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MITOSIS - When The Cell Splits Apart
有丝分裂——细胞分裂
What is mitosis?
什么是有丝分裂？
Eventually, cells need to duplicate.
最终，细胞需要复制。
There are two main methods of replication: mitosis and meiosis.
复制主要有两种方式：有丝分裂和减数分裂。
This tutorial will talk about mitosis.
本教程将讨论有丝分裂。
The big idea to remember is that mitosis is the simple duplication of a cell and all its parts.
要记住重要的一点是，有丝分裂是一个细胞及其所有部分的简单复制。
It duplicates its DNA and the two new cells, daughter cells, have the same pieces and genetic code.
它复制自己的DNA，而这两个新细胞，即子细胞，具有相同的片段和遗传密码。
Two identical copies come from one original.
两份相同的复制品来自一份原件。
Beyond the idea that two identical cells are created, there are certain steps in the process.
除了创建两个完全相同的细胞之外，这个过程中还有一些特定的步骤。
Before a cell divides, it is in resting phase.
在细胞分裂之前，它处于休眠阶段。
The cell in resting phase is not actually resting, since it has to maintain its reservoir before it undergoes division.
处于休眠阶段的细胞实际上并不是真正的休眠，因为它必须在经历分裂之前维持其储存库。
This phase is called Interphase.
这一阶段称为间期。
It prepares the cell for division i.E. protein synthesis, DNA duplication and enzymes.
它为细胞分裂做准备，即蛋白质合成，DNA复制和酶。
After this phase comes Mitosis, which is further divided into Karyokinesis (division of nucleus) and Cytokinesis (division of cytoplasm).
在这一阶段之后是有丝分裂，进一步分为核分裂（细胞核分裂）和胞质分裂（细胞质分裂）。
Karyokinesis involves the four basic steps of mitosis that are PROPHASE METAPHASE ANAPHASE TELOPHASE.
核分裂涉及四个基本步骤，即前期、中期、后期、末期。
Here we start with PROPHASE.
我们先从前期开始。
The chromosomes start coiling and become condensed.
染色体开始缠绕并缩短变粗。
Nuclear envelope disintegrates.
核膜解体。
Gene transcription ceases during prophase and does not resume until late anaphase to early G1 phase.
基因转录在前期停止，直到后期至G1前期才恢复。
The nucleolus also disappears during early prophase.
核仁也在前期早期消失了。
Centrosome gives rise to mitotic apparatus i.E. generation of spindle tubules.
中心体产生有丝分裂器，即产生纺锤体小管。
METAPHASE
中期
Now all the pieces are aligning themselves for the big split.
所有的部分都在为大的分裂调整自己。
The DNA lines up along a central axis and the DNA (chromatin) has now condensed into chromosomes.
DNA沿着中心轴排列，DNA（染色质）现在浓缩成染色体。
Two strands of chromosome are connected at the centre with centromere.
两条染色体在中心与着丝粒相连。
The tubules connect to the centromere, not the DNA.
这些小管连接着丝粒，而不是DNA。
ANAPHASE
后期
Here we go!
我们开始吧！
The separation begins.
分离开始了。
Half of the chromosomes are pulled to one side of the cell; half go the other way.
染色单体开始分向两极之间。
When the chromosomes get to the side of the cell, it's time to move on to telophase.
当染色体到达细胞一侧时，就是进入末期的时候了。
TELOPHASE
末期
Now the division is finishing up.
现在分裂就要结束了。
This is the time when the nuclear envelope begins to synthesize again along the separated chromosomes.
这是核膜开始沿着分离的染色体重新合成的时候。
Cytokinesis pinches the cell membrane in the middle.
胞质分裂将细胞膜夹在中间。
Cell membrane closes in and splits the cell into two.
细胞膜封闭并将细胞一分为二。
Now, we have two separate cells, each with half of the original DNA.
现在，我们有两个独立的细胞，每个细胞都有原始DNA的一半。
Up till now, we have discussed what is mitosis and its different phases.
到目前为止，我们已经讨论了什么是有丝分裂及其不同的阶段。
Now it's important to know about significance of mitosis.
现在重要的是要了解有丝分裂的意义。
SIGNIFICANCE
意义
It is an equational division through which identical daughter cells are produced having the same amount and type of genetic constitution as that of the parent cell.
这是一种平衡的分裂，通过这种分裂，相同的子细胞被产生，具有与父细胞相同的数量和遗传结构类型。
It is responsible for growth and development of multicellular organisms from a single-celled zygote.
它负责从单细胞受精卵到多细胞生物体的生长和发育。
The number of chromosomes remains the same in all the cells produced by this division.
在这种分裂产生的所有细胞中，染色体的数量保持不变。
Thus, the daughter cells retain the same character as those of the parent cell.
因此，子代细胞保留了与父代细胞相同的特征。
It helps the cell in maintaining proper size.
它可以帮助细胞保持适当的大小。
Mitosis helps in restoring wear and tear in body tissues, replacement of damaged or lost part, healing of wounds and regeneration of detached parts as in the tail of lizards.
有丝分裂有助于修复身体组织的磨损和撕裂，替换受损或丢失的部分，愈合伤口，以及再生脱落的部分，就像蜥蜴的尾巴一样。
It is a method of multiplication in unicellular organisms.
这是单细胞生物的一种繁殖方法。
If mitosis remains unchecked, it may result in uncontrolled growth of cells, leading to cancer or tumor.
如果有丝分裂不受控制，可能会导致细胞不受控制的生长，导致癌症或肿瘤。
The next important phase of cell cycle is meiosis.
细胞周期的下一个重要阶段是减数分裂。
