I'd like you to ask yourself, 我想让你问一下自己
what do you feel when you hear the words "organic chemistry?" 当听到"有机化学"这词儿的时候，你有啥感觉
What comes to mind? 脑子里出现啥
There is a course offered at nearly every university, 几乎所有大学都有这门课
and it's called Organic Chemistry, 叫做"有机化学"
and it is a grueling, heavy introduction to the subject, 入门介绍就已经很头疼了
a flood of content that overwhelms students, 更不用说没顶海量折磨人的内容了
and you have to ace it if you want to become a doctor or a dentist 但你想当医生、牙医、兽医的话 这门课必须修高分
or a veterinarian.
And that is why so many students perceive this science like this ... 这就是为毛很多学生对它的感受是这样的...
as an obstacle in their path, 路上的绊脚石
and they fear it and they hate it 让人又怕又恨
and they call it a weed-out course. 被称作"淘汰课程"
What a cruel thing for a subject to do to young people, 对年轻人而言好残酷的一门课
weed them out. 专门淘汰学生的
And this perception spread beyond college campuses long ago. 这种看法很久前在大学校园就传开来了
There is a universal anxiety about these two words. 大家普遍对它感觉焦虑
I happen to love this science, 我倒是很喜欢这门学课
and I think this position in which we have placed it 我觉得大家给它的定位
is inexcusable. 无可厚非
It's not good for science, and it's not good for society, 这对科学本身、还有社会是没好处的
and I don't think it has to be this way. 我觉得本可不必这样的
And I don't mean that this class should be easier. It shouldn't. 我不是说这门课可以被简化，不可能的
But your perception of these two words 但是大家对它的看法
should not be defined by the experiences of premed students 不应该被一群医科学生的经验定义了
who frankly are going through a very anxious time of their lives. 虽然他们正经历着人生中非常焦虑的一段时光
So I'm here today because I believe 我今天来这儿是因为我相信
that a basic knowledge of organic chemistry is valuable, 基础的有机化学只是是有价值的
and I think that it can be made accessible to everybody, 而且我觉得是每个人都可以入门的
and I'd like to prove that to you today. 希望今天我能证明给你们看
Would you let me try? 要不要让我试试?
Yeah! 要！
All right, let's go for it. 好的，那咱就开始了
Here I have one of these overpriced EpiPens. 我手上拿着的是肾上腺素笔
Inside it is a drug called epinephrine. 里面的药叫做肾上腺素
Epinephrine can restart the beat of my heart, 肾上腺素可以重启我们的心跳
or it could stop a life-threatening allergic reaction. 或者停止致命的过敏反应
An injection of this right here will do it. 打一针就可以了
It would be like turning the ignition switch 就像打开一个体内装置的点火开关
in my body's fight-or-flight machinery. 这个装置负责"战斗或者逃跑"
My heart rate, my blood pressure would go up so blood could rush to my muscles. 我的心率、血压上升的时候血液就会冲进我的肌肉
My pupils would dilate. I would feel a wave of strength. 我的瞳孔就会放大 我就能感到一股力量
Epinephrine has been the difference between life and death for many people. 对很多人来说，肾上腺素是生死的分界线
This is like a little miracle that you can hold in your fingers. 它是你可以掌握的小奇迹
Here is the chemical structure of epinephrine. 这是肾上腺素的化学结构
This is what organic chemistry looks like. 这就是有机化学物质看起来的样子
It looks like lines and letters ... 一堆线条和字母
No meaning to most people. 对大部分人而言毫无意义
I'd like to show you what I see when I look at that picture. 我想把我看到的内容告诉你
I see a physical object 我看的是实实在在的物质
that has depth and rotating parts, 有深度、有转动部件
and it's moving. 并且在运动
We call this a compound or a molecule, 我们管它叫化合物或分子
and it is 26 atoms that are stitched together by atomic bonds. 它是通过原子键连接在一起的26个原子
The unique arrangement of these atoms gives epinephrine its identity, 这个特定的原子组合方式 赋予肾上腺素特定的特性
but nobody has ever actually seen one of these, 不过没人真正看见过
because they're very small, 因为它们极小
so we're going to call this an artistic impression, 我们只能称之为美术图像
and I want to explain to you how small this is. 我想解释一下它到底多小
In here, I have less than half a milligram of it dissolved in water. 这个水里有不到半毫克的肾上腺素
It's the mass of a grain of sand. 就是一粒沙子的质量
The number of epinephrine molecules in here is one quintillion. 这里面的肾上腺素分子数量是"一百万的三次方"
That's 18 zeroes. 18个0
That number is hard to visualize. 这个数字很难形象化
Seven billion of us on this planet? 地球的人口是70亿
Maybe 400 billion stars in our galaxy? 银河系星星大约4000亿
You're not even close. 这些还都是小数字
If you wanted to get into the right ballpark, 你要这么想象
you'd have to imagine every grain of sand 所有海滩、河滩上的沙子
on every beach, under all the oceans and lakes, 还有所有海底、河底的沙子
and then shrink them all so they fit in here. 这么多的数量，都聚集在这里
Epinephrine is so small we will never see it, 肾上腺素太小了，我们永远看不见它
not through any microscope ever, 任何显微镜都不行
but we know what it looks like, 但是我们知道它是什么样的
because it shows itself through some sophisticated machines 因为通过一些精致复杂的工具
with fancy names 可以展示出来
like "nuclear magnetic resonance spectrometers." 比如这个名称花哨的"核磁共振分光仪"
So visible or not, we know this molecule very well. 无论可见与否，我们很了解这个分子了
We know it is made of four different types of atoms, 我们知道，它是由四种不同的原子构成的
hydrogen, carbon, oxygen and nitrogen. 氢、碳、氧和氮
These are the colors we typically use for them. 这是常用的标识颜色
Everything in our universe is made of little spheres 这个世界的所有东西都是由一种小球构成的
that we call atoms. 叫做原子
There's about a hundred of these basic ingredients, 大约有一百多种这类基础材料
and they're all made from three smaller particles: 它们都是由三种更小的粒子构成的
protons, neutrons, electrons. 质子、中子、电子
We arrange these atoms into this familiar table.
We give them each a name and a number.
But life as we know it doesn't need all of these,
just a smaller subset, just these.
And there are four atoms in particular that stand apart from the rest
as the main building blocks of life,
and they are the same ones that are found in epinephrine:
hydrogen, carbon, nitrogen and oxygen.
Now what I tell you next is the most important part.
When these atoms connect to form molecules,
they follow a set of rules.
Hydrogen makes one bond,
oxygen always makes two,
nitrogen makes three
and carbon makes four.
That's it.
HONC -- one, two, three, four.
If you can count to four, and you can misspell the word "honk,"
you're going to remember this for the rest of your lives.
(Laughter)
Now here I have four bowls with these ingredients.
We can use these to build molecules.
Let's start with epinephrine.
Now, these bonds between atoms, they're made of electrons.
Atoms use electrons like arms to reach out and hold their neighbors.
Two electrons in each bond, like a handshake,
and like a handshake, they are not permanent.
They can let go of one atom and grab another.
That's what we call a chemical reaction,
when atoms exchange partners and make new molecules.
The backbone of epinephrine is made mostly of carbon atoms,
and that's common.
Carbon is life's favorite structural building material,
because it makes a good number of handshakes
with just the right grip strength.
That's why we define organic chemistry as the study of carbon molecules.
Now, if we build the smallest molecules we can think of that follow our rules,
they highlight our rules, and they have familiar names:
water, ammonia and methane, H20 and NH3 and CH4.
The words "hydrogen," "oxygen" and "nitrogen" --
we use the same words
to name these three molecules that have two atoms each.
They still follow the rules,
because they have one, two and three bonds between them.
That's why oxygen gets called O2.
I can show you combustion.
Here's carbon dioxide, CO2.
Above it, let's place water and oxygen, and beside it, some flammable fuels.
These fuels are made of just hydrogen and carbon.
That's why we call them hydrocarbons. We're very creative.
(Laughter)
So when these crash into molecules of oxygen,
as they do in your engine or in your barbecues,
they release energy and they reassemble,
and every carbon atom ends up at the center of a CO2 molecule,
holding on to two oxygens,
and all the hydrogens end up as parts of waters,
and everybody follows the rules.
They are not optional,
and they're not optional for bigger molecules either,
like these three.
This is our favorite vitamin
sitting next to our favorite drug,
(Laughter)
and morphine is one of the most important stories in medical history.
It marks medicine's first real triumph over physical pain,
and every molecule has a story,
and they are all published.
They're written by scientists, and they're read by other scientists,
so we have handy representations to do this quickly on paper,
and I need to teach you how to do that.
So we lay epinephrine flat on a page,
and then we replace all the spheres with simple letters,
and then the bonds that lie in the plane of the page,
they just become regular lines,
and the bonds that point forwards and backwards,
they become little triangles,
either solid or dashed to indicate depth.
We don't actually draw these carbons.
We save time by just hiding them.
They're represented by corners between the bonds,
and we also hide every hydrogen that's bonded to a carbon.
We know they're there
whenever a carbon is showing us any fewer than four bonds.
The last thing that's done is the bonds between OH and NH.
We just get rid of those to make it cleaner,
and that's all there is to it.
This is the professional way to draw molecules.
This is what you see on Wikipedia pages.
It takes a little bit of practice, but I think everyone here could do it,
but for today, this is epinephrine.
This is also called adrenaline. They're one and the same.
It's made by your adrenal glands.
You have this molecule swimming through your body right now.
It's a natural molecule.
This EpiPen would just give you a quick quintillion more of them.
(Laughter)
We can extract epinephrine
from the adrenal glands of sheep or cattle,
but that's not where this stuff comes from.
We make this epinephrine in a factory
by stitching together smaller molecules that come mostly from petroleum.
And this is 100 percent synthetic.
And that word, "synthetic," makes some of us uncomfortable.
It's not like the word "natural," which makes us feel safe.
But these two molecules, they cannot be distinguished.
We're not talking about two cars that are coming off an assembly line here.
A car can have a scratch on it,
and you can't scratch an atom.
These two are identical in a surreal, almost mathematical sense.
At this atomic scale, math practically touches reality.
And a molecule of epinephrine ...
it has no memory of its origin.
It just is what it is,
and once you have it,
the words "natural" and "synthetic," they don't matter,
and nature synthesizes this molecule just like we do,
except nature is much better at this than we are.
Before there was life on earth,
all the molecules were small, simple:
carbon dioxide, water, nitrogen,
just simple things.
The emergence of life changed that.
Life brought biosynthetic factories that are powered by sunlight,
and inside these factories, small molecules crash into each other
and become large ones: carbohydrates, proteins, nucleic acids,
multitudes of spectacular creations.
Nature is the original organic chemist,
and her construction also fills our sky with the oxygen gas we breathe,
this high-energy oxygen.
All of these molecules are infused with the energy of the sun.
They store it like batteries.
So nature is made of chemicals.
Maybe you guys can help me to reclaim this word, "chemical,"
because it has been stolen from us.
It doesn't mean toxic, and it doesn't mean harmful,
and it doesn't mean man-made or unnatural.
It just means "stuff," OK?
(Laughter)
You can't have chemical-free lump charcoal.
That is ridiculous.
(Laughter)
And I'd like to do one more word.
The word "natural" doesn't mean "safe,"
and you all know that.
Plenty of nature's chemicals are quite toxic,
and others are delicious,
and some are both ...
(Laughter)
toxic and delicious.
The only way to tell whether something is harmful
is to test it,
and I don't mean you guys.
Professional toxicologists: we have these people.
They're well-trained,
and you should trust them like I do.
So nature's molecules are everywhere,
including the ones that have decomposed
into these black mixtures that we call petroleum.
We refine these molecules.
There's nothing unnatural about them.
We purify them.
Now, our dependence on them for energy --
that means that every one of those carbons gets converted into a molecule of CO2.
That's a greenhouse gas that is messing up our climate.
Maybe knowing this chemistry will make that reality easier to accept
for some people, I don't know,
but these molecules are not just fossil fuels.
They're also the cheapest available raw materials
for doing something that we call synthesis.
We're using them like pieces of LEGO.
We have learned how to connect them or break them apart with great control.
I have done a lot of this myself,
and I still think it's amazing it's even possible.
What we do is kind of like assembling LEGO
by dumping boxes of it into washing machines,
but it works.
We can make molecules that are exact copies of nature, like epinephrine,
or we can make creations of our own from scratch, like these two.
One of these eases the symptoms of multiple sclerosis;
the other one cures a type of blood cancer that we call T-cell lymphoma.
A molecule with the right size and shape, it's like a key in a lock,
and when it fits, it interferes with the chemistry of a disease.
That's how drugs work.
Natural or synthetic,
they're all just molecules that happen to fit snugly somewhere important.
But nature is much better at making them than we are,
so hers look more impressive than ours,
like this one.
This is called vancomycin.
She gave this majestic beast two chlorine atoms
to wear like a pair of earrings.
We found vancomycin in a puddle of mud in a jungle in Borneo in 1953.
It's made by a bacteria.
We can't synthesize this cost-efficiently in a lab.
It's too complicated for us, but we can harvest it from its natural source,
and we do, because this is one of our most powerful antibiotics.
And new molecules are reported in our literature every day.
We make them or we find them in every corner of this planet.
And that's where drugs come from,
and that's why your doctors have amazing powers ...
(Laughter)
to cure deadly infections and everything else.
Being a physician today is like being a knight in shining armor.
They fight battles with courage and composure,
but also with good equipment.
So let's not forget the role of the blacksmith in this picture,
because without the blacksmith, things would look a little different ...
(Laughter)
But this science is bigger than medicine.
It is oils and solvents and flavors, fabrics, all plastics,
the cushions that you're sitting on right now --
they're all manufactured, and they're mostly carbon,
so that makes all of it organic chemistry.
This is a rich science.
I left out a lot today:
phosphorus and sulfur and the other atoms,
and why they all bond the way they do,
and symmetry
and non-bonding electrons,
and atoms that are charged,
and reactions and their mechanisms, and it goes on and on and on,
and synthesis takes a long time to learn.
But I didn't come here to teach you guys organic chemistry --
I just wanted to show it to you,
and I had a lot of help with that today from a young man named Weston Durland,
and you've already seen him.
He's an undergraduate student in chemistry,
and he also happens to be pretty good with computer graphics.
(Laughter)
So Weston designed all the moving molecules
that you saw today.
He and I wanted to demonstrate through the use of graphics like these
to help someone talk about this intricate science.
But our main goal was just to show you
that organic chemistry is not something to be afraid of.
It is, at its core, a window
through which the beauty of the natural world looks richer.
Thank you.
(Applause)