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细胞中的液泡好象是中空的，但实际上充满了液体和可溶分子。最典型的液泡存在于植物细胞中，储备水，糖以及其它分子。动物中的液泡起吞噬和胞饮作用。
A subset of vacuoles are 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.
内织网，一组花边状的囊、泡、微管，可以是粗糙（RER）也可以是光滑（SER）的。二者都在蛋白质的合成和运输中起作用。粗糙型内织网上散布着多核糖体，似乎是细胞分裂后核膜的来源。光滑型内织网缺少多核糖体；它在细胞的脂肪胆固醇合成和有毒物质的氧化中起作用。两种类型的内织网都可以作为细胞内的间隔间，在那里特殊的物质能够被隔离并且被挤到特定的区域里或细胞之外。
真核细胞的核是最大的细胞器，容纳着染色体上的遗传物质（DNA），而在原核生物中，遗传物质存在于类核中，细胞核中还含有一至两个细胞器；核仁，在细胞分裂中起一定的作用。一个有穿孔的袋子叫做核膜，将细胞核与它的内涵物与细胞膜分开。小分子可以透过核膜，但是大分子。比如mRNA和核糖体则必须通过核孔来进出。
anelles: specialized work units细胞器：特化的工作单元
更小的液泡是叫做溶酶体的细胞器，含有消化酶（包裹在溶酶体和高尔基体中），可以分解大分子。他们起作用来消化食物颗粒和降解有害细胞的碎片。
Mitoehondria 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.
all eukaryotic cells contain most of the various kinds of organelles,and each organell performs a specialized function in the cell. Organelles described in this section include ribosomes, the endoplasmic reticulum, the endoplasmic reticulum, the Golgi complex, vacuoles, lysosomes, mitochondria, and the plastids of plant cells.
1. Cytoplasm: The Dynamic, Mobile Factory细胞质：动力工厂
Most of the properties we associate with life are properties of the cytoplasm.Must 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 netwok of the cytoskeleton. Dissolved in the cytoplasmic fluid are nutrients, ions, soluble proteins, and other materials needed for cell functioning.
the eukaryotic cell nucleus is the largest organelle and houses the geneticmaterial on chromosomes. (in prokaryotes the hereditary material is found in the nucleoid.) the nucleus also cantains one or two organelles-the nucleoli-that play a role in cell division. A pore-perforated sac called the nuclear envelop separates the nucleus and its contents from the cytoplasm. Small molecules can pass through the nuclear envelope, but larger molecules such as mRNter and exit via the pores.
我们能够联想到的与生命有关的特性与细胞质有关。一个细胞内容的大部分都是由这种半流质的物质组成，它的外部被细胞膜所包围着。细胞器悬浮在里面，由细胞架中的丝状结构所支撑，溶解在细胞质流质内部的是营养物离子，可溶性蛋白和其他细胞生理活动所需的物质。
2.the nucleus: information central细胞核：信息中心
Theendoplasmic reticulum,a lacy array of membranous sacs,tubules, and vesicles, may be either rough (RER) or 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 substances 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.
Transport vesicles may carry exportable molecules from the endoplasmic reticulum to another membranous organelle,theGolgi complex.Within the Golgi complex molecules are modified and packaged for export out of the cell or for delivery else where in the cytoplasm.
一个细胞内的核糖体数目可以从几百到几千。这些数量反映了这个事实：核糖体是氨基酸合成蛋白质的场所，再用于运输和在细胞中使用。一个完整的核糖体有一个大的和一个小的亚基组成。在蛋白质的合成过程中，两个亚基沿着一条mRNA链移动，阅读其上的基因序列密码，并将其翻译成蛋白质。几个核糖体可以附着在一条mRNA链上，这样的复合体叫做多核糖体。大多数的蛋白质是在细胞质内的核糖体上合成的。运输蛋白和膜蛋白的制造通常与内织网有关。
运输泡能够将可运输分子从内织网中转移另一个膜细胞器，高尔基体中。在高尔基体内，复杂的分子被修饰和包装，为了能够运输到细胞之外和转移到细胞质的其它地方。
Vacuolesin cells appear to be hollow sacs but are actually filled with fluid and soluble molecules.The most prominent vacuoles appear in plant cells and serve as water reservoirs and storage sites for sugars and other molecules. Vacuoles in animal cells carry outphagocytosis(the intake of particulate matter) andpinocytosis(vacuolar drinking).
所有的真核细胞都含有大部分的各种各样的细胞器，每一个胞器在细胞中执行一个特殊的功能。在这一节中所描述的细胞器包括核糖体、内织网、高尔基体、液泡、溶酶体、线粒体、和植物细胞的质体。
The number ofribosomeswithin 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 apolysome.Most cellular proteins are manufactured on ribosomes in the cytoplasm. Exportable proteins and membrane proteins are usually made in association with the endoplasmic reticulum.
A subset of vacuoles are 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.
内织网，一组花边状的囊、泡、微管，可以是粗糙（RER）也可以是光滑（SER）的。二者都在蛋白质的合成和运输中起作用。粗糙型内织网上散布着多核糖体，似乎是细胞分裂后核膜的来源。光滑型内织网缺少多核糖体；它在细胞的脂肪胆固醇合成和有毒物质的氧化中起作用。两种类型的内织网都可以作为细胞内的间隔间，在那里特殊的物质能够被隔离并且被挤到特定的区域里或细胞之外。
真核细胞的核是最大的细胞器，容纳着染色体上的遗传物质（DNA），而在原核生物中，遗传物质存在于类核中，细胞核中还含有一至两个细胞器；核仁，在细胞分裂中起一定的作用。一个有穿孔的袋子叫做核膜，将细胞核与它的内涵物与细胞膜分开。小分子可以透过核膜，但是大分子。比如mRNA和核糖体则必须通过核孔来进出。
anelles: specialized work units细胞器：特化的工作单元
更小的液泡是叫做溶酶体的细胞器，含有消化酶（包裹在溶酶体和高尔基体中），可以分解大分子。他们起作用来消化食物颗粒和降解有害细胞的碎片。
Mitoehondria 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.
all eukaryotic cells contain most of the various kinds of organelles,and each organell performs a specialized function in the cell. Organelles described in this section include ribosomes, the endoplasmic reticulum, the endoplasmic reticulum, the Golgi complex, vacuoles, lysosomes, mitochondria, and the plastids of plant cells.
1. Cytoplasm: The Dynamic, Mobile Factory细胞质：动力工厂
Most of the properties we associate with life are properties of the cytoplasm.Must 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 netwok of the cytoskeleton. Dissolved in the cytoplasmic fluid are nutrients, ions, soluble proteins, and other materials needed for cell functioning.
the eukaryotic cell nucleus is the largest organelle and houses the geneticmaterial on chromosomes. (in prokaryotes the hereditary material is found in the nucleoid.) the nucleus also cantains one or two organelles-the nucleoli-that play a role in cell division. A pore-perforated sac called the nuclear envelop separates the nucleus and its contents from the cytoplasm. Small molecules can pass through the nuclear envelope, but larger molecules such as mRNter and exit via the pores.
我们能够联想到的与生命有关的特性与细胞质有关。一个细胞内容的大部分都是由这种半流质的物质组成，它的外部被细胞膜所包围着。细胞器悬浮在里面，由细胞架中的丝状结构所支撑，溶解在细胞质流质内部的是营养物离子，可溶性蛋白和其他细胞生理活动所需的物质。
2.the nucleus: information central细胞核：信息中心
Theendoplasmic reticulum,a lacy array of membranous sacs,tubules, and vesicles, may be either rough (RER) or 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 substances 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.
Transport vesicles may carry exportable molecules from the endoplasmic reticulum to another membranous organelle,theGolgi complex.Within the Golgi complex molecules are modified and packaged for export out of the cell or for delivery else where in the cytoplasm.
一个细胞内的核糖体数目可以从几百到几千。这些数量反映了这个事实：核糖体是氨基酸合成蛋白质的场所，再用于运输和在细胞中使用。一个完整的核糖体有一个大的和一个小的亚基组成。在蛋白质的合成过程中，两个亚基沿着一条mRNA链移动，阅读其上的基因序列密码，并将其翻译成蛋白质。几个核糖体可以附着在一条mRNA链上，这样的复合体叫做多核糖体。大多数的蛋白质是在细胞质内的核糖体上合成的。运输蛋白和膜蛋白的制造通常与内织网有关。
运输泡能够将可运输分子从内织网中转移另一个膜细胞器，高尔基体中。在高尔基体内，复杂的分子被修饰和包装，为了能够运输到细胞之外和转移到细胞质的其它地方。
Vacuolesin cells appear to be hollow sacs but are actually filled with fluid and soluble molecules.The most prominent vacuoles appear in plant cells and serve as water reservoirs and storage sites for sugars and other molecules. Vacuoles in animal cells carry outphagocytosis(the intake of particulate matter) andpinocytosis(vacuolar drinking).
所有的真核细胞都含有大部分的各种各样的细胞器，每一个胞器在细胞中执行一个特殊的功能。在这一节中所描述的细胞器包括核糖体、内织网、高尔基体、液泡、溶酶体、线粒体、和植物细胞的质体。
The number ofribosomeswithin 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 apolysome.Most cellular proteins are manufactured on ribosomes in the cytoplasm. Exportable proteins and membrane proteins are usually made in association with the endoplasmic reticulum.