生物专业英文论文

生物专业英文论文

解读序列数据。
即使在出现的完整基因组和大型表达序列标签（ EST ）的调查， GenBank中[和与其对应，欧洲分子生物学图书馆（分子生物学） ，资料库和DNA数据库的日本]已成为一个大型，复杂的和国内冗余序列存档，需要相当丰富的经验和/或主要使用最有效。许多切实可行的建议就这个问题进行了讨论，本指南的一个挑战和必需品，为未来的重组和精简数据的更有效的利用。的国立生物技术信息中心，例如，开展了“参照基因”项目，部分解决这一问题。反补贴力量，然而，正在这个任务更艰巨，更紧迫。每日发布的“未完成”序列上大量网站使得极难生物学家保持现有的和全面地看待现有的数据，尽管事实是“消费指南” ，以这些网站已经出版和正在reasonahly的帮助。这种情况将得到更糟糕的是， 。有走向广阔加速生产中的未完成的，零零碎碎（组装鸟枪）序列数据从基因组测序实验室。生物学家将需要新的软件工具（和实验验证的资源） ，以最大限度地发挥效用对这些数据的。
即使是“完成” （即高精确度，毗连seouence ）的数据，有seriolls问题的诠释，影响我们的能力，依靠一贯的，最新的和质量氮保证有关的基因和基因组。这些问题已deserihed reeontly这是不必要的重申他们在这里。我只想说，注释，尤其是基因预测，仍然是一个具有挑战性的问题，基因组的解释。
新方向
我认为，最令人兴奋的是在边境之间的界面的计算和大腿通量实验生物学。多年来，出现了“之间的阻抗不匹配的快速输出的计算和预测的能力，传统的实验方法来测试和验证这些预测。通过发展和应用新的基因表达技术，如”湿板凳“生物学家能产生基因功能的信息产品几乎尽快计算生物学家可以分析潜在的基因组。有巨大的挑战和机会，在这里找到，和许多新的生物学发现。
最后，我不认为应该忽视生物学家计算领域的遗传流行病学和进化遗传学。在过去，这些都是相当小的和孤立的专业。但是，

急!!!!!求分子生物学方面的英文论文及其翻译!最近两年的

Congenital kidney maldevelopment and molecular biology research The abstract kidney maldevelopment is the kidney has theunusual clinical consequence, its typical histo-pathologycharacteristic is appears originally Beginning kidney pellet and 肾小管, 软骨样 metaplasia andso on. In recent years through application molecular technology and soon target gene and home position clone Has the molecular regulation mechanism research to the normalmammal kidney, has to the congenital kidney maldevelopmentpathogenesis More understandings. This article will make a discussion to thecongenital kidney maldevelopment molecular biology research recentsituation, and will be right Including the growth factor several kind of gene mutation,copies the regulative barrier and the expression change and the kidneysends the good relations Carries on the discussion. The kidney maldevelopment is the kidney has not been able to carry onthe congenital disease which the normal growth growth forms, in thepast arose to it The mechanism understanding are really few, along with themember biological technology development and the application, expoundsthe kidney occurrence from the member study mechanism Had a more thorough understanding from the molecular biologylevel to the kidney maldevelopment occurrence. This article onshort-term regarding this question The research progress makes an introduction. 1 kidney occurs with the kidney maldevelopment Before the normal mammalia kidney is located between liesbetween 中胚层, 中胚层 the differentiation forms the kidneydrive pipe, after further tempts Leads forms 中肾 the drive pipe to the ureter bud, under theureter bud induction, end the embrionic body two sides fresh reninssplits up into after The kidney 胚基, the kidney embryonic development isprecisely completes by the ureter bud and the latter kidney 胚基 twoparts, former gradually grows Becomes 肾盂, 肾盏 and 集合管, latter grows肾小管and the kidney pellet, finally 肾小管and集合管docking, Constitutes normally 肾单位. If the ureter bud and thelatter kidney 胚基 two parts cannot grow according to the normaldegree and implement rightly Meets namely creates the kidney maldevelopment. The kidneymaldevelopment may be partial, also may be complete. Most types The kidney maldevelopment partner has the cyst, prompts themaldevelopment each kind of form to have machine-made together in theformation. On clinical common congenital kidney maldevelopment including multi-pouches, obstruction kidney maldevelopment as well as with gene The related kidney growth is unusual. The histo-pathologyimportant characteristic appears primitive 肾小管and the metaplasiacartilage. Complete list The side kidney maldevelopment, may display for does not havethe symptom. In most maldevelopment case of illness, the kidney flawis the double side, prompts Gene mutation in normal kidney growth vital role. Shan Cexingdisease then possibly is one kind of obtaining damage is the resultof, This damage destroyed the gene normal expression, thenaffected maturely had the vital significance to the kidney the proteinproduction. 2 kidneys maldevelopment common type 2.1 congenital multi- pouches kidneys maldevelopment The multi- pouches kidney maldevelopment (multiple cystichypoplastic) is one common completeness The kidney maldevelopment, are many for the single sidepathological change (14-20% for double side nature), contracts thekidney to lose the normal shape, irregular The size cyst replaces, the kidney function loses and oftenthe partner has the ureter obstruction, is newborn abdomen Bao Kuaizuicommon One of reasons. The multi- pouches maldevelopment kidney outlook assumes thekidney-shaped structure, the most case of illness partner has a 闭锁ureter. Pregnancy The early polycystic kidney includes the normal growth to havethe ingredient, loses the urine including the induction after kidney胚基 island and the branch The tube drive pipe, may distinguish the pouch change in thisstage 肾单位 each Duan Yijun [ 1 ]. After lives the multi- pouchesmaldevelopment kidney The histo-pathology variation including the primitive肾小管pouch change, expands also the disarrangement of thestructure, has around the obvious tube Response nature, textile fiber myo- link formation, cartilageingredient as symbol organization transformation and so on. 2.2 congenital obstructions kidneys maldevelopment The congenital urine road obstruction in dissects in theposition often to occur to the ureter and urinary bladder 连接处,after congenitalness The urethra valve is the babies and infants uninary systemobstruction important reason. Congenital obstruction kidney histologycharacteristic and multi- pouches The kidney maldevelopment is similar, including 肾单位 eachDuan Rushen the pellet pouch transformation, the nature expands alsothe disarrangement of the structure, the marrow The nature and the straight small blood vessel remarkablehypoplasia, has around the tube the textile fiber myo- link, the manykinds of forms kidney pellet and the growth kidney Unit each section. Is same with the multi- pouches kidneymaldevelopment, the congenital obstruction kidney performance is aseries of diseases, its degree and The embryonic period urine 流阻 related fills the time whichoccurs [ 2 ]. The table partner has the kidney to grow the unusual syndrome ------------------------------------------------------ Syndrome chromosome heredity form ------------------------------------------------------ The tip and refers to (foot) to be abnormal (Apert ' s)常染色体 the dominance Sends chest gallery malnutrition 常染色体 recessivenesswhich suffocates Obese, reproduction hypofunction and so on 常染色体recessiveness Gill - ear - kidney 常染色体 dominance Campomelic growth exceptionally 常染色体 recessiveness Brain - liver - kidney (Passarge ' s) 常染色体recessiveness Fryns ' s 常染色体 recessiveness Goemine ' s X- connection Goldston (hereditary blood capillary expands) 常染色体recessiveness? Hall-Pallster ' s sending out Ivemark ' s 常染色体 recessiveness Marden-Walker ' s 常染色体 recessiveness Mecket-Gruber 常染色体 recessiveness Miranda ' s 常染色体 recessiveness Senlor-Loken ' s 常染色体 recessiveness? Three bodies chromosomes 16-18 (Edwards) Three bodies chromosomes 13-15 (Patau) Three bodies chromosomes 21 (Down) 结节性 hardened 常染色体 dominance Von Hippel-Lindau 常染色体 dominance ------------------------------------------------------ 2.3 kidneys maldevelopment syndrome The kidney maldevelopment syndrome is includes kidney abnormalthe and so on pouch maldevelopment hereditary indication group (seesthe table ). Presently expounds a part of syndromes its special gene andthe protein flaw. The maldevelopment phenotype apparent rate assumes Presently a band, prompts has other gene influence kidneysfinally 表型. The maldevelopment usually all contains the many kindsof organs, Explained the flaw the gene involves the normal organogenesisthe foundation. The histo-pathology discovered that, this kind ofsyndrome light is possible Appears the great pouch to form (for example 结节性hardening), heavy possibly appears the pouch growth exceptionally withthe renal failure (Meckel- Gruber syndrome). 3 kidneys maldevelopment molecular biology The present research discovery has the many kinds of genes andthe kidney maldevelopment related, like WT-1, Pax-2, GDNF, B Gene and so on F-2, BMP-7, PDGF, Wnt-4 in after kidney 胚基expression. Pax-2, c-ret, BMP-7, alpha 3 beta 1 and so on in ureter bud expression. When these genes lack ordestroys, the kidney cannot normally occur with the growth [ 3 ]. Sonnenberg and so on [ 4 ] 补体 RNA and the DNA probeconducts the research with the specificity immune body and theemission mark, the determination Multi- peptides growth factor, heparin structure growth factorand their acceptor, extracellular matrix member and cell surfaceentire Gathers gene and so on element in the kidney growth specificexpression position. For example liver cell growth factor mainly inafter kidney embryo gene Expression, but its acceptor c-met in ureter plumule epidermisexpression. This kind of peptides and its the acceptor are thin in twokind of types On butcher's expression explanation ureter drive pipe formsthe induction to the after 肾间 archery target. Schuchardt and so on[ 5 ] passes Using the gene recombination and the preparation 纯合子invalid sudden change mouse, discovers some influence kidney growththe gene and the multi- peptides, like The shift growth factor - beta, the liver cell growth factor,the insulin type growth factor - II, according to saw finally shows The inference specific gene has the function in the normalkidney. Tyrosine activating enzyme body acceptor c-ret leads in thebranch ureter The tube as well as matches in the nerve nutrition factorwhich the body - neuroglia grows to express. When the mouse c-ret geneis destroyed, leads Sends the entire kidney maldevelopment. Copies the factor genecode protein to be able with the DNA union, moreover has regulatesother gene tables Reaches function. In the mammal kidney growth, Wilms ' tumorgene WT-1 and Pax2 code copies the factor, Its expression form influence kidney cell differentiation [ 6,7 ]. The gene syndrome and the kidney form exceptionally related, inthe table arranges in order Leaves the disease, some syndromes have the heredity, somewhathas located the specific gene flaw with the home position clonetechnology [ 8 ]. These syndromes are being sick the family members to beable to have the remarkable 表型 variation. This kind of situationand in 纯合子 is invalid The sudden change mouse sees the variation is similar, namelythe kidney finally 表型 is decided by the experimental mouse's genebackground. The kidney maldevelopment occurrence is several kind of differentgenes flaws, perhaps meets in the embryo development period sends 畸the factor And so on many kinds of genes regulation barrier finaloutcome. 肾间 the nature - epidermis transforms process as well asureter branch and growth Is complex and the huge gene system guides by, some genes arethe kidney specificity, some rights and wrongs are special . Certain growth factor genes, although they have the timeexpression in the kidney to be active, but when they are destroyedcertainly not shade The loud kidney normal growth, this meant the growth kidneynormal expression each kind of gene has in the function overlaps [ 9]. Another one Plants the possibility is this kind of normal expression formdestruction in the kidney maldevelopment occurrence development thecertain function, or Is the kidney maldevelopment cause. The latter 肾间 nature flaw may cause the kidney er, the gene ill should is the dislocation expression, possiblyto kidney The maldevelopment plays the certain role. On clinical hasthe isolation the multi- pouches kidney maldevelopment and theobstruction kidney maldevelopment two Parallel existence case of illness. Congenitalness and theexperimental nature single gene mutation may cause the pouch kidneygrowth to be unusual, these genes The sudden change may change mutually relates. Theoreticallyspeaking, the sudden change may affect: (1) 胚基 proliferation andsplit up ureter drive pipe minute An institute must peptide and matrix protein expression; (2)Ureter drive pipe to after kidney 胚基 signal reaction capacity; (3)Loses After the ureter drive pipe expression starts and maintainsthe kidney 胚基 epidermis induction to need the protein the ability;(4) Latter kidney 胚基 to these letters The number carries on the response the ability; (5) Ureterbud and latter kidney 胚基 cell to signal reaction capacity [ 10 ]. Recently already separated the phosphoric acid glucose phaseomanniteglycoprotein gene, was called the GPC3 gene. The GPC3 flaw and aremany Pouch kidney maldevelopment related [ 11 ]. Although thesingle gene may finally cause the kidney maldevelopment with themulti- genes flaw, but Its 表型 possibly decided to receives the gene regulationwhich affects to be out of balance or the expression change at first,like congenital obstruction and pouch Kidney maldevelopment [ 12, 13 ]. The multi- pouchesmaldevelopment kidney, and in the nature has the growth factor gene inthe pouch epidermis Change. In the mouse obstruction growth kidney, the bloodvessel tense element and the shift growth factor assumes excessivelyexpresses [ 14 ]. Grinds Investigates the proof, in the after kidney growth unusualarea, promotes the acorn tube epidermis to appear the pouch changefactor Pax2 and Bcl-2 same Assumes excessively expresses [ 15, 16 ]. This researchpossibly can provide the important line to each kind of form kidneymaldevelopment pathogenesis Rope.

先天性肾发育不良与分子生物学的研究

摘要 肾发育不良是肾发生异常的临床后果，其典型病理组织学特征是出现原
始肾小球和肾小管、软骨样化生等。近年来通过应用靶基因和原位克隆等分子技术
对正常哺乳动物肾脏发生分子调控机制的研究，对先天性肾发育不良的发病机理有
了更多的了解。本文将对先天性肾发育不良的分子生物学研究近况作一讨论，并对
包括生长因子在内的几种基因突变、转录调控障碍及表达变化与肾发良不良的关系
进行探讨。

肾发育不良是肾脏未能进行正常生长发育形成的先天性疾病，过去对其发病
机理了解甚少，随着分子生物技术的发展和应用，从分子学机理来阐明肾脏的发生
，从分子生物学水平对肾发育不良的发生有了较深入的认识。本文就近期对此问题
的研究进展作一介绍。

1 肾发生与肾发育不良

正常哺乳类肾脏位于间介中胚层，中胚层分化形成前肾导管，经进一步诱
导形成中肾导管至输尿管芽，在输尿管芽诱导下，胚体尾端两侧的生肾素分化为后
肾胚基，肾脏的胚胎发育正是由输尿管芽和后肾胚基二部分完成的，前者逐步发育
成肾盂、肾盏和集合管，后者发育成肾小管和肾小球，最后肾小管和集合管对接，
构成正常的肾单位。如果输尿管芽和后肾胚基二部分不能按正常程度发育和实行对
接即造成肾发育不良。肾发育不良可以是部分性的，也可以是完全性的。多数类型
的肾发育不良伴有囊肿，提示发育不良的各种形式在形成中有共同机制。

临床上常见的先天性肾发育不良包括多囊性、梗阻性肾发育不良以及与基因
有关的肾发育异常。病理组织学重要特征是出现原始肾小管和化生软骨。完全性单
侧肾发育不良，可表现为无症状。多数发育不良病例中，肾缺陷是双侧性的，提示
基因突变在正常肾发育中起重要作用。单侧性疾病则可能是一种获得性损伤所致，
该损伤破坏了基因的正常表达，进而影响了对肾成熟有重要意义的蛋白质的产生。

2 肾发育不良常见类型

2.1 先天多囊性肾发育不良

多囊性肾发育不良（multiple cystic hypoplastic）是一种常见的完全性
肾发育不良，多为单侧病变（14-20%为双侧性），患肾失去正常形态，被不规则的
大小囊肿所代替，肾脏功能丧失并常伴有输尿管梗阻，是新生儿腹部包块最常见的
原因之一。

多囊性发育不良肾外型呈肾形结构，多数病例伴有一个闭锁的输尿管。妊娠
早期的多囊肾含有正常发育所必须的成份，包括未诱导的后肾胚基岛和分支的输尿
管导管，在此阶段肾单位各段已均可鉴别出囊性改变[1]。生后多囊性发育不良肾
的病理组织学变异包括原始肾小管的囊性改变、膨大且结构破坏、具有明显管周围
反应的间质、纤维肌环的形成、软骨成分为标志的组织转化等。

2.2 先天梗阻性肾发育不良

先天性尿路梗阻在解剖位置上常发生于输尿管和膀胱的连接处，先天性后
尿道瓣膜是婴幼儿泌尿系统梗阻的重要原因。先天梗阻性肾的组织学特征与多囊性
肾发育不良相似，包括肾单位各段如肾小球的囊性转化、间质膨大且结构破坏、髓
质和直小血管显著发育不全、发生管周围纤维肌环、多种形式的肾小球和发育的肾
单位各段。与多囊性肾发育不良一样，先天梗阻性肾表现为一系列疾病，其程度与
胚胎期尿流阻塞发生的时间有关[2]。

表 伴有肾发育异常的综合症
------------------------------------------------------
综合症 染色体遗传形式
------------------------------------------------------
尖头并指（趾）畸形（Apert’s） 常染色体显性
致窒息的胸廓营养不良 常染色体隐性
肥胖、生殖机能减退等 常染色体隐性
鳃-耳-肾 常染色体显性
Campomelic发育异常 常染色体隐性
脑-肝-肾（Passarge’s） 常染色体隐性
Fryns’s 常染色体隐性
Goemine’s X-连接的
Goldston(遗传性毛细血管扩张) 常染色体隐性？
Hall-Pallster’s 散发的
Ivemark’s 常染色体隐性
Marden-Walker’s 常染色体隐性
Mecket-Gruber 常染色体隐性
Miranda’s 常染色体隐性
Senlor-Loken’s 常染色体隐性？
三体染色体16-18（Edwards）
三体染色体13-15（Patau）
三体染色体21（Down）
结节性硬化 常染色体显性
Von Hippel-Lindau 常染色体显性
------------------------------------------------------

2.3 肾发育不良综合症

肾发育不良综合症是包括囊性发育不良等肾畸形在内的遗传性征候群（见表
）。现阐明一部分综合症其特异的基因和蛋白质缺陷。发育不良表现型的外显率呈
现一个谱带，提示有其他基因影响肾的最终表型。发育不良通常都包含多种器官，
说明缺陷的基因涉及正常器官发生的基础。病理组织学发现，此类综合症轻者可能
出现巨囊形成（如结节性硬化），重者可能出现囊性发育异常和肾衰竭（Meckel-
Gruber综合症）。

3 肾发育不良分子生物学

目前的研究发现有多种基因与肾发育不良有关，如WT-1、Pax-2、GDNF、B
F-2、BMP-7、PDGF、Wnt-4等基因在后肾胚基表达。Pax-2、c-ret、BMP-7、α3β
1等在输尿管芽表达。当这些基因缺乏或被破坏时，肾脏不能正常地发生与发育[3
]。Sonnenberg等[4]用特异性抗体与放射标记的补体RNA和DNA探针进行研究，确定
了多肽生长因子、肝素结构生长因子及它们的受体、细胞外基质分子和细胞表面整
合素等基因在肾发育中的特定表达位置。例如肝细胞生长因子主要在后肾胚基因内
表达，而其受体c-met则在输尿管胚芽上皮表达。这种多肽及其受体在两种类型细
胞上的表达说明输尿管导管对后肾间质的形成起诱导作用。Schuchardt等[5]通过
应用基因重组与制备纯合子无效突变小鼠，发现一些影响肾发育的基因和多肽，如
转移生长因子-β、肝细胞生长因子、胰岛素样生长因子-Ⅱ，根据所见到的最终表
型推断特定基因在正常肾发生中的作用。酪氨酸激酶体受体c-ret在分支输尿管导
管以及配体-神经胶质衍生的神经营养因子上表达。当小鼠c-ret基因被破坏时，导
致全肾发育不良。转录因子基因编码蛋白能与DNA结合，而且具备调控其它基因表
达的功能。在哺乳动物肾发育中，Wilms’肿瘤基因WT-1及Pax2均编码转录因子，
其表达形式影响肾细胞的分化[6，7]。基因性综合症与肾形成异常有关，表中所列
出的疾病，有些综合症有遗传性，有些用原位克隆技术已定位出特定的基因缺陷[
8]。这些综合症在患病家族成员能发生显著的表型变异。这种情况与在纯合子无效
突变小鼠所见的变异相似，即肾的最终表型取决于实验小鼠的基因背景。

肾发育不良的发生是几种不同的基因缺陷，或是在胚胎发育期遇到致畸因子
等多种基因调控障碍的最终结果。肾间质-上皮转化的过程以及输尿管分支和生长
，是由一个复杂而庞大的基因体系来导向，有些基因是肾特异性的，有些是非特异
的。某些生长因子基因，尽管它们在肾发生期表达活跃，但当它们被破坏时并不影
响肾的正常发育，这意味着发育肾正常表达的各种基因在功能上有重叠[9]。另一
种可能性是这种正常表达形式的破坏在肾发育不良的发生发展中起一定作用，或者
就是肾发育不良的起因。

后肾间质缺陷可导致肾发育不良。另外，基因不适应和错位表达，可能对肾
发育不良起一定作用。临床上有孤立的多囊性肾发育不良和梗阻性肾发育不良两者
并行存在的病例。先天性和实验性单基因突变均可导致囊性肾发育异常，这些基因
突变可改变相互联系。从理论上讲，突变可影响：①胚基增生和分化输尿管导管分
支所必需的肽和基质蛋白的表达；②输尿管导管对后肾胚基信号的反应能力；③输
尿管导管表达启动和维持后肾胚基上皮诱导所需蛋白的能力；④后肾胚基对这些信
号进行反应的能力；⑤输尿管芽和后肾胚基细胞对信号的反应能力[10]。

最近已经分离出磷酸葡萄糖肌醇糖蛋白基因，简称GPC3基因。GPC3缺失与多
囊性肾发育不良有关[11]。虽然单基因与多基因缺陷均可最终导致肾发育不良，但
其表型可能决定于最初受影响的基因调控失调或表达改变，如先天性梗阻性和囊性
肾发育不良[12，13]。多囊性发育不良肾，在囊性上皮和间质中均有生长因子基因
的改变。在小鼠梗阻性发育肾中，血管紧张素和转移生长因子呈过度表达[14]。研
究证明，在后肾发育异常区，促进小管上皮出现囊性改变的因子Pax2和Bcl-2同样
呈过度表达[15，16]。此研究可能会对各种形式肾发育不良的发病机制提供重要线
索。

求英语论文~~生物细胞有关的 150~200字

Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of an organism that is classified as a living thing, and is often called the building block of life.[1] Some organisms, such as most bacteria, are unicellular (consist of a single cell). Other organisms, such as humans, are multicellular. (Humans have an estimated 100 trillion or 1014 cells; a typical cell size is 10 µm; a typical cell mass is 1 nanogram.) The largest known cell is an unfertilized ostrich egg cell.[2]

In 1835 before the final cell theory was developed, Jan Evangelista Purkyně observed small "granules" while looking at the plant tissue through a microscope. The cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that all cells come from preexisting cells, that vital functions of an organism occur within cells, and that all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells.[3]

The word cell comes from the Latin cellula, meaning, a small room. The descriptive term for the smallest living biological structure was coined by Robert Hooke in a book he published in 1665 when he compared the cork cells he saw through his microscope to the small rooms monks lived in.[4]

[edit] General principles

Mouse cells grown in a culture dish. These cells grow in large clumps, but each individual cell is about 10 micrometres acrossEach cell is at least somewhat self-contained and self-maintaining: it can take in nutrients, convert these nutrients into energy, carry out specialized functions, and reproduce as necessary. Each cell stores its own set of instructions for carrying out each of these activities.

All cells have several different abilities:[5]

Reproduction by cell division: (binary fission/mitosis or meiosis).
Use of enzymes and other proteins coded for by DNA genes and made via messenger RNA intermediates and ribosomes.
Metabolism, including taking in raw materials, building cell components, converting energy, molecules and releasing by-products. The functioning of a cell depends upon its ability to extract and use chemical energy stored in organic molecules. This energy is released and then used in metabolic pathways.
Response to external and internal stimuli such as changes in temperature, pH or levels of nutrients.
Cell contents are contained within a cell surface membrane that is made from a lipid bilayer with proteins embedded in it.
Some prokaryotic cells contain important internal membrane-bound compartments,[6] but eukaryotic cells have a specialized set of internal membrane compartments.

[edit] Anatomy of cells
There are two types of cells: eukaryotic and prokaryotic. Prokaryotic cells are usually independent, while eukaryotic cells are often found in multicellular organisms.

[edit] Prokaryotic cells
Main article: Prokaryote

Diagram of a typical prokaryotic cellThe prokaryote cell is simpler than a eukaryote cell, lacking a nucleus and most of the other organelles of eukaryotes. There are two kinds of prokaryotes: bacteria and archaea; these share a similar overall structure.

A prokaryotic cell has three architectural regions:

on the outside, flagella and pili project from the cell's surface. These are structures (not present in all prokaryotes) made of proteins that facilitate movement and communication between cells;
enclosing the cell is the cell envelope – generally consisting of a cell wall covering a plasma membrane though some bacteria also have a further covering layer called a capsule. The envelope gives rigidity to the cell and separates the interior of the cell from its environment, serving as a protective filter. Though most prokaryotes have a cell wall, there are exceptions such as Mycoplasma (bacteria) and Thermoplasma (archaea)). The cell wall consists of peptidoglycan in bacteria, and acts as an additional barrier against exterior forces. It also prevents the cell from expanding and finally bursting (cytolysis) from osmotic pressure against a hypotonic environment. Some eukaryote cells (plant cells and fungi cells) also have a cell wall;
inside the cell is the cytoplasmic region that contains the cell genome (DNA) and ribosomes and various sorts of inclusions. A prokaryotic chromosome is usually a circular molecule (an exception is that of the bacterium Borrelia burgdorferi, which causes Lyme disease). Though not forming a nucleus, the DNA is condensed in a nucleoid. Prokaryotes can carry extrachromosomal DNA elements called plasmids, which are usually circular. Plasmids enable additional functions, such as antibiotic resistance.
[edit] Eukaryotic cells
Main article: Eukaryote

Diagram of a typical animal (eukaryotic) cell, showing subcellular components.
Organelles:
(1) nucleolus
(2) nucleus
(3) ribosome
(4) vesicle
(5) rough endoplasmic reticulum (ER)
(6) Golgi apparatus
(7) Cytoskeleton
(8) smooth endoplasmic reticulum
(9) mitochondria
(10) vacuole
(11) cytoplasm
(12) lysosome
(13) centrioles within centrosomeEukaryotic cells are about 15 times the size of a typical prokaryote and can be as much as 1000 times greater in volume. The major difference between prokaryotes and eukaryotes is that eukaryotic cells contain membrane-bound compartments in which specific metabolic activities take place. Most important among these is the presence of a cell nucleus, a membrane-delineated compartment that houses the eukaryotic cell's DNA. It is this nucleus that gives the eukaryote its name, which means "true nucleus." Other differences include:

The plasma membrane resembles that of prokaryotes in function, with minor differences in the setup. Cell walls may or may not be present.
The eukaryotic DNA is organized in one or more linear molecules, called chromosomes, which are associated with histone proteins. All chromosomal DNA is stored in the cell nucleus, separated from the cytoplasm by a membrane. Some eukaryotic organelles such as mitochondria also contain some DNA.
Many eukaryotic cells are ciliated with primary cilia. Primary cilia play important roles in chemosensation, mechanosensation, and thermosensation. Cilia may thus be "viewed as sensory cellular antennae that coordinate a large number of cellular signaling pathways, sometimes coupling the signaling to ciliary motility or alternatively to cell division and differentiation."[7]
Eukaryotes can move using motile cilia or flagella. The flagella are more complex than those of prokaryotes.
Table 1: Comparison of features of prokaryotic and eukaryotic cells Prokaryotes Eukaryotes
Typical organisms bacteria, archaea protists, fungi, plants, animals
Typical size ~ 1–10 µm ~ 10–100 µm (sperm cells, apart from the tail, are smaller)
Type of nucleus nucleoid region; no real nucleus real nucleus with double membrane
DNA circular (usually) linear molecules (chromosomes) with histone proteins
RNA-/protein-synthesis coupled in cytoplasm RNA-synthesis inside the nucleus
protein synthesis in cytoplasm
Ribosomes 50S+30S 60S+40S
Cytoplasmatic structure very few structures highly structured by endomembranes and a cytoskeleton
Cell movement flagella made of flagellin flagella and cilia containing microtubules; lamellipodia and filopodia containing actin
Mitochondria none one to several thousand (though some lack mitochondria)
Chloroplasts none in algae and plants
Organization usually single cells single cells, colonies, higher multicellular organisms with specialized cells
Cell division Binary fission (simple division) Mitosis (fission or budding)
Meiosis
Table 2: Comparison of structures between animal and plant cells Typical animal cell Typical plant cell
Organelles Nucleus
Nucleolus (within nucleus)
Rough endoplasmic reticulum (ER)
Smooth ER
Ribosomes
Cytoskeleton
Golgi apparatus
Cytoplasm
Mitochondria
Vesicles
Lysosomes
Centrosome
Centrioles
Vacuoles
Nucleus
Nucleolus (within nucleus)
Rough ER
Smooth ER
Ribosomes
Cytoskeleton
Golgi apparatus (dictiosomes)
Cytoplasm
Mitochondria

[edit] Subcellular components

The cells of eukaryotes (left) and prokaryotes (right)All cells, whether prokaryotic or eukaryotic, have a membrane that envelops the cell, separates its interior from its environment, regulates what moves in and out (selectively permeable), and maintains the electric potential of the cell. Inside the membrane, a salty cytoplasm takes up most of the cell volume. All cells possess DNA, the hereditary material of genes, and RNA, containing the information necessary to build various proteins such as enzymes, the cell's primary machinery. There are also other kinds of biomolecules in cells. This article will list these primary components of the cell, then briefly describe their function.

[edit] Cell membrane: A cell's defining boundary
Main article: Cell membrane
The cytoplasm of a cell is surrounded by a cell membrane or plasma membrane. The plasma membrane in plants and prokaryotes is usually covered by a cell wall. This membrane serves to separate and protect a cell from its surrounding environment and is made mostly from a double layer of lipids (hydrophobic fat-like molecules) and hydrophilic phosphorus molecules. Hence, the layer is called a phospholipid bilayer. It may also be called a fluid mosaic membrane. Embedded within this membrane is a variety of protein molecules that act as channels and pumps that move different molecules into and out of the cell. The membrane is said to be 'semi-permeable', in that it can either let a substance (molecule or ion) pass through freely, pass through to a limited extent or not pass through at all. Cell surface membranes also contain receptor proteins that allow cells to detect external signaling molecules such as hormones.

[edit] Cytoskeleton: A cell's scaffold
Main article: Cytoskeleton

Bovine Pulmonary Artery Endothelial cell: nuclei stained blue, mitochondria stained red, and F-actin, an important component in microfilaments, stained green. Cell imaged on a fluorescent cytoskeleton acts to organize and maintain the cell's shape; anchors organelles in place; helps during endocytosis, the uptake of external materials by a cell, and cytokinesis, the separation of daughter cells after cell division; and moves parts of the cell in processes of growth and mobility. The eukaryotic cytoskeleton is composed of microfilaments, intermediate filaments and microtubules. There is a great number of proteins associated with them, each controlling a cell's structure by directing, bundling, and aligning filaments. The prokaryotic cytoskeleton is less well-studied but is involved in the maintenance of cell shape, polarity and cytokinesis.[8]

[edit] Genetic material
Two different kinds of genetic material exist: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Most organisms use DNA for their long-term information storage, but some viruses (e.g., retroviruses) have RNA as their genetic material. The biological information contained in an organism is encoded in its DNA or RNA sequence. RNA is also used for information transport (e.g., mRNA) and enzymatic functions (e.g., ribosomal RNA) in organisms that use DNA for the genetic code itself. Transfer RNA (tRNA) molecules are used to add specific amino acids during the process of protein translation.

Prokaryotic genetic material is organized in a simple circular DNA molecule (the bacterial chromosome) in the nucleoid region of the cytoplasm. Eukaryotic genetic material is divided into different, linear molecules called chromosomes inside a discrete nucleus, usually with additional genetic material in some organelles like mitochondria and chloroplasts (see endosymbiotic theory).

A human cell has genetic material in the nucleus (the nuclear genome) and in the mitochondria (the mitochondrial genome). In humans the nuclear genome is divided into 23 pairs of linear DNA molecules called chromosomes. The mitochondrial genome is a circular DNA molecule distinct from the nuclear DNA. Although the mitochondrial DNA is very small compared to nuclear chromosomes, it codes for 13 proteins involved in mitochondrial energy production as well as specific tRNAs.

Foreign genetic material (most commonly DNA) can also be artificially introduced into the cell by a process called transfection. This can be transient, if the DNA is not inserted into the cell's genome, or stable, if it is. Certain viruses also insert their genetic material into the genome.

[edit] Organelles
Main article: Organelle
The human body contains many different organs, such as the heart, lung, and kidney, with each organ performing a different function. Cells also have a set of "little organs," called organelles, that are adapted and/or specialized for carrying out one or more vital functions.

There are several types of organelles within an animal cell. Some (such as the nucleus and golgi apparatus) are typically solitary, while others (such as mitochondria, peroxisomes and lysosomes) can be numerous (hundreds to thousands). The cytosol is the gelatinous fluid that fills the cell and surrounds the organelles.

Mitochondria and Chloroplasts – the power generators
Mitochondria are self-replicating organelles that occur in various numbers, shapes, and sizes in the cytoplasm of all eukaryotic cells. Mitochondria play a critical role in generating energy in the eukaryotic cell. Mitochondria generate the cell's energy by the process of oxidative phosphorylation, utilizing oxygen to release energy stored in cellular nutrients (typically pertaining to glucose) to generate ATP. Mitochondria multiply by splitting in two.
Organelles that are modified chloroplasts are broadly called plastids, and are involved in energy storage through the process of photosynthesis, which utilizes solar energy to generate carbohydrates and oxygen from carbon dioxide and water.[citation needed]
Mitochondria and chloroplasts each contain their own genome, which is separate and distinct from the nuclear genome of a cell. Both of these organelles contain this DNA in circular plasmids, much like prokaryotic cells, strongly supporting the evolutionary theory of endosymbiosis; since these organelles contain their own genomes and have other similarities to prokaryotes, they are thought to have developed through a symbiotic relationship after being engulfed by a primitive cell.[citation needed]
Ribosomes
The ribosome is a large complex of RNA and protein molecules. They each consist of two subunits, and act as an assembly line where mRNA from the nucleus is used to synthesise proteins from amino acids. Ribosomes can be found either floating freely or bound to a membrane (the rough endoplasmatic reticulum in eukaryotes, or the cell membrane in prokaryotes).[9]
Cell nucleus – a cell's information center
The cell nucleus is the most conspicuous organelle found in a eukaryotic cell. It houses the cell's chromosomes, and is the place where almost all DNA replication and RNA synthesis (transcription) occur. The nucleus is spherical in shape and separated from the cytoplasm by a double membrane called the nuclear envelope. The nuclear envelope isolates and protects a cell's DNA from various molecules that could accidentally damage its structure or interfere with its processing. During processing, DNA is transcribed, or copied into a special RNA, called mRNA. This mRNA is then transported out of the nucleus, where it is translated into a specific protein molecule. The nucleolus is a specialized region within the nucleus where ribosome subunits are assembled. In prokaryotes, DNA processing takes place in the cytoplasm.
Diagram of a cell nucleus
Endoplasmic reticulum – eukaryotes only
The endoplasmic reticulum (ER) is the transport network for molecules targeted for certain modifications and specific destinations, as compared to molecules that will float freely in the cytoplasm. The ER has two forms: the rough ER, which has ribosomes on its surface and secretes proteins into the cytoplasm, and the smooth ER, which lacks them. Smooth ER plays a role in calcium sequestration and release.
Golgi apparatus – eukaryotes only
The primary function of the Golgi apparatus is to process and package the macromolecules such as proteins and lipids that are synthesized by the cell. It is particularly important in the processing of proteins for secretion. The Golgi apparatus forms a part of the endomembrane system of eukaryotic cells. Vesicles that enter the Golgi apparatus are processed in a cis to trans direction, meaning they coalesce on the cis side of the apparatus and after processing pinch off on the opposite (trans) side to form a new vesicle in the animal cell.[citation needed]
Diagram of an endomembrane system
Lysosomes and Peroxisomes – eukaryotes only
Lysosomes contain digestive enzymes (acid hydrolases). They digest excess or worn-out organelles, food particles, and engulfed viruses or bacteria. Peroxisomes have enzymes that rid the cell of toxic peroxides. The cell could not house these destructive enzymes if they were not contained in a membrane-bound system. These organelles are often called a "suicide bag" because of their ability to detonate and destroy the cell.[citation needed]
Centrosome – the cytoskeleton organiser
The centrosome produces the microtubules of a cell – a key component of the cytoskeleton. It directs the transport through the ER and the Golgi apparatus. Centrosomes are composed of two centrioles, which separate during cell division and help in the formation of the mitotic spindle. A single centrosome is present in the animal cells. They are also found in some fungi and algae cells.[citation needed]
Vacuoles
Vacuoles store food and waste. Some vacuoles store extra water. They are often described as liquid filled space and are surrounded by a membrane. Some cells, most notably Amoeba, have contractile vacuoles, which are able to pump water out of the cell if there is too much water.

[edit] Structures outside the cell wall
[edit] Capsule
A gelatinous capsule is present in some bacteria outside the cell wall. The capsule may be polysaccharide as in pneumococci, meningococci or polypeptide as bacillus anthracis or hyaluronic acid as in streptococci.[citation needed] Capsules not marked by ordinary stain and can detected by special stain. The capsule is antigenic. The capsule has antiphagocytic function so it determines the virulence of many bacteria. It also plays a role in attachment of the organism to mucous membranes.[citation needed]

生物专业外语论文翻译

生物多样性和生态学的运转：
神奇的深海试验在不同的生态环境表现出 生物多样性和生态在运作过程中 之间关系接近全球性饱和
在对深海的分析中对此一般看法产生了致以
并指出种间的积极作用可能比预想的还要多样
Michel Loreau：人类正以各种行为改变生态社会的构成和多样性 导致了生物灭绝和生物入侵的加剧 并迈向全球化
这种变化在道德与美学的促使下受到关注 然而具有很大潜力改变生态的运转 并且同样作用于它们提供给人类的物品和辅助
生态运转时一把大伞 这个词用语形容生态工作的过程 也就是说 生化的能量周转与生态环境的关系（例，初级生产和营养的循环）
在过去的几十年里 这样的生物多样性的作用去没有体现在生态运转内成为很多专家关注并开发研究的方向
大多数有关生物多样性和生态学的运转的试验都采取野外试验的方式进行 这样在各种多样性中集中了典型的样品 以此测量人类影响对生物多样性和生态学的运转产生的变化
最近的meta-analyses研究表明生物多样性对生态运转大致会产生积极的效应 然而已达到饱和 一贯如此
在现代生物中近期发表的一篇学术报告却对此有所争议
在这片文章中Danovaro等人 通过比较全球的大量深海生态系统数据 指出 在海洋层面上 物种多样性与一些生态属性间的关系急剧增长
基于深海生态是世界上最泛的并且被认为在生物多样性中占到很大比例的 很大一部分尚未明了 比起以前更多人相信存在 不饱和的生物与环境的关系 这引起了很大关注 ：也许最简单的在深海生物环境的消退会对整个地球的生化运转产生巨大影响

最近正在学这个 比较感兴趣