Once you have a difference that occurs, two cells are difference, those differences can propagate as the cells continue to divide.
一旦产生差异,产生两个不同的细胞,这些差异会伴随着,细胞分裂过程代代相传
Retroviruses, for example, can only insert - can only transduce and express their DNA in cells that are dividing.
就以逆转录病毒为例,它们只能在分裂阶段的细胞里,转导并表达自己的基因
There's nothing in biology per se that rules out cell division.
生物学中没有排除细胞分裂的铁规则。
We talked about mitosis last time; it's described more completely in the chapter, where two cells are formed from one.
我们上节课说到过有丝分裂,在那一章里更详细的阐释了,细胞是怎么由一生二的
An asymmetrical division is not like that, it's when a parent cell forms two cells that are different in some way.
而不对称分裂就不是这样,当母细胞分裂为两个子细胞时,会有一些不同
It's really just the result of the virus dividing within cells of your skin, and producing a lot of dead cells.
这便是病毒在皮肤细胞内部,分裂的结果,这个过程会产生大量的死亡细胞
So if it's not a cell that's going through division you can't use a retrovirus to express the protein.
如果细胞不在分裂阶段,你就不能用逆转录病毒来表达某个蛋白
A capability for asymmetric division and the production of cells that become differentiating more mature cells, those are properties of stem cells.
能够完成不对称分裂,以及产生细胞,并分化成为一些更成熟的细胞,这些是干细胞的性质
Not all the cells are dividing; in fact, cells in your brain don't proliferate at all.
不是所有细胞都能分裂,事实上,脑细胞根本不增殖
So, in general, when cells are proliferating they're dividing and they're dividing at a regular rate.
因此,大致而言,当细胞增殖时,它们是在分裂,并以受调控的频率分裂
It's not self-renewing, in that division of the zygote results in two daughter cells that are no longer the zygote anymore, they're down some pathway.
它是不会自我更新的,受精卵分裂后成了两个子细胞,而这两个子细胞就不再是受精卵了,它们沿着某种路径进行了分化
Well, not all of the cells in your body are dividing at any one time.
然而不是体内所有细胞,都随时在分裂
This stem cell which is reproduced still has the potential to undergo asymmetric division but this one does not.
新生成的干细胞,仍然有潜能进行不对称分裂,但定向祖细胞就不行
It was a gene that was causing a cell to be malignant and to divide without control, for example.
例如,一个会使细胞恶化,并不受控制地无限分裂的基因
Well, what if this division takes place in an environment where there's one kind of extra cellular matrix here and another kind of extracellular matrix here?
那如果在细胞分裂的过程中,两个子细胞的细胞外基质不同,会对它们产生什么影响
It's time for you to reproduce', and so the cellular response would be mitosis.
该是复制的时候了",细胞就开始进行有丝分裂
We talked about last time that part of the process of going from this single cell to multi cellular many celled organisms like we are is cell division.
我们上节课说过,从一个单细胞分裂形成大量细胞,构成的器官的过程,叫做细胞分裂
There's one division, here it shows it at the 16 cell stage and then here, and this transformation as it goes from 16 cells to more like 64 cells.
这是第一次分裂,这里显示的是十六细胞期,然后在这里,在这里胚胎进一步的产生了变化,由十六个细胞分裂为约六十四个
The size of the cells could be different; maybe mitosis is asymmetrical in some way so that one of the cells ends up being bigger than the other.
细胞大小可能会不同,也许有丝分裂的过程是不对称的,致使子细胞一个大一个小
They can transduce non-dividing cells so that's a good part.
能够很好的转导非分裂的细胞,这很好
The cell divides, and divides, and divides many, many times and that's one of the signature events of embryogenesis until we have many, many cells that make up our bodies.
细胞不断分裂,持续进行,那是胚胎发育中,一个标志性的过程,在那之后,我们就有了许许多多构成我们身体的细胞
There are cells within your body that are always in the process of division and forming new cells, and sometimes this is for a tissue where cells only have a finite lifetime.
你体内的一些细胞,始终在不断分裂,并生成新的细胞,很多时候,是在一些细胞寿命有限的组织中
Indeed,on the contrary,right? We know cells can split.
事实上正相反,我们都知道细胞会分裂。
This process of cell proliferation or cell division is, of course, very important during development of an embryo.
细胞增殖和分裂的过程,在胚胎发育中至关重要
Mitosis is an orderly sequence of events by which one parent cell becomes two daughter cells.
有丝分裂是指一个亲代细胞,变为两个子细胞的有序的过程
They can insert genes into non-dividing cells and cause those genes to be expressed.
它使基因导入没有分裂的细胞,并使其表达
Mitosis is one event that happens during this larger event called the cell cycle.
有丝分裂就是发生在,较大的细胞周期中的一个小一点的环节
As division happens and the developing organism acquires more and more cells, individual cells become differentiated, they become more and more like their final mature form.
分裂过程不断发生,以及发育中的有机体对更多细胞的需求,细胞个体便逐渐分化,它们越来越接近成熟细胞的样子
When I talked about mitosis, I talked about cells making perfect copies of each other, so each parent cell becoming two daughter cells that are the same.
我讲有丝分裂的时候,谈到过细胞能够完美的复制自己,母细胞分裂成为,两个完全一样的子细胞
We talked about the parent cell forming two identical daughter cells.
我们说到母细胞,分裂成为两个一模一样的子细胞
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