復(fù)旦大學(xué)細(xì)胞生物學(xué)課件02細(xì)胞的統(tǒng)一性與多樣性

1、Chapter 2 Uniformity and Diversity of the cellLearning Objectives1. Look briefly at the history of cell theory;2. Consider the basic properties of cells;3. Compare some characteristics of two different classes of cells: prokaryotes and eukaryotes;4. Comprehend a special life: viruses1. The Cell Theo

2、ry: A Brief HistoryIn 1665, Robert Hooke saw a network of tiny boxlike compartments that reminded him of a honeycomb. Then He called these little compartments cellulae, a Latin term meaning little room. It is from this word we get our present-day term, cell. The microscope used by Robert Hooke and t

3、he honeycomb- like network of cell he drawed in 1665The discovery of cells followed from the invention of the microscopeCell theory has three basic tenets:1. All organisms are composed of one or more cells.2.The cell is basic unit of structure and function for all organisms.3.All cells arise only fr

4、om preexisting cells by division.2. Why are cells the basic units of life?A. The cell is the structural unit of life, All organisms is make up of cells.B.The cell is the functional unit of organisms. All metabolic activity is based on cells. C. The cell is the foundation of reproduce, and the bridge

5、 of inheritance. The cell possess common genetic language. D. The cell is the growing and developing basis of lifeHuman fetal development. (a)At 5 weeks, limb buds, eyes, the heart, the liver and rudiments of all other organs have started to develop in the embryo, which is only about 1cm long. (b)Gr

6、owth and development of the offspring, now called a fetus, continue during the second trimester. This fetus is 14 weeks old and about 6cm long. (c)The fetus in this photograph is 20 weeks old. Now the fetus grows to about 30cm in length.E. Cell (nucleus) is totipotent, which can create a new organis

7、m of the same type As a general rule, the cells of a multicellular organism all contain the same set of genes. For animals, the first evidence that even highly specialized cell carry a full complement of genes was verified by the experiment of tadpole nuclei transplanting into unfertilized egg that

8、had been deprived of its own nucleus. Some can develop swimming tadpoles. This is animal cloning. An especially dramatic example of animal cloning was reported in 1997. Dolly the first animal ever cloned from a cell derived from an adult. Dolly and her daughterThe process of cloning DollyIs there an

9、y practical value to such technology?Cell is end-result of life origin and fundation of organism evolutionG. No cell, No full life.Virus :Euvirus( virus): DNA or RNA and proteins complex Viroid: The infective RNA constitute, discover Grow about 20 remainings Virus of 朊 ( prion):infective proteins3.

10、Basic properties of cellsCells are highly complex and organized, capable of self-regulation;Cells acquire and utilize energy.C. All cells share similar structure, composition and metabolic features: Plasma membrane, DNA/RNA, and Ribosome.D. Cells can capable of producing more of themselves, even gro

11、w and reproduce in culture for extended periods.HeLa cells are cultured tumor cells isolated from a cancer patient named Henrietta Lacks in 1951. It is the first human cell to be kept in culture for long periods of time and is still used today.Johns Hopkins univesity,in 1951E. Cells are able to resp

12、ond to stimuli via surface receptors that sense changes in the chemical environment.Cells within plant or animal respond to stimuli less obviously than single-celled protist. But they respond. They posses receptors that interact with substances in the environment in highly specific ways. For example

13、, the receptor on the cell surface can respond to hormones and growth factors.5.The Size of Cellsdiameter Measured in units of Cell micrometers: 1um=10-6 meter nanometers: 1nm=10-9 meterc) Cell size is limited: nucleus/cytoplasm ratio;surface area/volume ratio;substances can efficiently travel throu

14、gh the cytoplasm via diffusion. 幾種顯微鏡觀察樣品大小的范圍6. Two fundamentally different classes of cells: Prokaryotes and eukaryotesA. Prokaryotic and eukaryotic cells are distinguished by the size and the types of internal structures, or organelles, especially if there is nuclear envelope. Bacteria are prokar

15、yotes, they arose 3.5 billion years ago;Protists, fungi, plants, and animals are eukaryotes. The first eukaryotes arose 1.5 billion years ago.B. Characteristics that distinguish prokaryotic and eukaryotic cellsComplexity: Prokaryotes are relatively simple, eukaryotes are more complex in structure an

16、d functionpp.36 Table 2-2;2-3真核細(xì)胞與原核細(xì)胞基本特征的比較 特征 原核細(xì)胞 真核細(xì)胞細(xì)胞膜核膜染色體核外DNA胞質(zhì)區(qū)域化細(xì)胞骨架核糖體細(xì)胞增殖有（行使多種功能） 有 無 有裸露DNA，無組蛋白 DNA與組蛋白結(jié)合 含有質(zhì)粒DNA 線粒體與葉綠體DNA 簡(jiǎn)單（無細(xì)胞器） 復(fù)雜有各種細(xì)胞器 無 有（MT、MF、IF） 70S型（30S和50S） 80S型（40S和60S） 無絲分裂 有絲分裂、減數(shù)分裂真核細(xì)胞與原核細(xì)胞的遺傳結(jié)構(gòu)裝置和基因表達(dá)的比較 特 征 原核細(xì)胞 真核細(xì)胞遺傳信息量基因組 DNA重復(fù)序列內(nèi)含子 RNA聚合酶 DNA復(fù)制轉(zhuǎn)錄與翻譯加工與修飾表達(dá)調(diào)控

17、 小 大 n 2n 環(huán)狀、裸露DNA 線形、染色體 罕見 大量存在 無 有 一種復(fù)合體 三種：pol、 無明顯周期性 有明顯周期性（S期） 同時(shí)、同地 先轉(zhuǎn)錄（核）后翻譯（質(zhì)） 無 有復(fù)雜的加工過程 操縱子形式 多層次、多環(huán)節(jié) 特 征 動(dòng)物細(xì)胞 植物細(xì)胞有無質(zhì)體（葉綠體）有無細(xì)胞壁有無大的中央液胞細(xì)胞膜離子泵營(yíng)養(yǎng)吸收無，異養(yǎng)營(yíng)養(yǎng) 有，自養(yǎng)營(yíng)養(yǎng) 無 有（纖維素和果膠質(zhì)） 無 有（代謝調(diào)節(jié)作用） 鈉-鉀ATP酶 質(zhì)子ATP酶 Na+驅(qū)動(dòng)共運(yùn)轉(zhuǎn) H+驅(qū)動(dòng)共運(yùn)轉(zhuǎn) 植物細(xì)胞與動(dòng)物細(xì)胞的比較 (2) Genetic material: All Cells Store Their Hereditary In

18、formation in the Same Liner Chemical Code (DNA)Packaging: Prokaryotes have a nucleoid region whereas ekukaryote have a true, membrane-bound nucleus.b. Amount:Eukaryotes have several orders of magnitude more genetic material than prokaryotes.c. Form: Eukaryotes have many chromosomes that are made of

19、both DNA and protein whereas prokaryotes have a single DNA chromosomePackaging: Prokaryotes have a nucleoid region whereas ekukaryote have a true, membrane-bound nucleus. (bacterinm:0.25-3.0 mm, to encode between several hundred and several thousand proteins,The simplest known cells have just under

20、500 genes).b. Amount:Eukaryotes have several orders of magnitude more genetic material than prokaryotes.(yeast:4.6mm DNA,encoding about 6200 proteins)c. Form: The Eukaryotes have many chromosomes that are made of both DNA and protein whereas prokaryotes have a single, naked DNA chromosome(3) Cytopla

21、sm: Eukaryotes have membrane-bound organelles and cytoskeletal proteins; prokaryotes have neither. Both have ribosomes, although they differ in size.(4) Cellular reproduction: Eukaryotes divide by mitosis; prokaryotes divide by simple fission.(5) Locomotion: Eukaryotes use both cytoplasmic movement,

22、 and cilia and flagella; prokaryotes have flagella, but they differ in both form and mechanism from eukaryotic flagella. The difference between prokaryotic and eukaryotic flagelaFlagellin Human spermC.Three structural systems in Eukaryotes:D. Tree of life has three primary branches.原核生物真核生物生命的六角大廈原核

23、生物古核生物真核生物細(xì)胞壁肽聚糖蛋白質(zhì)或假肽聚糖多糖、幾丁質(zhì)基因組結(jié)構(gòu)環(huán)狀DNA，有質(zhì)粒環(huán)狀DNA，有質(zhì)粒DNA與類組蛋白形成類似染色質(zhì)的結(jié)構(gòu)線形DNA具有染色質(zhì)結(jié)構(gòu)DNA復(fù)制DNA聚合酶的氨基酸序列介于二者之間RNA轉(zhuǎn)錄RNA聚合酶可在體外轉(zhuǎn)錄RNA聚合酶靠轉(zhuǎn)錄因子幫助以識(shí)別啟動(dòng)子。序列與真核生物更相似，有TATAbox結(jié)構(gòu)轉(zhuǎn)錄因子幫助以識(shí)別啟動(dòng)子。轉(zhuǎn)錄起點(diǎn)前有TATA box 結(jié)構(gòu)基因結(jié)構(gòu)具有操縱子結(jié)構(gòu)?；蛑袥]有內(nèi)含子具有操縱子結(jié)構(gòu)。蛋白質(zhì)序列更類似于真核生物。rRNA和tRNA基因中有內(nèi)含子基因中存在內(nèi)含子蛋白質(zhì)翻譯起始氨基酸為甲酰甲硫氨酸起始氨基酸為甲硫氨酸起始氨基酸為甲硫氨酸原核生

24、物，古核生物，真核生物的比較E.Types of Prokaryotic Cells: Two SubkingdomsSubkingdom ArchaeaSubkingdom Bacteria Most Bacteria and Archaea have 1000-4000 genes The smallest known cells -the Mycoplasma 0.1-0.3 ms; smallest genome: 482 genes, Minimal essential gene:256細(xì)菌性疾病1空氣傳播的細(xì)菌病 ：白喉；軍團(tuán)菌熱；腦膜炎；百日咳；丹毒；鏈球菌肺炎；結(jié)核病;猩紅熱；2節(jié)肢動(dòng)物媒介的病毒病 ：斑疹傷寒；鼠疫3直接接觸傳播的病毒?。禾烤?；淋??；麻風(fēng)??； 梅毒；破傷風(fēng)；砂眼；4食物和水傳播的病毒?。喝舛局卸?；霍亂；傷寒；膿毒性休克；5其它細(xì)菌病 ：牙菌斑；齲齒; 幽門螺旋桿菌；與A類鏈球菌感染有關(guān)的病癥煙草花葉病毒(tobacco mosaic virus, TMV)正常煙草葉煙草“花葉”1892年，俄國(guó)生物學(xué)家Dimitri Iwanovsky 發(fā)現(xiàn)患病煙草葉片汁經(jīng)細(xì)菌濾器過濾后仍有致病性。1935年，美國(guó)科學(xué)家