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    Where do cells come from?
    ::细胞从哪里来?

    No matter what the , all cells come from preexisting cells through the process of cell division. This is one of the core concepts of the . The cell may be the simplest or a complex muscle, , or cell. The cell may comprise the whole organism , or be just one cell of trillions. But whatever type of cell it is, it comes from a preexisting cell. And the new cell is genetically identical to its parent cell - that is, it has exactly the same .
    ::无论细胞是什么,所有细胞都是通过细胞分裂过程从原存在的细胞中产生的。这是细胞的核心概念之一。 细胞可能是最简单或复杂的肌肉, 或细胞。 细胞可能是整个生物体, 或只是数万亿的细胞。 但不管它是哪一类细胞, 它都来自一个原存在的细胞。 新的细胞在基因上与它的母细胞完全相同, 也就是说, 它有完全相同的细胞。

    Cell Division
    ::单元司

    A cell is the simplest unit of structure and function of all living organisms. From the smallest bacteria to the largest whale, all life is made of at least one cell.
    ::细胞是所有生物体的结构和功能中最简单的单位。 从最小的细菌到最大的鲸鱼,所有生命都由至少一个细胞组成。

    You are made of trillions of cells. Cells of many different types of cells. Nerve cells, skin cells, muscle cells, blood cells and many more. These cells obviously have many different functions, yet they all develop from the that makes you, the zygote . So do they all have the same DNA? Of course they do. Are all the cells in your body genetically identical? Of course they are. How does the first cell of an organism know to become two cells, then four cells, and so on? What tells these cells what to do? The answers to those questions are more complicated than a simple yes or no.
    ::细胞是由数万亿个细胞组成的。 细胞是由许多不同种类的细胞组成的。 神经细胞、 皮肤细胞、 肌肉细胞、 血细胞等等。 这些细胞显然有许多不同的功能, 但是它们都从形成你, zygote 中发展出来。 所以它们都有相同的DNA吗? 所以它们都有相同的DNA吗? 当然它们都有。 你身体里所有的细胞在基因上是否都是一样的? 当然它们是一样的。 一个生物体的第一个细胞怎么会变成两个细胞, 然后是四个细胞,等等? 什么告诉这些细胞该怎么做? 这些问题的答案比简单的回答要复杂得多。

    Your body produces about 25 million genetically identical cells every second. These new cells are formed when older cells divide, a process called cell division or cell . Cell division is the process by which a parent cell divides into two or more daughter cells , as seen in the Figure .
    ::您的身体每秒产生大约2500万个基因相同的细胞。这些新的细胞是老细胞分裂时形成的,一个叫做细胞分裂或细胞分裂的过程。如图所示,细胞分裂是母细胞分裂成两个或两个以上女儿细胞的过程。

    Eukaryotic cells and prokaryotic cells complete this division process by a number of different mechanisms. In eukaryotic cells, cell division is the final step in the life of a cell, otherwise known as the . The cell cycle is a repeating series of events, during which the eukaryotic cell carries out its necessary functions, including metabolism , cellular growth, and division, resulting in two genetically identical daughter cells. To produce two genetically identical daughter cells, the need to replicate, a process called DNA replication , and the and cytoplasm need to divide, two processes termed and cytokinesis , respectively. These are key events in the life of a cell.
    ::Eukaryatic细胞和蛋白质细胞通过若干不同机制完成这一分裂过程。在eukarycoy细胞中,细胞分裂是细胞生命的最后一步,也称为...。细胞循环是一系列的重复事件,在此期间,Eukarycoy细胞发挥必要的功能,包括新陈代谢、细胞生长和分裂,导致两个基因相同的女细胞。要生产两个基因相同的女细胞,需要复制两个基因相同的女细胞,一个叫DNA复制的过程,以及需要分化两个过程,这两个过程分别称为和细胞基质。这些都是细胞生命中的关键事件。

    Dividing cells

    This image depicts an animal cell in the final stages of cell division. Essentially, the cell grows in size, the nucleus divides (mitosis), and then the cytoplasm divides (cytokinesis), forming new plasma membrane between the two genetically identical daughter cells.
    ::此图像描述了处于细胞分裂最后阶段的动物细胞。 基本上, 细胞在体积上增长, 核分裂( 分裂 ) , 然后是细胞型分裂( cytokinesis ) , 形成两个基因相同的子细胞之间的新的等离子膜。

    Corresponding cell division in is known as binary fission . In binary fission, the cell divides, but of course, there is no nucleus, so mitosis does not occur. The DNA must still replicate prior to division. For single-celled organisms, which includes all bacteria and single-celled eukaryotes , cell division is how that organism reproduces, creating an entirely new organism.
    ::相应的细胞分裂被称为二进制裂变。 在二进制裂变中, 细胞分裂, 但当然, 没有核, 所以分裂不会发生。 DNA仍然必须在分裂前复制。 对于单细胞生物, 包括所有的细菌和单细胞的eukaryotes, 细胞分裂就是生物的繁殖方式, 创造了全新的生物体。

    In another type of called , a cell is permanently transformed into a haploid gamete , with half as much DNA as the parent cell, and may not divide again until .
    ::在另一类名为 : 的单元格中, 细胞会永久变换成杂乱的调子, 其DNA数量相当于父细胞的一半, 并且直到 。

    Summary
    ::摘要

    • Cell division is part of the life cycle of virtually all cells. Cell division is the process in which one cell divides to form two new cells.
      ::细胞分裂是几乎所有细胞生命周期的一部分,细胞分裂是一个细胞分裂形成两个新细胞的过程。
    • Most prokaryotic cells divide by the process of binary fission.
      ::大部分蛋白质细胞 被二进制裂变过程分割开来
    • In eukaryotes, cell division occurs in two major steps: mitosis and cytokinesis.
      ::在eukaryotes,细胞分裂分为两个主要步骤:肺硬化和细胞基质。

    Review
    ::回顾

    1. What is cell division?
      ::什么是细胞分裂?
    2. What is DNA replication?
      ::什么是DNA复制?
    3. Briefly describe cell division in prokaryotes
      ::简要描述直角圆形的单元格分隔
    4. Briefly describe cell division in eukaryotes.
      ::简要说明用eukaryotes表示的细胞分裂。
    5. What is zygote?
      ::什么是摇头丸?