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所在平台: Udemy |
课程主页: https://www.udemy.com/course/biology-cell-the-unit-of-life/
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本课程《生命的基本单位：细胞》深入探讨了构成所有生命形式的细胞。课程首先介绍了细胞的多样性，包括它们的形状、大小和功能，并根据是否存在膜结合的细胞核和其他细胞器，将细胞（以及生物体）分为真核细胞和原核细胞。 课程详细阐述了典型真核细胞的结构，包括细胞膜、细胞核和细胞质。特别指出，植物细胞在细胞膜外拥有细胞壁。 课程重点介绍了细胞膜（质膜）的选择性渗透特性及其在分子运输中的作用。 课程还详细介绍了内膜系统，包括内质网 (ER)、高尔基复合体、溶酶体和液泡，并解释了这些细胞器各自的特定功能。 此外，课程也讨论了中心体和中心粒在鞭毛和纤毛的基体形成中的作用，以及在动物细胞分裂中形成纺锤体。 细胞核被描述为包含核仁和染色质网络，它不仅调控细胞器的活动，还在遗传中扮演关键角色。 内质网（粗面内质网和滑面内质网）在物质运输、蛋白质、脂蛋白和糖原的合成中发挥作用。 高尔基体由扁平囊组成，负责包装和转运细胞的分泌物。 溶酶体含有消化各种大分子的酶。 核糖体是蛋白质合成的场所，它们可以游离于细胞质中，也可以附着于内质网。 线粒体是能量生成的中心，负责氧化磷酸化和三磷酸腺苷的产生，并具有双层膜结构，内膜形成嵴。 课程特别介绍了植物细胞中的质体，包括叶绿体（进行光合作用）和其它着色体（如类胡萝卜素和叶黄素）。叶绿体的基粒是光反应的场所，基质是暗反应的场所。 最后，课程描述了由双层核膜构成的细胞核，核膜上有核孔，内膜包裹着核质和染色质。 总而言之，本课程强调了细胞作为生命结构和功能基本单位的重要性。
SUMMARYAll organisms are made of cells or aggregates of cells. Cells vary in their shape, size and activities/functions. Based on the presence or absence of a membrane bound nucleus and other organelles, cells and hence organisms can be named as eukaryotic or prokaryotic.A typical eukaryotic cell consists of a cell membrane, nucleus and cytoplasm. Plant cells have a cell wall outside the cell membrane. The plasma membrane is selectively permeable and facilitates transport of several molecules. The endomembrane system includes ER, golgi complex, lysosomes and vacuoles. All the cell organelles perform different but specific functions. Centrosome and centriole form the basal body of cilia and flagella that facilitate locomotion. In animal cells, centrioles also form spindle apparatus during cell division. Nucleus contains nucleoli and chromatin network. It not only controls the activities of organelles but also plays a major role in heredity.Endoplasmic reticulum contains tubules or cisternae. They are of two types: rough and smooth. ER helps in the transport of substances, synthesis of proteins, lipoproteins and glycogen. The golgi body is a membranous organelle composed of flattened sacs. The secretions of cells are packed in them and transported from the cell. Lysosomes are single membrane structures containing enzymes for digestion of all types of macromolecules. Ribosomes are involved in protein synthesis. These occur freely in the cytoplasm or are associated with ER. Mitochondria help in oxidative phosphorylation and generation of adenosine triphosphate. They are bound by double membrane; the outer membrane is smooth and inner one folds into several cristae. Plastids are pigment containing organelles found in plant cells only. In plant cells, chloroplasts are responsible for trapping light energy essential for photosynthesis. The grana, in the plastid, is the site of light reactions and the stroma of dark reactions. The green coloured plastids are chloroplasts, which contain chlorophyll, whereas the other coloured plastids are chromoplasts, which may contain pigments like carotene and xanthophyll. The nucleus is enclosed by nuclear envelope, a double membrane structure with nuclear pores. The inner membrane encloses the nucleoplasm and the chromatin material. Thus, cell is the structural and functional unit of life.
