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Welcome to a new and very strange
world of nature.

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It's been taken over by
the weird subatomic particles of

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quantum physics.

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CHURCH BELL RINGS

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As a physicist, I've spent
my working life studying

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how these particles behave
<font color="

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But now I'm heading out
into the natural world.

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I'm on a mission to prove
that quantum physics can solve

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the greatest mysteries in biology.

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This is a real adventure for me.

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I'm very much out of my
<font color="

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the very careful ideas I'm familiar
with in a physics laboratory

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to the messy world of living things.

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I believe that quantum physics
could hold many of life's secrets,

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that deep in the cells of animals,

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particles glide through walls
<font color="

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..that when plants capture
sunlight...

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..their cells are invaded by
shimmering waves

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that can be everywhere
at the same time.

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And that even our human senses

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are tuning in to strange quantum
<font color="

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In the fantastic world
of quantum biology,

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life is a game of chance,

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played by quantum rules.

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This is what I hope to
convince you of,

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to show you that quantum mechanics
is essential in explaining

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<font color="
life, and potentially, that

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quantum mechanics may even underpin
the very existence of life itself.

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My quest begins with one of
the most majestic sights in nature.

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Migration.

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Every winter, barnacle geese
<font color="

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at the same Scottish river.

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The end of an epic 2,000-mile
voyage from Svalbard,

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high above the Arctic Circle.

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Of course, many birds
head south for winter

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then back home for summer.

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But for decades, exactly how birds
<font color="

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was one of the greatest
mysteries in biology.

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So the most recent discovery has
caused a sensation.

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In the past few years,

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one species of bird has helped

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create a scientific revolution.

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<font color="
shocked to discover that it

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navigates using one of the strangest
tricks in the whole of science.

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It utilises a quirk of
quantum mechanics,

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one that bamboozled even
the greatest of physicists,

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<font color="
Albert Einstein himself.

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So you might be surprised to
discover the identity of this

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mysterious creature.

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Say hello to the Quantum Robin.

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This is the European robin.

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Every year, she migrates from
northern Europe

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<font color="

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In this laboratory in the woods,

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biologist Henrik Mouritsen is
trying to solve the mystery

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of how she does it.

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But he's found himself in MY world,

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the strange world of
quantum mechanics.

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<font color="
the very weird behaviour of

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subatomic particles.

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Down in this realm
of the very small,

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we have to abandon
common sense and intuition.

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Instead, this is a world where
objects can spread out like waves.

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<font color="
in many places at once

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and send each other
mysterious communications.

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I set out to understand
how the bird finds its way,

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but it just turned out that the data

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more and more pointed towards this as

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<font color="
all the different results together.

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Henrik's investigating
a longstanding theory -

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that robins navigate by
the Earth's magnetic field.

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His laboratory is an ingenious
magnetic bird cage.

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<font color="
with scratch-sensitive paper

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provide the key measurements.

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Henrik's artificial magnetic field
is like the Earth's, except that

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HE can point it in
any direction he likes.

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Inside their cones, the robins
<font color="

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leaving scratches in
a single direction.

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The big mystery is HOW.

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The Earth's magnetic field
is incredibly weak,

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far too weak for any
living creature to detect.

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But Henrik has found
<font color="

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by giving the Quantum Robin a mask.

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We have a little leather hood similar
to what you put on a falcon,

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you know, but just for a robin,

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and you have then a
hole in front of one eye

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or a hole in front of the other eye.

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<font color="
cover up the right eye, you turn off

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their magnetic compass processing
in the left part of the brain.

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If you cover up this eye,

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you turn the compass off
in this part of the brain.

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The robin's magnetic compass
<font color="

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I can show you what's going
on using my own eye.

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Now, we use our eyes for vision,

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but we also have a second
light-detecting mechanism.

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If I shine this torch into my eye,

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you can see that
my pupil closes down.

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<font color="
to protect my eyes.

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My eye is responding to particles
of light - or photons.

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The energy provided by the photons

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is clearly enough to activate
chemical reactions.

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After all, that's what
<font color="

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Light must be causing similar
chemical reactions

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in the robin's eyes.

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In fact, it's the power supply for
a unique form of magnetic compass...

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..inside her cells...

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..in the weird world
of subatomic particles...

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<font color="

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can explain what's going on.

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To see why, imagine the chemical
reactions in the robin's eye

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taking place in mountains
and valleys of energy.

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To get a reaction to start,

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you have to push molecules
<font color="

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Thanks to Henrik's experiments,

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we now know that light does
most of the hard work.

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But when it reaches the very peak,

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the molecule becomes incredibly
sensitive to the slightest touch.

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The key point here is that
<font color="

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balanced on an energy peak
between two valleys.

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Going one way produces one set
of chemical products -

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the other, a different set.

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Now, even a tiny change in the
Earth's magnetic field can tip the

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<font color="
this happens defies common sense.

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The final piece of the puzzle

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depends on one of the truly

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mind-boggling ideas in physics.

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But don't worry if you find it

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hard to understand -

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even Albert Einstein

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<font color="

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The idea is called
quantum entanglement.

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It involves particles that
seem to communicate faster

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than the speed of light.

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In 1935, Einstein published
a famous paper

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arguing that it was impossible.

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<font color="

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In recent years, extremely delicate
experiments have shown that

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subatomic particles
really are entangled.

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It means they can subtly

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and instantaneously influence
each other across space.

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<font color="
going on inside the robin's eye.

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When a photon enters
the robin's eye,

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it creates what's called an
entangled pair of electrons.

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Here's how it works. Each electron
has two possible states.

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<font color="
call them Red and Green.

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Now, here's the weird thing.

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Until I measure it,
it's neither one nor the other,

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but both at the same time.

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Think of the electrons
like spinning discs.

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They're simultaneously
<font color="

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But by firing a dart...

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..I can force the first electron
to be one or the other.

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So far, it's just a game of chance.

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I don't know what I'll get
until I try it.

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So I know my first electron is red.

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Suppose I now measure
<font color="

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You'd think I'd have a 50/50 chance
of getting red or green.

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After all, that's what you'd expect
in the normal, everyday world.

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But you'd be wrong.

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In quantum entanglement, the
electrons are mysteriously linked.

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<font color="
if I get red on the first...

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..I ALWAYS get red on the second.

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It's not a game of chance any more.

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It's as if the first electron is
telling the second one what to do.

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That's why Einstein
called it spooky.

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should both have the same colour,

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no matter how far apart they are.

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The really important part is that

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the two electrons needn't be
the same colour.

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They can be entangled
in a different way,

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<font color="
electron is red...

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..the second one is always green.

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It seems that this mysterious
connection is the ultimate secret

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of the Quantum Robin's compass...

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..because the direction of
the Earth's magnetic field

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<font color="

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Near the equator, they may be
more likely to be red-red.

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But near the pole, they may be
more likely to be red-green.

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And that's the vital factor
that finally tips the balance of

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the robin's chemical compass.

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magnetic field change the way

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electrons in the robin's eye
are entangled,

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and that's just enough
to trigger her compass.

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Now, finally, we can see how
something as weak as the Earth's

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<font color="
balance one way or the other.

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If the message changes,

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the chemical reaction
tips a different way...

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..changing the robin's
compass reading.

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Suddenly it looks like it's
a fundamentally quantum mechanical

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<font color="

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It would be one of the first,
if not THE first, in biology.

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Biologists better get used
to the weirdness of physics.

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The robin is navigating by
"spooky" quantum entanglement.

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To see subtle quantum effects,

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<font color="
environment of a physics lab,

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is really difficult.

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And yet here's the robin
doing it with ease.

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These experiments are real
and verifiable, and yet even though

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I'm seeing them with my own eyes,
<font color="

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Bird navigation has brought physics

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and nature together as
the science of quantum biology.

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There's a whole new world
to explore.

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But its pioneers have found that
it doesn't just affect birds.

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<font color="

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Because the latest experiments say

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you're doing quantum physics
right now.

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And believe it or not,
you're doing it with your nose.

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Hello, Jem!

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Hello.

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Hello, little girl! Hello...

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<font color="

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and quite different from our other
senses of sight and hearing.

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Among the thousands of scents
that we can recognise,

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many of them may well trigger very
powerful memories and emotions.

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It's as though our sense of smell is

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<font color="
inner consciousness.

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It's also different in another way.

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The other senses of sight and
hearing rely on us detecting waves -

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light and sound.

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But our sense of smell
involves detecting particles -

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chemical molecules.

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<font color="
realise that when it comes to

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our sense of smell, something very
mysterious is going on.

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GUNSHOT

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For decades, biologists thought
they knew exactly how our noses

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sniffed out different chemicals.

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<font color="
think there could be a new

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ingredient in the mix.

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And it smells like
quantum mechanics.

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A lot of people speak of
the sense of smell and olfaction,

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and the science of olfaction as
<font color="

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and we know all about it -
and we do know a lot about it.

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We know about the ingredients,

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we know about the equipment
that we use to smell.

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But I would argue that there's
a little bit more to understand.

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<font color="
to help me with a smell test.

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And Jem is going to sniff him out.

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Every human being gives off
a cocktail of chemicals.

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Jem's nose could detect
a single gram of it

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dissolved over an entire city.

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00:16:36,720 --> 00:16:39,520
<font color="
the man I'm looking for.

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Meet Colin the gardener, a man
who's used to smelling the flowers.

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Right, then, Colin, I'm going to put
your sniffing skills to the test.

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Cool. I've got a selection of
<font color="

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and I want you to tell me
what they remind you of.

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OK.

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I'll start you off easily.

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COLIN SNIFFS

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Oh, that's...

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like a minty, minty vapour rub...
It is, yeah. ..sort of thing.

251
00:17:12,480 --> 00:17:14,920
<font color="
Something what you'd rub...

252
00:17:14,920 --> 00:17:18,280
This is men...menthol. Menthol.
Yeah. But it's that essence.

253
00:17:19,960 --> 00:17:21,560
Right, here's the next one.

254
00:17:22,960 --> 00:17:25,560
Ah. You should be able to
recognise this one.

255
00:17:26,560 --> 00:17:28,520
<font color="

256
00:17:28,520 --> 00:17:31,000
Mm-hm. Erm, icing sugar
sort of thing...

257
00:17:31,000 --> 00:17:32,760
Vanilla. Vanilla, yeah.

258
00:17:36,760 --> 00:17:39,120
When our noses detect a chemical,

259
00:17:39,120 --> 00:17:41,720
they fire a nerve signal
to our brains.

260
00:17:44,840 --> 00:17:48,080
But different chemicals create
<font color="

261
00:17:52,040 --> 00:17:54,680
The standard explanation for this
is to do with

262
00:17:54,680 --> 00:17:56,440
the shape of the molecules.

263
00:18:00,080 --> 00:18:03,080
The conventional theory
that goes back to the 1950s

264
00:18:03,080 --> 00:18:07,320
says that the scent molecule has
a particular shape that allows it

265
00:18:07,320 --> 00:18:10,960
<font color="
molecules in our nose.

266
00:18:15,120 --> 00:18:18,120
If it has the right shape,
it's like a hand in a glove,

267
00:18:18,120 --> 00:18:22,440
or a key in a lock. In fact, it's
called the lock and key mechanism.

268
00:18:22,440 --> 00:18:25,760
With the wrong shape,
it won't fit into the receptor.

269
00:18:25,760 --> 00:18:28,760
<font color="
it fits into the receptor,

270
00:18:28,760 --> 00:18:31,760
triggering that unique
smell sensation.

271
00:18:35,000 --> 00:18:38,960
Different receptors are wired to
different parts of our brains.

272
00:18:41,080 --> 00:18:45,040
So, when a menthol molecule
locks into its specific receptor,

273
00:18:45,040 --> 00:18:47,640
it triggers that
<font color="

274
00:18:50,960 --> 00:18:53,920
But the lock and key theory
has always had a problem...

275
00:18:55,160 --> 00:18:58,200
..and Colin's next test
will show you why.

276
00:18:58,200 --> 00:19:00,440
OK, how about...

277
00:19:00,440 --> 00:19:02,000
this one?

278
00:19:02,000 --> 00:19:03,760
Quite a strong smell.

279
00:19:03,760 --> 00:19:05,880
Oh, that's...

280
00:19:05,880 --> 00:19:08,840
<font color="
What does it conjure up?

281
00:19:08,840 --> 00:19:10,480
What memories?

282
00:19:10,480 --> 00:19:12,120
I think Christmas.

283
00:19:12,120 --> 00:19:15,320
Christmas cake. Yeah. Marzipan.

284
00:19:15,320 --> 00:19:17,560
Marz...marz...yeah, that's it, yeah.

285
00:19:17,560 --> 00:19:19,760
Almonds. Very, yeah.

286
00:19:19,760 --> 00:19:24,080
<font color="
marzipan or almonds.

287
00:19:24,080 --> 00:19:28,600
In fact, it's due to a scent
molecule called benzaldehyde.

288
00:19:28,600 --> 00:19:33,320
What I didn't give him to smell was
this other chemical - cyanide.

289
00:19:33,320 --> 00:19:36,080
Both benzaldehyde and cyanide
have the same smell,

290
00:19:36,080 --> 00:19:37,680
<font color="

291
00:19:37,680 --> 00:19:40,760
but these molecules are both
very different shapes,

292
00:19:40,760 --> 00:19:42,800
so the lock and key mechanism,

293
00:19:42,800 --> 00:19:46,400
as an explanation for how we smell,
can't be the whole story.

294
00:19:49,640 --> 00:19:54,080
So why would two molecules with
different shapes smell the same?

295
00:19:55,960 --> 00:19:59,120
<font color="
a head-spinning explanation.

296
00:20:02,680 --> 00:20:06,040
It says our noses aren't
smelling chemical molecules...

297
00:20:09,480 --> 00:20:11,200
..they're LISTENING to them.

298
00:20:14,560 --> 00:20:18,240
It's not just the shape of
a scent molecule that matters.

299
00:20:18,240 --> 00:20:21,680
Let's take a closer look at this
<font color="

300
00:20:21,680 --> 00:20:24,080
The white ball here is
a hydrogen atom,

301
00:20:24,080 --> 00:20:27,640
and the grey sticks are the bonds
that hold it together

302
00:20:27,640 --> 00:20:29,640
with the carbon and nitrogen.

303
00:20:29,640 --> 00:20:31,680
But the reality isn't
as simple as that.

304
00:20:31,680 --> 00:20:34,040
I can give you a better
<font color="

305
00:20:34,040 --> 00:20:36,880
if we look at this
larger white ball.

306
00:20:36,880 --> 00:20:39,840
You see, atoms don't just sit still.

307
00:20:39,840 --> 00:20:44,280
The bonds that hold them together
are like vibrating strings,

308
00:20:44,280 --> 00:20:48,040
and that gives us a whole new
way of thinking about smell.

309
00:20:51,240 --> 00:20:56,680
<font color="
smell is all about vibrating bonds.

310
00:20:58,400 --> 00:21:00,440
HE PLAYS HARMONICS ON GUITAR

311
00:21:04,440 --> 00:21:08,200
Chemical molecules are
playing music for our noses.

312
00:21:09,840 --> 00:21:14,480
Imagine a receptor molecule
in my nose is like my guitar.

313
00:21:14,480 --> 00:21:18,640
Before it can make a sound, a scent
<font color="

314
00:21:18,640 --> 00:21:22,600
and when that scent molecule
is in place, its chemical bonds

315
00:21:22,600 --> 00:21:26,920
provide the strings,
and it's ready to be played.

316
00:21:28,520 --> 00:21:31,760
The receptor molecules contain
quantum particles -

317
00:21:31,760 --> 00:21:33,040
electrons.

318
00:21:34,360 --> 00:21:38,160
As they leap from one atom to
<font color="

319
00:21:38,160 --> 00:21:40,280
the scent molecule,

320
00:21:40,280 --> 00:21:43,120
like my fingers plucking
a guitar string.

321
00:21:43,120 --> 00:21:44,960
GUITAR NOTE CHIMES

322
00:21:46,120 --> 00:21:49,040
What's remarkable about this
theory is that it tells us

323
00:21:49,040 --> 00:21:53,120
our sense of smell is about
the vibrations of molecules,

324
00:21:53,120 --> 00:21:54,640
<font color="

325
00:21:54,640 --> 00:21:59,000
and not so much about the shape
of a particular scent molecule.

326
00:21:59,000 --> 00:22:02,880
Our sense of smell may be much
more like our sense of hearing.

327
00:22:03,880 --> 00:22:05,920
HE PLUCKS HIGH NOTE

328
00:22:07,120 --> 00:22:09,960
A particular molecule,
say that of grass,

329
00:22:09,960 --> 00:22:12,960
will vibrate at
<font color="

330
00:22:12,960 --> 00:22:15,000
HE PLUCKS LOW NOTE

331
00:22:19,120 --> 00:22:21,960
But a different molecule,
say, that of mint,

332
00:22:21,960 --> 00:22:24,840
will vibrate at
a different frequency.

333
00:22:24,840 --> 00:22:26,880
HE PLUCKS MID-RANGE NOTE

334
00:22:31,480 --> 00:22:33,240
PLUCKED NOTE REVERBERATES

335
00:22:35,440 --> 00:22:36,960
HIGHER NOTE REVERBERATES

336
00:22:38,080 --> 00:22:41,840
<font color="
cyanide smells like almonds.

337
00:22:43,440 --> 00:22:46,520
The two molecules have
different shapes,

338
00:22:46,520 --> 00:22:50,320
but their chemical bonds
just happen to vibrate

339
00:22:50,320 --> 00:22:51,920
at the same frequency.

340
00:22:53,840 --> 00:22:57,080
The constant vibration
in the odorant is almost

341
00:22:57,080 --> 00:22:59,480
<font color="

342
00:22:59,480 --> 00:23:02,640
So, yeah, we're saying that
the process of smell could be

343
00:23:02,640 --> 00:23:05,880
exactly like an acoustic
resonance event,

344
00:23:05,880 --> 00:23:11,120
it could be very analogous to, erm,
hearing and seeing, actually.

345
00:23:12,400 --> 00:23:15,360
But can we really
<font color="

346
00:23:17,400 --> 00:23:20,800
A bizarre theory needs
a bizarre experiment to test it.

347
00:23:22,720 --> 00:23:24,160
Here's how it works.

348
00:23:24,160 --> 00:23:29,320
Scientists used a molecule that
smells fruity, like orange blossom.

349
00:23:31,040 --> 00:23:32,760
But if the theory is right,

350
00:23:32,760 --> 00:23:38,720
then I should be able to change its
<font color="

351
00:23:38,720 --> 00:23:40,520
The molecule contains

352
00:23:40,520 --> 00:23:43,280
lots of hydrogen atoms like this,

353
00:23:43,280 --> 00:23:47,240
bonded to carbon atoms, but what if
I were to replace all these atoms

354
00:23:47,240 --> 00:23:51,720
with a different form
of hydrogen called deuterium?

355
00:23:51,720 --> 00:23:54,560
Now, it won't change
<font color="

356
00:23:54,560 --> 00:23:57,520
but it will change
the way it vibrates.

357
00:23:57,520 --> 00:24:02,080
And here's why - deuterium is
twice as heavy as normal hydrogen,

358
00:24:02,080 --> 00:24:05,960
and so it vibrates more slowly.

359
00:24:05,960 --> 00:24:09,240
Now, different vibrations mean
different smells,

360
00:24:09,240 --> 00:24:12,160
so if I were to make
<font color="

361
00:24:12,160 --> 00:24:15,840
all packed with deuterium atoms
instead of normal hydrogen,

362
00:24:15,840 --> 00:24:17,840
it should smell different.

363
00:24:20,600 --> 00:24:25,880
Quantum biologists found a unique
way to carry out this experiment.

364
00:24:28,160 --> 00:24:29,840
A smell comparison,

365
00:24:29,840 --> 00:24:33,520
using the real experts
<font color="

366
00:24:33,520 --> 00:24:36,000
INSECTS BUZZ

367
00:24:36,000 --> 00:24:37,440
Fruit flies.

368
00:24:38,560 --> 00:24:41,880
First, the flies were trained to
avoid the modified version

369
00:24:41,880 --> 00:24:44,240
of the fruity molecule.

370
00:24:44,240 --> 00:24:46,000
To be honest,

371
00:24:46,000 --> 00:24:49,880
I haven't got a clue how you
go about training a fruit fly,

372
00:24:49,880 --> 00:24:51,600
<font color="

373
00:24:53,600 --> 00:24:58,320
In the laboratory, the flies had
to pass through a kind of maze.

374
00:25:01,360 --> 00:25:03,280
They were then given a choice.

375
00:25:07,000 --> 00:25:10,080
Go right for the nice, fruity smell,

376
00:25:10,080 --> 00:25:14,240
or left,
for the nasty, modified version.

377
00:25:14,240 --> 00:25:18,040
HE STRUMS GENTLY

378
00:25:21,400 --> 00:25:23,960
They could definitely
<font color="

379
00:25:27,400 --> 00:25:31,000
They always preferred
the original and turned right.

380
00:25:39,400 --> 00:25:42,440
The fruit fly experiment gives
hard evidence

381
00:25:42,440 --> 00:25:45,120
that quantum smell theory
really works.

382
00:25:47,920 --> 00:25:52,200
But ultimately, it works in harmony
with the lock and key theory.

383
00:25:53,920 --> 00:25:57,840
<font color="
fits into the receptor...

384
00:25:59,000 --> 00:26:02,160
..then those molecular
vibrations take over.

385
00:26:05,480 --> 00:26:09,040
Incredible as it seems,
flies, humans

386
00:26:09,040 --> 00:26:13,320
and dogs may be smelling
the sound of quantum biology.

387
00:26:17,320 --> 00:26:21,440
Our sense of smell is fascinating
<font color="

388
00:26:21,440 --> 00:26:24,840
but to think that when
I encounter a particular scent

389
00:26:24,840 --> 00:26:28,200
and that sets off
a whole wave of memories

390
00:26:28,200 --> 00:26:32,120
and emotions in my mind,
that it's underpinned,

391
00:26:32,120 --> 00:26:34,520
that it's triggered
by quantum mechanics,

392
00:26:34,520 --> 00:26:37,280
<font color="
more remarkable.

393
00:26:37,280 --> 00:26:40,440
CROWS CAW

394
00:26:49,120 --> 00:26:53,040
The mysterious influence
of quantum physics

395
00:26:53,040 --> 00:26:55,120
reaches into every corner
of the natural world.

396
00:26:59,680 --> 00:27:02,240
In fact, it inhabits the walls

397
00:27:02,240 --> 00:27:04,800
of every living cell on Earth.

398
00:27:08,360 --> 00:27:11,960
<font color="
suggest a magical solution

399
00:27:11,960 --> 00:27:14,640
to one of the greatest
mysteries of nature.

400
00:27:18,840 --> 00:27:21,800
The miracle of metamorphosis.

401
00:27:30,880 --> 00:27:34,400
The transformation of
a tadpole into a frog

402
00:27:34,400 --> 00:27:37,240
has never been fully explained.

403
00:27:37,240 --> 00:27:41,160
<font color="
the tadpole breaks down,

404
00:27:41,160 --> 00:27:44,600
then reassembles in its adult form.

405
00:27:44,600 --> 00:27:49,320
But the big mystery
is how it happens so fast.

406
00:27:49,320 --> 00:27:52,160
When you think about it,
there's nothing more extraordinary

407
00:27:52,160 --> 00:27:54,800
than a tadpole turning into a frog.

408
00:27:54,800 --> 00:27:56,960
<font color="

409
00:27:56,960 --> 00:28:00,840
Over a period of several weeks,
it gets reabsorbed into the body

410
00:28:00,840 --> 00:28:04,640
and the proteins and fibres
that make up the flesh

411
00:28:04,640 --> 00:28:08,320
get recycled to form
the frog's new limbs.

412
00:28:08,320 --> 00:28:10,160
But for this to happen,

413
00:28:10,160 --> 00:28:13,400
trillions and trillions of
<font color="

414
00:28:13,400 --> 00:28:18,560
breaking molecules, forming new ones
in a carefully orchestrated dance.

415
00:28:18,560 --> 00:28:22,600
But the fibres that hold flesh
together are very, very strong.

416
00:28:22,600 --> 00:28:26,320
They're a bit like these ropes
holding my raft together.

417
00:28:26,320 --> 00:28:31,480
In order to dismantle the raft, I'd
<font color="

418
00:28:33,000 --> 00:28:34,920
You could think of it like this...

419
00:28:36,240 --> 00:28:40,200
..a tadpole is held together
by long ropes of proteins

420
00:28:40,200 --> 00:28:42,680
knotted together by chemical bonds.

421
00:28:44,520 --> 00:28:48,440
The bonds are so strong
that they should last for years,

422
00:28:48,440 --> 00:28:52,240
much longer than the tadpole's
<font color="

423
00:28:52,240 --> 00:28:57,720
So how can it turn into
a frog in just a few weeks?

424
00:28:57,720 --> 00:29:01,800
The explanation involves one of the
most important molecules of life.

425
00:29:03,240 --> 00:29:07,800
Tiny widgets in all our cells
called enzymes.

426
00:29:07,800 --> 00:29:11,280
The enzymes are the actual
machinery of the cell.

427
00:29:11,280 --> 00:29:15,440
<font color="
machines inside cells

428
00:29:15,440 --> 00:29:19,400
that do the chemical transformations
that are involved in everyday life.

429
00:29:19,400 --> 00:29:21,360
They are absolutely crucial.

430
00:29:21,360 --> 00:29:24,920
And the reason they're so crucial
is because what they are able to do

431
00:29:24,920 --> 00:29:30,360
is to accelerate chemical
<font color="

432
00:29:30,360 --> 00:29:34,080
Let me show you just how quickly
enzymes get to work.

433
00:29:35,720 --> 00:29:39,680
Inside this bottle is a substance
called hydrogen peroxide.

434
00:29:39,680 --> 00:29:41,760
You're probably most familiar
with it

435
00:29:41,760 --> 00:29:43,400
as the chemical used to bleach hair.

436
00:29:43,400 --> 00:29:45,680
<font color="

437
00:29:45,680 --> 00:29:47,800
from my local hairdressers.

438
00:29:47,800 --> 00:29:50,520
Hydrogen peroxide is also
produced in the body,

439
00:29:50,520 --> 00:29:53,640
and it's the job of the liver
to get rid of it.

440
00:29:53,640 --> 00:29:55,840
The way it does that
is using an enzyme

441
00:29:55,840 --> 00:30:00,920
which breaks down hydrogen peroxide
<font color="

442
00:30:00,920 --> 00:30:04,120
Now, to show you just how quickly
this enzyme works,

443
00:30:04,120 --> 00:30:06,080
I'm going to do
a quick demonstration.

444
00:30:06,080 --> 00:30:08,720
I've got some liver here
which I've chopped up

445
00:30:08,720 --> 00:30:11,160
in order to release the enzyme.

446
00:30:13,480 --> 00:30:17,000
Now, watch what happens when
<font color="

447
00:30:17,000 --> 00:30:20,480
containing the enzyme
to the hydrogen peroxide.

448
00:30:20,480 --> 00:30:23,080
Watch how quickly the oxygen
is released.

449
00:30:35,280 --> 00:30:37,560
CROWS CAW

450
00:30:38,880 --> 00:30:44,040
Just 100 grams of liver
fired my rocket nearly 20 feet.

451
00:30:47,680 --> 00:30:50,840
Liver enzymes make the breakdown
<font color="

452
00:30:50,840 --> 00:30:52,440
incredibly efficient.

453
00:30:52,440 --> 00:30:55,120
It happens a trillion times faster.

454
00:30:55,120 --> 00:30:58,920
That's a million, million times
faster than it would otherwise.

455
00:31:01,080 --> 00:31:03,440
In metamorphosis, it's enzymes

456
00:31:03,440 --> 00:31:06,120
that dismantle the tadpole's tail.

457
00:31:07,400 --> 00:31:09,240
And that means breaking down

458
00:31:09,240 --> 00:31:11,080
<font color="

459
00:31:11,080 --> 00:31:12,480
called collagen.

460
00:31:14,120 --> 00:31:18,680
Collagen is one of the most important
proteins in the biological world.

461
00:31:18,680 --> 00:31:22,960
It's the protein which actually gives
that resilience, that elasticity

462
00:31:22,960 --> 00:31:25,480
to tendons, to cartilage,

463
00:31:25,480 --> 00:31:28,680
and of course to our skin, as well.

464
00:31:28,680 --> 00:31:32,600
<font color="
it provides the kind of scaffold

465
00:31:32,600 --> 00:31:35,720
that supports that structure.

466
00:31:35,720 --> 00:31:38,800
Now, when the tadpole is
transformed into the frog,

467
00:31:38,800 --> 00:31:42,160
what you need to do is to
essentially have an enzyme,

468
00:31:42,160 --> 00:31:45,640
collagenase, which will literally
<font color="

469
00:31:45,640 --> 00:31:49,400
into small pieces
and thereby take that scaffold apart.

470
00:31:53,520 --> 00:31:58,400
But how do enzymes break chemical
bonds apart so incredibly fast?

471
00:32:00,480 --> 00:32:05,560
Let me show you why it's a problem
only quantum biology can solve.

472
00:32:07,640 --> 00:32:11,640
Think of it this way, all these
<font color="

473
00:32:11,640 --> 00:32:15,240
are like subatomic particles -
electrons, protons -

474
00:32:15,240 --> 00:32:18,120
that hold the different parts
of the molecule together.

475
00:32:18,120 --> 00:32:23,720
Now, to untie the knot,
enzymes have to move protons about.

476
00:32:23,720 --> 00:32:27,400
But as you can see,
<font color="

477
00:32:27,400 --> 00:32:31,120
and a lot of time
if there are many knots to unpick.

478
00:32:32,240 --> 00:32:34,480
Physicists have a fancy way
of saying

479
00:32:34,480 --> 00:32:36,800
"put in effort to get
something done".

480
00:32:36,800 --> 00:32:40,200
They say you have to overcome
an energy barrier.

481
00:32:46,920 --> 00:32:49,240
<font color="

482
00:32:51,400 --> 00:32:53,320
And here's my proton.

483
00:32:55,120 --> 00:32:56,640
To break a bond apart,

484
00:32:56,640 --> 00:32:59,800
it needs enough energy
to get over the barrier.

485
00:33:01,560 --> 00:33:05,040
The trouble is, when we work out
how long this would take,

486
00:33:05,040 --> 00:33:08,040
it's much too slow to
break down a tadpole's tale.

487
00:33:10,920 --> 00:33:14,520
<font color="
turn into ghosts.

488
00:33:17,760 --> 00:33:20,600
I wouldn't blame you for thinking
that this is an idea

489
00:33:20,600 --> 00:33:23,160
that a clever theoretician
has come up with,

490
00:33:23,160 --> 00:33:27,920
that it's just mere speculation -
something that we have no proof of.

491
00:33:27,920 --> 00:33:31,120
But we do.
<font color="

492
00:33:33,200 --> 00:33:34,960
In the quantum world,

493
00:33:34,960 --> 00:33:38,200
protons don't have to go over
barriers.

494
00:33:41,320 --> 00:33:43,320
They can tunnel...

495
00:33:43,320 --> 00:33:45,040
straight through.

496
00:33:46,920 --> 00:33:49,920
Tunnelling strikes at the very
heart of what is most strange

497
00:33:49,920 --> 00:33:51,800
about quantum mechanics.

498
00:33:51,800 --> 00:33:54,880
<font color="
we see in our everyday world.

499
00:33:54,880 --> 00:33:58,440
A quantum particle can tunnel
from one place to another

500
00:33:58,440 --> 00:34:02,120
even if it has to pass through
an impenetrable barrier.

501
00:34:02,120 --> 00:34:07,760
They are not solid objects
like balls in our everyday world.

502
00:34:07,760 --> 00:34:10,520
<font color="

503
00:34:10,520 --> 00:34:15,240
wavelike behaviour that allows them
to leak through an energy barrier.

504
00:34:15,240 --> 00:34:18,360
A particle can disappear
on one side of the barrier

505
00:34:18,360 --> 00:34:21,680
and instantaneously
reappear on the other.

506
00:34:23,640 --> 00:34:27,120
In nuclear physics,
<font color="

507
00:34:28,760 --> 00:34:32,920
Without quantum tunnelling,
the Sun simply wouldn't shine.

508
00:34:35,400 --> 00:34:37,560
But I never thought I'd see it...

509
00:34:39,800 --> 00:34:41,760
..in a tadpole.

510
00:34:41,760 --> 00:34:45,440
It's hard to stress just how
weird this process is.

511
00:34:45,440 --> 00:34:48,720
It's as though I would approach
<font color="

512
00:34:48,720 --> 00:34:53,520
like a phantom, disappear from one
side and reappear on the other.

513
00:34:57,400 --> 00:35:01,040
The most important advantage
of tunnelling is its speed.

514
00:35:03,440 --> 00:35:06,120
It happens incredibly quickly -

515
00:35:06,120 --> 00:35:09,200
much faster than if protons
go OVER the barrier.

516
00:35:11,520 --> 00:35:15,160
<font color="
tunnelling is my bread and butter.

517
00:35:15,160 --> 00:35:18,880
Subatomic particles like protons
do it all the time.

518
00:35:18,880 --> 00:35:21,720
But what has this got to do
with biology?

519
00:35:27,680 --> 00:35:30,760
The answer is that without
quantum ghosts,

520
00:35:30,760 --> 00:35:33,960
the metamorphosis of a tadpole
<font color="

521
00:35:35,600 --> 00:35:38,960
Remember,
chemical bonds are basically knots.

522
00:35:41,040 --> 00:35:45,000
Tunnelling unties them - fast.

523
00:35:45,000 --> 00:35:47,320
Have a look at these two knots.

524
00:35:47,320 --> 00:35:50,840
Now, on the face of it
they look identical,

525
00:35:50,840 --> 00:35:52,960
but there's a subtle difference.

526
00:35:52,960 --> 00:35:55,480
<font color="

527
00:35:55,480 --> 00:35:57,720
of the rope on the same side.

528
00:35:57,720 --> 00:35:59,320
Whereas this one

529
00:35:59,320 --> 00:36:01,640
has the two short ends
on opposite sides.

530
00:36:02,640 --> 00:36:06,960
Now, you'd think that wouldn't make
a difference, but it does.

531
00:36:06,960 --> 00:36:08,440
You see, THIS knot...

532
00:36:09,880 --> 00:36:11,720
..is very hard to break,

533
00:36:11,720 --> 00:36:13,200
<font color="

534
00:36:14,600 --> 00:36:16,240
..is easy.

535
00:36:17,760 --> 00:36:19,280
Quantum tunnelling...

536
00:36:21,840 --> 00:36:24,920
..turns strong knots
into weak ones.

537
00:36:27,400 --> 00:36:28,960
So in a tadpole,

538
00:36:28,960 --> 00:36:33,040
the entire collagen scaffold
breaks apart easily.

539
00:36:33,040 --> 00:36:38,480
And finally, other enzymes rebuild
<font color="

540
00:36:42,920 --> 00:36:46,560
The quantum tunnelling of particles
is one of those weird features

541
00:36:46,560 --> 00:36:47,880
of the subatomic world

542
00:36:47,880 --> 00:36:50,560
that a physicist like me is very
familiar with.

543
00:36:50,560 --> 00:36:53,800
After all, it's
responsible for radioactive decay

544
00:36:53,800 --> 00:36:55,640
<font color="

545
00:36:55,640 --> 00:36:59,000
It's the reason why the Sun
and all stars shine.

546
00:36:59,000 --> 00:37:02,840
But to discover this going
on inside every cell of every

547
00:37:02,840 --> 00:37:07,040
living organism on the planet,
because every cell contains enzymes,

548
00:37:07,040 --> 00:37:09,760
now, THAT I find truly amazing.

549
00:37:13,600 --> 00:37:17,760
<font color="
over every living creature.

550
00:37:19,880 --> 00:37:23,280
We've seen that birds,
mammals, insects

551
00:37:23,280 --> 00:37:28,560
and amphibians are governed
by the strangest laws in science.

552
00:37:30,000 --> 00:37:32,880
But the most dramatic recent
breakthrough concerns

553
00:37:32,880 --> 00:37:37,400
<font color="
all these forms of life depend.

554
00:37:39,160 --> 00:37:42,560
The conversion of air and sunlight

555
00:37:42,560 --> 00:37:43,880
into plants.

556
00:37:49,240 --> 00:37:54,440
This fine specimen is
a Larix decidua, or European larch.

557
00:37:54,440 --> 00:37:57,520
It's about 100 feet high
and right at this moment,

558
00:37:57,520 --> 00:38:00,160
<font color="
of the planet Venus,

559
00:38:00,160 --> 00:38:02,560
is a bullet with this tree's
name on it.

560
00:38:05,240 --> 00:38:06,840
The bullet is a photon

561
00:38:06,840 --> 00:38:10,360
nearing the end of its long
journey from the Sun.

562
00:38:14,280 --> 00:38:17,000
Its ultimate destiny
is to kick-start

563
00:38:17,000 --> 00:38:21,800
<font color="
underpins all life on Earth...

564
00:38:23,000 --> 00:38:25,400
..photosynthesis.

565
00:38:25,400 --> 00:38:27,440
Every second of every day,

566
00:38:27,440 --> 00:38:32,160
16,000 tonnes of new plant life
are created on Earth.

567
00:38:32,160 --> 00:38:35,000
And for me, it's incredible to think
that our existence

568
00:38:35,000 --> 00:38:38,160
<font color="
on what happens

569
00:38:38,160 --> 00:38:40,840
in the next trillionth
of a second.

570
00:38:51,680 --> 00:38:54,560
The crucial first stage
of photosynthesis

571
00:38:54,560 --> 00:38:56,560
is the capture of energy
from the Sun.

572
00:38:58,680 --> 00:39:00,760
It's nearly 100% efficient,

573
00:39:00,760 --> 00:39:04,000
<font color="
technology.

574
00:39:06,880 --> 00:39:10,000
But the way that every plant
on Earth achieves this

575
00:39:10,000 --> 00:39:12,240
is one of the great puzzles
in biology.

576
00:39:13,360 --> 00:39:16,960
When it turned out that quantum
weirdness might hold the answer,

577
00:39:16,960 --> 00:39:19,080
physicists could hardly believe it.

578
00:39:21,720 --> 00:39:23,280
<font color="

579
00:39:23,280 --> 00:39:25,080
It was very exciting, because I was

580
00:39:25,080 --> 00:39:26,800
used to working on problems

581
00:39:26,800 --> 00:39:29,360
that were quite abstract experiments.

582
00:39:29,360 --> 00:39:33,040
I am a theoretician,
but I always related my theory

583
00:39:33,040 --> 00:39:35,160
to experiments that were very clean
in the lab,

584
00:39:35,160 --> 00:39:36,640
<font color="

585
00:39:36,640 --> 00:39:39,560
But now, finding out that the
things that I knew can help me

586
00:39:39,560 --> 00:39:42,440
to understand better how
nature works,

587
00:39:42,440 --> 00:39:46,600
really, scientifically,
it was like a...

588
00:39:46,600 --> 00:39:48,080
a new inspiration to my life,

589
00:39:48,080 --> 00:39:53,440
so I would say I fell in love with
<font color="

590
00:39:55,800 --> 00:39:59,480
Textbook biology says
the colour of green plants

591
00:39:59,480 --> 00:40:01,560
comes from chlorophyll molecules.

592
00:40:02,760 --> 00:40:06,800
Inside the living cells,
they absorb light from the Sun.

593
00:40:09,400 --> 00:40:12,560
This energy is then transferred
incredibly quickly

594
00:40:12,560 --> 00:40:15,640
to the food-making factory
<font color="

595
00:40:19,240 --> 00:40:21,040
The entire event takes

596
00:40:21,040 --> 00:40:24,320
just a millionth of a millionth
of a second.

597
00:40:24,320 --> 00:40:26,560
When the photon hits the cell,

598
00:40:26,560 --> 00:40:30,760
it knocks an electron out of the
middle of a chlorophyll molecule.

599
00:40:30,760 --> 00:40:35,040
This creates a tiny packet
<font color="

600
00:40:35,040 --> 00:40:36,840
The exciton then bounces its way

601
00:40:36,840 --> 00:40:39,640
through a forest of
chlorophyll molecules

602
00:40:39,640 --> 00:40:43,120
until it reaches what is
called the reaction centre.

603
00:40:43,120 --> 00:40:46,800
Now, that is where its energy is
used to drive chemical processes

604
00:40:46,800 --> 00:40:51,000
<font color="
biomolecules of life.

605
00:40:51,000 --> 00:40:54,680
The problem is, the exciton needs to
find its way to the reaction centre

606
00:40:54,680 --> 00:40:56,680
in the first place.

607
00:41:02,440 --> 00:41:06,400
Textbook biology can't explain
how the exciton does this.

608
00:41:09,640 --> 00:41:12,680
Because, of course, it doesn't
<font color="

609
00:41:15,320 --> 00:41:17,760
It just bounces around
like a pinball

610
00:41:17,760 --> 00:41:20,440
in a process called a random walk.

611
00:41:24,600 --> 00:41:26,000
Sooner or later,

612
00:41:26,000 --> 00:41:28,960
it will pass through every
single part of the cell.

613
00:41:31,840 --> 00:41:35,000
But this isn't the most
efficient way to get around.

614
00:41:38,520 --> 00:41:42,240
<font color="
does reach the reaction centre...

615
00:41:43,600 --> 00:41:45,160
..it's by pure chance.

616
00:41:50,640 --> 00:41:53,120
If the exciton just blindly
and randomly

617
00:41:53,120 --> 00:41:55,680
hops between the chlorophyll
molecules,

618
00:41:55,680 --> 00:41:58,600
it would take too long to reach
the reaction centre

619
00:41:58,600 --> 00:42:01,840
<font color="
its energy as waste heat.

620
00:42:01,840 --> 00:42:05,400
But it doesn't. Something very
different must be going on.

621
00:42:07,160 --> 00:42:10,680
The vital clue comes from recent
experiments

622
00:42:10,680 --> 00:42:12,680
that stunned the world of science.

623
00:42:15,400 --> 00:42:18,800
Chemists fired lasers at plant cells

624
00:42:18,800 --> 00:42:21,160
<font color="
from the Sun.

625
00:42:23,880 --> 00:42:27,480
They confirmed the exciton wasn't
bouncing along a haphazard route

626
00:42:27,480 --> 00:42:28,800
through the cell.

627
00:42:30,000 --> 00:42:32,640
This original understanding
didn't explain what

628
00:42:32,640 --> 00:42:34,280
we were observing in the lab.

629
00:42:34,280 --> 00:42:36,440
So the mystery lies in, OK,

630
00:42:36,440 --> 00:42:40,200
<font color="
for what we are observing in the lab?

631
00:42:42,560 --> 00:42:46,080
The solution is that plants
obey the most famous law

632
00:42:46,080 --> 00:42:48,640
in all of quantum mechanics...

633
00:42:50,880 --> 00:42:52,920
..the uncertainty principle.

634
00:42:56,320 --> 00:42:58,240
It says it you can never be certain

635
00:42:58,240 --> 00:43:01,800
that the exciton is
<font color="

636
00:43:04,240 --> 00:43:07,720
Instead, it behaves like
a quantum wave,

637
00:43:07,720 --> 00:43:10,440
smearing itself out across the cell.

638
00:43:15,000 --> 00:43:18,600
The exciton doesn't simply
move from A to B.

639
00:43:20,920 --> 00:43:23,440
In a bizarre but very real sense,

640
00:43:23,440 --> 00:43:28,360
it's heading in every direction
at the same time.

641
00:43:28,360 --> 00:43:30,760
<font color="

642
00:43:30,760 --> 00:43:34,640
so that it can explore all possible
routes simultaneously.

643
00:43:34,640 --> 00:43:36,200
This strikes at the very heart

644
00:43:36,200 --> 00:43:38,680
of what's so strange about
quantum mechanics.

645
00:43:38,680 --> 00:43:42,680
The exciton wave isn't just
going this way or that way,

646
00:43:42,680 --> 00:43:45,920
<font color="
at the same time.

647
00:43:45,920 --> 00:43:48,960
That's what gives it such
incredible efficiency.

648
00:44:02,200 --> 00:44:03,440
The beauty of it is...

649
00:44:05,520 --> 00:44:07,920
..if the exciton is trying
every route

650
00:44:07,920 --> 00:44:09,920
to the reaction centre at once...

651
00:44:11,600 --> 00:44:15,480
..it's bound to find the fastest
<font color="

652
00:44:19,200 --> 00:44:22,640
It's hard to express how
incredible this discovery seems

653
00:44:22,640 --> 00:44:24,280
to physicists like me.

654
00:44:25,400 --> 00:44:28,800
Biological cells are full
of the random jiggling

655
00:44:28,800 --> 00:44:31,040
of billions of atoms and molecules.

656
00:44:32,880 --> 00:44:36,160
But somehow, excitons
<font color="

657
00:44:36,160 --> 00:44:40,760
as beautiful, perfect quantum waves,

658
00:44:40,760 --> 00:44:45,520
transporting the energy that
guarantees life on Earth.

659
00:44:49,360 --> 00:44:53,840
It opened a whole new
scientific path for me.

660
00:44:53,840 --> 00:44:55,920
And I really enjoy the fact that

661
00:44:55,920 --> 00:44:59,080
to be able to understand fully what
<font color="

662
00:44:59,080 --> 00:45:00,880
you have to interact with scientists

663
00:45:00,880 --> 00:45:03,560
that have completely
different approaches,

664
00:45:03,560 --> 00:45:06,520
like biologists and chemists.

665
00:45:06,520 --> 00:45:08,600
But we all have to come together

666
00:45:08,600 --> 00:45:11,200
to actually understand what
is the relevant of this,

667
00:45:11,200 --> 00:45:12,880
<font color="

668
00:45:12,880 --> 00:45:15,640
So, for me, this is one of the most
exciting parts of this field.

669
00:45:18,880 --> 00:45:22,560
Real scientific experiments
leave no doubt.

670
00:45:24,200 --> 00:45:27,440
The strange hand of
quantum mechanics has shaped

671
00:45:27,440 --> 00:45:29,160
the entire living world.

672
00:45:31,680 --> 00:45:36,000
<font color="
find quantum tricks being used

673
00:45:36,000 --> 00:45:37,920
in biological systems.

674
00:45:37,920 --> 00:45:40,040
The reason is,
because they're better.

675
00:45:44,720 --> 00:45:46,960
Quantum entanglement
is normally seen

676
00:45:46,960 --> 00:45:50,240
in the tightly-controlled
conditions of the physics lab.

677
00:45:51,560 --> 00:45:53,600
<font color="

678
00:45:53,600 --> 00:45:56,160
to navigate with
extraordinary precision.

679
00:46:00,640 --> 00:46:04,320
Quantum vibrations mean our noses
LISTEN to chemicals...

680
00:46:05,760 --> 00:46:08,560
..enhancing our perception
of the world around us.

681
00:46:12,880 --> 00:46:16,160
The living cells of all animals
depend on protons

682
00:46:16,160 --> 00:46:19,240
<font color="
like ghosts...

683
00:46:21,600 --> 00:46:24,440
..speeding up
the vital processes of life.

684
00:46:30,080 --> 00:46:32,800
And photosynthesis reveals
the big picture.

685
00:46:34,880 --> 00:46:36,200
A shimmering world

686
00:46:36,200 --> 00:46:40,400
where quantum waves capture
the Sun's energy in an instant.

687
00:46:42,280 --> 00:46:44,760
<font color="
"Ah, but physicists have been

688
00:46:44,760 --> 00:46:47,040
"looking for this for decades."

689
00:46:47,040 --> 00:46:49,960
Well, biology has
had millions of years.

690
00:46:51,000 --> 00:46:54,400
The ultramodern science
of quantum mechanics

691
00:46:54,400 --> 00:46:56,360
is an ancient fact of life.

692
00:46:58,720 --> 00:47:00,480
For the end of my journey,

693
00:47:00,480 --> 00:47:03,200
<font color="
to their logical conclusion.

694
00:47:03,200 --> 00:47:04,600
Of course, as a scientist,

695
00:47:04,600 --> 00:47:09,280
any speculations I have have to be
backed up by careful experiments.

696
00:47:09,280 --> 00:47:12,440
So I want to concoct a thought
experiment that helps me

697
00:47:12,440 --> 00:47:16,720
to answer the biggest biological
<font color="

698
00:47:16,720 --> 00:47:19,880
Does quantum physics play any role

699
00:47:19,880 --> 00:47:22,520
in the mechanism of
evolution itself?

700
00:47:28,440 --> 00:47:32,200
In 1859, Charles Darwin
stunned the world

701
00:47:32,200 --> 00:47:35,480
with his Theory Of Evolution
By Natural Selection.

702
00:47:36,840 --> 00:47:39,200
He went on to explain
<font color="

703
00:47:39,200 --> 00:47:41,200
between humans and other apes.

704
00:47:43,080 --> 00:47:46,640
150 years later, there's
no doubt that Darwin's theory

705
00:47:46,640 --> 00:47:48,320
accounts for every living organism

706
00:47:48,320 --> 00:47:50,560
on land and sea.

707
00:47:53,080 --> 00:47:55,200
But I'd like to explore the latest,

708
00:47:55,200 --> 00:47:58,640
extraordinary
interpretation of his ideas.

709
00:47:58,640 --> 00:48:00,680
<font color="

710
00:48:03,720 --> 00:48:08,120
Could there be a quantum theory
of evolution?

711
00:48:08,120 --> 00:48:13,120
MUSIC: Adagio of Spartacus and
Phrygia from Spartacus Suite No.2
by Aram Khachaturian

712
00:48:35,120 --> 00:48:39,800
Can quantum evolution explain
how the snail got its shell?

713
00:48:43,120 --> 00:48:45,640
The snails I'm used to seeing
<font color="

714
00:48:45,640 --> 00:48:48,600
tend to have
rather bland, boring shells.

715
00:48:48,600 --> 00:48:50,720
So have a look at this beauty.

716
00:48:52,120 --> 00:48:55,320
The patterns on its shell
very perfectly match

717
00:48:55,320 --> 00:48:57,480
the lines on the stem.

718
00:48:59,960 --> 00:49:03,680
It's called a banded snail.
Ceapea is not moral.

719
00:49:04,880 --> 00:49:07,720
<font color="
there by accident.

720
00:49:11,840 --> 00:49:13,400
Come and have a look at this.

721
00:49:17,200 --> 00:49:19,240
Less well adapted snails

722
00:49:19,240 --> 00:49:21,880
are more likely to be found here.

723
00:49:21,880 --> 00:49:25,320
This stone is called
a thrush's anvil.

724
00:49:25,320 --> 00:49:27,880
The song thrush is
the snail's main predator.

725
00:49:27,880 --> 00:49:29,080
<font color="

726
00:49:29,080 --> 00:49:32,120
and smashes its shell against
the stone to get to the snail.

727
00:49:32,120 --> 00:49:33,640
Now, what I can see here

728
00:49:33,640 --> 00:49:36,720
is that there aren't many
banded snail shells,

729
00:49:36,720 --> 00:49:40,280
suggesting that its colours
camouflage it very well,

730
00:49:40,280 --> 00:49:41,640
hiding it from the bird.

731
00:49:45,400 --> 00:49:47,000
<font color="

732
00:49:47,000 --> 00:49:51,040
that evolution depends
on variation within a species.

733
00:49:53,440 --> 00:49:57,560
Snails with camouflage are more
likely to survive and reproduce...

734
00:50:00,000 --> 00:50:02,720
..passing on their shells
to the next generation

735
00:50:02,720 --> 00:50:06,680
so that the species as a whole
<font color="

736
00:50:09,480 --> 00:50:13,520
So, variation - the random
differences between snails -

737
00:50:13,520 --> 00:50:16,400
is the driving force
behind their evolution.

738
00:50:18,440 --> 00:50:22,200
Now, all species evolve and adapt
to their environment.

739
00:50:22,200 --> 00:50:24,320
But the question
I'd like to explore is

740
00:50:24,320 --> 00:50:27,280
<font color="
plays a role in this.

741
00:50:31,360 --> 00:50:33,000
The only way to find out

742
00:50:33,000 --> 00:50:35,280
is by scientific experiments.

743
00:50:37,440 --> 00:50:41,480
So, my adventures in quantum biology
finally bring me home...

744
00:50:43,560 --> 00:50:45,600
..to the University of Surrey.

745
00:50:48,080 --> 00:50:49,600
Here, in the laboratories,

746
00:50:49,600 --> 00:50:54,080
<font color="
most celebrated molecule in science.

747
00:50:57,880 --> 00:51:01,720
Deoxyribonucleic acid, or DNA.

748
00:51:04,800 --> 00:51:09,640
Its double helix holds the genetic
code for every living organism.

749
00:51:12,000 --> 00:51:15,800
It's a remarkable fact that Darwin
himself had no idea

750
00:51:15,800 --> 00:51:18,920
what created variation
<font color="

751
00:51:18,920 --> 00:51:22,560
The structure of DNA wasn't
discovered until 1953

752
00:51:22,560 --> 00:51:25,280
by Francis Crick and James Watson.

753
00:51:25,280 --> 00:51:28,160
The most famous feature of DNA
is of course

754
00:51:28,160 --> 00:51:30,920
its beautiful double helix
structure.

755
00:51:30,920 --> 00:51:32,600
But that's just scaffolding.

756
00:51:32,600 --> 00:51:35,640
<font color="
lies in between.

757
00:51:38,720 --> 00:51:42,520
The four different-coloured
molecules are called bases.

758
00:51:44,080 --> 00:51:48,240
The colour code on one side -
say blue, red, blue -

759
00:51:48,240 --> 00:51:52,680
forms a gene that parents
pass on to their offspring.

760
00:51:52,680 --> 00:51:55,760
A gene is a bit like a jigsaw
<font color="

761
00:51:55,760 --> 00:51:57,760
It fits together like this.

762
00:51:59,520 --> 00:52:04,080
A full strand of the double helix
forms a coloured pattern.

763
00:52:06,040 --> 00:52:09,160
But the other strand always
pairs up the same way.

764
00:52:12,360 --> 00:52:15,160
A blue base always goes with yellow

765
00:52:15,160 --> 00:52:18,520
and green always goes with red...

766
00:52:19,960 --> 00:52:24,440
<font color="
the right shape to fit together.

767
00:52:24,440 --> 00:52:27,800
What Crick and Watson realised
was that this provides

768
00:52:27,800 --> 00:52:30,960
a mechanism for passing
on the genetic code.

769
00:52:32,280 --> 00:52:36,360
When cells reproduce,
the two strands of DNA separate,

770
00:52:36,360 --> 00:52:38,000
<font color="

771
00:52:40,160 --> 00:52:42,520
But red still goes with green...

772
00:52:44,800 --> 00:52:47,000
..and yellow still goes with blue.

773
00:52:48,560 --> 00:52:50,160
So bit by bit,

774
00:52:50,160 --> 00:52:52,400
the cell creates two new strands.

775
00:52:54,080 --> 00:52:57,840
Two perfect copies of the entire
genetic code.

776
00:52:59,080 --> 00:53:01,880
So far, there's
no genetic variation.

777
00:53:01,880 --> 00:53:05,480
<font color="
identical to the original.

778
00:53:05,480 --> 00:53:07,240
But here's the interesting bit.

779
00:53:07,240 --> 00:53:11,440
During the copying process,
something very important can happen.

780
00:53:11,440 --> 00:53:13,480
Sometimes, mistakes creep in.

781
00:53:16,520 --> 00:53:18,480
They're called mutations.

782
00:53:19,840 --> 00:53:23,240
Let's have a look at
<font color="

783
00:53:24,880 --> 00:53:29,600
The two prongs that hold them
together are subatomic particles.

784
00:53:29,600 --> 00:53:31,000
They're protons.

785
00:53:31,000 --> 00:53:34,800
They're basically the bonds
between the strands of DNA.

786
00:53:34,800 --> 00:53:38,560
These protons can jump across
to the other side.

787
00:53:40,440 --> 00:53:44,360
If the strands split
<font color="

788
00:53:44,360 --> 00:53:47,160
they find themselves
in the wrong position.

789
00:53:49,160 --> 00:53:54,760
Now, this red base will no longer
bind to a green base.

790
00:53:54,760 --> 00:53:59,280
Instead,
it has to bond to a yellow base.

791
00:54:00,480 --> 00:54:02,240
Slotting this back in,

792
00:54:03,280 --> 00:54:07,040
we see that now this copy is no
<font color="

793
00:54:07,040 --> 00:54:11,040
because I have a yellow base here
instead of a green one.

794
00:54:11,040 --> 00:54:13,960
We've brought in a genetic mutation.

795
00:54:15,560 --> 00:54:20,360
Jumping protons would change
the snail's DNA.

796
00:54:20,360 --> 00:54:23,360
It could make a new gene
for camouflaged shells.

797
00:54:24,800 --> 00:54:27,720
<font color="
how do protons jump?

798
00:54:30,560 --> 00:54:34,040
It's my belief that quantum's
spookiness can take over.

799
00:54:35,600 --> 00:54:38,080
Now, for these mutations
to take place,

800
00:54:38,080 --> 00:54:41,800
the protons have to overcome
an energy barrier.

801
00:54:41,800 --> 00:54:44,280
And if you remember
<font color="

802
00:54:44,280 --> 00:54:47,560
well, you can probably
guess what's coming next.

803
00:54:50,960 --> 00:54:54,480
Protons can behave
as if barriers don't exist.

804
00:54:56,640 --> 00:54:59,280
They tunnel straight through.

805
00:55:00,560 --> 00:55:03,400
But does this ghostly effect
really happen?

806
00:55:07,600 --> 00:55:10,400
My colleagues in biology
<font color="

807
00:55:10,400 --> 00:55:13,520
for the very first evidence
of quantum mutations.

808
00:55:16,480 --> 00:55:19,320
Biologists didn't really even
know about quantum mechanics,

809
00:55:19,320 --> 00:55:23,120
so when you tell them that particles
can be in two places at once,

810
00:55:23,120 --> 00:55:25,520
they kind of say,
<font color="

811
00:55:26,920 --> 00:55:30,000
Our experiment
involves samples of bacteria.

812
00:55:31,360 --> 00:55:34,080
The first sample is
prepared in normal water,

813
00:55:34,080 --> 00:55:37,320
containing hydrogen nuclei,
or protons.

814
00:55:39,000 --> 00:55:43,440
When the bacteria reproduce,
we simply count the mutations.

815
00:55:44,920 --> 00:55:46,680
<font color="

816
00:55:46,680 --> 00:55:50,440
then we should be able to change
the rate at which mutations occur.

817
00:55:51,960 --> 00:55:55,400
Remember how we tested
the quantum theory of smell?

818
00:55:55,400 --> 00:56:00,040
What if I replaced the proton
with its big brother, the deuteron?

819
00:56:00,040 --> 00:56:03,120
This is the nucleus
<font color="

820
00:56:03,120 --> 00:56:06,920
Now, crucially, a deuteron is
twice as heavy as a proton

821
00:56:06,920 --> 00:56:09,840
and this should influence
how easy it is for

822
00:56:09,840 --> 00:56:12,760
the deuteron to quantum tunnel.

823
00:56:12,760 --> 00:56:15,240
Quantum mechanics is
full of surprises.

824
00:56:16,560 --> 00:56:18,480
Protons tunnel easily.

825
00:56:20,560 --> 00:56:22,960
<font color="

826
00:56:28,400 --> 00:56:32,440
These heavier particles are much
more likely to bounce straight back.

827
00:56:35,600 --> 00:56:39,800
So the second sample of bacteria is
prepared in heavy water,

828
00:56:39,800 --> 00:56:41,720
which is full of deuterons.

829
00:56:43,440 --> 00:56:47,040
Our theory says you should get
far fewer mutations.

830
00:56:48,640 --> 00:56:52,320
<font color="
are extremely encouraging.

831
00:56:52,320 --> 00:56:56,440
The preliminary experiments that
we've done gives us a hint

832
00:56:56,440 --> 00:57:00,000
that the mutation rate is indeed
depressed in deuterated water.

833
00:57:00,000 --> 00:57:04,640
We find that it is lower.
So my hunch is that we're right,

834
00:57:04,640 --> 00:57:08,640
<font color="
while before we're sure.

835
00:57:11,000 --> 00:57:12,800
Final proof lies in the future.

836
00:57:14,280 --> 00:57:15,760
Even if we're right,

837
00:57:15,760 --> 00:57:18,800
quantum tunnelling is a rare
form of mutation.

838
00:57:20,960 --> 00:57:23,640
But our results promise
hard evidence

839
00:57:23,640 --> 00:57:27,840
for a new explanation of one of the
<font color="

840
00:57:29,920 --> 00:57:33,600
Even the merest possibility
of a new quantum mechanism

841
00:57:33,600 --> 00:57:37,080
for evolution itself is
tremendously exciting.

842
00:57:37,080 --> 00:57:41,560
In fact, the story of quantum
biology is only just beginning.

843
00:57:41,560 --> 00:57:45,760
What the frog, the robin, the fruit
<font color="

844
00:57:45,760 --> 00:57:50,440
is that real quantum effects
are going on in nature all the time.

845
00:57:50,440 --> 00:57:52,360
And if there's anything
we've learnt

846
00:57:52,360 --> 00:57:54,920
from the history of
quantum mechanics, it's this -

847
00:57:54,920 --> 00:57:59,120
we can never be certain where
<font color="

848
00:58:08,320 --> 00:58:11,920
Quantum biology is
a revolution in science.

849
00:58:12,960 --> 00:58:15,960
But it's time I got back to
the physics department.