《生物科学专业英语》PPT课件.ppt

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1、生物专业英语Inside the Living CellStructure and Function of Internal Cell partsGlossaryn nCytoplasm Cytoplasm 细胞质细胞质细胞质细胞质n nThe living contents of a cell bounded The living contents of a cell bounded externally by the plasmalemma,externally by the plasmalemma,including an aqueous ground including an aque

2、ous ground substance(hyaloplasm,substance(hyaloplasm,透明质，透明质，透明质，透明质，cell cell sap,or cell matrix)containing sap,or cell matrix)containing organelles and various inclusions but organelles and various inclusions but excluding the nucleus and visible excluding the nucleus and visible vacuoles.vacuoles

3、.细胞中的亚器官n nChloroplast Chloroplast 叶绿体叶绿体叶绿体叶绿体n n A plastid in which photosynthesis is A plastid in which photosynthesis is carried out.Chloroplasts occur in all carried out.Chloroplasts occur in all photosynthetic organisms except photosynthetic organisms except photosynthetic bacteria and blue-gr

4、een photosynthetic bacteria and blue-green algae.algae.n nStroma 子座，基质n n Region within a chloroplast that has no chlorophyll.n nPlastid 质体n n An organelle present in all plants except bacteria,blue-green algae,and fungi;it is enclosed by two membranes(the envelope)and has various functionsn nEndopl

5、asmic reticulum Endoplasmic reticulum 内质网内质网内质网内质网n n Folded membranes and tubes Folded membranes and tubes throughout the eukaryotic cell that throughout the eukaryotic cell that provide a large surface upon which provide a large surface upon which chemical activities take place.chemical activities

6、 take place.n nGolgi complex Golgi complex 高尔基复合体高尔基复合体高尔基复合体高尔基复合体n n A stack of flattened,smooth,A stack of flattened,smooth,memebranous sacs;the site of memebranous sacs;the site of synthesis and packaging of certain synthesis and packaging of certain molecules in eukaryotic cells.molecules in eu

7、karyotic cells.n nMitochondrion Mitochondrion 线粒体线粒体线粒体线粒体n n A membranous organelle resembling a A membranous organelle resembling a small bag with a larger bag inside that is small bag with a larger bag inside that is folded back on itself;serve as the site of folded back on itself;serve as the si

8、te of aerobic cellular respiration.aerobic cellular respiration.n nRibosome Ribosome 核糖体核糖体n n Small structures composed of two protein Small structures composed of two protein and ribonucleic acid subunits involved in the and ribonucleic acid subunits involved in the assembly of proteins from amino

9、 acidsassembly of proteins from amino acidsn nPolysome 多核糖体n n Of protein synthesis,several ribosomes all translating the same messenger RNA molecule,one after the other.n nVacuole Vacuole 液泡液泡n n Storage container within the cytoplasm Storage container within the cytoplasm of a cell having a surrou

10、nding membrane.of a cell having a surrounding membrane.n nLysosome 溶酶体溶酶体n n A specialized organelle that holds a mixture of hydrolytic enzymesn nCentriole 中心粒中心粒n n An organelle located close to the nucleus in most animal and lower plant cells but absent from prokaryotes and higher plants细胞的遗传亚结构细胞

11、核和染色体细胞核和染色体n nChromosome 染色体染色体n n A DNA-histone thread residing in the nucleus of a cell.Each chromosome possesses two telomeres and a centromere,and some contain a nucleous organizer.RNA proteins are invariably associated with the chromosome.n nNuclear envelope Nuclear envelope 核膜，核被膜核膜，核被膜核膜，核被膜

12、核膜，核被膜n n A double membrane(two lipid A double membrane(two lipid bilayers and associated proteins)that bilayers and associated proteins)that is the outermost portion of a cell is the outermost portion of a cell nucleous.nucleous.n nNucleoid Nucleoid 核质体核质体核质体核质体n n The DNA-containing area of a The

13、DNA-containing area of a prokaryote cell,analogous to prokaryote cell,analogous to eukaryote nucleus but not membrane eukaryote nucleus but not membrane bounded.bounded.n nNucleoli Nucleoli 核仁核仁核仁核仁n n Nuclear structures composed of Nuclear structures composed of completed or partially completed com

14、pleted or partially completed ribosomes and the specific parts of ribosomes and the specific parts of chromosomes that contain the chromosomes that contain the information for their construction.information for their construction.n nNucleus 细胞核，神经核细胞核，神经核n n The organelle of the eukaryote cell that

15、contains the chromosomes and hence ultimately controls cellular activity and inheritance through the activity of the genetic material,DNA.细胞运动结构和骨架细胞运动结构和骨架n nCytoskeleton Cytoskeleton 细胞骨架细胞骨架细胞骨架细胞骨架n n Of eukaryotic cells,an internal“skeleton”.Of eukaryotic cells,an internal“skeleton”.Its microtu

16、bules and other components Its microtubules and other components structurally support the cell,organize and structurally support the cell,organize and move its internal components.The move its internal components.The cytoskeleton also helps free-living cells cytoskeleton also helps free-living cells

17、 move through their environmentmove through their environment.n nMicrotubule Microtubule 微管微管微管微管n n Small,hollow tubes of protein that Small,hollow tubes of protein that function throughout the cytoplasm to function throughout the cytoplasm to provide strucutural support and provide strucutural sup

18、port and enable movement.enable movement.n nMicrofilament Microfilament 微丝，纤丝微丝，纤丝微丝，纤丝微丝，纤丝n n Long,fiberlike structures made of Long,fiberlike structures made of protein and found in cells,often in protein and found in cells,often in close association with the close association with the microtubul

19、e;provide structural microtubule;provide structural support and enable movement.support and enable movement.n nCilia 纤毛纤毛n n Numerous short,hairlike structures projecting from the cell surface that enable locomotion.n nFlagella 鞭毛鞭毛n n Long,hairlike structures projecting from the cell surface that e

20、nable locomotion.n nActin Actin 肌动蛋白肌动蛋白肌动蛋白肌动蛋白n n A globular contractile protein.In muscle A globular contractile protein.In muscle cells,actin interacts with another protein,cells,actin interacts with another protein,myosein,to bring about contraction.myosein,to bring about contraction.n nDynein

21、Dynein 动力蛋白动力蛋白动力蛋白动力蛋白n n A group of at least four distinct proteins A group of at least four distinct proteins found in the flagella and microtubules of found in the flagella and microtubules of eukaryotic cells and possessing ATPase eukaryotic cells and possessing ATPase activity.activity.n nMyos

22、in Myosin 肌球蛋白肌球蛋白肌球蛋白肌球蛋白n n A protein that,with actin,constitutes the A protein that,with actin,constitutes the principal element of the contractile principal element of the contractile apparatus of muscle.apparatus of muscle.n nTubulin 微管蛋白n n A protein that is the major constituent of microtubul

23、es.n nBasal body 基体基体n n A body identical in structure to a centriole,found always at the base of a cilium or eukaryote flagellum.n nChemotaxis 趋化性趋化性n n A locomotory movement of an organism or cell in response to,and directed by,an external directional stimulus.n nPhagocytosis 吞噬作用n n The process b

24、y which the cell wraps around a particle and engulfs it.n nPinocytosis 胞饮作用n n The process by which a cell engulfs some molecules dissolved in water.胞饮作用胞饮作用Cytoplasm细胞质The dynamic,Mobile FactorySemifluid 半流体Plasma membrane 质膜Organelle细胞器官Cytoskeleton 细胞骨架n nMost of the properties we associated with

25、 life are properties of the cytoplasm.n nMuch of the mass of a cell consists of this semifluid substance,which is bounded on the outside by the plasma membrane.n nOrganelles are suspended within it,supported by the filamentous network of the cytoskeleton.n nDissolved in the cytoplasmic fluid are nut

26、rients,ions,soluble proteins,and other materials needed for cell functioning.Nucleus细胞核Eukaryotic 真核细胞的Prokaryote 原核细胞Hereditary 遗传的Sac 液囊细胞核和染色体细胞核和染色体n n The eukaryotic cell nucleus is the largest organelle and houses the genetic material(DNA)on chromosomes.n n In prokaryotes the hereditary materi

27、al is found in the nucleoid.n n The nucleus also contains one or two orgenelles-the nucleoli-that play a role in cell division.n nA pore-perforated sac called the nuclear envelope separates the nucleus and its contents from the cytoplasm.n nSmall molecules can pass through the nuclear envelope,but l

28、arger molecules such as MRNA and ribosomes must enter and exit via the poresOrganelle 细胞器官Amino acid Amino acid 氨基酸氨基酸 LacyLacy花边花边 Vesicle Vesicle 小泡小泡Stud Stud 布满布满Fat Fat 脂肪脂肪Steroid Steroid 胆固醇胆固醇Oxidation Oxidation 氧化氧化Sugar Sugar 糖糖digestive 消化的carbohydrate 碳水化合物Leucoplast白色体Pigment色素Starch淀粉C

29、hromoplast色素细胞Grana叶绿素基粒细胞结构细胞结构n nAll eukaryotic cells contain most of the various kinds of organelles,and each organelle performs a specialized function in the cell.n nOrganelles described in this section include ribosomes,the endoplasmic reticulum,the Golgi complex,vacuoles,mitochondria,and the p

30、lastids of plant cells.n n The number of ribosomes within a cell may range from a few hundred to many thousands.n n 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.n nA complete ribosome is composed

31、 of one larger and one smaller subunit.n nDuring protein synthesis the two subunits move along a strand of MRNA,“reading”the genetic sequence coded in it and translating that sequence into protein.n nSeveral ribosomes may become attached to a single MRNA strand;such a combination is called a polysom

32、e.n nMost cellular proteins are manufactured on ribosomes in the cytoplasm.n nExportable proteins and membrane proteins are usually made in association with the endoplasmic reticulum.n nThe endoplasmic reticulum,a lacy array of membranous sacs,tubules,and vesicles,may be either rough(RER)and smooth(

33、SER).n nBoth types play roles in the synthesis and transport of proteins.n nThe RER,which is studded with polysomes,also seems to be the source of the nuclear envelope after a cell divides.n nSER lacks polysomes;it is active in the synthesis of fats and steroids and in the oxidation of toxic substan

34、ce in the cell.n nBoth 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.内质网内质网n n Transport vesicles may carry exportable molecules from the endoplasmic reticulum to anothe

35、r membranous organelle,the Golgi complex.n nWithin the Golgi complex molecules are modified and packaged for export out of the n ncell or for delivery else where in n nthe cytoplasm.高尔基体高尔基体液泡液泡n nVacuoles in cells appear to be hollow sacs but are actually filled with fluid and soluble molecules.n n

36、The most prominent vaculoes appear in plant cells and serve as water reservoirs and storage sites for surgars and other molecules.n nVacuoles in animal cells carry out phagocytosis(吞噬作用吞噬作用)(the intake of particulate matter)and pinocytosis(胞饮作用胞饮作用)(vacuolar drinking).胞饮作用胞饮作用n nA subset of vacuoles

37、 is the A subset of vacuoles is the organelles known as lysosomes which organelles known as lysosomes which contain digestive enzymes(packaged contain digestive enzymes(packaged in lysosomes in the Golgi complex)in lysosomes in the Golgi complex)that can break down most biological that can break dow

38、n most biological macromolecules.macromolecules.n nThey act to digest food particles and They act to digest food particles and to degrade damaged cell parts.to degrade damaged cell parts.线粒体线粒体n nMitochondria are the sites of energy-yielding chemical reactions in all cells.n nin addition,plant cells

39、 contain plastids that utilize light energy to manufacture carbohydrates in the process of photosynthesis.n nIt is on the large surface area provided by the inner cristae of mitochondria that ATP-generating enzymes are located.n nMitochondria are self-replicating,and probably they are the evolutiona

40、ry descendants of what were once free-living prokaryotes.叶绿体立体结构n nThere are two types of plastids,leucoplasts(白色体白色体),which lack pigments and serve as storage sites for starch,proteins,and oils;and chromoplasts(色素母细胞色素母细胞),which contain pigments.n n The most important chromoplasts are chloroplasts-

41、organelles that contain the chlorophyll used in photosynthesis.n nThe internal structure of chloroplasts includes stacks of membranes called grana(叶绿体基叶绿体基粒粒),which are embedded,in a matrix called the stroma(基质基质).Cytoskeleton细胞骨架Convoluted 回旋Latticework格子状Mechanoenzyme功能酶Kinesin运动蛋白n nAll eukryotes

42、 cells have a cytoskeleton,which is a convoluted latticework of filaments and tubules that appears to available space in the cell and provides support for various other organelles.n nA large portion of the cytoskeleton consists of threadlike microfilaments composed mainlly of the contractile protein

43、 actin.n nThey are involved in many types of intracellular movements in plant and animal cells.n nA second protein,myosin is involve in the contraction of muscle cells.n nAnother main structural component of the cytoskeleton consists of microtubules,which are composed of the globular protein tubulin

44、 and together act as scaffolding that provides a stable cell shape.n nCytoskeletal intermediate filaments appear to impart tensile strength to the cell cytoplasm.Mechanoenzymes such as myosin,dynein and kinesin interact with the cytoskeletal filaments and tubulins to generate forces that cause movem

45、ents.Cellular movements细胞运动Creep 爬行Glide 滑动Geometry 几何Propel推动Spindle 纺锤体n nAlthough the cytosketeton provides some stability to cells,its microtubules and filaments and their associated proteins enable cells to move by creeping or gliding.n nSuch movements require a substrate to which the cell can

46、adhere and can be guided by the geometry of the surface.n nSome cells also exhibit chemotaxis,the ability to move toward or away from the source of a diffusing chemical.n nCertain eukaryotic cells can swim Certain eukaryotic cells can swim freely in liquid environments,freely in liquid environments,

47、propelled by whiplike cilia(propelled by whiplike cilia(纤毛纤毛纤毛纤毛)and)and flagellaflagella（鞭毛）（鞭毛）（鞭毛）（鞭毛）.n nBoth cilia and flagella have the Both cilia and flagella have the same internal structure:nine doublets same internal structure:nine doublets(pairs or microtubules)are arraged in(pairs or mic

48、rotubules)are arraged in a ring and extend the length of the a ring and extend the length of the cilium or flagellum,and two more cilium or flagellum,and two more microtubules run down the enter of microtubules run down the enter of the ring.the ring.n nEvery cilium or flagellum grows only from the

49、cell surface where a basal body is located.n nMovement is based on the activities of tiny dynein side arms that extend from one of the microtubules of each doublet.n nNutrients,proteins,and other materials within most plant cells are moved about via cytoplasmic streaming.n nThe process occurs as myo

50、sin proteins attached to organelles push against microfilaments arrayed throughout the cell.n nMicrofilaments and microtubules are responsible for almost all major cytoplasmic movements.n nDuring cell division,microtubules of the spindle-assembled from tubulin subunits near organells called centriol