內(nèi)嵴上提供了很大的表面積并分布著產(chǎn)ATP酶。線粒體自我復(fù)制，并且可能是自由生活的原核生物在進(jìn)化中形成的后代。質(zhì)體有兩種類型：白色體，缺乏色素，是淀粉，蛋白質(zhì)和油的儲(chǔ)備場所；色質(zhì)體，含有色素。葉綠體是最重要的色質(zhì)體，含有與光合作用有關(guān)的葉綠素。葉綠體的內(nèi)部結(jié)構(gòu)是由 多層膜形成的葉綠體基粒，其中包埋在基質(zhì)中的基

5、粒稱子座。The Cytoskeleton（細(xì)胞骨架）所有的細(xì)胞都有細(xì)胞骨架，網(wǎng)絡(luò)結(jié)構(gòu)的纖絲充滿了它所能觸及的全部空間并且對細(xì)胞器提供支持作用。細(xì)胞骨架大部分由微絲組成，微絲主要由可收縮的肌動(dòng)蛋白組成。動(dòng)植物細(xì)胞的許多種類型細(xì)胞內(nèi)運(yùn)動(dòng)與肌動(dòng)蛋白有關(guān)。第二類蛋白是肌球蛋白，它與肌肉細(xì)胞的收縮有關(guān)。細(xì)胞骨架的另一個(gè)主要結(jié)構(gòu)成分是微管，由球狀的微管蛋白組成，象腳手架一般維持細(xì)胞的穩(wěn)定形態(tài)。細(xì)胞骨架的中間絲提供了細(xì)胞質(zhì)伸縮動(dòng)力。機(jī)械酶，例如，肌球蛋白，動(dòng)力蛋白，驅(qū)動(dòng)蛋白與微絲，微管相互作用產(chǎn)生動(dòng)力而引起細(xì)胞運(yùn)動(dòng)。Cellular Movements（細(xì)胞運(yùn)動(dòng)）盡管細(xì)胞骨架提供了細(xì)胞的某些穩(wěn)定性，微絲，

6、微管及相關(guān)蛋白能使細(xì)胞爬行或滑動(dòng)。這種運(yùn)動(dòng)需要固體基質(zhì)依托并通過表面幾何形狀的改變而運(yùn)動(dòng)。某些細(xì)胞具備趨藥性，即 趨向或逃離擴(kuò)散開的化學(xué)源。某些真核細(xì)胞能在液體液體中自由運(yùn)動(dòng)，由纖毛或鞭毛推動(dòng)。纖毛和鞭毛具有同樣的內(nèi) 部結(jié)構(gòu)：九個(gè)雙微管環(huán)形排列，縱向延伸，環(huán)中心是兩個(gè)或以上微管組成。纖毛或鞭毛從細(xì)胞表面的基體出生長，雙微管的動(dòng)力蛋白臂從一側(cè)延伸到另一側(cè)而引起運(yùn)動(dòng)。大部分植物細(xì)胞的營養(yǎng)，蛋白質(zhì)和其它物質(zhì)由細(xì)胞質(zhì)流運(yùn)輸。這個(gè)過程是由于依附在細(xì) 胞器上的肌球蛋白反推排列在細(xì)胞周圍的微絲形成的。絕大部分細(xì)胞質(zhì)運(yùn)動(dòng)由微絲和微管 完成。在細(xì)胞分裂期間，中心粒周圍的由微管蛋白亞基裝配形成的紡錘體微管移向染色

7、體。Glossarycytoplasm （細(xì)）胞質(zhì)Thelivingcontentsofacellbounded externally by the plasmalemma, including an aqueous ground substance (hyaloplasm, cell sap, or cell matrix) containing organelles and various inclusions but excluding the nucleus and visible vacuoles.cytoskeleton細(xì)胞骨架Of eukaryotic cells, an int

8、ernal skeleton. Its microtubules and other components structurally support the cell, organize and move its inteftial components. The cytoskeleton also helps free-living cells move through their environment.nucleus細(xì)胞核，核(復(fù)數(shù)nuclei)The organelle of the eukaryote cell that containsthechromosomes and henc

9、e ultimately controls cellular activity and inheritance through the activity of the genetic material, DNAchromosome 染色體A DNA-histone thread residing in the nucleus of a cell.Each chromosome possesses two telomeres and a centromere, and some contain a nucleolus organizer.RNA proteins are invariably a

10、ssociated with the chromosome.nucleoid擬核，類核，核質(zhì)體The DNA-containing area of a prokaryote cell, analogous to the eukaryote nucleus but not membrane bounded.nucleoli核仁( 單數(shù)nucleolus)Nuclear structures composed of completed or partially completed ribosomes and the specific parts of chromosomes that contai

11、n the infon-nation for their construction. nuclear envelope核膜，核被膜A double membrane (two lipid bilayers andassociated proteins) that is the outermost portion of a cell nucleus.ribosome核糖體Small structures composed of two protein and ribonucleic acid subunits involved in the assembly of proteins from a

12、mino acids. polysome多核糖體Of protein synthesis, several ribosomes all translating the same messenger RNA molecule,one after the other. endoplasmic reticulum內(nèi)質(zhì)網(wǎng)Folded membranes and tubes throughout the eukaryotic cell that provide a large surface upon which chemical activities take place.Golgi complex高

13、爾基復(fù)合體A stack of flattened, smooth, membranous sacs; the site of synthesis and packaging of certain molecules in eukaryotic cells.vacuole液泡Storage container within the cytoplasm of a cell having a surrounding membrane. phagocytosis吞噬作用The process by which the cell wraps around a particle and engulfs

14、it.pinocytosis胞飲作用The process by which a cell engulfs some molecules dissolved in waterlysosome溶酶體A specialized organelle that holds a mixture of hydrolytic enzymes.mitochondrion線粒體(復(fù)數(shù)mitochondria )A membranous organelle resembling a small bag with a larger bag resembling a small bag with a larger b

15、ag inside that is folded back on itself; serves as the site of aerobic cellular respiration. plastid質(zhì)體An organelle present in all plants exceptbacteria, blue-green algae, and fungi; it isenclosed by two membranes (the envelope) and has various functionschloroplast葉綠體A plastid in which photosynthesis

16、 is carried out. Chloroplasts occur in all photosynthetic organisms except photosynthetic bacteria blue-green algae.stroma基質(zhì)，子座（復(fù)數(shù)stromata）Region within a chloroplast that has no chlorophyll.microfilament微絲，纖絲Long, fiberlike structures made of protein and found in cells, often in close association w

17、ith the microtubules; provide structural support and enable movement.actin肌動(dòng)蛋白A globular contractile protein. In muscle cells, actin interacts with another protein, myosin, to bring about contraction. myosin maiesin肌球蛋白A protein that, with actin, constitutes the principal element of the contractile

18、apparatus of muscle.microtubute微管Small, hollow tubes of protein that function throughout the cytoplasm to provide structural support and enable movement. tubulin微管蛋白A protein that is the major constituent of microtubules.dynein動(dòng)力蛋白，動(dòng)素A group of at least four distinct proteins found in the flagella a

19、nd microtubules of eukaryotic cells and possessing ATPase activity.chemotaxis趨化性A locomotory movement of an organism or cell in response to, and directed by, an directional stimulus.cilia纖毛Numerous short, hairlike structures projecting from the cell surface that enable locomotion. flagella鞭毛 (單數(shù)flag

20、ellum)Long, hairlike structures projecting from the cell surface that enable locomotion.basal body基體A body identical in structure to a centriole, foundalwaysatthebaseofa cilium or eukaryote flagellum.centriole中心粒An organelle located close to the nucleus in most animal and lower plant cells but absen

21、t from prokaryotes and higher plants.Lesson Two（2學(xué)時(shí)）Photosynthesis光合作用只發(fā)生在含有葉綠素的綠色植物細(xì)胞，海藻，某些原生動(dòng)物和細(xì)菌之中。總體來說，這是一個(gè)將光能轉(zhuǎn)化成化學(xué)能，并將能量貯存在分子鍵中，從化學(xué)和動(dòng)能學(xué)角度來看，它是細(xì)胞呼吸作用的對立面。細(xì)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過程。光合作用以二氧化碳和水為原材料并經(jīng)歷兩步化學(xué)反應(yīng)。第一步，稱光反應(yīng)，水分子分 解，氧分子釋放，ATP和NADPH形成。此反應(yīng)需要光能的存在。第二步，稱暗反應(yīng)，二氧化碳被還原成碳水化合物，這步反應(yīng)依賴電子載體NADPH以及第一

22、步反應(yīng)產(chǎn)生的ATP。兩步反應(yīng)都發(fā)生在葉綠體中。光反應(yīng)需要的大部分酶和色素包埋在葉綠體的類囊體膜上。暗反應(yīng)發(fā)生在基質(zhì)中。生物分子能捕獲可見光譜中的光能。植物細(xì)胞中葉綠素在不同光波下吸收部分吸收光 譜。在吸收分子中，光的作用使分子中的電子發(fā)生重排。光子的能量激活了分子的能量狀態(tài)，使其從穩(wěn)定態(tài)進(jìn)入不穩(wěn)定的激活態(tài)。所有的光合作用生物含有不同等級(jí)的葉綠素和一個(gè)或多個(gè)類胡蘿卜素（光合作用的輔助 色素）。稱作天線復(fù)合體的色素分子群存在于類囊體中。激活色素分子的光能進(jìn)入葉綠素反應(yīng)中心，其直接參與光合作用。大部分光反應(yīng)細(xì)胞器擁有兩套反應(yīng)中心，P680和P700， 每個(gè)光系統(tǒng)都含有一個(gè)電子受體和電子供體。這些集合

23、體就是大家熟識(shí)的光合系統(tǒng)和光合系統(tǒng) 。光反應(yīng)：光能轉(zhuǎn)化成化學(xué)鍵能光反應(yīng)的光系統(tǒng)將光能轉(zhuǎn)化成化學(xué)復(fù)合物ATP和NADPH。當(dāng)光激活光系統(tǒng)的光反應(yīng)中 心時(shí)，通過一系列的氧化還原反應(yīng)實(shí)現(xiàn)能量的傳遞。反應(yīng)開始時(shí)，水被分解，氧被釋放并提供電子。電子首先傳遞給質(zhì)體醌，然后通過一系列載體形成的電子傳遞鏈。每傳遞4個(gè) 電子，形成2個(gè)ATP。最后一個(gè)受體存在于光反應(yīng)系統(tǒng)的反應(yīng)中心里。此處光子激活電子，電子傳遞給鐵氧還蛋白。鐵氧還蛋白再氧化，并且輔酶NADP+還原成NADPH。早期產(chǎn)生的ATP和NADPH進(jìn)入暗反應(yīng)。由電子傳遞鏈偶連產(chǎn)生ATP的過程稱為光合磷酸化。通過光合系統(tǒng)流經(jīng)光合系統(tǒng)的電子路徑稱非循環(huán)式光合磷

24、酸化；植物通過循環(huán)式光合磷酸化獲得額外的ATP，一些電子 在光合系統(tǒng)和之間的電子傳遞鏈中回流。暗反應(yīng)：碳水化合物的形成由ATP和NADPH驅(qū)動(dòng)的暗反應(yīng)中，二氧化碳轉(zhuǎn)化成碳水化合物。即卡爾文循環(huán)。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）大部分植物是碳3植物，在高溫干旱條件下，由于光呼吸作用而使碳水化合物的合成降低。而在大多數(shù)的碳4植物中，由于葉脈的特殊構(gòu)造和獨(dú)特的化學(xué)路徑使植物依然很茂盛。這是碳固定的一個(gè)新機(jī)制。Glossarylight-dependent reactions 光反

25、應(yīng)-The first stage in photosynthesis, driven by light energy.Electrons that trap the suns energy pass the energy to high-energy carriers such as ATP or NADPH, where it is stored in chemical bonds.light-independent reactions 暗反應(yīng)The second stage of photosynthesis, also called the Calvin-Benson cycle, w

26、hich does not require light.During the six steps of the cycle, carbon is fixed and carbohydrates are formed.chloroplast 葉綠體A plastid in which photosynthesis is carried out. Chloroplasts occur in all photosynthetic organisms except photosynthetic bacteria and blue-green algae.absorption spectrum 吸收光譜

27、，吸收譜The spectrum obtained when radiation (light, ultraviolet radiation, etc.) from a source giving a continuous spectrum is passed through a substance.Calvin-Benson cycle卡爾文本森循環(huán)Cyclic reactions that are the synthesis part of the light-independent reactions of photosynthesis.In land plants, RUBP, or

28、some other compound to which carbon has been affixed, under goes rearrangements thatregeneration of the RUBP. The cycle runs on ATP and NADPH from light-dependent reactions.carotenoid 類胡蘿卜素Light-sensitive,accessory pigmentsthat transfer absorbed energy to chlorophylls.They absorb violet and blue wav

29、e-lengths but transmit red, orange, and yellow. chlorophyll 葉綠素The green substance of plants by which photosynthesis is accomplished; it is usually localized in intracellular organelles called chloroplasts.cyclic photophosphorylation環(huán)形光合磷酸化（作用）Cyclic photophosphorylation is coupled to cyclicelectron

30、 flow, in which ATP is the only product.C3 plant 三碳植物Aplantinwhichthelight-independent reactionsofphotosynthesisstartwithathreecarbon compound.Most plants are C3 plants.C4 plant 四碳植物A plant such as corn in which the light independent reactions of photosynthesis star with a four-carbon compound.noncy

31、clic photophosphorylation非環(huán)形光合磷酸化作用Noncyclic photophosphorylation is coupled to noncyclic electron flow, the electrons being used to reduce NADP+ as well as to make ATP.photon光子A particle that has zero mass or charge and unit spin, the quantum of the electromagnetic field and carrier of the electrom

32、agnetic force. photophosphorylation 光合磷酸化作用The synthesis of ATP from phosphate and ADP during photosynthesis, using light energy.photorespiration光呼吸A light-dependent type of respiration that occurs in most photosynthetic plants and differs from normal (or dark) respiration. photosynthesis 光合作用The sy

33、nthesis of organic compounds by reduction of carbon dioxide using light energy absorbed by chorophyll.photosystem 光合系統(tǒng)Oneoftheclustersoflight-trapping pigmentsembeddedinphotosyntheticpathways. ribulose biphosphate (RUBP) 核酮糖二磷酸A compound with a backbone of five carbon atoms that is required for carb

34、on fixation in the Calvin-Benson cycle of photosynthesis.thylakoid 類囊體One of a number of flattened fluid-filled sacs that form the photosynthetic lamellar system of chloroplasts, photosynthetic bacteria, and blue-green algae.membranes.Photosystem I operates during the cyclic pathway; photosystem ope

35、ratesduringboththecyclicandnoncyclic PAGE 32Lesson Three（2學(xué)時(shí)）Cellular Reproduction:Mitosis and Meiosis細(xì)胞核是貯藏遺傳信息的主要場所。DNA盤繞成螺旋線以及相關(guān)的成簇蛋白質(zhì)。DNA 螺旋線纏繞成簇的組蛋白形成珠鏈狀的核小體。這些螺旋和超螺旋形成致密的染色體組結(jié)構(gòu)。每個(gè)長鏈DNA與組蛋白和非組蛋白一起構(gòu)成染色質(zhì)物質(zhì)。染色體致密的超螺旋狀態(tài)我們稱染色體組。除了性染色體外，大多數(shù)細(xì)胞的染色體組成對出 現(xiàn)，稱同源染色體對。非性染色體稱常染色體。生物細(xì)胞含有兩套父母本染色體的稱二倍體； 含有單套染色體的

36、稱單倍體。在細(xì)胞生長過程中，細(xì)胞循環(huán)遵循特定程序，分裂準(zhǔn)備，分裂成2個(gè)子細(xì)胞，子細(xì)胞再循環(huán)。此循環(huán)使得單細(xì)胞永生。多細(xì)胞生物中的許多細(xì)胞，包括動(dòng)物肌肉和神經(jīng)細(xì)胞， 要么降低循環(huán)速度，要么同時(shí)分裂。1212正常細(xì)胞循環(huán)由4個(gè)時(shí)期組成。頭三期包括G ,正常新陳代謝；S期,正常新陳代謝同時(shí)，DNA 復(fù)制，組蛋白合成； G 期，短期的新陳代謝和少許生長。G , S, 和G 稱分裂間期。最后是M期，有絲分裂期，復(fù)制的染色體組濃縮，移動(dòng)并細(xì)胞分裂。據(jù)稱是染色質(zhì)控制了細(xì)胞循環(huán)，伴隨外部激活因子和抑制因子如抑素。生物學(xué)家將有絲分裂劃分為4個(gè)階段。分裂前期，高度濃縮的兩個(gè)染色單體通過著絲 粒連接在一起。在分裂前

37、期后期和分裂中期前期，濃縮的染色體與紡錘體相連，最后以正確的角度排列在赤道板上。在分裂后期，兩個(gè)姊妹單體分離，分別拽向細(xì)胞兩極。在分裂末期，在每套染色體周圍形成核膜，細(xì)胞質(zhì)發(fā)生分裂。在有絲分裂過程中，是紡錘體微管確保了染色單體在適當(dāng)時(shí)間以正確方向進(jìn)行分離。紡錘體微管由兩極向赤道板延伸。在分裂前期，其它微管，著絲粒纖維延伸到染色體的 動(dòng)粒。在分裂后期，纖維開始變短，染色單體分離。植物和動(dòng)物細(xì)胞形成的紡錘體不同。動(dòng)物細(xì)胞與中心粒相連，而在植物和真菌細(xì)胞中，紡 錘體與微管組織中心的離子相連。Cytokinesis: Partitioning the Cytoplasm胞質(zhì)分裂：細(xì)胞質(zhì)分離在動(dòng)物細(xì)胞中

38、，環(huán)形肌動(dòng)蛋白絲延赤道板收縮而使細(xì)胞一分為二。在植物細(xì)胞中，在赤道板形成新的細(xì)胞板。減數(shù)分裂是性細(xì)胞分裂的特殊形式。如有絲分裂，它也是發(fā)生在DNA復(fù)制后并有連續(xù)的兩個(gè)核分裂。產(chǎn)生4個(gè)子細(xì)胞，分別含有親本一半的染色體數(shù)。正如在有絲分裂中一樣，兩個(gè)同源染色單體通過蛋白質(zhì)和RNA橋配對形成聯(lián)會(huì)復(fù)合體。與有絲分裂不同的是，每組染色體的兩個(gè)染色單體連接在著絲點(diǎn)上并一起移向細(xì)胞兩極的 一級(jí)。由此而導(dǎo)致4個(gè)子細(xì)胞染色體數(shù)減半。第二次核分裂開始于分裂中期，子細(xì)胞中染色體重新排列在赤道板上。著絲粒最終分離，每個(gè)姊妹染色單體分向兩極。接著胞質(zhì)分裂。產(chǎn)生4個(gè)單倍體，父母染色體隨機(jī)分配。有絲分裂和減數(shù)分裂在傳遞遺傳信

39、息過程中各有優(yōu)勢。體細(xì)胞的繁殖就是父母本的克隆，其 優(yōu)勢是保留了父母本的成功遺傳信息，不需要特殊器官，比性復(fù)制快的多。但一個(gè)簡單災(zāi)難性 事件或疾病都可能摧毀一個(gè)細(xì)胞群體。性復(fù)制的優(yōu)勢是它提供了遺傳可變性和現(xiàn)存排除有害突 變的機(jī)制。也可以產(chǎn)生新的基因并在種群中蔓延。Glossarymitosis 有絲分裂Process that results in equal and identical distribution of replicated chromosomes into two newly formed nuclei. meiosis 減數(shù)分裂The process by which a

40、nucleus divides into four daughter nuclei, each containinghalf the number of chromosomes of the parent nucleus.histone 組蛋白One of a group of simple proteins that have a high content of the basic amino acids arginine or lysine and are foundassociated with nucleic acids in the chromatin of eukaryotic c

41、ells. nucleosome 核小體The basic unit of chromatin structure in eukaryotic cells.A nucleosome consists of eight histone molecules of four different types, together with about 140 base pairs of DNA coiled around it.chromatin 染色質(zhì)The material of which the chromosomes are composed.DNA and protein are the m

42、ain constituents of chromatin, most of the protein being histone.karyotype 核型，染色體組型 ,The appearance of the chromosome complement of an organism or cell. homologous pair 同源染色體對Chromosomes that pair during meiosis.Each homologue is a duplicate of one of the chromosomes contributed at syngamy by the mo

43、ther or father.Homologous chromosomes contain the same linear sequence of genes and as a consequence each gene is present in duplicate.diploid二倍體Any nucleus, cell, or organism that possesses twice the haploid number of chromosomes.haploid 單倍體Any nucleus, cell, or organism that possesses a single set

44、 of unpaired chromosomes,interphase (cycle) 分裂間期（周期）In a cell preparing to duplicate, the interphase stage can divided into a period of initial growth (G1), a period of DNA synthesis (S), and a second growth period (G2).chalone 抑素Substances found in mammalian tissue homogenates that, when applied to

45、 intact tissue cells, inhibit mitosis, particularly in the presence of adrenaline and phase （分裂）前期First stage of mitosis, during which individual chromosomes become visible.chromatid 染色單體A replicated chromosome physically attached to an identical chromatid at the centromere.centro

46、mere 著絲粒The small area of a chromosome that does not stain with basic dyes during mitosis and meiosis; at interphase it is single while the rest of the chromosome is made up of two chromatids.metaphase （分裂）中期Second stage in mitosis, during which the chromosomes align at the equatorial plane. spindle

47、 紡錘體cytokinesis 胞質(zhì)分裂cell plate細(xì)胞板An array of microtubutes extending from pole to pole and used in the movement of chromosomes.metaphase plate 赤道板，中期板The grouping of the chromosomes in a plane at the equator of the spindle during the metaphase stage of mitosis.anaphase 分裂后期The third stage of mitosis,

48、 during which the centromeres split and the chromosomes move to the poles.telophase （分裂）末期Last stage in mitosis during which daughter nuclei are formed.Division of the cytoplasm of one cell into two new cells.A plant cell structure that begins to formin the center of the cell and proceeds to the cel

49、l membrane, resulting in cytokinesis.Lesson Four（2學(xué)時(shí)）Foundations of Genetics遺傳學(xué)的早期理論包括泛生說和種質(zhì)理論?；谛∈髮?shí)驗(yàn)，維絲曼提出遺傳信息儲(chǔ)存在配子中并將遺傳信息傳遞給后代。這兩個(gè)早期觀點(diǎn)合起來形成融合理論：子代擁有父母本混合的遺傳特征，而不完全象親代。孟德爾，眾所周知的遺傳學(xué)之父，是一名修道士。當(dāng)他還是大學(xué)生時(shí)就提出了物質(zhì)的粒子屬性。孟德爾進(jìn)行了一系列周密安排的實(shí)驗(yàn)來證實(shí)遺傳的顆粒性。直到他去世后，他的理論才被理解和接受。孟德爾通過豌豆實(shí)驗(yàn)研究遺傳學(xué)，豌豆是自花授粉植物和純品系。為驗(yàn)證融合理論，他的研究主要集

50、中在7個(gè)特征上。例如，種子顏色，植株高度，這些特征只有兩個(gè)明確的可 能性。他記錄了產(chǎn)生的每一個(gè)子代類型和數(shù)量，在雜交產(chǎn)生子2代。對于每個(gè)特征而言，要么顯形，要么隱性。在子2代中顯形與隱性比為31。只有在每個(gè)個(gè)體僅擁有兩個(gè)研究遺傳單元，并每個(gè)單元來自一個(gè)親代時(shí)，實(shí)驗(yàn)結(jié)果才成立。此遺傳單元就是今天共識(shí)的等位基因。兩個(gè)一樣的等位基因決定一個(gè)特征，稱純合。相反，稱雜合。當(dāng)生物是雜合時(shí)，它的表型由顯性基因決定。因此，生物的表型與基因型是不同的。旁納特方格可以陳列所有可能的遺傳組合。分離定律，生物只遺傳父母本等位基因?qū)Φ囊粋€(gè)等位基因。減數(shù)分裂期形成配子時(shí)兩 個(gè)等位基因分離。為驗(yàn)證此理論，他做了測交實(shí)驗(yàn)，即

51、基因型未知的植物與純合的隱性基因植物雜交。子代顯性表型可以明確測得雜合基因或純合基因的基因型。雙因子雜合試驗(yàn)，兩個(gè)特征是如何相互影響遺傳的。試驗(yàn)結(jié)果產(chǎn)生獨(dú)自分配定律，即等 位基因獨(dú)立遺傳。特例是，不完全顯性。子代的表型是父母本的中間類型。不完全顯性說明了兩個(gè)等位基因?qū)Ρ硇投加杏绊?。，等位基因?huì)繼續(xù)分離。1866年，孟德爾在自然史上發(fā)表了他的科學(xué)論文，陳訴了他的觀點(diǎn)。不幸的是，他的研究不被當(dāng)時(shí)科學(xué)家接受。在1900年，他的著作再被發(fā)現(xiàn)利用。孟德爾著作被再發(fā)現(xiàn)不久，Walter Sutton 和Theodor Boveri提出，遺傳單位可能定位在染色體組上。伴性遺傳又導(dǎo)致了不分離現(xiàn)象的發(fā)現(xiàn)，即在減

52、數(shù)分裂中，染色體對不分離。Glossarypangenesis 泛生論，泛生說The theory of heredity postulating that germs, humours, or essences migrate from individual body cells to the sex organs and contribute to the gametes.germ plasm theory 種質(zhì)學(xué)說A substance thought to be transmitted in the gametes (germ cells) in an unchangedform fr

53、om generation to generation.The germ plasm was believed to be unaffected by the environment and to give rise to the body cells.dominant 顯性The member of a pair of alleles that shows its effect in the phenotype whatever other allele is present.recessive 隱形的The member of a pair of alleles that does not

54、 show its effect in the presence of any other allelic partner.allele 等位基因Alternative forms of a gene for a particular characteristic (e.g., attached earlobe genes and free earlobe genes are alternative alleles for ear shape).gene 基因A unit of heredity located on a chromosome and composed a sequence o

55、f DNA nucleotides.homozygous 純合的A diploid organism that has two identical alleles for particular characteristic. heterozygous 雜合的A diploid organism that has two different alletic forms of a particular gene. Genotype 基因型The catalog of genes of an organism, whether or not these genes are expressed.phe

56、notype 表型The physical, chemical, and psychological expressionofgenespossessedbyan organism.Punnett square 旁納特方格Amethodusedtodeterminethe probabilities of combination in a zygote.law of segregation 分裂定律When gametes are formed by a diploid organism, the alleles that control a trait separate from one a

57、nother into different gametes, retaining their individuality.test cross 測交A cross between a heterozygote of unknown genotype and an individual homozygous for the recessive genes in question.dihybrid cross 雙因子雜種，雙因子雜合子A cross between individuals that differ with respect to two specified gene pairs. l

58、aw of independent assortment 獨(dú)立分配定律，自由組合定律Members of one gene pair will separate from each other independently of the members of other gene pairs.incomplete dominance 不完全顯性The condition in which two allelic genes have a different effect when they are together as a heterozygote in a diploid cell than

59、 either of them have in the homozygous state nondisjunction 不分離The failure of separation of paired chromosomes at metaphase, resulting in one daughter receiving both and the other daughter cell none of the chromosomes in question. Nondisjunction can occur duringLesson Five（2學(xué)時(shí)）a meiotic or mitotic d

60、ivision.Discovering the Chemical Nature of the GeneArchibald Garrod是第一個(gè)研究基因是如何影響表型的科學(xué)家，他對尿黑酸癥的研究揭示了基因與酶之間的關(guān)系。Beadle 和Ephrussi在三十年后對果蠅眼睛顏色的研究發(fā)現(xiàn)特殊基因與相關(guān)反應(yīng)的生物合成有關(guān)。接著對面包發(fā)霉粗糙脈孢菌的突變試驗(yàn)得出一個(gè)基因一個(gè)酶的假說。他們的工作為其他工作者鋪平了道路，即精確地闡明了酶影響了復(fù)雜的新陳代謝途徑。在1949年，對鐮刀狀細(xì)胞貧血癥的研究對一個(gè)基因一個(gè)酶的假說進(jìn)一步上升為一個(gè)基因一個(gè)多肽。在1871年，核酸最初是由Johann Miescher