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That there are other molecules in the lipid bilayer and they're important for cells getting information or getting molecules from outside.
还有一些其它分子在这个脂质双分子层上,它们对于细胞接收信息,和接受外来分子十分重要
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So what you get on the plate is many copies of the small number of plasmids that you've put in.
我们只要放入少量质粒,就能在培养基上得到大量的复制品
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Or in some cases they go to the dendrite of the neuron and they kind of put a paste over it so that the neurotransmitters can't connect.
有时这些药物会渗透到神经元的树突,这些药物就像是在树突上涂了一层涂料,使得神经递质无法将树突与轴突相连
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I mentioned a little bit that this membrane is not just lipid bilayer but there's also proteins that are inserted into the membrane.
我之前说过,这层膜不仅仅是一层脂质双分子层,而是有很多蛋白质嵌插在膜上的
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If this reforms, so the plasmid reforms back to its native state, that resistance will be recovered.
如果它自己合上了,质粒就会回到原本的状态,抗性就会恢复
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Now how do you find those colonies on a plate that have the plasmid that you want?
那我们如何辨别培养基上的哪些菌落,有我们需要的质粒呢
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So having a place that the cell knows - where the cell knows how to replicate is important and so plasmids have an origin of replication.
所以得有一个细胞能识别的区域,能使细胞知道,怎样来复制 这很重要,因此质粒上带有一个复制起点
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How would I put a gene that I'm interested in into a plasmid?
怎么把我想要的基因整合到质粒上呢
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So if you have plasmid where you know all the base pairings than you could go through that plasmid and say I want to cut it right here.
如果你已经知道某个质粒上的所有序列,你就可以决定从哪里切开质粒
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These chemicals are known as neurotransmitters and they affect the dendrites.
这些化学物质被称为神经递质,它们会作用于树突上
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You could imagine strategies where you have multiple resistance genes on a plasmid, resistance to Ampicillin, to Penicillin, to Erythromycin for example, and you design strategies for separating out which cells are carrying the plasmid that you're interested in.
若质粒上有多种抗性基因,你就有很多筛选方法,例如对氨苄青霉素,青霉素,红霉素的抗性,而且你可以设计方法分离出,含有你感兴趣质粒的细胞
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This is where - this is the region of the plasmid where we're going to insert the DNA that we're interested in.
这就是我们将在质粒上,插入我们感兴趣的DNA的位置
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How did we put our gene fragments into this plasmid DNA in order to make multiple copies of it, or to clone the gene?
如何把基因片段整合到质粒DNA上,来获得大量拷贝,或者说来克隆基因呢
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that means that the cells have to be able to replicate the DNA on the plasmids, in order to make many more copies of it.
就是说这些细胞要能够,复制质粒上的DNA,以得到更多的拷贝
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This region here of this particular plasmid is called the ori or origin of replication.
质粒上的这个区域叫,ori,或者叫复制起点
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That's a really good question because if I open this up, why wouldn't it just reform with itself, why would it want to have this in here?
这是个很好的问题,如果我把质粒打开,为什么它不会自己合上,为什么它会与DNA片段重组呢
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If I cut both the plasmid and my DNA of interest with the same restriction enzyme I'm going to end up with the same sticky ends on both molecules.
如果用同一种限制性内切酶,来切割质粒和我感兴趣的DNA,在两个分子上就能得到同样的粘性末端
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Some are going to reform and some are going to reform with the gene in, and some probably aren't going to reseal at all under the conditions that I've used.
有些质粒会自己合上,有些质粒会与DNA片段重组并合上,还有的在我提供的条件下,也根本合不上
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Let's assume that we have this plasmid cloning vector and we have some pieces of DNA that we would like to put into a plasmid that we would like to make copies of.
假设我们已经有了克隆质粒载体,也有了我们想要将之,整合到质粒上的某些DNA片段,同时也是我们所要复制的DNA片段
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The answer is it will want to reform with itself, and if I have these in solution then how many reform with itself and how many reform with the molecule I'm interested probably depends on the relative concentrations of both in the solution and what conditions I have it at.
答案是质粒有可能会自己闭合,如果质粒和我感兴趣的DNA片段,都在溶液里那有多少质粒会自己合上,有多少与我感兴趣的DNA重组呢,这大概取决于两者在溶液里的相对浓度,和我让溶液处在什么条件下
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