正在播放:你为什么活着——生命,能量和ATP

At this very second, you are on a narrow ledge between life and death.
此时此刻 你正在生死之间徘徊
You probably don’t feel it,
你可能感觉不到
but there’s an incredible amount of activity
但你的体内正进行着
going on inside you,
大量的活动
and this activity can never stop.
而且这些活动绝不能停止
Picture yourself as a Slinky
把自己想象成一个
falling down an escalator moving upwards.
从上行扶梯上翻滚下落的玩具弹簧
The falling part represents the self-replicating processes of your cells.
下落的部分代表细胞的自我复制过程
The escalator represents the laws of physics driving you forwards.
自动扶梯则代表着驱动你前进的物理定律
To be alive is to be in motion but never arriving anywhere.
活着就是一直处于运动状态 但从未到达某处
If you reach the top of the escalator,
如果你到达扶梯的顶端
there’s no more falling possible,
就不可能再向下走了
and you’re dead forever.
也就是说 你永远地死去了
Somewhat unsettlingly, the universe wants you to reach the top.
令人不安的是 宇宙希望你到达这个顶端
How do you avoid that? And why are you alive?
如何避免到达顶端?你又为什么活着呢?
[Amazing-sounding Kurz Intro Music]
[动听的科学坚果前奏音乐]
《科学坚果》
All life is based on the cell.
细胞是所有生命的基础
A cell is a piece of the dead universe
每个细胞都是死寂宇宙中
that separated itself from the rest
分离出的一部分
so it could do its own thing for a while.
因此 它可以自己存活运转一段时间
When this separation breaks down,
当这种分离状态瓦解
it dies and joins the rest of the dead universe again.
细胞就会死亡 再度回到死寂宇宙中
Unfortunately, the universe would like for life to be done with doing its own thing.
不幸的是 宇宙希望生命自然凋亡
For some reason, it’s not a fan of exciting things,
出于某些原因 它并不喜欢刺激
but tries to be as boring as possible.
而是越枯燥乏味越好
We call this principle “entropy,”
我们将这一原理称为“熵”
and it’s a fundamental rule of our universe.
这也是宇宙运行的基本法则
It’s pretty complicated and counterintuitive,
它相当复杂 又违反直觉
so we’ll explain it in detail in another video.
所以我们将在另一个视频中详细解释
For now, all you need to know is living things are inherently exciting.
现在 你只要知道 生命天生就很活跃
A cell is filled up with millions of proteins
一个细胞由数百万蛋白质分子
and millions more simpler molecules like water.
和更多的简单分子(如水分子)组成
Thousands of complex, self-replicating processes are happening
每秒内 数千种复杂的自我复制过程
up to hundreds of thousands of times every second.
要进行多达数十万次
To stay alive and exciting,
为了生存并保持活跃
it has to constantly work to keep itself from achieving entropy
细胞需要不停工作 以抵抗熵增
and becoming boring and dead.
并避免沉寂与死亡
The cell has to maintain a separation from the rest of the universe.
细胞需要与外界的其他部分隔离
It’s doing this, for example, by keeping the concentration of certain molecules different on the inside and the outside
比如 细胞会通过排出多余分子
by actively pumping out excess molecules.
使细胞内外保持分子浓度差
To do stuff like this, a cell needs energy.
要进行这样的活动 细胞就需要能量
Energy is the ability of things in the universe to do work;
能量使宇宙中的事物得以运转
to move or manipulate a thing; to create change.
可以移动或控制其他事物 可以产生改变
This ability cannot be created or destroyed.
这种能力无法创造 也无法消灭
The set amount of energy in the universe will never change.
宇宙中的能量是守恒的
We don’t know why, it just is that way.
我们不知道原因 但事实就是如此
So, billions of years ago, one of the most crucial challenges for the first living beings
数十亿年前 最初的生物所面临的重大挑战之一
was to get usable energy.
就是获取可用的能量
We don’t know a lot about the first cells,
我们对最原始的细胞所知甚少
except that they got their energy from simple chemical reactions.
只知道它们通过简单的化学反应获取能量
And they found the ultimate energy transfer system:
还发现了最佳的能量传递系统:
the energetic building block of life.
为生命提供能量的基本要素
The molecule Adenosine Triphosphate, or ATP.
即三磷酸腺苷 ATP
Its structure makes it uniquely good at accepting and releasing energy.
它的结构使其极其擅长吸收和释放能量
When a cell needs energy, for example,
当细胞需要能量时 例如
to pump out molecules or to repair a broken micro machine,
向外排出分子 或修复受损的微小结构
it can break down ATP,
就可以分解ATP
and use the chemical energy to do work and create change.
利用其化学能工作并改造自身
This is why living beings are able to do stuff.
以此维持生物体的生命活动
We don’t know when or how
我们并不知道
exactly the first ATP molecule was made on earth,
地球上第一个ATP分子何时出现 怎样产生的
but every living thing we know uses ATP,
但我们知道所有生物都利用ATP
or something very similar, to keep its internal machinery running.
或极其相似的分子 来保证内部机制运转
It’s crucial for almost every process
ATP至关重要
plants, fungi, bacteria, and animals need to survive.
植物 真菌 细菌和动物生存所需的几乎每个过程都需要它
Without ATP, no life on Earth,
没有ATP 地球上也就不会有生命存在
possibly anywhere.
也许在任何地方都是如此
While breaking down chemicals for energy is nice and all,
尽管分解化学物质以获取能量的确很不错
early life did miss out on the greatest available source of energy:
早期生物错过了最佳的可用能源:
the Sun.
太阳
The Sun merges atoms and radiates photons away
太阳合并原子(进行聚变) 同时向外辐射光子
that carry energy into the solar system.
光子携带能量传播到太阳系
But this energy is raw and indigestible.
但这种能量未经处理 难以吸收
It needs to be refined.
它需要被进一步处理
After hundreds of millions of years of evolution,
经过数亿年的进化演变
finally, a cell figured out how to eat the Sun.
终于 有一种细胞想出了吸收太阳能的方法
It absorbed radiation and converted much of it into
它吸收太阳辐射 并将其中的大部分转化为
neat little chemical packages that it could use to stay alive.
一组组小而简单的化学物质 并以此维持生命
We call this process photosynthesis.
我们将这一过程称为光合作用
You take photons that are wobbly with electromagnetic energy,
它能获取具有不稳定电磁能量的光子
and use a part of this energy to merge and combine different molecules together.
并使用部分能量将不同的分子结合
The electromagnetic energy is converted into chemical energy stored in the ATP molecule.
电磁能被转化为化学能 储存在ATP分子中
This process became even better,
这一转换过程得到了进一步优化
as some cells learned to create better chemical packages:
因为一些细胞学会了制造更好的化学物质组合:
glucose, or sugar.
葡萄糖 或糖
Easy to break down, high in energy, and pretty tasty.
它们易分解 能量高 还好吃
This is so convenient, that some cells decided that
这太方便了 以至于一些细胞决定
instead of doing all that pesky photosynthesis work themselves,
与其自己进行讨厌的光合作用
they would just swallow other cells that did,
不如直接吞噬其它进行光合作用的细胞
and take their glucose and ATP.
夺走它们的葡萄糖和ATP
This is widely considered one of the biggest anime betrayals in evolutionary history.
这被广泛认为是进化史上最具动漫色彩的背叛之一
And so things went on.
事情就这样继续发展下去
Photosynthesizing cells could mostly harness energy at their surfaces,
进行光合作用的细胞基本都在其表面利用能量
which limited their maximum energy production,
这限制了它们能量产出的最大值
which limited their evolutionary avenues somewhat.
某种程度上 也限制了其进化路线
So, time passed.
时间继续流逝
Some cells made sugar, others ate them.
一些细胞制造糖 另外的细胞则吃掉他们
Evolution did its thing, but overall
进化已经尽了自己的职责 但总体上
things stayed pretty much the same for hundreds of millions of years.
生命在数亿年都没有发生太多变化
Until, one day, a cell ate another, and did not kill it.
直到有一天 一个细胞吃掉了另一个 但没有杀死它
Instead, they became one cell.
它们合并成了一个细胞
Nothing had changed that day, but Earth would be different forever.
那一天 什么都没有改变 但地球从此不同了
This cell became the ancestor of all animals on this planet.
这个细胞成为了地球上所有动物的祖先
Blue whales, amoeba,
蓝鲸 变形虫
dinosaurs, jellyfish,
恐龙 水母
pink fairy armadillos, and Sunda colugos.
倭犰狳 巽他猫猴
And of course, you.
当然 也包括你
All can trace back their existence to this moment.
所有生物都可以追溯到这个时刻
The merging of two living beings is so important,
两个有机体的合并意义重大
because when those two cells became one, they became way more powerful.
因为当它们合二为一时 它们变得远比之前强大
The formerly independent cell in the inside, could stop trying to survive.
原本独立的细胞进入另一细胞内部 不必再疲于奔命
It could concentrate on one thing: make ATP.
只需要专注一件事:生产ATP
It became the powerhouse of the cell: the first mitochondria.
它成为了细胞的动力车间:第一个线粒体
The host cell’s job became to ensure survival in the dangerous world,
宿主细胞则需要在危险的世界中生存
and provide the mitochondria with food.
同时为线粒体提供食物
Mitochondria basically reverse photosynthesis, in a similarly complex process.
线粒体基本上是进行逆光合作用 过程也同样复杂
They take sugar molecules that we got from eating other living things,
它们从我们食用的其他生物中摄取糖分子
combust them with oxygen and precursor molecules,
将其与氧气和前体分子一起燃烧
to make new, energy-rich ATP molecules.
由此生产出新的高能ATP分子
This process works like a tiny furnace
这一过程就像一个小型熔炉在运作
and spits out waste products like CO2, water, and a little bit of kinetic energy
并排出二氧化碳 水 和一小部分动能
that you experience as body heat.
这些表现为体温的废料
This first division of labor, meant the new cell had way more energy available
这第一次分工意味着新细胞拥有的可用能量
than any cell before,
比之前的任何细胞都多
which meant more possibilities for evolution
也意味着更加可能
to enable more complex cells.
进化出复杂的细胞
At some point, these cells began to form small groups or communities,
在某一时刻 这些细胞开始形成小的组织或群落
which lead to multicellular life, and finally, to you.
发展成为多细胞生物 最终成为你
Today, you are a pile of trillions of cells,
现在 你是数万亿细胞的集合
each filled with dozens, if not hundreds of little machines
每个细胞里都有几十甚至几百个微型机器
that provides you with usable energy to stay alive.
为你提供生存所需的能量
If this process is interrupted,
如果这个过程中断
even for a few minutes, you die.
哪怕只有几分钟 你也会死亡
But if life is so fragile,
但如果生命如此脆弱
wouldn’t it be a good idea to store ATP,
那储存ATP不是一个好主意吗?
like we store sugar in our fat cells,
就像我们在脂肪细胞里储存糖一样
so we don’t die if we stop breathing for a while?
这样 即使我们短暂停止呼吸 也不至于死亡
If life has solved so many problems to make you live today,
如果生命克服了诸多问题才让你得以生存
what’s up with the dying quickly thing?
那些生命短暂的生物又是怎么回事呢?
Even simple bacteria like E. Coli
即便是像大肠杆菌这样简单的细菌
make about 50 times their body weight in ATP for every cell division.
每次分裂时也要产生50倍于自重的ATP
Your trillions of cells
你体内的数十亿细胞
need a lot of ATP to keep you around.
需要大量ATP来维持你的生命
Every day, your body produces and converts
你的身体每天要生产和转化
about 90 million, billion, billion molecules of ATP:
大约9×10^25个ATP分子
about your own body weight.
相当于你自身的重量
You need a whole person’s worth of ATP just to make it through a single day.
仅仅度过一天 你就需要一人重的ATP
Even storing enough ATP to last you a few minutes is basically impossible.
甚至储存ATP以维持几分钟的生命 也基本不可能
An ATP molecule is really good for shifting energy around quickly,
ATP分子非常擅于快速转移能量
but it’s terrible for storage,
但极难储存
since it has only one percent of a glucose molecule’s energy
因为单个ATP分子能量只有葡萄糖的百分之一
at three times its mass.
质量却是它的三倍
So ATP is constantly produced and used up fairly quickly.
所以 ATP不停地被制造出来 又被快速消耗
This was the short and simplified story of the molecule
这就是关于ATP分子的简单小故事
that allows you to be different from the dead universe,
它使你与死寂宇宙截然不同
and to be the Slinky on the escalator.
使你成为扶梯上的玩具弹簧
It is a weird story.
这是个奇异的故事
There is this molecule you need to survive at all times.
为了生存 你无时无刻需要这种分子
You need it to keep moving,
你需要用它保持运动
because even a short break brings your Slinky to a stop.
因为即使短暂的休息 也会让弹簧走向终点
And you need to make it yourself.
而且 你需要自食其力
It’s like driving a car at full speed while producing fuel in the trunk
这就像开着车全速前进 同时在后备箱中
with junk that you pick up from the side of the road.
用从路边捡来的废品生产燃料
As far as we know, this all began billions of years ago,
我们知道 这一切都源于数十亿年前
when tiny parts of the dead universe came together
死寂宇宙中的微小部分聚在一起
and became something else for a moment.
在某一时刻成为新事物的时候
It could keep itself going,
它可以维持自己运转
it could grow.
可以生长
That moment set the Slinky in motion, and it’s been going ever since.
那个时刻使弹簧开始运动 并一直运动下去
From the very first cells, to you watching this now.
从最原始的细胞 到现在正看着这个视频的你
At some point, you will merge with the rest of the dead universe again.
某个时刻 你将再度与死寂宇宙融为一体
Maybe you’ll tell it stories about your adventures,
也许你会向它讲述自己的冒险故事
maybe not.
也许不会
But before you find out,
但在你弄清楚这一切前
you get to do what life does best,
你要好好生活
making a dead universe, much more interesting.
让死气沉沉的宇宙更加有趣精彩
If you are currently bored for whatever reason,
无论出于何种原因 你要是正感到无聊
and you want to make your life more interesting,
想为生活增添一些趣味
we’ve got something for you.
那我们为你准备了些东西
We partnered with Skillshare: an online learning community
我们与Skillshare建立了合作 这是一个线上学习社区
that offers thousands of classes for all skill levels on tons of creative skills
为各种水平层次的多种创意技能提供上千节课程
like illustration, animation, cooking, creative writing, or film and video.
比如插画 动画 烹饪 创意写作 或影视
Learning something while creating stuff for yourself is pretty fun and fulfilling.
学习并为自己创作是一件快乐而充实的事
If you want to learn animation,
如果你想学习动画制作
we made a few Skillshare classes
我们也在Skillshare准备了一些课程
where we explained how we animated scenes from our videos,
介绍我们如何通过视频课程和动手项目
with video lessons and hands-on projects.
制作视频中的动画场景
You can get unlimited access to all classes for less than $10 a month,
若成为年费会员 每月花费不到10美元
with an annual premium membership.
就可以不限次数观看所有课程
And, the first 1,000 Kurzgesagt viewers to click the link in the description
前1000位点击简介中链接的《科学坚果》观众
will get a two month free trial.
还将获得两个月的免费试用机会
And if you’re just getting started,
如果你刚刚入门
for beginners who want to dip a toe into illustrations similar to ours,
是初学者 想学习和我们风格类似的插画
we recommend “Vector Illustration: Using Creative Constraints to Find Your Style”
我们推荐《矢量插画:通过创造性约束寻找个人风格》
by Rick Burke Osmond.
主讲人是里克·伯克·奥斯蒙德
Just try something to improve your skills, and at the same time,
试着做些事情提高自己的技能 同时
fight the boredom of being stuck inside.
打发一下被困在家的无聊日子
If you want to get creative with new skills
如果你想学习新技能 变得更有创造力
and support Kurzgesagt, give it a try!
并且支持《科学坚果》 那就试试吧!
[Quack]
[鸭叫声]

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