How quantum biology might explain life’s biggest questions

I'd like to introduce you
to an emerging area of science.

One that is still speculative,
but hugely exciting.

It's certainly one that's
growing very rapidly.

Quantum biology asks
a very simple question.

Does quantum mechanics, that weird
and wonderful, and powerful theory

of the subatomic world
of atoms and molecules

that underpins so much of modern
physics and chemistry, also play

a role inside the living cell?

In other words, are there processes,
mechanisms, phenomena in living organisms

that can only be explained with a helping
hand from quantum mechanics?

Now, quantum biology isn't new.
It's been around since the early 1930s.

But its only in the last decade or so,
that careful experiments

in biochemistry labs, using spectroscopy
that have shown very clear, firm evidence

that there are certain specific mechanisms
that require quantum mechanics

to explain them.

Quantum biology brings together
quantum physicists, biochemists,

molecular biologists.

It's a very interdisciplinary field.

I come from quantum physics.
So, I'm a nuclear physicist.

I've spent more than three decades trying
to get my head around quantum mechanics.

One of the founders of quantum
mechanics, Neil Bohr said,

If you're not astonished by it,
then you haven't understood it.

So, I sort of feel happy that I'm still
astonished by it and that's a good thing.

But it means I study the very smallest
structures in the universe.

The building blocks of reality.

If we think about the scale of size,
start with something, an everyday object

like the tennis ball, and just go down
orders of magnitude and size.

From the eye of a needle, down to a cell,
down to a bacterium, down to an enzyme.

You eventually reach the nano world.

Now, nanotechnology may
be a term you've heard of.

A nanometer is
a billionth of a meter.

My area is the atomic nucleus,
which is the tiny dot inside an atom.

It's even smaller in scale.

This is the domain of quantum mechanics,
and physicists and chemists have had

a long time to get used to it.

Biologists on the other hand
have got off lightly, in my view.

They are very happy with their
balls-and-sticks models of molecules.

(Laughter)

The balls are the atoms, the sticks
are the bonds between the atoms

and when they can't build them
physically in the lab,

nowadays they have very powerful
computers that will simulate a huge model.

This is a protein made up
of 100,000 atoms.

It doesn't really require much in the way
of quantum mechanics to explain it.

Quantum mechanics was
developed in the 1920s.

It is a set of beautiful and powerful
mathematical rules and ideas

that explain the world
of the very small.

And it's a world that very different
from our everyday world

made up of trillions of atoms.

It's a world built on probability
and chance.

It's a fuzzy world.

It's a world of phantoms, where particles
can also behave like spread out waves.

If we imagine quantum mechanics
or quantum physics, then as

the fundamental
foundation of reality itself.

That's not surprising
that we say quantum physics

underpins organic chemistry.

After all, it gives us
the rules that tells us

how the atoms fit together
to make organic molecules.

Organic chemistry, scaled up in complexity
gives us molecular biology,

which of course leads
to life itself.

So, in a way, it's sort
of not surprising.

It's almost trivial.

Say, well of course life ultimately
must depend of quantum mechanics.

But, so does everything else.

So does all inanimate matter,
made up of trillions of atoms.

Ultimately, there's a quantum level
that we know where we have to delve

into this weridness.

But in everyday life,
we can forget about it.

Because once you put together trillions
of atoms, that quantum weirdness

just dissolves away.

Quantum biology isn't about this.
Quantum biology isn't this obvious.

Of course quantum mechanics underpins
life at some molecular level.

Quantum biology is about looking
for the non-trivial, the counterintuitive

ideas in quantum mechanics and to see
if they do indeed play an important role

in describing the processes of life.

Here is my perfect example
of the counterintuitiveness

of the quantum world.

This is the quantum skiier.

He seems to be intact, he seems
to be perfectly healthy.

And yet, he seems to have gone around
both sides of that tree at the same time.

Well, if you saw some tracks like that
you'd guess some sort of stunts of course.

But in the quantum world,
this happens all the time.

Particles can multitask, they can be
in two places at once.

They can do more than
one thing at the same time.

Particles can behave
like spread out waves.

It's almost like magic.

Physicists and chemists have had
nearly a century of trying

to get used to this weirdness.

I don't blame the biologists for not
having or wanting to learn

quantum mechanics.

You see, this weirdness is very delicate
and we physicists work very hard

to maintain it on our labs.

We sort of cool our system down
to near absolute zero,

We carry out our experiments
in vacuums, we try and isolate it

from any external disturbance.

That's very different from the warm,
messy, noisy environment of a living cell.

Biology itself, if you think of molecular
biology, seems to have done very well

in describing all the processes of life,
in terms of chemistry.

Chemical reactions!

And these are reductionist, deterministic
chemical reactions showing that

essentially life, is made of the same
stuff as everything else,

and if we can forget about quantum
mechanics in the macro world,

then we should be able to forget
about it in biology, as well.

Well, one man begged
to differ with this idea.

Erwin Schrödinger, he of Schrödinger's Cat
fame, an Austrian physicist.

He was one of the founders
of quantum mechanics in the 1920s.

In 1944, he wrote a book
called "What is Life?"

It was tremendously influential.

It influenced Francis Crick
and James Watson,

the discoverer's of the double helix
structure of DNA.

To paraphrase a description in the book,
he says, at the molecular level,

living organism have a certain order,
a structure to them that's very

different from the random thermodynamic
jostling of atoms and molecules

in inanimate matter
of the same complexity.

In fact, living matter seems to behave
in its order, in its structure

just like inanimate matter cooled
down to near absolute zero,

where quantum effects
play a very important role.

There's something special about
the structure, the order

inside a living cell.

So, Schrödinger speculated that maybe
quantum mechanics plays a role in life.

It's a very speculative, sort of
far-reaching idea and it didn't

really go very far.

But, as I mentioned at the start,
in the last 10 years

there have been experiment emerging,
showing where some of these certain

phenomena in biology, do seem
to require quantum mechanics.

I want to share with you
just a few of the exciting ones.

This is one of the best known
phenomena in the quantum world.

Quantum tunneling.

The box on the left, shows the wavelike
spread out distribution of quantum entity.

A particle, like an electron.

Which is not a little ball
bouncing off a wall.

It's a wave that has a certain probability
of being able to permeate through

a solid wall, like a phantom
leaping through to the other side.

You can see a faint smudge of light
in the right hand box.

Quantum tunneling suggests that a particle
can hit an impenetrable barrier and yet,

somehow, as if by magic, disappear from
one side and reappear on the other.

The nicest way of explaining it,
is if you want to throw a ball

over a wall, you have to give it enough
energy to get over the top of the wall.

In the quantum world, you don't have
to throw it over the wall.

You can throw it at the wall and three's
a certain non-zero probability that it'll

disappear on your side,
and reappear on the other.

This isn't speculation,
by the way, we're happy

-- I'm sorry, happy is not the right word.

(Laughter)

We are familiar with this.

(Laughter)

Quantum tunneling takes place
all the time, in fact

it's the reason our sun shines.

The particles fuse together in the sun
is turning hydrogen into helium

through quantum tunneling.

Back in the 70s and 80s, it was discovered
that quantum tunneling also takes place

inside living cells.

Enzymes, those workhorses of life,
the catalysts of chemical reaction.

Enzymes are biomolecules that speed
up chemical reactions in living cells.

By many, many orders of magnitude.

And it's always been a mystery
how they do this.

Well, it was discovered that one
of the tricks that enzymes have evolved

to make use of, is by transferring
subatomic particles, like electrons

and indeed protons, from one part
of a molecule to another via

quantum tunneling.

It's efficient, it's fast,
it can disappear

-- a proton can disappear from one place
and a reappear on the other.

Enzymes help this take place.

This is research that's been carried out
back in the 80s, particularly by a group

in Berkeley, Judith Klinman.

Other groups in the UK have now also
confirmed that enzymes really do this.

Research carried out by my group
-- so I mentioned I'm a nuclear physicist,

but I've realize I've got these tools
of using quantum mechanics

in atomic nuclei and so can apply those
tools in other areas, as well.

One question we asked was, whether
quantum tunneling plays a role

in mutations in DNA.

Again, this is not a new idea.
It goes all the way back to the early 60s.

The two strands of DNA, the double helix
structure are held together by rungs,

it's like a twisted ladder.

And those rungs of the ladder
are hydrogen bonds.

Protons that act as the glue
between the two strands.

So, if you zoom in, what they're doing
is holding these large molecules,

nucleotides, together.

Zoom in a bit more.

So, this a computer simulation.

The two white balls in the middle
are protons and you can see that

it's a double hydrogen bond.

One prefers to sit one side,
the other on the other side of the stands.

The two strands of the vertical lines
going down, which you can't see.

It can happen that these
two protons can hop over.

Watch the two white balls.
They can jump over to the other side.

If the two strands then separate,
leading to the process of replication,

and the two protons are in the wrong
positions, this can lead to a mutation.

This has been known for half a century.

The question is how likely can they do
that, and if they do, how do they do it?

Do they jump across, like the ball
going over the wall?

Or can they quantum tunnel across,
even if they don't have enough energy?

Early indications suggest that quantum
tunneling can play a role here.

We still don't know yet how important
it is, it's still an open question.

It's speculative, but it's one of those
questions that it is so important,

that if quantum mechanics plays
a role in mutations, surely this must

have big implications, to understand
certain types of mutations, possibly even

those that lead to turning
a cell cancerous.

Another example of quantum mechanics
in biology is quantum coherence

in one of the most important process
in biology, photosynthesis.

Plants and bacteria taking sunlight,
using that energy to create biomass.

Quantum coherence is the idea
of quantum entities multitasking.

It's the quantum skier.

It's an object that behaves like a wave,
so that it doesn't just move

in one direction or the other, but can
follow multiple pathways at the same time.

Some years ago, the world of science
was shocked when a paper was published

showing experimental evidence,
that quantum coherence takes place

inside bacteria,
carrying out photosynthesis.

The idea is that the photon,
the particle of light, the sunlight,

the quantum of light, captured by
a chlorophyl molecule, is then delivered

to what's called the reaction center where
it can be turned into chemical energy.

And in getting there, it doesn't just
follow one root, it follows multiple

pathways at once, to optimize the most
efficient way of reaching the reaction

center, without dissipating
as waste heat.

Quantum coherence taking place
inside a living cell.

A remarkable idea, and yet evidence
is growing almost weekly with new papers

coming out, confirming that
this does indeed take place.

My third and final example is the most
beautiful, wonderful idea.

It's also still a very speculative,
but I have to share it with you.

The European Robin migrates from
Scandinavia, down to the Mediterranean

every autumn and like a lot of other
marine animals and even insects,

they navigate by sensing
the Earth's magnetic field.

Now the Earth's magnetic
field is very, very weak.

It's 100 times weaker than
a fridge magnet and yet

it affects the chemistry, somehow,
within a living organism.

That's not in doubt,
a German couple of onothologists

Wolfgang and Roswitha Wiltschko,
in the 1970s confirmed that indeed

the robin does find it's way by somehow
sensing the Earth's magnetic field,

to give it directional information,
a built-in compass.

The puzzle, the mystery was
how does it do it?

Well, the only theory in town,
we don't know if it's the correct theory,

but the only theory in town, is that
it does it via something called

quantum entanglement.

Inside the robin's retina
-- I kid you not.

Inside the robin's retina,
is a protein called cryptochrome,

which is light sensitive.

Within cryptochrome, a pair of electrons
are quantum entangled.

Now quantum entanglement is when two
particles are far apart and yet somehow

remain in contact with each other.

Even Einstein hated that idea, he called
it spooky action at a distance.

(Laughter)

If Einstein doesn't like it, then we can
all be uncomfortable with it.

Two quantum entangled electrons within
a single molecule, dance a delicate dance

that is very sensitive
to the direction the bird flies

in the Earth's magnetic field.

We don't know if it's the correct
explanation, but wow wouldn't it be

exciting if quantum mechanics
helps birds navigate.

Quantum biology is still in it infancy.
It's still speculative.

But I believe it's built on solid science.

I also think that in the coming decade,
or so, we're going to start to see

that actually it pervades life, that life
has evolved tricks that utilize

the quantum world.

Watch this space.

Thank you.

(Applause)