The pasting back together occurs partly naturally by this process of hybridization, but hybridization only re-establishes the base pairing.
片段和载体的重新粘合一定程度上,是通过杂交自然发生的,但杂交只能重建碱基配对
Because it takes three units where there's only four choices at each position to have at least 20 unique combinations.
因为每个位点上仅有四种可能性,只有采用三个碱基一组,才能取得至少二十种不同的组合方式
We talked about base pairing and how that leads to this process of hybridization or very specific matching between complimentary strands.
我们讲了碱基配对,以及它们如何引起杂交过程,或者说,互补链之间的特异配对
There are 64 combinations of three bases and I only need to describe 20, so there's combinations to spare.
三个一组的碱基产生六十四种组合,而我只需对应二十种氨基酸,所以一种氨基酸会对应不同密码子
One of the things about these plasmids that makes them very useful is that their entire base pair sequences is known.
质粒之所以有用,其中一个原因就是,它的全部碱基序列都是已知的
They do that because the bases can interact with one another in particular ways, and this you know about.
它们结构稳定,是因为碱基之间,以特定方式相互作用,这是你需要知道的
What's hanging off of the side of this long molecule that's formed by polymerizing nucleotides are - is this base unit.
在这条由多聚核苷酸,构成的长链分子,一侧悬挂着碱基单位
The correct complement is made because of these principles of Watson-Crick base pairing that we talked about before.
剪接配对的正确性源自,沃森克里克碱基互补配对原则的作用,这我们讲过的
One that's . 2 kilobases long and one that's 1.1 kilobases long - kilobase is 1,000 bases.
一段长0.2千碱基,另一段长,1.1千碱基,千碱基指一千个碱基
I'd only have 16 possible two base sequences, that's not enough to specify over 20 amino acids.
如果两个碱基一组那一共只有十六种组合,不够和二十种氨基酸来一一对应
There's just more sequences in a three unit codon than I need for the amino acids.
一个氨基酸对应不止一个密码子,由三碱基所构成的密码子
It's oriented in the oppose direction and it has the complementary base pairs at each position.
它们方向相反,并且所有的碱基都是互补的
These will naturally want to reform and they'll want to reform to re-establish this base pairing.
它们会自然地重新进行碱基配对
That means the gene that encodes insulin, the sequence of base pairs that encode insulin.
这意味着基因编码了胰岛素,碱基序列编码了胰岛素
I just give you one of those, right, because you could write down the other one because you know the other complimentary sequence from base pairing?
我只写了一条链的序列,因为你们能够写出另一条,因为你们根据碱基配对,就能推测出互补链的序列
They face in the opposite direction and you could predict the properties of one from base pairing rules of the other but they're not the same.
它们是反向的,尽管你能够通过一条链上的碱基序列,预测另一条链的序列,但这两条链是不同的
They do that in a very special way in that they - restriction enzymes are able to identify a particular sequence of bases in a gene.
限制性内切酶的工作机制很特别,它能识别基因中的一段特定的碱基序列
If you do the base pairing goes exactly the same sequence backwards down here.
如果将它碱基配对,就会得到相同,但反过来的序列
To give you all the detail, there's two classes of bases that appear here.
为了尽量讲的详细,这里出现的碱基有两种类型
It's on the gene for hemoglobin and the hemoglobin that you produce if you have sickle cell anemia is not quite right because there's one base difference.
这个缺陷基因和血红蛋白有关,如果你有镰状红细胞贫血症,那你所产生的血红蛋白就不太正常,因为这里有一个碱基不同
There are four different bases, which I'll talk about in a moment.
有四种不同的碱基,一会我们会讲到
If I only had two per codon I wouldn't have enough.
所以如果每个密码子只有两个碱基不够
The 5' carbon has a phosphate off of it and that phosphate is linked to the 3' carbon of the next one and they all have a base hanging off the side.
'碳的磷酸基,连接到下一个戊糖的3'碳部位,它们都有连接在一侧的碱基
Why are there three bases in a codon?
为什么一个密码子有三个碱基呢
What base sequence does it recognize?
它能识别什么碱基序列
If I drew this altogether and this is one particular nucleic acid, now shown in more detail, all of the carbons of the pentose are shown here, the phosphate is shown, and a base is shown.
如果我把这个放在一起,这个核酸分子,让你们看得到更多细节,戊糖的五个碳都在这儿,磷酸基在这儿,碱基在这儿
It's the phosphate and the pentose that make up the backbone - that make up the upright struts of the ladder and it's the bases that make up the connecting struts, so the bases are the colors.
磷酸基和戊糖,共同构成了主链,主链又构成了梯子上下的支柱,而碱基,则构成连接支柱的梯阶,碱基是用各种颜色表示的
It wouldn't be the same if I turned it upside down because the carbons - the rings here, the pentose's would all be turned over, the chemistry would look different and the sequence of bases would look different.
记住单链倒过来,就和原来不一样了,这是因为碳原子和糖环结构,戊糖会翻转,使得这个化学结构看起来不一样了,碱基的顺序也不一样了
Now the bases, and you don't need to memorize the structures of these I'm going - I'm describing the whole molecule to you in its molecular detail and then we're going to simplify it down to a version that we can talk about more easily.
现在讲碱基,你不需要记住这些结构,我将给你们详述整个分子,的结构细节,然后我们把它简化为一个模板,使我们更容易讨论
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