細(xì)菌的生物學(xué)性狀ppt課件

1、第二章第二章 微生物的生物學(xué)性狀微生物的生物學(xué)性狀 (The biological Morphology of microbiology)微生物微生物microorganism包括包括 細(xì)菌、支原體、立克次體、衣原體、細(xì)菌、支原體、立克次體、衣原體、螺旋體和放線菌、病毒以及真菌。微生物的生物學(xué)性狀包括其形狀、螺旋體和放線菌、病毒以及真菌。微生物的生物學(xué)性狀包括其形狀、染色特性與構(gòu)造、生長繁衍與培育、理化性狀與分類。染色特性與構(gòu)造、生長繁衍與培育、理化性狀與分類。第一節(jié)第一節(jié) 細(xì)細(xì) 菌菌(bacterium)細(xì)菌細(xì)菌(bacterium)的定義的定義: 細(xì)菌是一種形體微小、構(gòu)造簡(jiǎn)單、無成形細(xì)細(xì)菌

2、是一種形體微小、構(gòu)造簡(jiǎn)單、無成形細(xì)胞核、亦無核仁和核膜胞核、亦無核仁和核膜,僅有核蛋白體的原核單細(xì)僅有核蛋白體的原核單細(xì)胞微生物胞微生物(prokaryote single-cell microorganism)。 細(xì)菌的根本特點(diǎn)細(xì)菌的根本特點(diǎn)(bacterias basic character)：具有細(xì)胞壁：具有細(xì)胞壁(cell wall)、原始的核質(zhì)、原始的核質(zhì)(original karyoplasm)，以二分裂方，以二分裂方式繁衍和對(duì)抗生素等藥物敏感式繁衍和對(duì)抗生素等藥物敏感(sensitive to antibiotic) 。一、一、 細(xì)菌的大小與形狀細(xì)菌的大小與形狀 (Size an

3、d shapes of bacterial )SIZE OF BACTERIA Unit for measurement : Micron or micrometer,m: 1m=10-3mm Size: Varies with kinds of bacteria, and also related to their age and external environment.lCocci: sphere, 1m lBacilli: rods , 0.5-1 m in width -3 m in length lSpiral bacteria: 13 m in length and 0.3-0.

4、6 m in width.細(xì)菌的大小細(xì)菌的大小(size of bacteria) 光學(xué)顯微鏡光學(xué)顯微鏡(light microscope); 丈量單位丈量單位:微微米米(m) 細(xì)菌的察看細(xì)菌的察看(optical methods)：細(xì)菌本身為無色半透明，：細(xì)菌本身為無色半透明，需經(jīng)過染色需經(jīng)過染色(staining)才干察看到細(xì)菌的形狀才干察看到細(xì)菌的形狀(morphology)輪廓輪廓figure和其構(gòu)造和其構(gòu)造(structure). 細(xì)菌的形狀細(xì)菌的形狀(morphology) :三大類形狀三大類形狀球菌球菌(coccus)、 桿菌桿菌(bacillus)和螺形菌和螺形菌(spiral

5、a bacterium)三大類三大類1、球菌、球菌(coccus):0.81.2m,外觀呈圓球性或近似外觀呈圓球性或近似球性球性(腎形、豆形等腎形、豆形等)(often occur in characteristic aggregates (pairs, chains, tetrads, clusters, etc.). 雙球菌雙球菌(diplococcus):一個(gè)平面上分裂一個(gè)平面上分裂,如腦膜炎如腦膜炎球菌、肺炎球菌。球菌、肺炎球菌。.鏈球菌鏈球菌(streptococcus):一個(gè)平面上分裂一個(gè)平面上分裂,分裂后多個(gè)菌體粘連分裂后多個(gè)菌體粘連成鏈狀。如溶血性鏈球菌成鏈狀。如溶血性鏈球菌(

6、hemolytic streptococcus) 。四聯(lián)球菌四聯(lián)球菌八疊球菌八疊球菌. 四聯(lián)球菌四聯(lián)球菌(retrad)、 八疊球菌八疊球菌(sarcina).葡萄球菌葡萄球菌(staphylococcus):多個(gè)不規(guī)那么的平面上分裂多個(gè)不規(guī)那么的平面上分裂,粘粘連成葡萄串狀。如金黃色葡萄球菌連成葡萄串狀。如金黃色葡萄球菌(staphyloccus aurea)。桿菌桿菌(bacillus) (bacilli, or cylindrical or rod-shapes cell)s 外形呈桿形，其大小、長短及粗細(xì)不一致，外形呈桿形，其大小、長短及粗細(xì)不一致，最大的如炭疽桿菌最大的如炭疽桿菌球桿

7、菌、鏈桿菌、梭桿菌、棒狀桿菌如白喉?xiàng)U球桿菌、鏈桿菌、梭桿菌、棒狀桿菌如白喉?xiàng)U菌及分支桿菌如結(jié)核分支桿菌。菌及分支桿菌如結(jié)核分支桿菌。 球桿菌球桿菌棒狀桿菌如白喉?xiàng)U菌棒狀桿菌如白喉?xiàng)U菌 diphtheria bacillus分支桿菌如結(jié)核分支桿菌分支桿菌如結(jié)核分支桿菌tubercle bacillus螺形菌螺形菌(spirala bacterium)(spiral or curved forms )弧菌弧菌(vibrio)：只需一個(gè)彎曲菌體長：只需一個(gè)彎曲菌體長23m，呈弧狀或逗點(diǎn)狀圖，呈弧狀或逗點(diǎn)狀圖1螺菌螺菌(spirillum)：有數(shù)個(gè)彎曲菌體較長：有數(shù)個(gè)彎曲菌體較長36m圖圖2圖圖1圖圖

8、2.總結(jié)總結(jié)(summarize) 細(xì)菌的形狀受溫度細(xì)菌的形狀受溫度(temperature)、PH、離子和培育時(shí)間等要素的影響。、離子和培育時(shí)間等要素的影響。選擇生長繁衍的對(duì)數(shù)期察看其大小及選擇生長繁衍的對(duì)數(shù)期察看其大小及形狀為宜形狀為宜Structure of BacteriaParticular structures capsule 莢膜莢膜flagella 鞭毛鞭毛pili 菌毛菌毛spore 芽胞芽胞細(xì)細(xì) 菌菌 的的 結(jié)結(jié) 構(gòu)構(gòu)(bacterias structure) 細(xì)菌的根本構(gòu)造細(xì)菌的根本構(gòu)造(Essential structure)細(xì)胞壁、細(xì)胞膜、細(xì)胞質(zhì)、核質(zhì)、核蛋細(xì)胞壁、細(xì)

9、胞膜、細(xì)胞質(zhì)、核質(zhì)、核蛋白體和質(zhì)粒白體和質(zhì)粒 細(xì)菌的特殊構(gòu)造細(xì)菌的特殊構(gòu)造(Particular structure)莢膜、鞭毛、菌毛、芽孢莢膜、鞭毛、菌毛、芽孢 二、細(xì)菌的根本構(gòu)造二、細(xì)菌的根本構(gòu)造(basic structure) 細(xì)菌的構(gòu)造分根本構(gòu)造細(xì)胞壁、細(xì)胞膜、細(xì)胞質(zhì)、核質(zhì)、核蛋細(xì)菌的構(gòu)造分根本構(gòu)造細(xì)胞壁、細(xì)胞膜、細(xì)胞質(zhì)、核質(zhì)、核蛋白體和質(zhì)粒和特殊構(gòu)造莢膜、鞭毛、菌毛、芽孢。白體和質(zhì)粒和特殊構(gòu)造莢膜、鞭毛、菌毛、芽孢。(Cell Wall、Cell Membrane、Cytoplasm 、Nucleics acids、plasmid) (一一)細(xì)胞壁細(xì)胞壁(cell wall):一種

10、膜狀構(gòu)造一種膜狀構(gòu)造;主要組分是主要組分是肽聚糖肽聚糖(peptidoglycan)(又稱粘肽又稱粘肽mucopeptide、糖肽或胞壁質(zhì)糖肽或胞壁質(zhì)),為細(xì)菌細(xì)胞壁原核生物細(xì)胞為細(xì)菌細(xì)胞壁原核生物細(xì)胞所特有的物質(zhì)。所特有的物質(zhì)。細(xì)胞壁的察看方法：膜壁分別法、特殊染色法以及電子顯微鏡察細(xì)胞壁的察看方法：膜壁分別法、特殊染色法以及電子顯微鏡察看等方法看等方法1.G+菌菌(Gram-Positive Cell Wall)的肽聚糖的肽聚糖(peptidoglycan):三部分組成三部分組成(1) 聚糖骨架：由聚糖骨架：由N-乙酰葡糖胺和乙酰葡糖胺和N-乙酰胞壁乙酰胞壁兩種氨基糖交替間隔陳列組成經(jīng)兩種

11、氨基糖交替間隔陳列組成經(jīng)-1,4糖苷糖苷鍵結(jié)合而成鍵結(jié)合而成(2) 四肽側(cè)鏈四肽側(cè)鏈:由由L-丙氨酸、丙氨酸、D-谷氨酸、谷氨酸、L-賴賴氨酸、氨酸、D-丙氨酸組成。丙氨酸組成。(3) 五肽交鏈橋：五個(gè)苷氨酸組成五肽交鏈橋：五個(gè)苷氨酸組成五肽交鏈橋?qū)⑾嗯R的兩條聚糖骨架銜接起來五肽交鏈橋?qū)⑾嗯R的兩條聚糖骨架銜接起來成三維立體構(gòu)造。成三維立體構(gòu)造。 Gram-Positive Cell Wall Most Gram-positive bacteria have a relatively thick (about 20 to 80 nm), continuous cell wall, which i

12、s composed largely of peptidoglycan (also known as mucopeptide or murein). In thick cell walls, other cell wall polymers (such as the teichoic acids, polysaccharides, and peptidoglycolipids) are covalently attached to the peptidoglycan.MMMMMMMMMMMMGGGGGGGGGGGGabcdabcdabcdabcdabcdabcdabcdabcdabcdabcd

13、abcdabcdG+ 菌的肽聚糖構(gòu)造： G：N-乙酰葡萄糖胺乙酰葡萄糖胺 M：N-乙酰胞壁酸乙酰胞壁酸2.G的肽聚糖的肽聚糖(peptidoglycan):二部分組二部分組成成(1) 聚糖骨架聚糖骨架:同同G+菌菌(2)四肽側(cè)鏈四肽側(cè)鏈:第三位氨基酸第三位氨基酸(L-賴氨酸賴氨酸)被被二氨基庚二酸二氨基庚二酸(DAP)取代取代G菌沒有五肽交鏈橋菌沒有五肽交鏈橋,故只構(gòu)成二維構(gòu)故只構(gòu)成二維構(gòu)造造Gram-Negative Cell Wall In contrast, the peptidoglycan layer in Gram-negative bacteria is thin (about

14、5 to 10 nm thick); in E coli, the peptidoglycan is probably only a monolayer thick. Outside the peptidoglycan layer in the Gram-negative envelope is an outer membrane structure (about 7.5 to 10 nm thick). In most Gram-negative bacteria, this membrane structure is anchored noncovalently to lipoprotei

15、n molecules (Brauns lipoprotein), which, in turn, are covalently linked to the peptidoglycan. The lipopolysaccharides of the Gram-negative cell envelope form part of the outer leaflet of the outer membrane structure.丙MGGGDAPMG丙丙丙谷谷DAPG-菌的肽聚糖構(gòu)造DAP：二氨基庚二酸：二氨基庚二酸3.G+菌細(xì)胞壁的特殊組分菌細(xì)胞壁的特殊組分(Special component

16、s of Gram positive cell wall ):磷壁酸磷壁酸(teichoic acid)及外及外表特殊蛋白組分表特殊蛋白組分(1)壁磷壁酸壁磷壁酸:經(jīng)過磷脂與肽聚糖的經(jīng)過磷脂與肽聚糖的M共價(jià)連結(jié)共價(jià)連結(jié)膜磷壁酸膜磷壁酸(又稱脂磷壁酸又稱脂磷壁酸LTA):末端糖脂與細(xì)胞末端糖脂與細(xì)胞膜外層的糖脂共價(jià)連結(jié)。另外，與細(xì)胞壁其他成膜外層的糖脂共價(jià)連結(jié)。另外，與細(xì)胞壁其他成分協(xié)同，能粘附在人體細(xì)胞外表，與細(xì)菌的致病分協(xié)同，能粘附在人體細(xì)胞外表，與細(xì)菌的致病性有關(guān)。性有關(guān)。 磷壁酸的抗原性很強(qiáng)，是磷壁酸的抗原性很強(qiáng)，是G+G+菌的重要外表抗原，與菌的重要外表抗原，與血清學(xué)分型有關(guān)。血清學(xué)分

17、型有關(guān)。G+ 菌的特殊組分:磷壁酸及一些外表蛋白膜磷壁酸壁磷壁酸肽聚糖細(xì)胞膜磷脂蛋白質(zhì)細(xì)胞壁脂質(zhì)雙層細(xì)胞膜肽聚糖微孔蛋白 脂多糖脂蛋白營養(yǎng)結(jié)合蛋白外膜周漿間隙4.G菌細(xì)胞壁的特殊組分菌細(xì)胞壁的特殊組分 Special components of Gram negative cell wall :外膜外膜(outer membrane)，是，是G-菌細(xì)胞壁的主要構(gòu)造。由三部分組成菌細(xì)胞壁的主要構(gòu)造。由三部分組成脂質(zhì)雙層：中間嵌有蛋白質(zhì)，稱為外膜蛋白脂質(zhì)雙層：中間嵌有蛋白質(zhì)，稱為外膜蛋白lipoprotein ，其中，其中包括孔蛋白，具有物質(zhì)交換作用，并具有通透性屏障作用，能阻止包括孔蛋白，具有物

18、質(zhì)交換作用，并具有通透性屏障作用，能阻止多種大分子物質(zhì)和青霉素、溶菌酶等進(jìn)入細(xì)胞。所以，多種大分子物質(zhì)和青霉素、溶菌酶等進(jìn)入細(xì)胞。所以， G菌對(duì)青菌對(duì)青霉素、溶菌酶以及去污劑和堿性染料等比霉素、溶菌酶以及去污劑和堿性染料等比G+菌有較大的抵抗力。菌有較大的抵抗力。有的外膜蛋白還是噬菌體、細(xì)菌素和性菌毛的受體有的外膜蛋白還是噬菌體、細(xì)菌素和性菌毛的受體 脂質(zhì)雙層脂多糖脂多糖LipopolysacchrideLipopolysacchride，LPSLPS : :由脂質(zhì)由脂質(zhì)A,A,中心多中心多糖和特異性多糖組成糖和特異性多糖組成脂質(zhì)A:內(nèi)毒素生物活性主要組分,無種屬 特異性中心多糖:有屬特異性特

19、異多糖: G-菌的菌體抗原(O抗原), 有種特異性 Gram negative bacteria major permeability barrier(通透性屏障通透性屏障 space between inner and outer membrane periplasmic space周漿間隙周漿間隙 store degradative enzymes降解酶降解酶 Gram positive bacteria no periplasmic spaceOuter Membrane5.細(xì)胞壁細(xì)胞壁(cell wall)的功能的功能(function):(1) 維持菌體的固有形狀及抵抗低滲環(huán)境維持菌

20、體的固有形狀及抵抗低滲環(huán)境;(2) 參與菌體內(nèi)外物質(zhì)交換；參與菌體內(nèi)外物質(zhì)交換；(3)帶有多種抗原，誘發(fā)機(jī)體產(chǎn)生免疫應(yīng)對(duì)并與血帶有多種抗原，誘發(fā)機(jī)體產(chǎn)生免疫應(yīng)對(duì)并與血清分型有關(guān)如清分型有關(guān)如 磷壁酸、磷壁酸、M蛋白。蛋白。(4) 參與細(xì)菌的致?。簠⑴c細(xì)菌的致?。篖TA具有粘附致病作用具有粘附致病作用; M蛋白具有抗吞噬作用，并對(duì)蛋白具有抗吞噬作用，并對(duì)Tcel及及Bcel等免疫細(xì)胞等免疫細(xì)胞有生物活性作用。有生物活性作用。Functions of Cell Wall Maintaining the cells characteristic shape- the rigid wall compe

21、nsates for the flexibility of the phospholipid membrane and keeps the cell from assuming a spherical shape Countering the effects of osmotic pressure Providing attachment sites for bacteriophages Providing a rigid platform for surface appendages- flagella, fimbriae, and pili all emanate from the wal

22、l and extend beyond it Play an essential role in cell division Be the sites of major antigenic determinants of the cell surface。 Resistance of Antibiotics 6細(xì)胞壁缺陷型細(xì)菌細(xì)胞壁缺陷型細(xì)菌L型細(xì)菌型細(xì)菌L-formed bacteria ：(1)構(gòu)成緣由構(gòu)成緣由:肽聚糖構(gòu)造受理化或生物要素肽聚糖構(gòu)造受理化或生物要素(例青霉例青霉素素(penicillin)和溶菌酶和溶菌酶(lysozyme) )的破壞及合成被的破壞及合成被抑制抑制Wall-

23、less forms of Bacteria. When bacteria are treated with 1) enzymes that are lytic for the cell wall e.g. lysozyme or 2) antibiotics that interfere with biosynthesis of peptidoglycan, wall-less bacteria are often produced. Usually these treatments generate non-viable organisms. Wall-less bacteria that

24、 can not replicate are referred to as spheroplasts (when an outer membrane is present) or protoplasts (if an outer membrane is not present). Occasionally wall-less bacteria that can replicate are generated by these treatments (L forms).(2) 形狀形狀:多型性多型性;均為均為G陰性；去除誘導(dǎo)要素后，陰性；去除誘導(dǎo)要素后，L型型可回復(fù)為原菌可回復(fù)為原菌L型葡萄球菌

25、葡萄球菌(3)培育特性培育特性(properties of culturing): 需 提 高 培 育 基 的 浸 透 壓 需 提 高 培 育 基 的 浸 透 壓 ( 補(bǔ) 充補(bǔ) 充 3 -5%NaCl,10-20%的蔗糖的蔗糖;另加另加10-20%的人的人或馬血清或馬血清);菌落特點(diǎn)菌落特點(diǎn):荷包蛋樣菌落或在液體培育基荷包蛋樣菌落或在液體培育基中呈疏松的絮狀顆粒、沉于管底而培育基中呈疏松的絮狀顆粒、沉于管底而培育基廓清。廓清。原菌菌落原菌菌落荷包蛋樣荷包蛋樣L型菌落型菌落(4)致病性致病性(pathogenesis): 通常引起慢性感染，如尿路感染多見、骨通常引起慢性感染，如尿路感染多見、骨髓

26、炎、心內(nèi)膜炎髓炎、心內(nèi)膜炎(普通培育往往陰性普通培育往往陰性) ；常在運(yùn)用；常在運(yùn)用了作用于細(xì)胞壁的抗菌藥物后發(fā)生了作用于細(xì)胞壁的抗菌藥物后發(fā)生二細(xì)胞膜二細(xì)胞膜(cell envelope) 參與物質(zhì)轉(zhuǎn)運(yùn)、生物合成和分泌、呼吸并與參與物質(zhì)轉(zhuǎn)運(yùn)、生物合成和分泌、呼吸并與細(xì)胞分裂有關(guān)等作用細(xì)胞分裂有關(guān)等作用 三細(xì)胞質(zhì) (cytoplasm)1.核蛋白體(ribosome):細(xì)菌合成蛋白質(zhì)的場(chǎng)所;70%RNA+30%蛋白質(zhì);70S(50S+30S): Ribosomal are 70S with subunits 30S (16S rRNA) and 50S (5S & 23S rRNA)鏈

27、霉素和紅霉素作用于50S及30S亞基,干擾蛋白質(zhì)的合成2.質(zhì)粒質(zhì)粒(plasmid): 染色體外的遺傳物質(zhì)；染色體外的遺傳物質(zhì)； 閉合環(huán)狀雙股閉合環(huán)狀雙股DNA,控制細(xì)菌的某些特定遺傳控制細(xì)菌的某些特定遺傳性狀性狀; 能獨(dú)立進(jìn)展復(fù)制而分配到子代細(xì)胞中去能獨(dú)立進(jìn)展復(fù)制而分配到子代細(xì)胞中去; 控制的外形非細(xì)菌生命活動(dòng)所必需控制的外形非細(xì)菌生命活動(dòng)所必需; 分子生物學(xué)研討中重要的載體工具。分子生物學(xué)研討中重要的載體工具。質(zhì)粒控制的外形有：性菌毛生成、耐藥性、細(xì)質(zhì)?？刂频耐庑斡校盒跃?、耐藥性、細(xì)菌素產(chǎn)生、毒素構(gòu)成等。菌素產(chǎn)生、毒素構(gòu)成等。PlasmidPlasmids are small，cir

28、cular/line，extrachromosomal，double-stranded DNA molecules。They are capable of self-replication and contain genes that confer some properties，such as antibiotic resistance，virulence factors。Plasmids are not essential for cellular survival. lInclusions are aggregates of various compounds that are norm

29、ally involved in storing energy reserves or building blocks for the cell. Inclusions accumilate when a cell is grown in the presence of excess nutrients and they are often observed under laboratory conditions.granulosegranulose bacterial replication3.胞質(zhì)顆粒胞質(zhì)顆粒(cytoplasmic granules,又稱內(nèi)含物又稱內(nèi)含物) 大多為貯藏的營

30、養(yǎng)物質(zhì)大多為貯藏的營養(yǎng)物質(zhì);主要成分主要成分:RNA和多偏磷酸和多偏磷酸(嗜堿性強(qiáng)嗜堿性強(qiáng),甲基蘭染色成異染顆粒甲基蘭染色成異染顆粒,亦稱紆回體。在白亦稱紆回體。在白喉?xiàng)U菌中稱極體喉?xiàng)U菌中稱極體)(五五) 核核 質(zhì)質(zhì)(nuclear material)1. Size and shapes of bacterial1. Size and shapes of bacterialThe shapesof medically important bacteria are classified into the The shapesof medically important bacteria are

31、classified into the following general forms: following general forms: (1)(1)cocci, or spherical cells; often occur in characteristic cocci, or spherical cells; often occur in characteristic aggregates (pairs, chains, tetrads, clusters, etc.).aggregates (pairs, chains, tetrads, clusters, etc.).(2)(2)

32、bacilli, or cylindrical or rod-shapes cells;bacilli, or cylindrical or rod-shapes cells;(3)(3)spiral or curved forms.spiral or curved forms.conclusionconclusion2. Bacterial Cell Structure2. Bacterial Cell Structure2.1 Basic Structures of Bacterial2.1 Basic Structures of Bacterial2.1.1 Cell Wall2.1.1

33、 Cell Wall Most bacteria of medical importance possess one of Most bacteria of medical importance possess one of two basic types of cell wall architecture, which are two basic types of cell wall architecture, which are referred to as Gram-positive or Gram-negative. The one referred to as Gram-positi

34、ve or Gram-negative. The one component common to both walls is a large polymer, component common to both walls is a large polymer, commonly referred to as peptidoglycan or monly referred to as peptidoglycan or murein.2.1.1.1 Gram-Positive Cell Wall2.1.1.1 Gram-Positive Cell Wall Most Gram-positive b

35、acteria have a relatively thick Most Gram-positive bacteria have a relatively thick (about 20 to 80 nm), continuous cell wall, which is (about 20 to 80 nm), continuous cell wall, which is composed largely of peptidoglycan (also known as composed largely of peptidoglycan (also known as mucopeptide or

36、 murein). In thick cell walls, other cell mucopeptide or murein). In thick cell walls, other cell wall polymers (such as the teichoic acids, wall polymers (such as the teichoic acids, polysaccharides, and peptidoglycolipids) are covalently polysaccharides, and peptidoglycolipids) are covalently atta

37、ched to the peptidoglycan.attached to the peptidoglycan.2.1.1.2 Gram-Negative Cell Wall2.1.1.2 Gram-Negative Cell Wall In contrast, the peptidoglycan layer in Gram-negative bacteria In contrast, the peptidoglycan layer in Gram-negative bacteria is thin (about 5 to 10 nm thick); in E coli, the peptid

38、oglycan is is thin (about 5 to 10 nm thick); in E coli, the peptidoglycan is probably only a monolayer thick. Outside the peptidoglycan layer probably only a monolayer thick. Outside the peptidoglycan layer in the Gram-negative envelope is an outer membrane structure in the Gram-negative envelope is

39、 an outer membrane structure (about 7.5 to 10 nm thick). In most Gram-negative bacteria, this (about 7.5 to 10 nm thick). In most Gram-negative bacteria, this membrane structure is anchored noncovalently to lipoprotein membrane structure is anchored noncovalently to lipoprotein molecules (Brauns lip

40、oprotein), which, in turn, are covalently molecules (Brauns lipoprotein), which, in turn, are covalently linked to the peptidoglycan. The lipopolysaccharides of the Gram-linked to the peptidoglycan. The lipopolysaccharides of the Gram-negative cell envelope form part of the outer leaflet of the oute

41、r negative cell envelope form part of the outer leaflet of the outer membrane structure.membrane structure.2.1.2 Cell Membrane2.1.2 Cell Membrane Oxidative phosphorylation( Oxidative phosphorylation(氧化磷酸化氧化磷酸化 occurs at cell occurs at cell membrane (since there are no mitochondria).membrane (since there are no mitochondria). Cell membraneThe cell wall is outside of cell membrane rigid, protecting cell from osmotic lysis.Cell Wall2.1.3 Cytoplasm2.1.3 Cytoplas