Nova (1974–…): Season 48, Episode 4 - Beyond the Elements: Life - full transcript
The molecules that allowed life on Earth to begin and thrive; how scientists use evolution in chemistry.
What's it take to make
our modern world?
Ah!
That's amazing!
I'm David Pogue.
Join me on a high-speed chase
through the elements...
and beyond.
Oh, my God!
As we smash our way into
the materials,
molecules,
and reactions...
It's a really cool enzyme
because it makes life on Earth
possible.
That make the places we live,
the bodies we live in,
and the stuff we can't seem
to live without.
The only thing between me and
certain death...
is chemistry?
From killer snails...
Just when
you think you've heard of everything,
nature will surprise you.
And exploding glass
to the price a pepper-eating
Pogue pays.
There's got to be some easier
way to learn about molecules.
We'll dig into
the surprising way
different elements
combine together
and blow apart.
In this hour,
we tackle one of the biggest
mysteries of all:
the origin of life.
How do a bunch of chemicals
get together
and start acting like a cell?
Part of the answer might be...
soap?
Cell division!
We explore how the chemistry of
life transformed the planet.
So everything that we eat,
and the air that we breathe,
all have to do
with the process
of photosynthesis.
All right, so let's find
the lipids aisle.
I go shopping for the
macromolecules of my body.
You're telling me that
that’s only half the amount of fats
in my body?
Absolutely.
And I meet an engineer who uses
nature's tools
to invent new molecules.
Humans have been using microbes
to make beer and wine.
Instead of making sake,
we make jet fuel.
"Beyond the Elements: Life"...
right now on "NOVA".
The world we live in is made
of atoms...
all listed here as elements
on the periodic table.
They're the building blocks
of everything around us
and putting atoms together to
make molecules and compounds
is what we call chemistry.
And maybe the strangest event
in the history of chemistry
is the birth of biology.
How do a bunch of chemicals
somehow get together
to form life?
And if you look back at the
conditions on early Earth,
how did life get off
the starting block?
There was a turning point,
the evolution of a
transformative series
of chemical reactions that,
over time,
remade the planet,
even allowing us to come along.
But first,
let's take a trip back,
to Life 1.0.
So, here's the ad:
Planet available.
Recently scoured by asteroids.
New construction.
Now with many water views.
The atmosphere?
Eh... a fixer-upper.
Devoid of oxygen.
Likely full of whatever
the volcanoes spewed forth...
gases like hydrogen sulfide
and methane.
Somehow in that very harsh
environment,
primitive life got its start.
But the going stayed tough.
Food... molecules and minerals
that early organisms
could use for energy...
consisted of whatever was left
over from Earth's formation,
or was welling up
from the Earth's core
at places like deep sea vents.
But in a surprisingly short
amount of time...
perhaps 500 million years...
a new survival strategy
evolved...
possibly the most important
chemical process for life
on Earth today...
Photosynthesis...
The ability
to turn sunlight into fuel.
Life now had access to the vast
power of the sun.
In the words of one biologist,
"When photosynthesis
"entered the picture,
life connected
up to the cosmos."
So, everything that we eat,
what we wear,
the air that we breathe,
the ecosystem services
that we rely on...
so things like having
clean water...
all have to do with the process
of photosynthesis.
It's an incredibly important,
probably the most important,
process on the planet.
Photosynthesis harnesses
the power of sunlight
to break down water molecules.
Discarding the oxygen,
it uses the electrons
from the hydrogen atoms
to power the assembly
of carbon dioxide molecules
into carbohydrates,
which become both
building blocks
and long-term energy storage.
It's not an overstatement to say
that all life on this planet
depends on photosynthesis.
It's exactly where
all of our food comes from...
directly or indirectly.
So understanding
how this process works
is so important to humanity.
Steve Long and Don Ort,
two plant biologists
at the University of Illinois
Urbana-Champaign,
along with thousands of
other scientists from around the world
have spent decades teasing
apart the workings of photosynthesis.
Light intensity is 900
right now?
Right now, yeah. Oh yeah.
For... that makes sense.
Sorghum is an important grain.
Now, with that knowledge
in hand,
there is a new international
research effort based here
at the university
with an audacious goal.
The program's called RIPE:
Realizing Increased
Photosynthetic Efficiency.
This year was a huge hit
for the canola farmers
because it was too wet.
So I've been wondering
whether it would be worth
trying to find a substitute
as our test bed.
That'd be perfect.
These folks
want to hack photosynthesis.
But why would you want
to do that?
Because experts think the Earth
is about to get
a whole lot more people.
Today, the world's population
is close to eight billion.
And that's forecast to hit
9.7 billion by 2050.
Raising the question:
will there be enough food?
If you look at the current rate
at which we're improving
crop productivity
per acre of land,
we're not going to get there.
Part of the answer
is going to be
redesigning photosynthesis.
To learn more about
RIPE's plans,
I've joined Lisa Ainsworth,
a U.S.D.A. scientist,
and professor at the
University of Illinois...
You can see just how
different the height is
- just in walking from one.
- Wow.
On an early morning tour
of a field
that contains 600 different
varieties of soybeans.
Usually you hear about
efficiency,
like of a gas engine, measured
in terms of a percentage,
how much of the fuel
is ultimately converted
to energy.
What's the percentage efficiency
for a plant?
Well, in terms of
how much of the light
energy it turns into sugar,
it's pretty low...
maybe around three percent.
Three percent?!
That's terrible!
But you guys are going
to help it.
That's the plan.
To improve photosynthesis,
two other researchers
with RIPE...
Amanda Cavanagh and Paul South...
have focused on one of
its key molecules.
It has a very catchy name.
So the molecule is what we
biologists call an enzyme.
And so it does the work.
Enzymes are like
biological workers.
And the enzyme's called rubisco.
It's R.U.B.P...
or ribulose bisphosphate
carboxylase oxygenase.
And it's,
for most plant biologists,
one of our favorite enzymes
on the planet.
Yeah, rubisco is our shortened
term for it.
Mainly because it's fun to say.
Well, it's super fun to say.
Rubisco. Of course.
Rubisco.
But, it's also
a really cool enzyme
because it makes life on Earth
possible.
Rubisco may not look so special
but it is arguably the most
important enzyme on the planet
because of its critical role
in photosynthesis.
Rubisco's job is to grab
a molecule of carbon dioxide
and feed it into
a molecular machine
that's building carbon chains.
That means any carbon atom
that's part of any plant
anywhere
got there thanks to rubisco,
or one of its close variants.
And because we eat plants,
or animals that ate plants,
that also includes just about every
carbon atom in your body.
All approximately 800 million
billion billion of them.
That's 26 zeroes.
Not bad, rubisco, not bad.
Yeah, so, if it's ever
come from a plant,
it had to have gone through
that enzyme of rubisco.
That's wild!
Yeah.
How come there's not like a...
a memorial to rubisco
in Washington?
It seems, like,
sort of important.
Rubisco is important
and that's why it's the
most plentiful protein on Earth.
But just because
you're important
doesn't mean you're entirely...
competent.
It's... in this case, not the
best enzyme in the world.
It's got a hard job,
so it's doing its best,
but at the same time it exists
in an atmosphere that's not
predominantly carbon dioxide,
it's mostly oxygen.
And about one in every four or
five reactions it grabs oxygen
instead of carbon dioxide.
That's right.
Rubisco screws up
about a fifth of the time.
Instead of attaching
a carbon dioxide
it attaches an oxygen molecule.
And that's trouble.
You're saying nature
has created a screwed-up
little worker enzyme?
Yeah, so, 400 million years ago,
when this enzyme evolved,
there wasn't very much oxygen
in the air.
All right, so I'm the little
- rubisco enzyme...
- Yup.
- And I'm like on the conveyor belt here.
- Yeah.
And like, okay, carbon dioxide,
carbon dioxide, carbon dioxide,
carbon dioxide, oxygen
and I, I don't notice
I accidentally grabbed an oxygen
out of the box.
And it produces
compounds that are inhibitory
to photosynthesis,
so it kind of starts to
shut things down.
I mean it's been going on
for billions of years
and nobody has cared. Yeah, well...
I mean, it all...
all basically works.
Photosynthesis, right now,
is sort of a victim
of its own success...
rubisco certainly is.
So by oxygenating the atmosphere
via photosynthesis,
you now have a huge amount
of oxygen in the atmosphere
but you need a carbon dioxide
to make the reaction work.
So what happens when rubisco
screws up?
The result gets shipped out
through a couple other parts
of the cell
to where the mess is taken apart
and recycled,
all of which consumes
a lot of energy.
If you could fix
this inefficiency problem,
the plant might make more...
soybeans, corn, whatever it is?
That's exactly it.
Then they will have that energy
to put towards something
that we would consider useful
like making more food for us
to eat.
Is this just a crazy theory
or is there some indication
that this could actually work?
There's quite a bit of evidence
that this is working.
So right now,
we have this tested
in a couple of model species.
It is tropical in here.
Amanda and Paul take me to the
greenhouse to see one example.
Using two genes,
one from algae
and the other from a pumpkin,
they've modified tobacco plants
to address rubisco's
sloppy work.
And why are we using tobacco plants?
Yeah, tobacco's a really useful
model crop for us.
Why tobacco?
Turns out it's one of
the easiest plants
to genetically manipulate,
which makes it a common
test subject.
They have definitely shown
improvements in plant growth
and total biomass,
and we've been studying
the rates of photosynthesis.
And we are pretty confident now
that our model crop
is successful in this pathway,
and now we're really interested
in moving these into something
we like to eat.
Reducing the energy penalty
crops pay for rubisco's mistakes
could be huge.
In soybeans, a 25% reduction
could result in plants
that produce
more than 60 million
more bushels a year.
This to a lot of people
is an idea
that might be out there,
but if we can get it,
if we can get this moonshot
approach to work,
then we're going to have
more food.
And so that's really what drives
what I do.
The RIPE program
is international.
And, likely, so will be the reach
of any of its discoveries.
But work like theirs is not
without controversy.
Some of RIPE's solutions depend
on cross-breeding plants
chosen for their genes.
But other solutions,
like the rubisco work,
depend on genetic engineering...
also called genetic
modification, or GM...
Adding new genes
from other types of plants,
or even organisms, entirely.
The laws governing genetically
modified crops vary
from country to country,
especially when it comes to
labeling their use in food.
And there have been objections
to some companies
that patent their new crops
and control who can plant them.
But the general scientific
consensus
is that they are
no more dangerous
than conventional crops,
though they need to be carefully
studied for potential health
and environmental effects.
The U.S., unlike Europe,
has largely adopted GM plants.
An overwhelming percentage
of corn, soybeans, and cotton
grown in the United States
is genetically modified.
I understand there are concerns.
As a scientist,
I feel those concerns
have very little validity,
although clearly people have
become very concerned...
particularly in Europe.
Of course,
in this part of the world,
genetically modified crops have
been grown for over 20 years.
This technology has spread
throughout the Americas.
In fact, as the global
population grows,
it's in poorer countries
that RIPE's work may end up
having the greatest impact.
Especially if genetically modified
foods gain acceptance.
The place where I see
the technology needed most
is actually in sub-Saharan
Africa.
And this opposition to GM
is having quite an influence
in Africa.
It's keeping the science,
which is needed, out
and I fear that
this could risk people starving
when we could actually
be giving them seed
which would allow them
to feed themselves
into the future.
Even if scientists succeed
in improving photosynthesis,
it won't have anywhere near
the dramatic impact
of the original version
introduced about three billion
years ago.
Back then, scientists believe,
photosynthetic cyanobacteria
began cranking out oxygen
as a waste product.
Eventually, bacteria produced
enough oxygen
that it started to accumulate
in the atmosphere.
Which, in turn, gave rise
to one of life's
underappreciated molecular
allies... the ozone layer.
It's in the lowest level
of the stratosphere,
between roughly
eight and 22 miles up.
Atmospheric research planes
venture up here...
...but not much else.
The ozone comes from a process
even higher up
in the stratosphere.
There, solar radiation
busts up O2 molecules
into individual oxygen atoms.
They drift down
to the ozone layer
where they convert O2 into O3...
Ozone.
Despite the name,
there's not that much ozone
in the ozone layer...
less than ten parts
per million...
yet it's had a profound effect
on the evolution
of life on Earth.
To find out more...
So ozone is O3, right?
Ozone is O3.
I travel to the University
of California, Riverside,
to meet Kerry Hanson...
We came alive because...
a research chemist
who studies how molecules
like ozone
and those in sunscreens
interact with light.
So any molecule can absorb light.
It turns out
the ozone layer and sunscreens
have a lot in common.
This O3 gas is out there in the
atmosphere in such quantity
that there's an envelope
around the whole planet?
Yeah. It's a layer.
Think of like a sunscreen.
You know, how we use
sunscreen on our skin? Yeah.
So it's the exact same thing.
The ozone layer is earth's sunscreen.
Both the ozone layer
and sunscreens
protect us
from the harmful effects
of ultraviolet radiation...
Or U.V...
A kind of sunlight that,
unlike the colors of
the rainbow, we can't see.
On the electromagnetic spectrum,
visible light sits here,
but U.V. sits up here
at a higher energy.
Scientists divide it roughly
into three kinds...
A, B, and C.
And while A and B,
aren't good for you...
and they're the reason
to wear sunscreen...
it's C that's the big problem
for living things
because it's particularly
destructive to DNA.
Kerry tells me how all this
relates to ozone.
Just another Sunday
watching volleyball.
And it's kind of like
volleyball.
Oh! He's good.
Well... if the balls were
different kinds of U.V.
In the early days
of life on Earth,
before photosynthetic bacteria
oxygenated our atmosphere...
Get it, get it, get it...
yeah, yeah, yeah!
There was no ozone layer
and no global defense against
ultra violet radiation.
Aw... ooh...
The most dangerous kind, U.V.C.,
bathed the planet,
which may have effectively
limited where life could grow.
But oxygen accumulating
in the atmosphere
and the rise of the ozone layer
changed all that.
The layer blocks
all the U.V.C.
and most of the U.V.B.
from reaching
the Earth's surface.
Oh... good block!
Here's how it works:
when U.V. radiation
hits a molecule of ozone,
it splits it into an oxygen atom
and a molecule of O2.
The U.V. light has been absorbed
and neutralized.
The lone atom quickly rejoins
another molecule of O2
to reform ozone.
The net result is a conversion
of that harmful radiation
into heat.
Despite the ozone layer,
we can still get hit
by unhealthy amounts of U.V.
And that's why it's a good idea
to use sunscreen.
If you read the label,
and if it says broad spectrum,
that means it's blocking U.V.B.
and U.V.A.
- Wow.
- Not U.V.C.,
like ozone, but U.V.A. and B.
Just like we use
sunscreen to block harmful
U.V.A. and B radiation
from our skin...
the ozone layer protects
planet Earth from harmful
U.V.C. radiation...
that would destroy the
building blocks of life... DNA.
Without the blocking of U.V.C.
by the ozone layer,
life would not have been able
to come out of those oceans,
come up on to land,
and you and I wouldn't
be talking here today.
Thanks, ozone!
Without that global protection,
the grand story of evolution
that began from single-cell
ocean-dwelling life
and led to the wondrous
complexity of multicellular
animals occupying
land, sea, and sky would
probably never have been told.
And yada yada yada...
Yeah, yeah, I know,
the evolution of life
is important,
but let's talk about something
really important... me!
Or at least me and my molecules.
I know what elements
I'm made of:
CHNOPS... carbon, hydrogen,
nitrogen, oxygen,
phosphorus, sulfur... CHNOPS!
There are other elements
in the human body,
but these are the main six.
And, of course, a good chunk
of me by mass is good old H2O.
But if you take that water
away...
most of what's left
is macromolecules...
mostly big, long polymers...
chains of smaller molecules.
Yeah, so I once went "CHNOPing."
That's C-H-N-O...
To learn more about them,
biologist Monica Hall-Porter...
formerly at Lasell University,
now at the University of Texas...
offers to show me around
a local...
supermarket?
It's kind of weird,
I ask you about the molecules of my body,
and you bring us to a grocery store.
Yeah, so today's shopping trip
is about the macromolecules
that actually make up the human body.
Specifically protein,
lipids or fats, carbohydrates,
and nucleic acid.
And if you take a look around
the grocery store,
there are many examples
of those macromolecules here.
All right, show me the ropes.
Let's go shopping.
Our first objective?
Protein molecules.
Monica tells me, by weight,
that's about 20% of my body.
Does that mean pure
masculine muscle?
Is that what you're saying?
Well, not necessarily muscle.
Proteins are the molecules
that actually do work in cells.
So not just composing muscle
but also the proteins that
serve as the structural proteins
in our hair, fingernails.
The most abundant protein
in your body is collagen,
making up fibrous tissues like
skin, tendons, and ligaments.
There's also collagen
in teeth and bone.
But even though there are
tens of thousands
of different proteins
in the human body...
maybe millions, no one is sure...
amazingly, they're all made from
stringing together
about 20 different kinds
of small molecules
called amino acids,
which we get by breaking down
the proteins we eat
in a variety of foods.
And so when we consume
protein, like in turkey for example...
Whoa!
Our body breaks
the amino acids down
and then the amino acids
are incorporated into proteins
that our bodies synthesizes
or makes.
Yep, there you go!
Handsome little gobbler.
Next on the macromolecule
shopping list: lipids.
All right let's find
the lipids aisle.
Well, there's no lipidsaisle,
but we can get oils and fats.
So let's head down this way
and let's get some oil.
This is massive, how
much fats are we getting?
A lot.
Oh, man.
This seems like we've got
15 pounds of fats here.
Yes. And you're telling me
that's only half the amount in my body?
Absolutely, you're about
30 pounds of fat.
Now, I have to say I
find that a little insulting.
Well, you shouldn't.
Compared to proteins,
lipids or fats do get a bad rap.
But in addition to their role
in cell membranes,
and long-term energy storage...
you know, body fat...
they also provide protection
for internal organs.
Oh, and don't forget
the lipids in earwax!
And so literally
there's fat
in every part of you.
So even a slim, lean,
handsome, physically fit person
could have thirty pounds of fat in him?
Absolutely.
Next up, the third most
common macromolecule type...
Oh, this is my kind of
food group.
Carbohydrates.
Sugar!
Sugar!
Does this count as carbs?
Absolutely.
While I would have thought
I was sweeter,
turns out on average
there's only about
two pounds of carbs in me.
Glucose is the most abundant
carb in the human body.
It circulates to provide
energy for cells.
Now we're talking carbs...
Carb city,
carb heaven, carb central...
We are in the bread aisle, my friend.
I like it!
All right, we can toast this up
and put some butter on it...
Many glucose molecules
joined together
can make a plant starch,
the kind you find in cereals
and root vegetables.
It's the most common carb in the
human diet.
So did I under...
Hey, we're workin' here!
So we've got lipids.
Yeah.
Proteins.
Yeah.
And carbohydrates.
Yeah, the three
macromolecules of the human body.
Right, but we're missing one.
- There's another one?
- Yeah, we don't have anything
that's representative
of nucleic acids.
Nucleic acids are better known
as DNA and RNA.
DNA is the famous double helix.
It's usually two long chains
of molecules
that wrap around each other.
It contains genetic instructions
for making proteins.
RNA is often a long molecular
chain as well.
If DNA is the cookbook,
RNA is the chef,
reading DNA's instructions
for proteins,
gathering the ingredient
amino acids,
and assembling them in the
right order
in a macromolecular
protein printing machine
called a ribosome.
Life on Earth exists
in a spectacular
variety of forms,
but in the end,
it all depends on the
arrangement
of a handful of different small
molecules...
the nucleotides...
in the nucleic acids DNA
and RNA.
And we are now arriving
at the DNA aisle.
All righty.
And why strawberries?
Well, strawberries actually
have eight copies
of each chromosome per cell.
So relative to other fruits,
strawberries are actually
very rich in DNA.
Wow, all right.
Here's our DNA-ey berries.
Actually seeing DNA... you know,
the code of life...
has always seemed beyond
the reach of ordinary folks.
You can't just find some,
can you?
When you said we were going
to extract DNA
from strawberries, I figured
we would go to some humming,
high-tech lab with millions
of dollars of equipment...
No, actually DNA extraction
from strawberries
is something that can be
achieved at home.
As it turns out,
using some easily available
household items
like plastic bags,
detergent, rubbing alcohol,
cheesecloth and strawberries,
along with a little bit
of waiting time,
you too can catch a glimpse
of the code of life... DNA.
There it is.
You'll see an accumulation
of white, stringy substance.
That's actually a very crude
prep of DNA.
Basically, what's going to happen is,
it's going to clump on
the end of your glass rod.
Strawberry DNA slime,
right there.
Pretty amazing.
And so are the other three
macromolecules
that make up my body.
But all their wondrous
complexity
raises a deeply
mysterious question:
how did chemistry give rise
to biology?
How did life get its start?
A famous experiment in 1952
suggested the answer might
not be that hard to find.
At the University of Chicago,
graduate student Stanley Miller,
with help from his doctoral
advisor Harold Urey...
Mixed what were then
thought to be
the dominant ingredients of
Earth's early atmosphere...
methane, ammonia, and hydrogen...
Inside some sealed glassware.
Boiling water added water vapor
to the mix.
Then Miller created sparks
between electrodes
simulating lightning,
and let the mixture cool
and condense.
After running the experiment
for a week,
Miller found five amino acids...
some of them critical building
blocks of proteins.
You know, it was a dramatic
breakthrough at the time
for people to realize that
amino acids could be made
in such a simple way.
At Massachusetts General
Hospital,
Jack Szostak runs one of the
several research labs
around the world that are trying
to figure out
how chemistry gave rise
to biology.
So this is like increasing the
amount of sodium hydroxide,
and so increasing...
Oh, okay.
Today, it's clear
even the Miller Urey experiment,
while groundbreaking,
just scratched the surface
of the problem.
In retrospect,
it kind of fooled people
into thinking that
the answers might be easier than
they turned out to be, right?
Once you've got the right
chemicals, then what?
Right, right.
How do a bunch of chemicals
get together
and start acting like a cell?
A key requirement seems
to be a container.
All life on Earth,
from the simplest
to the most complex,
is made of cells,
with "outer membranes."
So on the road to life,
how did that happen?
Scientists like Anna Wang,
a former post-doc in
Jack Szostak's lab,
now a professor at UNSW Sydney,
have been working with
a simple molecule
that is one
of the prime suspects.
It's also present here.
Wow.
Shaped into bars in a wide
variety of colors and scents.
Smells good in here.
Smells amazing.
At Molly's Apothecary
outside of Boston.
Oh, that's wonderful.
That's right... soap!
Soap's interesting because
a soap molecule
is a combination of two
different types of molecules,
called polar and non-polar.
For example,
water molecules are polar.
Each one has a concentration
of electrons in one part,
making it negative, which leaves
another part more positive.
That's polarity.
And it makes water molecules
want to stick together,
each negative part attracted
to another molecule's
positive part.
An oil molecule, made
up of carbon and hydrogen,
is an example of a non-polar
molecule.
It has an even distribution
of electrons...
No polarity.
And less stickiness
between molecules.
In fact, polarity is why oil
and water don't mix.
The polar water molecules
stick together,
keeping the oil molecules
at bay.
The less dense oil floats
on top.
That's also why trying to clean
oily grease off your hands
with water alone,
doesn't work very well.
It actually won't come off,
it's super oily.
The two just don't interact.
And that's where soap molecules
come in.
They're hybrids; at one end
are some negatively charged,
electron-rich oxygens,
ready to interact
with polar molecules like water,
but the rest is a long,
non-polar hydrocarbon tail,
with no positive
or negative charge.
It's more comfortable mixing with
other non-polar molecules,
like grease.
Put some soap on your
greasy hands...
Soapy!
And the soap's non-polar tails
stick into the grease
while its polar heads
act like handles,
ready to interact with the water
taking the grease
along for the ride.
Here's another interesting
soap fact.
Drop some soap into water,
and the molecules form little
balls called micelles,
with their water-loving
polar heads sticking out,
and their water-hating non-polar
tails sticking in.
That naturally occurring
little container
has piqued the interest
of scientists like Anna.
Back at the lab, she adds some
soap molecules to water
containing short fragments
of RNA.
They've been tagged with a
molecule that makes them glow.
Why RNA?
The current scientific consensus
is that a primitive form of RNA may
have been the first molecule
with the ability
to replicate itself,
jump-starting evolution.
Next stop...
Now we're going to go look
at it under the microscope.
The microscope room...
where Anna loads up a sample
she prepared yesterday.
So this is what
our soap molecules
have self-assembled
into overnight.
What are they, bubbles?
Yeah, they're almost
like bubbles
and so what we're looking here
is not the soap molecules
themselves
but what they've
been able to trap
inside these
cell-sized structures.
Overnight, the soap micelles
have self-assembled
into larger spheres, trapping
the fluorescing RNA inside.
And if we could zoom
into one of them...
we'd see that it actually
consists
of two layers of soap molecules,
arranged with the water-loving
heads
toward the inside and outside,
and the water-hating tails
brought together.
When you have molecules
that have a polar head group
and a non-polar tail
but you don't give
the many oil to interact with,
the oily tails actually want to
interact with each other.
And so you end up forming
these bi-layer structures.
Wait, so these are soap
molecules
and these are also
soap molecules?
Yeah.
And they like to...
assemble into this position?
Yeah, that's right, so they like to form
these really thin envelopes,
and you can imagine
this structure extending onwards
and onwards and curving around
and forming a sphere.
And that's what we're
seeing here.
We're seeing this bi-layer
structure
encapsulating some
green-dyed RNA molecules.
This lipid, bi-layer
structure isn't alive,
but it's familiar to biologists.
It's similar to the bi-layer
structure of the membranes
that surrounds something
that is alive... cells.
Of course those are much more
complicated
and more stable containers,
better at keeping things
in or out,
though that feature comes
at a price.
If you take the membranes
that we have now
but get rid of all the highly
evolved protein machinery,
what you're left with
is just an inert sack.
It can't grow, it can't divide.
It can't even get nutrients
in and out.
That's why in the days
of proto-life,
less-stable membranes built out
of simpler molecules like soap
may have been an advantage.
Anna shows me an example.
So what I'm about
to do is I have
some soapy water in here
and I'm just going to add it.
What happens is those soap
molecules start incorporating
onto the existing membrane...
Look at this, look at this!
Yeah!
It just split!
So they look pretty
spherical now,
but they're starting
to wiggle a bit.
And all of a sudden...
it looks like
they might melt. Cell division!
Wow.
Our cells grow and divide
because we have something
giving instructions.
Yes.
But you're saying that
billions of years ago,
none of that existed.
There's none of that in here,
so what we're kind of simulating
is a condition where maybe
these protocells have
floated somewhere
down the stream,
and they've come across a pool
of excess soap molecules,
and these soap molecules can
join the membrane and grow it.
So I think what it means is that
we can still get simple cells
to divide by purely physical
mechanisms,
and that's what we're trying
to understand in the field,
like how do you get to do things
that kind of seem like life
and mimic life
but without any biology?
In the early days of Earth,
soap or similar molecules
may have self-assembled
into cell-like containers...
Did they have
the bi-layer thing already?
They have a bi-layer membrane.Yeah.
But Jack Szostak realizes
that's just a start.
There are many more steps on
the road from chemistry to biology.
Once you got the right kinds of
molecules,
which are pretty simple,
they can assemble
into membranes.
But they can't actually start
to do anything interesting
in terms of, like,
getting more complicated
and being more, like,
more and more advanced life
until you have genetics.Yeah.
You need a hereditary material,
something like RNA or DNA.
And once you've done that,
you have cycles of replication,
because that's got to go on
inside these protocells.
And it's got to happen just by
chemistry and physics
because there were no enzymes.
There was no evolved machinery,
right?
So, in a sense,
the answer has to be simple.Yeah.
And we just have to figure
out how it works.
Scientists like Jack and Anna
are searching
for the mysterious road
that led not only to life
but to the mechanism that's
allowed it
to overcome adversity...
Evolution.
Today, some scientists wonder
what if we could harness
evolution's creative power
to solve some of our own
challenges?
Wow.
Nature is constantly changing.
Hi, boys.
Because there is this tremendous
effort to survive.
If you can harness that power,
that innovation
that nature is doing
and direct it in a
beneficial way,
then we can use
that power of innovation
to solve some of our really
tough problems.
Harnessing the innovative
power of evolution
is at the heart of the work
of chemical engineer
Frances Arnold of Caltech
in Pasadena, California.
That could be a huge deal
in the world.
I hope so.
And she's used it
to engineer new molecules
to solve a wide range
of problems.
From the search for new
antibiotics,
or methods to convert waste
into biofuels,
to teaching cells
to bond elements
in ways never before seen
in nature.
So do come if you're interested
in the process
of protein engineering,
because that's the future,
so all of you
who are going to do...
She's achieved her successes
by discovering new catalysts,
the materials that speed up
chemical reactions
without getting consumed
by them.
In C edge functionalization...
In living things,
catalysts are called enzymes...
For example,
the protein rubisco.
Enzymes help facilitate
the reactions
that make life possible.
The reason that you
and I can sit here and talk
is that we have thousands
of catalysts in us, proteins,
that can convert the food we eat
into the thoughts
that you think...
and the motor mouth, right?
These are catalysts that
do all this chemistry.
These are chemical
transformations
that make life possible.
In fact they work so well,
engineers and scientists have
wanted to find a way
to co-opt the idea,
to create new enzymes
that would do our bidding,
assisting reactions that
aren't found in nature at all.
The question is how?
Many scientists
and engineers feel that
in order to design
a new product,
you sit down and you calculate,
you know, the right angles and
the right weights and loads.
I come from a different
point of view, that these
very complicated things
are the products of evolution.
So I say, "Let's just
go straight to the answer,
using this gift given to us."
Frances uses an approach
called directed evolution.
One way to think about
directing evolution,
is it's like breeding.
It's like breeding cats or dogs.
With a specific end goal
in mind,
She starts with DNA
that encodes for some
protein catalysts
that have some promising traits,
depending on what
she's looking for.
The DNA gets copied in a
way that produces random mutations.
She puts that into
microorganisms that multiply
and produce a variety of
slightly different proteins.
So you have a gene,
the organism reads the gene,
makes the proteins,
and they're all
slightly different,
just like your children...
but now I can decide who goes on
to parent the next generation
because I measure what
those proteins do.
Frances tests the results
to see if any represent a step
in the right direction.
If so, that becomes
the new starting point,
and she repeats the process.
To see how quickly you can train
enzymes, that's what we're
doing, we're training them,
we're breeding them...
to do something that perhaps
nature never did before.
When you discover that they've
learned how to do that
and they do it better than
any human can do, it is so exciting.
To see how directed evolution
can work outside the lab...
Farming has always been about
increasing productivity.
Frances suggested that I contact
one of her former students,
Pedro Coelho.
Along with a partner,
she and Pedro founded a company
Provivi,
based in Santa Monica.
Pedro is the CEO.
Provivi makes a chemical to
fight this agricultural pest,
the fall army worm.
It's a pest that is native
to the Americas,
but in the last three years,
it's invaded all of Africa
and now, all of Asia,
going from India to China,
and it's a very difficult pest
to control
because once it
infests the corn,
it hides inside the corn plant
where the insecticides
can't touch it.
But Provivi's chemical
isn't a pesticide,
it doesn't kill anything.
Instead it disrupts the way
fall army worms mate.
Here's how it works:
Fall army worms eventually
become adult moths,
and that's when they mate.
To attract males, female moths
release a pheromone,
a molecule that acts
as a chemical signal.
So the female moth will release
a little bit of pheromone,
and then the male will pick up
that signal with his antenna
and will fly towards her to mate
and reproduce.
She uses only a small amount,
but it's incredibly potent.
It can attract males
from up to a mile away.
These are complicated molecules.
These are the Chanel No. 5
of insects.
But such a powerful
"sex perfume"
can become a means of control.
So imagine, now, you come with
a bottle of Chanel No. 5
and you spray it everywhere.
Then he can't find her,
and they don't mate
and have caterpillars.
Provivi has figured out
how to replicate
the fall army pheromone,
and put it into a slow release
spray for crops.
Which you have to imagine
is very confusing
for the male moths.
They have so much trouble
finding females
that in the end there are fewer
eggs, and worms.
So you're not killing
these things,
and you're not driving
them away,
you're just confusing them?
Yeah, so it's not a repellant,
and it's not a kill agent,
it's simply a mating disruptor.
Pedro tells me using pheromones
to combat pests isn't new.
But until now,
it's been expensive,
and therefore limited
to high-value smaller crops
like apples or grapes.
So the real breakthrough at
Provivi isn't using pheromones
but making them inexpensively.
They've studied the enzyme
catalysts the insect uses
to make the pheromone,
and moved the genes for those
enzyme catalysts into yeast.
Then, through directed
evolution,
they optimize those little yeast
cell factories
for larger scale production
in vessels similar
to those used for brewing beer.
And the key is that
by just changing the microbe,
we can make many different
pheromones
but using the same
infrastructure,
which gives us the economies
of scale
and should make this
cost effective.
Making it possible to use
on staple crops grown around the
world,
like corn,
and rice.
Our mission very much
is to take this proven tool
of pheromones
to the largest markets
of agriculture,
which are the staples
of humankind.
Companies like Provivi aren't
the only sign
that directed evolution
and cell factories
are having a big impact
on manufacturing.
Well, I teach this course
called Reaction Engineering
which is how do you take
chemical reactions
and scale them up?
In 2018, Frances Arnold won
the Nobel Prize in Chemistry,
for her pioneering work
in directed evolution.
Is this idea
of chemistry and biology
to manufacture stuff,
is that catching on these days?
It is, it most definitely is.
I think the future
is so exciting,
because now what happens
is with these tools
of being able to manipulate DNA,
and the code of life, really,
we can now merge all
these beautiful mechanisms
of the biological world
with the inventions of
human chemistry.
And that way,
it merges in new innovations.
That both chemists and
biologists have a lot to learn
from each other should come
as no surprise.
But what is surprising is that
biology would arise out of
chemistry at all.
Look at this, look at this!
Cell division!
The blueprints of life!
The origin of life
remains one of the great
unsolved mysteries of science.
Was the mix of chemicals
on early Earth
destined to give rise to life?
And once it started,
was the road that lead to the
chemical complexity
of photosynthesis
and the harnessing of the power
of the sun...
Probably the most important
process on the planet.
The only road to be taken?
Are we alone in the universe?
Or just the local branch
of cosmic bio-chem?
The answers to questions like
these will be found
only through science...
as we go beyond the elements.
To order this program on DVD,
visit ShopPBS
or call 1-800-PLAY-PBS.
Episodes of "NOVA" are available
with Passport.
"NOVA" is also available
on Amazon Prime Video.
our modern world?
Ah!
That's amazing!
I'm David Pogue.
Join me on a high-speed chase
through the elements...
and beyond.
Oh, my God!
As we smash our way into
the materials,
molecules,
and reactions...
It's a really cool enzyme
because it makes life on Earth
possible.
That make the places we live,
the bodies we live in,
and the stuff we can't seem
to live without.
The only thing between me and
certain death...
is chemistry?
From killer snails...
Just when
you think you've heard of everything,
nature will surprise you.
And exploding glass
to the price a pepper-eating
Pogue pays.
There's got to be some easier
way to learn about molecules.
We'll dig into
the surprising way
different elements
combine together
and blow apart.
In this hour,
we tackle one of the biggest
mysteries of all:
the origin of life.
How do a bunch of chemicals
get together
and start acting like a cell?
Part of the answer might be...
soap?
Cell division!
We explore how the chemistry of
life transformed the planet.
So everything that we eat,
and the air that we breathe,
all have to do
with the process
of photosynthesis.
All right, so let's find
the lipids aisle.
I go shopping for the
macromolecules of my body.
You're telling me that
that’s only half the amount of fats
in my body?
Absolutely.
And I meet an engineer who uses
nature's tools
to invent new molecules.
Humans have been using microbes
to make beer and wine.
Instead of making sake,
we make jet fuel.
"Beyond the Elements: Life"...
right now on "NOVA".
The world we live in is made
of atoms...
all listed here as elements
on the periodic table.
They're the building blocks
of everything around us
and putting atoms together to
make molecules and compounds
is what we call chemistry.
And maybe the strangest event
in the history of chemistry
is the birth of biology.
How do a bunch of chemicals
somehow get together
to form life?
And if you look back at the
conditions on early Earth,
how did life get off
the starting block?
There was a turning point,
the evolution of a
transformative series
of chemical reactions that,
over time,
remade the planet,
even allowing us to come along.
But first,
let's take a trip back,
to Life 1.0.
So, here's the ad:
Planet available.
Recently scoured by asteroids.
New construction.
Now with many water views.
The atmosphere?
Eh... a fixer-upper.
Devoid of oxygen.
Likely full of whatever
the volcanoes spewed forth...
gases like hydrogen sulfide
and methane.
Somehow in that very harsh
environment,
primitive life got its start.
But the going stayed tough.
Food... molecules and minerals
that early organisms
could use for energy...
consisted of whatever was left
over from Earth's formation,
or was welling up
from the Earth's core
at places like deep sea vents.
But in a surprisingly short
amount of time...
perhaps 500 million years...
a new survival strategy
evolved...
possibly the most important
chemical process for life
on Earth today...
Photosynthesis...
The ability
to turn sunlight into fuel.
Life now had access to the vast
power of the sun.
In the words of one biologist,
"When photosynthesis
"entered the picture,
life connected
up to the cosmos."
So, everything that we eat,
what we wear,
the air that we breathe,
the ecosystem services
that we rely on...
so things like having
clean water...
all have to do with the process
of photosynthesis.
It's an incredibly important,
probably the most important,
process on the planet.
Photosynthesis harnesses
the power of sunlight
to break down water molecules.
Discarding the oxygen,
it uses the electrons
from the hydrogen atoms
to power the assembly
of carbon dioxide molecules
into carbohydrates,
which become both
building blocks
and long-term energy storage.
It's not an overstatement to say
that all life on this planet
depends on photosynthesis.
It's exactly where
all of our food comes from...
directly or indirectly.
So understanding
how this process works
is so important to humanity.
Steve Long and Don Ort,
two plant biologists
at the University of Illinois
Urbana-Champaign,
along with thousands of
other scientists from around the world
have spent decades teasing
apart the workings of photosynthesis.
Light intensity is 900
right now?
Right now, yeah. Oh yeah.
For... that makes sense.
Sorghum is an important grain.
Now, with that knowledge
in hand,
there is a new international
research effort based here
at the university
with an audacious goal.
The program's called RIPE:
Realizing Increased
Photosynthetic Efficiency.
This year was a huge hit
for the canola farmers
because it was too wet.
So I've been wondering
whether it would be worth
trying to find a substitute
as our test bed.
That'd be perfect.
These folks
want to hack photosynthesis.
But why would you want
to do that?
Because experts think the Earth
is about to get
a whole lot more people.
Today, the world's population
is close to eight billion.
And that's forecast to hit
9.7 billion by 2050.
Raising the question:
will there be enough food?
If you look at the current rate
at which we're improving
crop productivity
per acre of land,
we're not going to get there.
Part of the answer
is going to be
redesigning photosynthesis.
To learn more about
RIPE's plans,
I've joined Lisa Ainsworth,
a U.S.D.A. scientist,
and professor at the
University of Illinois...
You can see just how
different the height is
- just in walking from one.
- Wow.
On an early morning tour
of a field
that contains 600 different
varieties of soybeans.
Usually you hear about
efficiency,
like of a gas engine, measured
in terms of a percentage,
how much of the fuel
is ultimately converted
to energy.
What's the percentage efficiency
for a plant?
Well, in terms of
how much of the light
energy it turns into sugar,
it's pretty low...
maybe around three percent.
Three percent?!
That's terrible!
But you guys are going
to help it.
That's the plan.
To improve photosynthesis,
two other researchers
with RIPE...
Amanda Cavanagh and Paul South...
have focused on one of
its key molecules.
It has a very catchy name.
So the molecule is what we
biologists call an enzyme.
And so it does the work.
Enzymes are like
biological workers.
And the enzyme's called rubisco.
It's R.U.B.P...
or ribulose bisphosphate
carboxylase oxygenase.
And it's,
for most plant biologists,
one of our favorite enzymes
on the planet.
Yeah, rubisco is our shortened
term for it.
Mainly because it's fun to say.
Well, it's super fun to say.
Rubisco. Of course.
Rubisco.
But, it's also
a really cool enzyme
because it makes life on Earth
possible.
Rubisco may not look so special
but it is arguably the most
important enzyme on the planet
because of its critical role
in photosynthesis.
Rubisco's job is to grab
a molecule of carbon dioxide
and feed it into
a molecular machine
that's building carbon chains.
That means any carbon atom
that's part of any plant
anywhere
got there thanks to rubisco,
or one of its close variants.
And because we eat plants,
or animals that ate plants,
that also includes just about every
carbon atom in your body.
All approximately 800 million
billion billion of them.
That's 26 zeroes.
Not bad, rubisco, not bad.
Yeah, so, if it's ever
come from a plant,
it had to have gone through
that enzyme of rubisco.
That's wild!
Yeah.
How come there's not like a...
a memorial to rubisco
in Washington?
It seems, like,
sort of important.
Rubisco is important
and that's why it's the
most plentiful protein on Earth.
But just because
you're important
doesn't mean you're entirely...
competent.
It's... in this case, not the
best enzyme in the world.
It's got a hard job,
so it's doing its best,
but at the same time it exists
in an atmosphere that's not
predominantly carbon dioxide,
it's mostly oxygen.
And about one in every four or
five reactions it grabs oxygen
instead of carbon dioxide.
That's right.
Rubisco screws up
about a fifth of the time.
Instead of attaching
a carbon dioxide
it attaches an oxygen molecule.
And that's trouble.
You're saying nature
has created a screwed-up
little worker enzyme?
Yeah, so, 400 million years ago,
when this enzyme evolved,
there wasn't very much oxygen
in the air.
All right, so I'm the little
- rubisco enzyme...
- Yup.
- And I'm like on the conveyor belt here.
- Yeah.
And like, okay, carbon dioxide,
carbon dioxide, carbon dioxide,
carbon dioxide, oxygen
and I, I don't notice
I accidentally grabbed an oxygen
out of the box.
And it produces
compounds that are inhibitory
to photosynthesis,
so it kind of starts to
shut things down.
I mean it's been going on
for billions of years
and nobody has cared. Yeah, well...
I mean, it all...
all basically works.
Photosynthesis, right now,
is sort of a victim
of its own success...
rubisco certainly is.
So by oxygenating the atmosphere
via photosynthesis,
you now have a huge amount
of oxygen in the atmosphere
but you need a carbon dioxide
to make the reaction work.
So what happens when rubisco
screws up?
The result gets shipped out
through a couple other parts
of the cell
to where the mess is taken apart
and recycled,
all of which consumes
a lot of energy.
If you could fix
this inefficiency problem,
the plant might make more...
soybeans, corn, whatever it is?
That's exactly it.
Then they will have that energy
to put towards something
that we would consider useful
like making more food for us
to eat.
Is this just a crazy theory
or is there some indication
that this could actually work?
There's quite a bit of evidence
that this is working.
So right now,
we have this tested
in a couple of model species.
It is tropical in here.
Amanda and Paul take me to the
greenhouse to see one example.
Using two genes,
one from algae
and the other from a pumpkin,
they've modified tobacco plants
to address rubisco's
sloppy work.
And why are we using tobacco plants?
Yeah, tobacco's a really useful
model crop for us.
Why tobacco?
Turns out it's one of
the easiest plants
to genetically manipulate,
which makes it a common
test subject.
They have definitely shown
improvements in plant growth
and total biomass,
and we've been studying
the rates of photosynthesis.
And we are pretty confident now
that our model crop
is successful in this pathway,
and now we're really interested
in moving these into something
we like to eat.
Reducing the energy penalty
crops pay for rubisco's mistakes
could be huge.
In soybeans, a 25% reduction
could result in plants
that produce
more than 60 million
more bushels a year.
This to a lot of people
is an idea
that might be out there,
but if we can get it,
if we can get this moonshot
approach to work,
then we're going to have
more food.
And so that's really what drives
what I do.
The RIPE program
is international.
And, likely, so will be the reach
of any of its discoveries.
But work like theirs is not
without controversy.
Some of RIPE's solutions depend
on cross-breeding plants
chosen for their genes.
But other solutions,
like the rubisco work,
depend on genetic engineering...
also called genetic
modification, or GM...
Adding new genes
from other types of plants,
or even organisms, entirely.
The laws governing genetically
modified crops vary
from country to country,
especially when it comes to
labeling their use in food.
And there have been objections
to some companies
that patent their new crops
and control who can plant them.
But the general scientific
consensus
is that they are
no more dangerous
than conventional crops,
though they need to be carefully
studied for potential health
and environmental effects.
The U.S., unlike Europe,
has largely adopted GM plants.
An overwhelming percentage
of corn, soybeans, and cotton
grown in the United States
is genetically modified.
I understand there are concerns.
As a scientist,
I feel those concerns
have very little validity,
although clearly people have
become very concerned...
particularly in Europe.
Of course,
in this part of the world,
genetically modified crops have
been grown for over 20 years.
This technology has spread
throughout the Americas.
In fact, as the global
population grows,
it's in poorer countries
that RIPE's work may end up
having the greatest impact.
Especially if genetically modified
foods gain acceptance.
The place where I see
the technology needed most
is actually in sub-Saharan
Africa.
And this opposition to GM
is having quite an influence
in Africa.
It's keeping the science,
which is needed, out
and I fear that
this could risk people starving
when we could actually
be giving them seed
which would allow them
to feed themselves
into the future.
Even if scientists succeed
in improving photosynthesis,
it won't have anywhere near
the dramatic impact
of the original version
introduced about three billion
years ago.
Back then, scientists believe,
photosynthetic cyanobacteria
began cranking out oxygen
as a waste product.
Eventually, bacteria produced
enough oxygen
that it started to accumulate
in the atmosphere.
Which, in turn, gave rise
to one of life's
underappreciated molecular
allies... the ozone layer.
It's in the lowest level
of the stratosphere,
between roughly
eight and 22 miles up.
Atmospheric research planes
venture up here...
...but not much else.
The ozone comes from a process
even higher up
in the stratosphere.
There, solar radiation
busts up O2 molecules
into individual oxygen atoms.
They drift down
to the ozone layer
where they convert O2 into O3...
Ozone.
Despite the name,
there's not that much ozone
in the ozone layer...
less than ten parts
per million...
yet it's had a profound effect
on the evolution
of life on Earth.
To find out more...
So ozone is O3, right?
Ozone is O3.
I travel to the University
of California, Riverside,
to meet Kerry Hanson...
We came alive because...
a research chemist
who studies how molecules
like ozone
and those in sunscreens
interact with light.
So any molecule can absorb light.
It turns out
the ozone layer and sunscreens
have a lot in common.
This O3 gas is out there in the
atmosphere in such quantity
that there's an envelope
around the whole planet?
Yeah. It's a layer.
Think of like a sunscreen.
You know, how we use
sunscreen on our skin? Yeah.
So it's the exact same thing.
The ozone layer is earth's sunscreen.
Both the ozone layer
and sunscreens
protect us
from the harmful effects
of ultraviolet radiation...
Or U.V...
A kind of sunlight that,
unlike the colors of
the rainbow, we can't see.
On the electromagnetic spectrum,
visible light sits here,
but U.V. sits up here
at a higher energy.
Scientists divide it roughly
into three kinds...
A, B, and C.
And while A and B,
aren't good for you...
and they're the reason
to wear sunscreen...
it's C that's the big problem
for living things
because it's particularly
destructive to DNA.
Kerry tells me how all this
relates to ozone.
Just another Sunday
watching volleyball.
And it's kind of like
volleyball.
Oh! He's good.
Well... if the balls were
different kinds of U.V.
In the early days
of life on Earth,
before photosynthetic bacteria
oxygenated our atmosphere...
Get it, get it, get it...
yeah, yeah, yeah!
There was no ozone layer
and no global defense against
ultra violet radiation.
Aw... ooh...
The most dangerous kind, U.V.C.,
bathed the planet,
which may have effectively
limited where life could grow.
But oxygen accumulating
in the atmosphere
and the rise of the ozone layer
changed all that.
The layer blocks
all the U.V.C.
and most of the U.V.B.
from reaching
the Earth's surface.
Oh... good block!
Here's how it works:
when U.V. radiation
hits a molecule of ozone,
it splits it into an oxygen atom
and a molecule of O2.
The U.V. light has been absorbed
and neutralized.
The lone atom quickly rejoins
another molecule of O2
to reform ozone.
The net result is a conversion
of that harmful radiation
into heat.
Despite the ozone layer,
we can still get hit
by unhealthy amounts of U.V.
And that's why it's a good idea
to use sunscreen.
If you read the label,
and if it says broad spectrum,
that means it's blocking U.V.B.
and U.V.A.
- Wow.
- Not U.V.C.,
like ozone, but U.V.A. and B.
Just like we use
sunscreen to block harmful
U.V.A. and B radiation
from our skin...
the ozone layer protects
planet Earth from harmful
U.V.C. radiation...
that would destroy the
building blocks of life... DNA.
Without the blocking of U.V.C.
by the ozone layer,
life would not have been able
to come out of those oceans,
come up on to land,
and you and I wouldn't
be talking here today.
Thanks, ozone!
Without that global protection,
the grand story of evolution
that began from single-cell
ocean-dwelling life
and led to the wondrous
complexity of multicellular
animals occupying
land, sea, and sky would
probably never have been told.
And yada yada yada...
Yeah, yeah, I know,
the evolution of life
is important,
but let's talk about something
really important... me!
Or at least me and my molecules.
I know what elements
I'm made of:
CHNOPS... carbon, hydrogen,
nitrogen, oxygen,
phosphorus, sulfur... CHNOPS!
There are other elements
in the human body,
but these are the main six.
And, of course, a good chunk
of me by mass is good old H2O.
But if you take that water
away...
most of what's left
is macromolecules...
mostly big, long polymers...
chains of smaller molecules.
Yeah, so I once went "CHNOPing."
That's C-H-N-O...
To learn more about them,
biologist Monica Hall-Porter...
formerly at Lasell University,
now at the University of Texas...
offers to show me around
a local...
supermarket?
It's kind of weird,
I ask you about the molecules of my body,
and you bring us to a grocery store.
Yeah, so today's shopping trip
is about the macromolecules
that actually make up the human body.
Specifically protein,
lipids or fats, carbohydrates,
and nucleic acid.
And if you take a look around
the grocery store,
there are many examples
of those macromolecules here.
All right, show me the ropes.
Let's go shopping.
Our first objective?
Protein molecules.
Monica tells me, by weight,
that's about 20% of my body.
Does that mean pure
masculine muscle?
Is that what you're saying?
Well, not necessarily muscle.
Proteins are the molecules
that actually do work in cells.
So not just composing muscle
but also the proteins that
serve as the structural proteins
in our hair, fingernails.
The most abundant protein
in your body is collagen,
making up fibrous tissues like
skin, tendons, and ligaments.
There's also collagen
in teeth and bone.
But even though there are
tens of thousands
of different proteins
in the human body...
maybe millions, no one is sure...
amazingly, they're all made from
stringing together
about 20 different kinds
of small molecules
called amino acids,
which we get by breaking down
the proteins we eat
in a variety of foods.
And so when we consume
protein, like in turkey for example...
Whoa!
Our body breaks
the amino acids down
and then the amino acids
are incorporated into proteins
that our bodies synthesizes
or makes.
Yep, there you go!
Handsome little gobbler.
Next on the macromolecule
shopping list: lipids.
All right let's find
the lipids aisle.
Well, there's no lipidsaisle,
but we can get oils and fats.
So let's head down this way
and let's get some oil.
This is massive, how
much fats are we getting?
A lot.
Oh, man.
This seems like we've got
15 pounds of fats here.
Yes. And you're telling me
that's only half the amount in my body?
Absolutely, you're about
30 pounds of fat.
Now, I have to say I
find that a little insulting.
Well, you shouldn't.
Compared to proteins,
lipids or fats do get a bad rap.
But in addition to their role
in cell membranes,
and long-term energy storage...
you know, body fat...
they also provide protection
for internal organs.
Oh, and don't forget
the lipids in earwax!
And so literally
there's fat
in every part of you.
So even a slim, lean,
handsome, physically fit person
could have thirty pounds of fat in him?
Absolutely.
Next up, the third most
common macromolecule type...
Oh, this is my kind of
food group.
Carbohydrates.
Sugar!
Sugar!
Does this count as carbs?
Absolutely.
While I would have thought
I was sweeter,
turns out on average
there's only about
two pounds of carbs in me.
Glucose is the most abundant
carb in the human body.
It circulates to provide
energy for cells.
Now we're talking carbs...
Carb city,
carb heaven, carb central...
We are in the bread aisle, my friend.
I like it!
All right, we can toast this up
and put some butter on it...
Many glucose molecules
joined together
can make a plant starch,
the kind you find in cereals
and root vegetables.
It's the most common carb in the
human diet.
So did I under...
Hey, we're workin' here!
So we've got lipids.
Yeah.
Proteins.
Yeah.
And carbohydrates.
Yeah, the three
macromolecules of the human body.
Right, but we're missing one.
- There's another one?
- Yeah, we don't have anything
that's representative
of nucleic acids.
Nucleic acids are better known
as DNA and RNA.
DNA is the famous double helix.
It's usually two long chains
of molecules
that wrap around each other.
It contains genetic instructions
for making proteins.
RNA is often a long molecular
chain as well.
If DNA is the cookbook,
RNA is the chef,
reading DNA's instructions
for proteins,
gathering the ingredient
amino acids,
and assembling them in the
right order
in a macromolecular
protein printing machine
called a ribosome.
Life on Earth exists
in a spectacular
variety of forms,
but in the end,
it all depends on the
arrangement
of a handful of different small
molecules...
the nucleotides...
in the nucleic acids DNA
and RNA.
And we are now arriving
at the DNA aisle.
All righty.
And why strawberries?
Well, strawberries actually
have eight copies
of each chromosome per cell.
So relative to other fruits,
strawberries are actually
very rich in DNA.
Wow, all right.
Here's our DNA-ey berries.
Actually seeing DNA... you know,
the code of life...
has always seemed beyond
the reach of ordinary folks.
You can't just find some,
can you?
When you said we were going
to extract DNA
from strawberries, I figured
we would go to some humming,
high-tech lab with millions
of dollars of equipment...
No, actually DNA extraction
from strawberries
is something that can be
achieved at home.
As it turns out,
using some easily available
household items
like plastic bags,
detergent, rubbing alcohol,
cheesecloth and strawberries,
along with a little bit
of waiting time,
you too can catch a glimpse
of the code of life... DNA.
There it is.
You'll see an accumulation
of white, stringy substance.
That's actually a very crude
prep of DNA.
Basically, what's going to happen is,
it's going to clump on
the end of your glass rod.
Strawberry DNA slime,
right there.
Pretty amazing.
And so are the other three
macromolecules
that make up my body.
But all their wondrous
complexity
raises a deeply
mysterious question:
how did chemistry give rise
to biology?
How did life get its start?
A famous experiment in 1952
suggested the answer might
not be that hard to find.
At the University of Chicago,
graduate student Stanley Miller,
with help from his doctoral
advisor Harold Urey...
Mixed what were then
thought to be
the dominant ingredients of
Earth's early atmosphere...
methane, ammonia, and hydrogen...
Inside some sealed glassware.
Boiling water added water vapor
to the mix.
Then Miller created sparks
between electrodes
simulating lightning,
and let the mixture cool
and condense.
After running the experiment
for a week,
Miller found five amino acids...
some of them critical building
blocks of proteins.
You know, it was a dramatic
breakthrough at the time
for people to realize that
amino acids could be made
in such a simple way.
At Massachusetts General
Hospital,
Jack Szostak runs one of the
several research labs
around the world that are trying
to figure out
how chemistry gave rise
to biology.
So this is like increasing the
amount of sodium hydroxide,
and so increasing...
Oh, okay.
Today, it's clear
even the Miller Urey experiment,
while groundbreaking,
just scratched the surface
of the problem.
In retrospect,
it kind of fooled people
into thinking that
the answers might be easier than
they turned out to be, right?
Once you've got the right
chemicals, then what?
Right, right.
How do a bunch of chemicals
get together
and start acting like a cell?
A key requirement seems
to be a container.
All life on Earth,
from the simplest
to the most complex,
is made of cells,
with "outer membranes."
So on the road to life,
how did that happen?
Scientists like Anna Wang,
a former post-doc in
Jack Szostak's lab,
now a professor at UNSW Sydney,
have been working with
a simple molecule
that is one
of the prime suspects.
It's also present here.
Wow.
Shaped into bars in a wide
variety of colors and scents.
Smells good in here.
Smells amazing.
At Molly's Apothecary
outside of Boston.
Oh, that's wonderful.
That's right... soap!
Soap's interesting because
a soap molecule
is a combination of two
different types of molecules,
called polar and non-polar.
For example,
water molecules are polar.
Each one has a concentration
of electrons in one part,
making it negative, which leaves
another part more positive.
That's polarity.
And it makes water molecules
want to stick together,
each negative part attracted
to another molecule's
positive part.
An oil molecule, made
up of carbon and hydrogen,
is an example of a non-polar
molecule.
It has an even distribution
of electrons...
No polarity.
And less stickiness
between molecules.
In fact, polarity is why oil
and water don't mix.
The polar water molecules
stick together,
keeping the oil molecules
at bay.
The less dense oil floats
on top.
That's also why trying to clean
oily grease off your hands
with water alone,
doesn't work very well.
It actually won't come off,
it's super oily.
The two just don't interact.
And that's where soap molecules
come in.
They're hybrids; at one end
are some negatively charged,
electron-rich oxygens,
ready to interact
with polar molecules like water,
but the rest is a long,
non-polar hydrocarbon tail,
with no positive
or negative charge.
It's more comfortable mixing with
other non-polar molecules,
like grease.
Put some soap on your
greasy hands...
Soapy!
And the soap's non-polar tails
stick into the grease
while its polar heads
act like handles,
ready to interact with the water
taking the grease
along for the ride.
Here's another interesting
soap fact.
Drop some soap into water,
and the molecules form little
balls called micelles,
with their water-loving
polar heads sticking out,
and their water-hating non-polar
tails sticking in.
That naturally occurring
little container
has piqued the interest
of scientists like Anna.
Back at the lab, she adds some
soap molecules to water
containing short fragments
of RNA.
They've been tagged with a
molecule that makes them glow.
Why RNA?
The current scientific consensus
is that a primitive form of RNA may
have been the first molecule
with the ability
to replicate itself,
jump-starting evolution.
Next stop...
Now we're going to go look
at it under the microscope.
The microscope room...
where Anna loads up a sample
she prepared yesterday.
So this is what
our soap molecules
have self-assembled
into overnight.
What are they, bubbles?
Yeah, they're almost
like bubbles
and so what we're looking here
is not the soap molecules
themselves
but what they've
been able to trap
inside these
cell-sized structures.
Overnight, the soap micelles
have self-assembled
into larger spheres, trapping
the fluorescing RNA inside.
And if we could zoom
into one of them...
we'd see that it actually
consists
of two layers of soap molecules,
arranged with the water-loving
heads
toward the inside and outside,
and the water-hating tails
brought together.
When you have molecules
that have a polar head group
and a non-polar tail
but you don't give
the many oil to interact with,
the oily tails actually want to
interact with each other.
And so you end up forming
these bi-layer structures.
Wait, so these are soap
molecules
and these are also
soap molecules?
Yeah.
And they like to...
assemble into this position?
Yeah, that's right, so they like to form
these really thin envelopes,
and you can imagine
this structure extending onwards
and onwards and curving around
and forming a sphere.
And that's what we're
seeing here.
We're seeing this bi-layer
structure
encapsulating some
green-dyed RNA molecules.
This lipid, bi-layer
structure isn't alive,
but it's familiar to biologists.
It's similar to the bi-layer
structure of the membranes
that surrounds something
that is alive... cells.
Of course those are much more
complicated
and more stable containers,
better at keeping things
in or out,
though that feature comes
at a price.
If you take the membranes
that we have now
but get rid of all the highly
evolved protein machinery,
what you're left with
is just an inert sack.
It can't grow, it can't divide.
It can't even get nutrients
in and out.
That's why in the days
of proto-life,
less-stable membranes built out
of simpler molecules like soap
may have been an advantage.
Anna shows me an example.
So what I'm about
to do is I have
some soapy water in here
and I'm just going to add it.
What happens is those soap
molecules start incorporating
onto the existing membrane...
Look at this, look at this!
Yeah!
It just split!
So they look pretty
spherical now,
but they're starting
to wiggle a bit.
And all of a sudden...
it looks like
they might melt. Cell division!
Wow.
Our cells grow and divide
because we have something
giving instructions.
Yes.
But you're saying that
billions of years ago,
none of that existed.
There's none of that in here,
so what we're kind of simulating
is a condition where maybe
these protocells have
floated somewhere
down the stream,
and they've come across a pool
of excess soap molecules,
and these soap molecules can
join the membrane and grow it.
So I think what it means is that
we can still get simple cells
to divide by purely physical
mechanisms,
and that's what we're trying
to understand in the field,
like how do you get to do things
that kind of seem like life
and mimic life
but without any biology?
In the early days of Earth,
soap or similar molecules
may have self-assembled
into cell-like containers...
Did they have
the bi-layer thing already?
They have a bi-layer membrane.Yeah.
But Jack Szostak realizes
that's just a start.
There are many more steps on
the road from chemistry to biology.
Once you got the right kinds of
molecules,
which are pretty simple,
they can assemble
into membranes.
But they can't actually start
to do anything interesting
in terms of, like,
getting more complicated
and being more, like,
more and more advanced life
until you have genetics.Yeah.
You need a hereditary material,
something like RNA or DNA.
And once you've done that,
you have cycles of replication,
because that's got to go on
inside these protocells.
And it's got to happen just by
chemistry and physics
because there were no enzymes.
There was no evolved machinery,
right?
So, in a sense,
the answer has to be simple.Yeah.
And we just have to figure
out how it works.
Scientists like Jack and Anna
are searching
for the mysterious road
that led not only to life
but to the mechanism that's
allowed it
to overcome adversity...
Evolution.
Today, some scientists wonder
what if we could harness
evolution's creative power
to solve some of our own
challenges?
Wow.
Nature is constantly changing.
Hi, boys.
Because there is this tremendous
effort to survive.
If you can harness that power,
that innovation
that nature is doing
and direct it in a
beneficial way,
then we can use
that power of innovation
to solve some of our really
tough problems.
Harnessing the innovative
power of evolution
is at the heart of the work
of chemical engineer
Frances Arnold of Caltech
in Pasadena, California.
That could be a huge deal
in the world.
I hope so.
And she's used it
to engineer new molecules
to solve a wide range
of problems.
From the search for new
antibiotics,
or methods to convert waste
into biofuels,
to teaching cells
to bond elements
in ways never before seen
in nature.
So do come if you're interested
in the process
of protein engineering,
because that's the future,
so all of you
who are going to do...
She's achieved her successes
by discovering new catalysts,
the materials that speed up
chemical reactions
without getting consumed
by them.
In C edge functionalization...
In living things,
catalysts are called enzymes...
For example,
the protein rubisco.
Enzymes help facilitate
the reactions
that make life possible.
The reason that you
and I can sit here and talk
is that we have thousands
of catalysts in us, proteins,
that can convert the food we eat
into the thoughts
that you think...
and the motor mouth, right?
These are catalysts that
do all this chemistry.
These are chemical
transformations
that make life possible.
In fact they work so well,
engineers and scientists have
wanted to find a way
to co-opt the idea,
to create new enzymes
that would do our bidding,
assisting reactions that
aren't found in nature at all.
The question is how?
Many scientists
and engineers feel that
in order to design
a new product,
you sit down and you calculate,
you know, the right angles and
the right weights and loads.
I come from a different
point of view, that these
very complicated things
are the products of evolution.
So I say, "Let's just
go straight to the answer,
using this gift given to us."
Frances uses an approach
called directed evolution.
One way to think about
directing evolution,
is it's like breeding.
It's like breeding cats or dogs.
With a specific end goal
in mind,
She starts with DNA
that encodes for some
protein catalysts
that have some promising traits,
depending on what
she's looking for.
The DNA gets copied in a
way that produces random mutations.
She puts that into
microorganisms that multiply
and produce a variety of
slightly different proteins.
So you have a gene,
the organism reads the gene,
makes the proteins,
and they're all
slightly different,
just like your children...
but now I can decide who goes on
to parent the next generation
because I measure what
those proteins do.
Frances tests the results
to see if any represent a step
in the right direction.
If so, that becomes
the new starting point,
and she repeats the process.
To see how quickly you can train
enzymes, that's what we're
doing, we're training them,
we're breeding them...
to do something that perhaps
nature never did before.
When you discover that they've
learned how to do that
and they do it better than
any human can do, it is so exciting.
To see how directed evolution
can work outside the lab...
Farming has always been about
increasing productivity.
Frances suggested that I contact
one of her former students,
Pedro Coelho.
Along with a partner,
she and Pedro founded a company
Provivi,
based in Santa Monica.
Pedro is the CEO.
Provivi makes a chemical to
fight this agricultural pest,
the fall army worm.
It's a pest that is native
to the Americas,
but in the last three years,
it's invaded all of Africa
and now, all of Asia,
going from India to China,
and it's a very difficult pest
to control
because once it
infests the corn,
it hides inside the corn plant
where the insecticides
can't touch it.
But Provivi's chemical
isn't a pesticide,
it doesn't kill anything.
Instead it disrupts the way
fall army worms mate.
Here's how it works:
Fall army worms eventually
become adult moths,
and that's when they mate.
To attract males, female moths
release a pheromone,
a molecule that acts
as a chemical signal.
So the female moth will release
a little bit of pheromone,
and then the male will pick up
that signal with his antenna
and will fly towards her to mate
and reproduce.
She uses only a small amount,
but it's incredibly potent.
It can attract males
from up to a mile away.
These are complicated molecules.
These are the Chanel No. 5
of insects.
But such a powerful
"sex perfume"
can become a means of control.
So imagine, now, you come with
a bottle of Chanel No. 5
and you spray it everywhere.
Then he can't find her,
and they don't mate
and have caterpillars.
Provivi has figured out
how to replicate
the fall army pheromone,
and put it into a slow release
spray for crops.
Which you have to imagine
is very confusing
for the male moths.
They have so much trouble
finding females
that in the end there are fewer
eggs, and worms.
So you're not killing
these things,
and you're not driving
them away,
you're just confusing them?
Yeah, so it's not a repellant,
and it's not a kill agent,
it's simply a mating disruptor.
Pedro tells me using pheromones
to combat pests isn't new.
But until now,
it's been expensive,
and therefore limited
to high-value smaller crops
like apples or grapes.
So the real breakthrough at
Provivi isn't using pheromones
but making them inexpensively.
They've studied the enzyme
catalysts the insect uses
to make the pheromone,
and moved the genes for those
enzyme catalysts into yeast.
Then, through directed
evolution,
they optimize those little yeast
cell factories
for larger scale production
in vessels similar
to those used for brewing beer.
And the key is that
by just changing the microbe,
we can make many different
pheromones
but using the same
infrastructure,
which gives us the economies
of scale
and should make this
cost effective.
Making it possible to use
on staple crops grown around the
world,
like corn,
and rice.
Our mission very much
is to take this proven tool
of pheromones
to the largest markets
of agriculture,
which are the staples
of humankind.
Companies like Provivi aren't
the only sign
that directed evolution
and cell factories
are having a big impact
on manufacturing.
Well, I teach this course
called Reaction Engineering
which is how do you take
chemical reactions
and scale them up?
In 2018, Frances Arnold won
the Nobel Prize in Chemistry,
for her pioneering work
in directed evolution.
Is this idea
of chemistry and biology
to manufacture stuff,
is that catching on these days?
It is, it most definitely is.
I think the future
is so exciting,
because now what happens
is with these tools
of being able to manipulate DNA,
and the code of life, really,
we can now merge all
these beautiful mechanisms
of the biological world
with the inventions of
human chemistry.
And that way,
it merges in new innovations.
That both chemists and
biologists have a lot to learn
from each other should come
as no surprise.
But what is surprising is that
biology would arise out of
chemistry at all.
Look at this, look at this!
Cell division!
The blueprints of life!
The origin of life
remains one of the great
unsolved mysteries of science.
Was the mix of chemicals
on early Earth
destined to give rise to life?
And once it started,
was the road that lead to the
chemical complexity
of photosynthesis
and the harnessing of the power
of the sun...
Probably the most important
process on the planet.
The only road to be taken?
Are we alone in the universe?
Or just the local branch
of cosmic bio-chem?
The answers to questions like
these will be found
only through science...
as we go beyond the elements.
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