A crash course in organic chemistry | Jakob Magolan

261,237 views ・ 2018-07-27

TED


Please double-click on the English subtitles below to play the video.

00:12
I'd like you to ask yourself,
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what do you feel when you hear the words "organic chemistry?"
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What comes to mind?
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There is a course offered at nearly every university,
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and it's called Organic Chemistry,
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and it is a grueling, heavy introduction to the subject,
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a flood of content that overwhelms students,
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and you have to ace it if you want to become a doctor or a dentist
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or a veterinarian.
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And that is why so many students perceive this science like this ...
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as an obstacle in their path,
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and they fear it and they hate it
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and they call it a weed-out course.
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What a cruel thing for a subject to do to young people,
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weed them out.
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And this perception spread beyond college campuses long ago.
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There is a universal anxiety about these two words.
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I happen to love this science,
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and I think this position in which we have placed it
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is inexcusable.
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It's not good for science, and it's not good for society,
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and I don't think it has to be this way.
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And I don't mean that this class should be easier. It shouldn't.
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But your perception of these two words
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should not be defined by the experiences of premed students
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who frankly are going through a very anxious time of their lives.
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So I'm here today because I believe
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that a basic knowledge of organic chemistry is valuable,
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and I think that it can be made accessible to everybody,
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and I'd like to prove that to you today.
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Would you let me try?
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Audience: Yeah!
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Jakob Magolan: All right, let's go for it.
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(Laughter)
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Here I have one of these overpriced EpiPens.
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Inside it is a drug called epinephrine.
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Epinephrine can restart the beat of my heart,
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or it could stop a life-threatening allergic reaction.
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An injection of this right here will do it.
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It would be like turning the ignition switch
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in my body's fight-or-flight machinery.
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My heart rate, my blood pressure would go up so blood could rush to my muscles.
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My pupils would dilate. I would feel a wave of strength.
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Epinephrine has been the difference between life and death for many people.
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This is like a little miracle that you can hold in your fingers.
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Here is the chemical structure of epinephrine.
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This is what organic chemistry looks like.
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It looks like lines and letters ...
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No meaning to most people.
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I'd like to show you what I see when I look at that picture.
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I see a physical object
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that has depth and rotating parts,
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and it's moving.
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We call this a compound or a molecule,
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and it is 26 atoms that are stitched together by atomic bonds.
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The unique arrangement of these atoms gives epinephrine its identity,
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but nobody has ever actually seen one of these,
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because they're very small,
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so we're going to call this an artistic impression,
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and I want to explain to you how small this is.
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In here, I have less than half a milligram of it dissolved in water.
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It's the mass of a grain of sand.
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The number of epinephrine molecules in here is one quintillion.
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That's 18 zeroes.
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That number is hard to visualize.
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Seven billion of us on this planet?
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Maybe 400 billion stars in our galaxy?
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You're not even close.
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If you wanted to get into the right ballpark,
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you'd have to imagine every grain of sand
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on every beach, under all the oceans and lakes,
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and then shrink them all so they fit in here.
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Epinephrine is so small we will never see it,
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not through any microscope ever,
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but we know what it looks like,
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because it shows itself through some sophisticated machines
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with fancy names
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like "nuclear magnetic resonance spectrometers."
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So visible or not, we know this molecule very well.
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We know it is made of four different types of atoms,
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hydrogen, carbon, oxygen and nitrogen.
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These are the colors we typically use for them.
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Everything in our universe is made of little spheres
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that we call atoms.
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There's about a hundred of these basic ingredients,
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and they're all made from three smaller particles:
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protons, neutrons, electrons.
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We arrange these atoms into this familiar table.
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We give them each a name and a number.
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But life as we know it doesn't need all of these,
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just a smaller subset, just these.
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And there are four atoms in particular that stand apart from the rest
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as the main building blocks of life,
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and they are the same ones that are found in epinephrine:
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hydrogen, carbon, nitrogen and oxygen.
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Now what I tell you next is the most important part.
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When these atoms connect to form molecules,
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they follow a set of rules.
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Hydrogen makes one bond,
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oxygen always makes two,
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nitrogen makes three
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and carbon makes four.
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That's it.
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HONC -- one, two, three, four.
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If you can count to four, and you can misspell the word "honk,"
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you're going to remember this for the rest of your lives.
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(Laughter)
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Now here I have four bowls with these ingredients.
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We can use these to build molecules.
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Let's start with epinephrine.
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Now, these bonds between atoms, they're made of electrons.
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Atoms use electrons like arms to reach out and hold their neighbors.
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Two electrons in each bond, like a handshake,
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and like a handshake, they are not permanent.
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They can let go of one atom and grab another.
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That's what we call a chemical reaction,
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when atoms exchange partners and make new molecules.
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The backbone of epinephrine is made mostly of carbon atoms,
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and that's common.
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Carbon is life's favorite structural building material,
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because it makes a good number of handshakes
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with just the right grip strength.
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That's why we define organic chemistry as the study of carbon molecules.
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Now, if we build the smallest molecules we can think of that follow our rules,
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they highlight our rules, and they have familiar names:
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water, ammonia and methane, H20 and NH3 and CH4.
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The words "hydrogen," "oxygen" and "nitrogen" --
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we use the same words
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to name these three molecules that have two atoms each.
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They still follow the rules,
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because they have one, two and three bonds between them.
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That's why oxygen gets called O2.
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I can show you combustion.
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Here's carbon dioxide, CO2.
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Above it, let's place water and oxygen, and beside it, some flammable fuels.
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These fuels are made of just hydrogen and carbon.
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That's why we call them hydrocarbons. We're very creative.
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(Laughter)
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So when these crash into molecules of oxygen,
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as they do in your engine or in your barbecues,
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they release energy and they reassemble,
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and every carbon atom ends up at the center of a CO2 molecule,
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holding on to two oxygens,
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and all the hydrogens end up as parts of waters,
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and everybody follows the rules.
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They are not optional,
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and they're not optional for bigger molecules either,
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like these three.
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This is our favorite vitamin
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sitting next to our favorite drug,
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(Laughter)
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and morphine is one of the most important stories in medical history.
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It marks medicine's first real triumph over physical pain,
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and every molecule has a story,
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and they are all published.
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They're written by scientists, and they're read by other scientists,
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so we have handy representations to do this quickly on paper,
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and I need to teach you how to do that.
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So we lay epinephrine flat on a page,
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and then we replace all the spheres with simple letters,
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and then the bonds that lie in the plane of the page,
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they just become regular lines,
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and the bonds that point forwards and backwards,
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they become little triangles,
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either solid or dashed to indicate depth.
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We don't actually draw these carbons.
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We save time by just hiding them.
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They're represented by corners between the bonds,
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and we also hide every hydrogen that's bonded to a carbon.
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We know they're there
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whenever a carbon is showing us any fewer than four bonds.
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The last thing that's done is the bonds between OH and NH.
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We just get rid of those to make it cleaner,
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and that's all there is to it.
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This is the professional way to draw molecules.
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This is what you see on Wikipedia pages.
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It takes a little bit of practice, but I think everyone here could do it,
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but for today, this is epinephrine.
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This is also called adrenaline. They're one and the same.
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It's made by your adrenal glands.
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You have this molecule swimming through your body right now.
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It's a natural molecule.
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This EpiPen would just give you a quick quintillion more of them.
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(Laughter)
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We can extract epinephrine
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from the adrenal glands of sheep or cattle,
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but that's not where this stuff comes from.
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We make this epinephrine in a factory
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by stitching together smaller molecules that come mostly from petroleum.
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And this is 100 percent synthetic.
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And that word, "synthetic," makes some of us uncomfortable.
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It's not like the word "natural," which makes us feel safe.
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But these two molecules, they cannot be distinguished.
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We're not talking about two cars that are coming off an assembly line here.
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A car can have a scratch on it,
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and you can't scratch an atom.
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These two are identical in a surreal, almost mathematical sense.
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At this atomic scale, math practically touches reality.
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And a molecule of epinephrine ...
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it has no memory of its origin.
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It just is what it is,
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and once you have it,
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the words "natural" and "synthetic," they don't matter,
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and nature synthesizes this molecule just like we do,
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except nature is much better at this than we are.
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Before there was life on earth,
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all the molecules were small, simple:
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carbon dioxide, water, nitrogen,
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just simple things.
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The emergence of life changed that.
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Life brought biosynthetic factories that are powered by sunlight,
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and inside these factories, small molecules crash into each other
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and become large ones: carbohydrates, proteins, nucleic acids,
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multitudes of spectacular creations.
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Nature is the original organic chemist,
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and her construction also fills our sky with the oxygen gas we breathe,
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this high-energy oxygen.
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All of these molecules are infused with the energy of the sun.
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They store it like batteries.
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So nature is made of chemicals.
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Maybe you guys can help me to reclaim this word, "chemical,"
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because it has been stolen from us.
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It doesn't mean toxic, and it doesn't mean harmful,
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and it doesn't mean man-made or unnatural.
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It just means "stuff," OK?
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(Laughter)
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You can't have chemical-free lump charcoal.
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That is ridiculous.
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(Laughter)
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And I'd like to do one more word.
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The word "natural" doesn't mean "safe,"
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and you all know that.
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Plenty of nature's chemicals are quite toxic,
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and others are delicious,
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and some are both ...
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(Laughter)
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toxic and delicious.
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The only way to tell whether something is harmful
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is to test it,
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and I don't mean you guys.
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Professional toxicologists: we have these people.
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They're well-trained,
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and you should trust them like I do.
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So nature's molecules are everywhere,
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including the ones that have decomposed
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into these black mixtures that we call petroleum.
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We refine these molecules.
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There's nothing unnatural about them.
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We purify them.
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Now, our dependence on them for energy --
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that means that every one of those carbons gets converted into a molecule of CO2.
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That's a greenhouse gas that is messing up our climate.
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Maybe knowing this chemistry will make that reality easier to accept
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for some people, I don't know,
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but these molecules are not just fossil fuels.
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They're also the cheapest available raw materials
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for doing something that we call synthesis.
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We're using them like pieces of LEGO.
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We have learned how to connect them or break them apart with great control.
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I have done a lot of this myself,
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and I still think it's amazing it's even possible.
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What we do is kind of like assembling LEGO
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by dumping boxes of it into washing machines,
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but it works.
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We can make molecules that are exact copies of nature, like epinephrine,
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or we can make creations of our own from scratch, like these two.
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One of these eases the symptoms of multiple sclerosis;
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the other one cures a type of blood cancer that we call T-cell lymphoma.
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A molecule with the right size and shape, it's like a key in a lock,
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and when it fits, it interferes with the chemistry of a disease.
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That's how drugs work.
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Natural or synthetic,
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they're all just molecules that happen to fit snugly somewhere important.
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But nature is much better at making them than we are,
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so hers look more impressive than ours,
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like this one.
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This is called vancomycin.
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She gave this majestic beast two chlorine atoms
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to wear like a pair of earrings.
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We found vancomycin in a puddle of mud in a jungle in Borneo in 1953.
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It's made by a bacteria.
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We can't synthesize this cost-efficiently in a lab.
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It's too complicated for us, but we can harvest it from its natural source,
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and we do, because this is one of our most powerful antibiotics.
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And new molecules are reported in our literature every day.
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We make them or we find them in every corner of this planet.
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And that's where drugs come from,
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and that's why your doctors have amazing powers ...
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(Laughter)
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to cure deadly infections and everything else.
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Being a physician today is like being a knight in shining armor.
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They fight battles with courage and composure,
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but also with good equipment.
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So let's not forget the role of the blacksmith in this picture,
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because without the blacksmith, things would look a little different ...
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(Laughter)
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But this science is bigger than medicine.
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It is oils and solvents and flavors, fabrics, all plastics,
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the cushions that you're sitting on right now --
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they're all manufactured, and they're mostly carbon,
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so that makes all of it organic chemistry.
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This is a rich science.
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I left out a lot today:
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phosphorus and sulfur and the other atoms,
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and why they all bond the way they do,
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and symmetry
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and non-bonding electrons,
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and atoms that are charged,
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14:58
and reactions and their mechanisms, and it goes on and on and on,
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and synthesis takes a long time to learn.
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But I didn't come here to teach you guys organic chemistry --
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I just wanted to show it to you,
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and I had a lot of help with that today from a young man named Weston Durland,
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and you've already seen him.
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He's an undergraduate student in chemistry,
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and he also happens to be pretty good with computer graphics.
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(Laughter)
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So Weston designed all the moving molecules
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that you saw today.
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He and I wanted to demonstrate through the use of graphics like these
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to help someone talk about this intricate science.
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But our main goal was just to show you
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that organic chemistry is not something to be afraid of.
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It is, at its core, a window
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through which the beauty of the natural world looks richer.
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Thank you.
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(Applause)
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About this website

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