Name: 【TED】Elizabeth Blackburn: The science of cells that never get old (The science of cells that never get old | Elizabeth Blackburn)
Uploaded: 2017-12-15T17:00:57.000Z
Duration: 18 min 47 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

Well, for me, it all began with this little fellow.

is called Tetrahymena and it's a single-celled creature.

So that's right, my career started with pond scum.

Now, it was no surprise I became a scientist.

I used to pick up lethally poisonous stinging jellyfish and sing to them.

I was deadly curious about fundamental mysteries

of the most basic building blocks of life,

and I was fortunate to live in a society where that curiosity was valued.

Now, for me, this little pond scum critter Tetrahymena

was a great way to study the fundamental mystery

those bundles of DNA in our cells called chromosomes.

And it was because I was curious about the very ends of chromosomes,

all we knew was that they helped protect the ends of chromosomes.

but I wanted to find out what telomeres consisted of,

And it so happens that cute little Tetrahymena

And I discovered that telomeres consisted of special segments

of noncoding DNA right at the very ends of chromosomes.

It multiples to two. Two becomes four. Four becomes eight,

and on and on to form the 200 million billion cells

And some of those cells have to divide thousands of times.

In fact, even as I stand here before you,

all throughout my body, cells are furiously replenishing

to, well, keep me standing here before you.

So every time a cell divides, all of its DNA has to be copied,

all of the coding DNA inside of those chromosomes,

because that carries the vital operating instructions

that keep our cells in good working order,

so my heart cells can keep a steady beat,

which I assure you they're not doing right now,

and our brain cells can save the memory of our first kiss

But there is a glitch in the way DNA is copied.

Every time the cell divides and the DNA is copied,

some of that DNA from the ends gets worn down and shortened,

like the protective caps at the ends of your shoelace.

And those keep the shoelace, or the chromosome, from fraying,

and when that tip gets too short, it falls off,

and that worn down telomere sends a signal to the cells.

because life hasn't died off the face of the earth.

how on earth does Mother Nature make sure

Now, remember that little pond scum critter Tetrahymena?

The craziest thing was, Tetrahymena cells never got old and died.

Their telomeres weren't shortening as time marched on.

and believe me, that something was not in any textbook.

So working in my lab with my extraordinary student Carol Greider --

and Carol and I shared the Nobel Prize for this work --

and we discovered cells do have something else.

that could replenish, make longer, telomeres,

And when we removed our pond scum's telomerase,

So it was thanks to their plentiful telomerase

that our pond scum critters never got old.

OK, now, that's an incredibly hopeful message

for us humans to be receiving from pond scum,

that as we humans age, our telomeres do shorten,

and remarkably, that shortening is aging us.

Generally speaking, the longer your telomeres,

that leads us to feel and see signs of aging.

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【TED】Elizabeth Blackburn: The science of cells that never get old (The science of cells that never get old | Elizabeth Blackburn)

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