The Cytoskeleton

Most eukaryotic cells contain a complex network of protein fibers called the cytoskeleton. It forms a framework for the movement of organelles around the cytoplasm - most of the organelles are attached to the cytoskeleton. The network consists of protein microfilaments, intermediate filaments, and microtubules.

The cytoskeleton provides an important structural framework for:

1. Cell shape. For cells without cell walls, the cytoskeleton determines the shape of the cell. This is one of the functions of the intermediate filaments.
   细胞形状。对于没有细胞壁的细胞，细胞骨架决定细胞的形状。这是中间纤维的一种功能。
2. Cell movement. The dynamic collection of microfilaments and microtubles can be continually in the process of assembly and disassembly, resulting in forces that move the cell. There can also be sliding motions of these structures. Audesirk and Audesirk give examples of white blood cells "crawling" and the migration and shape changes of cells during the development of multicelled organisms.
   细胞运动。微丝和微管的动态集合可以持续处于组装和解聚的过程中，从而产生使细胞移动的力。这些结构还可能发生滑动运动。Audesirk和Audesirk给出了白细胞‘爬行’以及多细胞生物发育过程中细胞迁移和形态变化的例子。
3. Organelle movement. Microtubules and microfilaments can help move organelles from place to place in the cell. In the case of endocytosis when a vesicle is formed to engulf some particle from outside the cell, microfilaments attach to the vesicle and pull it into the cell. Much of the complex synthesis and distribution function of the endoplasmic reticulum and the Golgi complex makes use of transport vescicles, and it is thought that the movement of these vesicles is guided by the cytoskeleton.
   细胞器运动。微管和微丝可以帮助细胞内将细胞器从一个地方移动到另一个地方。在内吞作用的情况下，当一个囊泡形成以吞噬细胞外的一些粒子时，微丝会附着在囊泡上并将其拉入细胞内。内质网和高尔基复合体的复杂合成和分布功能很大程度上利用了运输囊泡，人们认为这些囊泡的运动是由细胞骨架引导的。
4. Cell division. During cell division, microtubules accomplish the movement of the chromosones to the daughter nucleus. Then for animal cells, a ring of microfilaments helps divide the two developing cells by constricting the central region between the cells.
   细胞分裂。在细胞分裂过程中，微管负责将染色体移动到子细胞核。然后对于动物细胞，微丝环帮助通过收缩细胞之间的中央区域来分裂两个正在形成的新细胞。