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But within those cells that DNA needs to be functioning all the time
不过在这些细胞内DNA需要一直发生作用
Not just to make a new cells but to provide the information that is needed
不只是产生新细胞，还要提供必要的信息
So if I can cartoon this for you
我用卡通示意下
Here's a typical cell
这是典型细胞
In this case, we pick the macrophage but it could just as well be a breast ductal tissue cell. It doesn't matter
这里还是先那个巨噬细胞，也可以是别的什么细胞，关系不大
They get some kind of a signal
细胞会得到信号
In this case it's a microbe but it could be estrogen circulating in the blood perfectly normal hormones
这里是微生物，当然也可以是血液循环中的雌性激素什么的
Signal but the cell says to itself is that gee, I don't have the equipment I need
这是信号，不过细胞却发现没有所需要的"设备"
but then it says, hey, I've got the plans for what I need in my DNA library
此时细胞意识到DNA库中有相应内容
And so it takes the signal and transports it into the nucleus where finds the information it needs
于是它将信号送到细胞核去找需要的信息
And in a matter of minutes, it synthesizes the needed cellular equipment and that constitutes a cell response
几分钟后，所需"设备"得以合成，这就得到细胞反应
This is how we now think of cells
这就是我们现在对细胞的认识
It turns out that 1,25D is the key that unlocks the DNA library in virtually every tissue in the human body
而1,25D是开启DNA信息库的关键，几乎所有人体组织都是如此
1,25D's synthesized in the cell itself for itself and by itself not dependent upon what's outside the cell
1,25D在细胞内合成，且用于该细胞，同细胞外部无关
It perceives a signal. It says I've got to go and get the information I need in order to respond to this
细胞接收信号，然后找到应答所需要的信息
The only thing I need from the outside is some 25D there so that I can bring it in and make what I need
唯一从外界需要的是25D，将其引入然后进行剩下工作
