生物工程专业英语1.ppt

* * * * * * * * * * * * Mitochondria are self-replicating, and probably they are the evolutionary descendants of what were once free-living prokaryotes.线粒体自我复制，并且可能是自由生活的原核生物在进化中形成的后代。 There are two types of plastids: leucoplasts, which lack pigments and serve as storage sites for starch, proteins, and oils; and chromoplasts, which contain pigments. 质体有两种类型：白色体，缺乏色素，是淀粉，蛋白质和油的储备场所；色质体，含有色素。 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, which are embedded in a matrix called the stroma. 叶绿体是最重要的色质体，含有与光合作用有关的叶绿素。叶绿体的内部结构是由多层膜形成的叶绿体基粒，其中包埋在基质中的基粒称子座。 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. The Cytoskeleton（细胞骨架） All eukaryotic cells have a cytoskeleton, which is a convoluted（回旋） latticework(格子状) of filaments and tubules that appears to fill all available space in the cell and provides support for various other organelles. 所有的细胞都有细胞骨架，网络结构的纤丝充满了它所能触及的全部空间并且对细胞器提供支持作用。 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. A large portion of the cytoskeleton consists of threadlike microfilaments composed mainly of the contractile protein actin. They are involved in many types of intracellular movements in plant and animal cells. 细胞骨架大部分由微丝组成，微丝主要由可收缩的肌动蛋白组成。动植物