2.5|生物-中文版-细胞“变形记”：细胞分化

摸摸自己的鼻子，摸摸自己的嘴巴，摸摸自己的眼睛，是不是觉得都长得不一样呢？如果是人是从一个受精卵发育而来的，那么为什么我们身上各个部分都长得不同呢？

这是因为呀，我们体内不仅存在细胞分裂，还存在着细胞分化。细胞分化，是指细胞分裂过程中朝着不同方向发展的过程。科学队长向带你来了解一下细胞分化。

遗传物质DNA

图片来源：Pixabay，Public Domain

每个细胞中都含有遗传物质DNA，从遗传物质DNA中选择不同任务来执行的过程，就是细胞分化。遗传物质中有一部分是细胞必须执行的，叫作管家基因。而另外一部分物质是细胞可以选择性执行的，叫作组织特异性基因。

干细胞

图片来源：OpenStax College - Wikimedia Commons, CC BY SA 3.0

不同的细胞变形的能力是不同的，这种能力叫作细胞全能性。全能干细胞可以变成任意一种样子。有的细胞虽然不能变成任意一种样子，但是它们还是有多种选择，我们把它们叫作多能干细胞。

肝移植数目逐年上增

图片来源：Joffers951 - Wikimedia Commons, CC BY SA 4.0

科学家们尝试着把一些不擅长分化的细胞提取出来，对它的遗传物质进行改写，让它们重新具有全能性或多能性，能够分化成人类的器官，用于治愈很多复杂的疾病，造福人类。

每日英语

Daily English

Hello, the topic Captain Science would like to talk about today is cell differentiation (细胞分化). We human beings come from fertilized eggs, and the fertilized eggs replicate (复制) and increase the cell numbers via cell division. A human adult can have around 37.2 trillion cells. You may get confused (困惑的) if all parts of a human body come from the same kind of cell, then why different parts of the human being vary so much? That can be attribute to cell differentiation. Cell differentiation means the process that cells are developing towards different directions(方向) during cell division. Every cell has a copy of genetic material, which can be seen as an essential file. The process of executing different tasks from such essential files, is called cell differentiation.

In the list of tasks within this file, there are some tasks that cells have to execute (执行), which is called housekeeper genes (管家基因). These genes are critical for the normal performance of the cell. Another set of tasks that cells can choose to execute, is called tissue-specific genes (组织特异性基因). Different cells have different abilities to turn into other types of cells, and such ability is called cell totipotency (细胞全能性). Some cells can turn into whatever cell type they want, we call them totipotent stem cells. Some other cells, although they cannot turn into whatever they want, they still have several options to choose. We call these cells pluripotent stem cells (多能干细胞). For these cells who can only turn into one specific type of cells, we call them monopotent stem cells (单能干细胞). However, nowadays scientists are trying to extract some cells bad at differentiation, and then to modify their genetic material in order to make them have the totipotency or pluripotency. In that case, those cells can differentiate into human organs for organ transplantation (移植) to cure some diseases. Do you see it? There is critical potential (潜能) of the knowledge of cell differentiation. Studying the knowledge of cell biology can contribute (贡献) to human beings in the future.

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