生物科学专业英语.ppt

生物专业英语,Inside the Living Cell,Structure and Function of Internal Cell parts,Glossary,Cytoplasm 细胞质 The living contents of a cell bounded externally by the plasmalemma, including an aqueous ground substance (hyaloplasm, 透明质，cell sap, or cell matrix) containing organelles and various inclusions but excluding the nucleus and visible vacuoles.,细胞中的亚器官,Chloroplast 叶绿体 A plastid in which photosynthesis is carried out. Chloroplasts occur in all photosynthetic organisms except photosynthetic bacteria and blue-green algae.,Stroma 子座，基质 Region within a chloroplast that has no chlorophyll. Plastid 质体 An organelle present in all plants except bacteria, blue-green algae, and fungi; it is enclosed by two membranes (the envelope) and has various functions,Endoplasmic reticulum 内质网 Folded membranes and tubes throughout the eukaryotic cell that provide a large surface upon which chemical activities take place.,Golgi complex 高尔基复合体 A stack of flattened, smooth, memebranous sacs; the site of synthesis and packaging of certain molecules in eukaryotic cells.,Mitochondrion 线粒体 A membranous organelle resembling a small bag with a larger bag inside that is folded back on itself; serve as the site of aerobic cellular respiration.,Ribosome 核糖体 Small structures composed of two protein and ribonucleic acid subunits involved in the assembly of proteins from amino acids,Polysome 多核糖体 Of protein synthesis, several ribosomes all translating the same messenger RNA molecule, one after the other.,Vacuole 液泡 Storage container within the cytoplasm of a cell having a surrounding membrane.,Lysosome 溶酶体 A specialized organelle that holds a mixture of hydrolytic enzymes Centriole 中心粒 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,细胞核和染色体,Chromosome 染色体 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.,Nuclear envelope 核膜，核被膜 A double membrane (two lipid bilayers and associated proteins) that is the outermost portion of a cell nucleous. Nucleoid 核质体 The DNA-containing area of a prokaryote cell, analogous to eukaryote nucleus but not membrane bounded. Nucleoli 核仁 Nuclear structures composed of completed or partially completed ribosomes and the specific parts of chromosomes that contain the information for their construction.,Nucleus 细胞核，神经核 The organelle of the eukaryote cell that 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,Cytoskeleton 细胞骨架 Of eukaryotic cells, an internal “skeleton”. Its microtubules and other components structurally support the cell, organize and move its internal components. The cytoskeleton also helps free-living cells move through their environment.,Microtubule 微管 Small, hollow tubes of protein that function throughout the cytoplasm to provide strucutural support and enable movement. Microfilament 微丝，纤丝 Long, fiberlike structures made of protein and found in cells, often in close association with the microtubule; provide structural support and enable movement.,Cilia 纤毛 Numerous short, hairlike structures projecting from the cell surface that enable locomotion. Flagella 鞭毛 Long, hairlike structures projecting from the cell surface that enable locomotion.,Actin 肌动蛋白 A globular contractile protein. In muscle cells, actin interacts with another protein, myosein, to bring about contraction. Dynein 动力蛋白 A group of at least four distinct proteins found in the flagella and microtubules of eukaryotic cells and possessing ATPase activity. Myosin 肌球蛋白 A protein that, with actin, constitutes the principal element of the contractile apparatus of muscle.,Tubulin 微管蛋白 A protein that is the major constituent of microtubules.,Basal body 基体 A body identical in structure to a centriole, found always at the base of a cilium or eukaryote flagellum. Chemotaxis 趋化性 A locomotory movement of an organism or cell in response to, and directed by, an external directional stimulus.,Phagocytosis 吞噬作用 The process by which the cell wraps around a particle and engulfs it. Pinocytosis 胞饮作用 The process by which a cell engulfs some molecules dissolved in water.,胞饮作用,Cytoplasm细胞质The dynamic, Mobile Factory,Semifluid 半流体 Plasma membrane 质膜 Organelle细胞器官 Cytoskeleton 细胞骨架,Most of the properties we associated with life are properties of the cytoplasm. Much of the mass of a cell consists of this semifluid substance, which is bounded on the outside by the plasma membrane.,Organelles are suspended within it, supported by the filamentous network of the cytoskeleton. Dissolved in the cytoplasmic fluid are nutrients, 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,The eukaryotic cell nucleus is the largest organelle and houses the genetic material (DNA) on chromosomes. In prokaryotes the hereditary material is found in the nucleoid. The nucleus also contains one or two orgenelles-the nucleoli-that play a role in cell division.,A pore-perforated sac called the nuclear envelope separates the nucleus and its contents from the cytoplasm. Small molecules can pass through the nuclear envelope, but larger molecules such as MRNA and ribosomes must enter and exit via the pores,Organelle 细胞器官,Amino acid 氨基酸 Lacy花边 Vesicle 小泡 Stud 布满 Fat 脂肪 Steroid 胆固醇 Oxidation 氧化 Sugar 糖,digestive 消化的 carbohydrate 碳水化合物 Leucoplast白色体 Pigment色素 Starch淀粉 Chromoplast色素细胞 Grana叶绿素基粒,细胞结构,All eukaryotic cells contain most of the various kinds of organelles, and each organelle performs a specialized function in the cell. Organelles described in this section include ribosomes, the endoplasmic reticulum, the Golgi complex, vacuoles, mitochondria, and the plastids of plant cells.,The number of ribosomes within a cell may range from a few hundred to many thousands. 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. A complete ribosome is composed of one larger and one smaller subunit.,During protein synthesis the two subunits move along a strand of MRNA, “reading” the genetic sequence coded in it and translating that sequence into protein. Several ribosomes may become attached to a single MRNA strand; such a combination is called a polysome.,Most cellular proteins are manufactured on ribosomes in the cytoplasm. Exportable proteins and membrane proteins are usually made in association with the endoplasmic reticulum.,The endoplasmic reticulum, a lacy array of membranous sacs, tubules, and vesicles, may be either rough (RER) and smooth (SER). Both types play roles in the synthesis and transport of proteins. The RER, which is studded with polysomes, also seems to be the source of the nuclear envelope after a cell divides.,SER lacks polysomes; it is active in the synthesis of fats and steroids and in the oxidation of toxic substance in the cell. Both 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, Transport vesicles may carry exportable molecules from the endoplasmic reticulum to another membranous organelle, the Golgi complex. Within the Golgi complex molecules are modified and packaged for export out of the cell or for delivery else where in the cytoplasm.,高尔基体,液泡,Vacuoles in cells appear to be hollow sacs but are actually filled with fluid and soluble molecules. The most prominent vaculoes appear in plant cells and serve as water reservoirs and storage sites for surgars and other molecules.,Vacuoles in animal cells carry out phagocytosis (吞噬作用) (the intake of particulate matter) and pinocytosis (胞饮作用) (vacuolar drinking).,胞饮作用,A subset of vacuoles is the organelles known as lysosomes which contain digestive enzymes (packaged in lysosomes in the Golgi complex) that can break down most biological macromolecules. They act to digest food particles and to degrade damaged cell parts.,线粒体,Mitochondria are the sites of energy-yielding chemical reactions in all cells. in addition, plant cells contain plastids that utilize light energy to manufacture carbohydrates in the process of photosynthesis.,It is on the large surface area provided by the inner cristae of mitochondria that ATP-generating enzymes are located. Mitochondria are self-replicating, and probably they are the evolutionary descendants of what were once free-living prokaryotes.,叶绿体立体结构,There are two types of plastids, leucoplasts (白色体), which lack pigments and serve as storage sites for starch, proteins, and oils; and chromoplasts(色素母细胞), which contain pigments. The most important chromoplasts are chloroplasts-organelles that contain the chlorophyll used in photosynthesis.,The internal structure of chloroplasts includes stacks of membranes called grana(叶绿体基粒) , which are embedded, in a matrix called the stroma (基质).,Cytoskeleton细胞骨架,Convoluted 回旋 Latticework格子状 Mechanoenzyme功能酶 Kinesin运动蛋白,All eukryotes 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.,A large portion of the cytoskeleton consists of threadlike microfilaments composed mainlly of the contractile protein actin. They are involved in many types of intracellular movements in plant and animal cells.,A second protein, myosin is involve in the contraction of muscle cells. Another main structural component of the cytoskeleton consists of microtubules, which are composed of the globular protein tubulin and together act as scaffolding that provides a stable cell shape.,Cytoskeletal 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 movements.,Cellular movements细胞运动,Creep 爬行 Glide 滑动 Geometry 几何 Propel推动 Spindle 纺锤体,Although the cytosketeton provides some stability to cells, its microtubules and filaments and their associated proteins enable cells to move by creeping or gliding.,Such movements require a substrate to which the cell can adhere and can be guided by the geometry of the surface. Some cells also exhibit chemotaxis, the ability to move toward or away from the source of a diffusing chemical.,Certain eukaryotic cells can swim freely in liquid environments, propelled by whiplike cilia (纤毛) and flagella（鞭毛）. Both cilia and flagella have the same internal structure: nine doublets (pairs or microtubules) are arraged in a ring and extend the length of the cilium or flagellum, and two more microtubules run down the enter of the ring.,Every cilium or flagellum grows only from the cell surface where a basal body is located. Movement is based on the activities of tiny dynein side arms that extend from one of the microtubules of each doublet.,Nutrients, proteins, and other materials within most plant cells are moved about via cytoplasmic streaming. The process occurs as myosin proteins attached to organelles push against microfilaments arrayed throughout the cell.,Microfilaments and microtubules are responsible for almost all major cytoplasmic movements. During cell division, microtubules of the spindle-assembled from tubulin subunits near organells called centrioles (中心粒)-move the chromosomes,Matching,Polysome (g) RNA and ribosomes Golgi complex (o) packaging Flagella (m) whiplike Phagocytosis (f) engulfment,Basal body (d) where flagella grow Chemotactic (e) toward or away from a chemical stimulus Ribosome (a) protein synthesis Cytoskeleton (h) weblike Mitochondrion (c) power generator,Ture or False,1 the DNA of prokaryotic cells is concentrated in the nucleus (F) 3 Unlike other cell membranes, the nuclear envelope has no pores (F),6 The nuclear envelope is produced by the rough endoplasmic reticulum (T) 7 Most celluar proteins are manufactured on ribosomes (T),10 Mitochondria are self-replicating (T) 11 Pinocytosis describes the intake of fluid into a cell by a vacuole (T),