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探索DNA和RNA的奥秘

DNA vs RNA (Updated)

阿米巴姐妹
Sometimes it feels like DNA gets all the credit.
有的时候DNA好像抢走了全部风头
Yes, the structure DNA is amazing.
的确 DNA的结构是精妙的
It has a beautiful double helix structure!
它有着美丽的双螺旋结构
A twisted ladder!
像一个扭曲的梯子
It has its own emoji!
它有自己的动画表情
DNA stores genetic information and codes for your traits.
DNA储存基因的信息 并且为你的特征编码
However, sometimes what gets left out is how important RNA is.
然而 有时人们忘记了RNA有多么重要
Without RNA, you actually couldn’t get that genetic message out to your cells
如果没有RNA 你就不能将基因的信息传递给细胞
so that they can start producing proteins.
让它们可以开始生产蛋白质
We talk about this in protein synthesis.
我们在蛋白质的合成中讨论这个
RNA is a very important biomolecule –
RNA是一个非常重要的生物分子
just as important as DNA.
正如DNA一样重要
In fact, RNA is even hypothesized as coming first before DNA in the RNA World hypothesis
事实上 在“RNA世界假说”中RNA的出现早于DNA
—something we need to make a separate video about.
这些我们需要另制作一个独立的视频来讲
So let’s compare and contrast DNA with RNA.
现在让我们来比较和对比DNA和RNA
First you will find DNA and RNA in all living organisms.
首先你会发现 在所有的活体中都有DNA和RNA
In eukaryotic cells, DNA tends to be found in the nucleus
在真核生物中 DNA一般会在细胞核里
while you can find RNA both
而你也可以在这里发现RNA
in and out of the nucleus.
存在于细胞核的里面和外面
Prokaryotic cells don’t have a nucleus.
原核生物没有细胞核
Both DNA and RNA are nucleic acids, which are a type of biomolecule.
DNA和RNA都是核酸 这是一种生物分子
Nucleic acids have a monomer–
核酸中含有单体
-which if you remember from our biomolecules video,
如果你记得我们之前的生物分子的视频
a monomer is a building block.
一个单体就是一个基础材料
The monomer for nucleic acids is a nucleotide
核酸的单体是核苷酸
so both DNA and RNA have nucleotides.
所以DNA和RNA都有核苷酸
The nucleotides of both RNA and DNA have three parts:
RNA和DNA的核苷酸都有三个部分:
a phosphate, sugar, and a base.
一个磷酸 糖 和一个碱基
Let’s draw 6 nucleotides of DNA and 6 nucleotides of RNA.
让我们分别画6个DNA和RNA的核苷酸
DNA is generally double stranded,
DNA通常是双螺旋的
and if focusing on these two strands of nucleotides here,
并且如果聚焦于这两股核苷酸链
you can see they run antiparallel to each other.
你可以看见它们以反向双螺旋的方式彼此延伸
RNA is generally single-stranded so you are just seeing one strand here.
RNA通常是单链的 所以你只能看见一股链
The sugar in DNA is deoxyribose and the sugar in RNA is ribose.
在DNA里的糖是脱氧核糖 而在RNA里的则是核糖
This makes sense because DNA stands for deoxyribonucleic acid.
这是说得通的 因为DNA代表脱氧核糖核酸
That’s helpful to know because the “deoxyribose” is a sugar,
了解这一点很有帮助 因为脱氧核糖是一种糖
and “nucleic acid” is that type of biomolecule it is.
且核酸正是那种生物分子
RNA stands for ribonucleic acid as its sugar is ribose.
RNA代表核糖核酸 鉴于它含有的糖是核糖
The bases in DNA are adenine, thymine, guanine, and cytosine.
在DNA中的碱基是腺嘌呤 胸腺嘧啶 鸟嘌呤和胞嘧啶
It helps to remember the popular mnemonic device: apples in the tree
有一种流行的方法来帮助记住它们:苹果长在苹果树上
(that helps you remember that A goes with T)
那帮助你记住A和T是配对的
and car in the garage (so C goes with G)
另外 汽车在车库里 所以C和G配对
to understand how DNA bases pair.
以此来了解DNA的碱基配对规则
The bases in RNA are adenine, uracil, guanine, and cytosine.
RNA的碱基是腺嘌呤 尿嘧啶 鸟嘌呤和胞嘧啶
Notice the different one?
注意到有一个不同了吗?
It’s uracil!
它是尿嘧啶!
So you have to change that popular mnemonic device here…
因此你不得不改变流行的记忆规则
instead of apples in the tree…maybe the apples are…under?
不再是苹果长在苹果树上 或许是苹果在 下面
Car in the garage still works.
汽车在车库里的规则仍然发挥作用
We mentioned earlier that DNA codes for your traits,
在早些时候 我们提到了DNA为你的特质编码
but it couldn’t do that without RNA’s help.
但没有RNA的帮助这是不能做到的
In our protein synthesis video,
在我们的蛋白质合成的视频里
we talk about three different types of RNA
我们谈到了三种不同的RNA
and their very important roles.
和它们各自扮演的非常重要的角色
mRNA, which stands for messenger RNA.
mRNA代表信使RNA
mRNA’s job is to carry a message based off of the DNA.
mRNA的任务是携带基于DNA的信息
In eukaryotic cells, DNA generally stays in the nucleus
在真核细胞里 DNA一般待在细胞核里
but mRNA has the ability to leave the nucleus to take this message to a ribosome.
但是mRNA有能力离开细胞核 把信息传递给核糖体
Ribosomes make protein
核糖体制造蛋白质
and RNA is actually a major component of ribosomes.
且RNA实际上是组成核糖体的主要成分
This type of RNA is called rRNA, which stands for ribosomal RNA.
组成核糖体的RNA叫做rRNA 代表核糖体RNA
Finally, we discuss transfer RNA or abbreviated tRNA.
最后 我们讨论转运RNA 或者简称做tRNA
Its job is to transfer amino acids to match the correct mRNA codon.
它的工作是转运氨基酸 来和正确的mRNA密码子配对
Codon charts using mRNA codons have been developed
已经开发出使用mRNA密码子的密码子图
so that you can actually see which amino acid
因此事实上你可以看到哪个氨基酸
is brought for each mRNA codon.
被哪些mRNA密码子所携带
When those amino acids are joined together, they make a polypeptide chain.
当那些氨基酸连在一起 它们就形成了一条多肽链
Proteins are made of one or more of these polypeptide chains,
蛋白质是由一条或者多条这种多肽链组成的
and proteins have tons of different roles.
并且蛋白质有数不清的作用
But we don’t want to spoil it-
但是我们不想搞砸它
–check out more in our protein synthesis video.
在我们的蛋白质合成视频中查看更多内容
Before we go, let’s try a little 3 question quiz shall we?
在我们继续前 让我们先做3道题
Just pause it after the question so you have time to think about it!
在题目出现后暂停 这样你有时间思考答案
Question 1) If I have 8 DNA nucleotides, how many DNA bases do I have?
问题1 如果有8个DNA核苷酸 那么有多少个DNA碱基?
And also how many base pairs?
多少个碱基对呢?
The answer: Each nucleotide—regardless of whether it’s a DNA or RNA nucleotide—
答案是:每一个核苷酸——不管它是DNA还是RNA的核苷酸——
has a phosphate, sugar, and a base.
都有一个磷酸基团 糖和一个碱基
So 8 DNA nucleotides would have 8 bases.
所以8个DNA核苷酸就会有8个碱基
DNA bases pair like this- and that’s 4 DNA base pairs.
DNA碱基像这样配对——那么就有4个DNA碱基对
Question 2) If one strand of DNA has these bases shown here— A, T, T, G, A, C—
问题2 如果一股DNA链有如下所示的碱基序列 ATTTGAC
can you complete what the complementary DNA bases would be for the other DNA strand?
你能否写出另一股DNA链上互补的DNA碱基?
The answer: So remember those base pairing rules for DNA
答案是:记住DNA的碱基配对原则
and the popular mnemonic.
以及流行的记忆方式
If placing the bases in this image,
如果将碱基放置在此图像中
reading in the direction shown on this image,
并按照此图像所示的方向进行读取
they’d be T, A, A, C, T, G.
它们将会是 TAACTG
Question 3) In a process known as transcription, a complementary RNA strand called messenger RNA
问题3 在转录的过程中 一股叫做信使RNA的互补RNA链
has to complement the DNA.
必须与DNA互补
More about that in our protein synthesis video.
在我们的蛋白质合成的视频有更多内容
So if I still had that original portion of DNA here,
因此 如果这里仍然有DNA的原始部分
what would the complementary RNA bases here be?
那么这里互补的RNA碱基会是什么
The answer: So remember it’s asking for RNA.
答案显示出来了 要记住问的是RNA
No thymine here; it’s uracil instead.
这里没有胸腺嘧啶 而是尿嘧啶
Apples under helps you remember A with U.
苹果在下面 帮助你记忆A和U配对
Car in the garage helps you remember C with G.
汽车在车库里 帮助你记忆C和G配对
So in this portion, reading in the direction shown on this image,
因此在这个部分 朝图像上所显示的方向读取
we’d have these RNA bases.
我们就会得到RNA的碱基序列
Notice the answer is similar to the last answer,
注意答案和上一道题的很像
but there are uracil bases here instead of thymine.
但是这里是尿嘧啶而不是胸腺嘧啶
One last thing.
最后一件事
Our models here— they’re unable to show the beautiful 3D shape,
我们这里的模型不能展示美妙的立体形状
the exact number of bases per turn, the chirality-
和每个回转上精确的碱基数目 以及手性特征
–but we’ve left you some links to explore
但是我们为你留下了有待于探索的联系
because the goal of our videos is always to introduce topics
因为我们的目标一直都是介绍一些主题
so you can discover all the fascinating
使你能够探索全部精妙的
details and exceptions.
细节和不同寻常之处
Check out our further reading description to keep that curiosity going.
请查看我们的进一步阅读描述 以保持好奇心
Well, that’s it for the Amoeba Sisters and we remind you to stay curious.
这就是这期的阿米巴姐妹 保持好奇心

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视频概述

DNA和RNA在蛋白质的合成中扮演着什么角色 让我们跟随阿米巴姐妹一起探索吧

听录译者

收集自网络

翻译译者

Karasu

审核员

审核员XY

视频来源

https://www.youtube.com/watch?v=JQByjprj_mA

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