Quantum Life: How Physics Can Revolutionise Biology: Jim Al-Khalili at TEDxSalford


Translator: Maria Boura
Reviewer: Maria K. Hello! Ready for some more science, Salford? Ready to have your brains fried? Yeah, okay! In 1944, an Austrian physicist
by the name of Erwin Schrödinger – some of you may have heard the name – Schrödinger’s cat, the famous paradox,
the guy puts the cat in the box and somehow the cat is both dead
and alive at the same time. I’ll try and explain
what this is all about. Erwin Schrödinger in 1944 – he was one of the pioneers
of quantum mechanics, one of the greatest and most important
theories in the whole of science – in 1944, he published a book
called “What is life?” You see, until that point, from the late 19th century
to the first half of the 20th century, physicists ruled. We were the top dogs in science. And all the big discoveries – chemists and biologists may disagree – but back then we had
the Einsteins and others, who were revolutionizing physics. Erwin Schrödinger was one of the pioneers
of this new theory of quantum mechanics. Physicists became so cocksure
of themselves, so arrogant, they felt they could answer
all problems in science. His book “What is life?” was somewhere where he felt he could try
and use physics to explain life itself. Physics to explain biology. Now, he was very ambitious
in this project. It did influence and inspire
many other scientists. In fact, Francis Crick and James Watson
were inspired by his work in their discovery of the DNA
and the double helix. In fact, Francis Crick was himself
really a physicist. Two decades later,
in the early 60s, in 1963, another physicist published a paper which didn’t really make a big splash. His name was Per-Olov Löwdin,
who was a Swedish physicist, and he wrote a paper about biology. He wrote a paper in which he suggested
a way that DNA might mutate. Now, DNA has two strands
of very complicated molecules wrapped around in this double helix, and DNA contains the blueprint of life. We hear these days that biologists
are mapping the human genome; we’ve made tremendous strides
in the last decade. Well, back in 1963, Löwdin was trying to understand
what is it that goes wrong – or actually, not wrong, we need mutations
for life to evolve, to change. How do mutations take place? We sort of know there are
lots of different mechanisms. Sometimes it’s just random copying errors, when these two strands unravel and split, and then they make another pair
of strands and they replicate. Sometimes just things copy wrongly. Sometimes you get radiation from outside,
cosmic radiation from outer space, that comes through and collides
with the DNA inside our cells and causes them to break,
and new patterns form. Löwdin said there might be another way. The two strands of DNA
are held together by – it’s like a ladder,
that’s sort of twisted around – those rungs of the ladder, the glue that holds
the two strands together, are basically hydrogen atoms. Hydrogens atoms provide
the glue, they’re bonds. They bond to an atom on one strand
and to an atom of the other strand, and keep them fixed together. Löwdin suggested that maybe this hydrogen atom can do
something rather strange, something quantum mechanical, something called quantum tunneling. Basically, it might be sitting closer
to one atom on one strand, and spontaneously,
for strange quantum reasons, jump across to the other side. Because if this happens, the structure of the molecules
of DNA would change, a mutation could take place. It was a mathematical model, he had no experimental evidence
that this would actually take place. That’s nearly half a century ago. To this day, we don’t know
whether quantum tunneling explains certain types of mutations. But in his paper,
in the very first paragraph, he says, “The fact that quantum physics
might explain certain phenomena in biology would lead me to propose
a new area of science, a new field, which I would call quantum biology.” Things sort of went quiet
and nothing really happened. In the last few years,
certainly in the last three or four years, quantum biology, as a new field,
has started to gain prominence again. Not because the quantum physicists have got cleverer
in some of their wacky ideas, but because the molecular biologists
have got very clever in designing experiments
to test the wacky ideas. I’ll give you a few examples in a moment. But let me just say something
about what quantum mechanics is. It was discovered in the early part
of the 20th century. Once people like Ernest Rutherford – who was the first person
to look inside an atom and saw that atoms were,
actually, mostly empty space with a tiny little nucleus and electrons
buzzing around the outside, like a miniature solar system – they realized they needed
to try and understand the structure of these atoms. And they realized
that the normal laws of physics that everyone understood, going all the way back to Isaac Newton,
just didn’t seem to work. Strange things were going on
down at the level of atoms and below. A new type of mechanics,
not Newtonian mechanics, but what’s called quantum mechanics,
had to be developed. And throughout the 1920s, this became a full, powerful
mathematical theory. Today, quantum mechanics
is really not in doubt. Quantum mechanics tells us
how the electrons fit around atoms, in orbits. It tells us how atoms fit together,
[about] the forces between them, to make molecules, to make everything we see in the universe. But quantum mechanics
is down at the level of atoms. We don’t see, generally, the effects of quantum mechanics
on the everyday scale. It happens at such tiny scales
that are completely invisible to us. And yet, we design experiments
all the time in physics labs that seem to prove, time and time again,
that quantum mechanics really works. Quantum mechanics, therefore,
underpins a lot of physics, pretty much most of,
if not all of chemistry; chemistry underpins biology; biology at a molecular level
is basically molecules, chemical reactions going on between them,
and bonds bonding together; biology is basically organic chemistry; organic chemistry is basically
quantum mechanics. Quantum mechanics is,
I would argue, the most important, the most powerful theory
in the whole realm of science; it beats Darwinian natural selection
with one arm behind its back – and Darwinian natural selection
is one of the greatest ideas human kind has ever come up with. But, at its heart,
quantum mechanics is strange. So strange that one of the founding fathers,
Niels Bohr, once said, “If you are not baffled
by quantum mechanics, then you haven’t understood it.” You have to think, “How can that be?” If you think, “Yeah, OK, I get it,” you have a problem. Because it really is ungettable
at a sort of common sense level. It really is strange. Quantum mechanics really does say
that an atom can be in two places at the same time – one atom. When you look to see
which place it really is, it’ll disappear in one place
and pop up in the other. How do you know
it was in two places at once? We can design experiments that would prove that had it not been
in both places at once, you wouldn’t get the results that you see. An electron – a tiny particle that orbits
around an atom – spins, not in the way that the Earth
spins on its axis, but in a rather stranger way. To the extent that an electron,
when we are not looking, is spinning both clockwise
and anti-clockwise at the same time. It sounds like, “You physicists come up
with all this nonsense; how do you know?” That’s what really happens, and without that we wouldn’t have
so much of modern science. Anyone of you who uses any device – smartphones, TVs, computers,
anything with a chip – all rely on quantum mechanics. Without quantum mechanics we wouldn’t have understood
the nature of matter. We wouldn’t have understood
the nature of semiconductors; therefore, we wouldn’t have
developed chips; we wouldn’t have computers. Most of modern technology today
relies on quantum mechanics. And yet, at its heart,
it’s very, very strange. Well, I’ve said, you know, biology at its heart is chemistry, and chemistry is basically
quantum mechanics. So, surely, biology, ultimately,
relies on quantum mechanics. Well, it does rely on quantum mechanics in the sense that quantum mechanics
describes how the atoms fit together to make the molecules of life, but this new field,
this field of quantum biology, is really asking whether
the weirder aspects of quantum mechanics play a role in biology. Just last week – the week before last, now – the Nobel prize of physics was announced. And it was given to two physicists
who led two research teams, one in Paris and one in Boulder, Colorado. So the two guys who won the Nobel prize
were essentially the team leaders, but really the credit
goes to these two teams. What they’ve done over the last decade
or two is design experiments that show that quantum weirdness
really does happen. You might have heard phrases
like quantum entaglement or quantum coherence. In the physical world – by physical, I mean the non-living,
non-biological world – we do see these
quantum effects all the time. Quantum tunneling, for instance, is weird. Quantum tunneling is a bit
like Harry Potter and his friends when they run through
that brick wall on Platform Nine – is it Nine and a Half? I forget – in King’s Cross station. Right? Magic. In the quantum world
that happens all the time; particles run through walls. It’s like you’re kicking a ball up a bump,
and you got it kick it hard enough to get it to the top
and roll down the other side. If it’s a quantum ball,
down at the level of atoms, you could kick it half-way up, it doesn’t have enough energy
to get to the top, doesn’t want to roll down again
and decides to go the other side. Disappears and reappears
on the other side, like a magic trick. But that’s what happens. That’s the reason we are here
because that’s the reason our Sun shines. Where the Sun gets its energy is from a process
called thermal nuclear fusion, and thermal nuclear fusion
is basically atoms of hydrogen, basically the nuclei of atoms of hydrogen,
protons squeezing together. Now, protons both have
positive electric charge, and, as you surely remember from school, like charges repel –
[you] got positive and positive – you can’t push them together. The closer you push them, the harder they will repel each other
and want to fly apart. And yet, in the Sun,
they do stick together because hydrogen gas in the Sun
is slowly being converted into helium gas, the next element in the periodic table. And in the process of that change
from hydrogen to helium, a lot of energy is produced,
energy in the form of heat and light. What happens is the protons
are not tiny, real little balls that are very very small; they are like fuzzy, wavy objects
that can get close enough to each other, and they sort of want to repel each other, but every now and again, one of them says “Oh, I’d like to punch
through that force barrier, jump through to the other side.” Once they get close enough
together, they will stick because there’s another force that wings over
their repulsive electric force. That nuclear force is what binds
the two protons together. But without quantum mechanics
we wouldn’t understand how they’d ever get close enough
for that nuclear force to win. And yet, it does happen. So, quantum tunneling happens
all the time in the world. I’d like to tell you, very briefly,
two effects in quantum biology – one that relies on electrons
spinning two ways at once, and one that relies on quantum tunneling. The robin is probably
the most common bird in Britain; our best loved bird. Robins live in Britain all year round. But the European robins, that live in Northern Europe,
in Scandinavia and Russia, many of them migrate during the winter. They migrate down to Southern Europe,
even to the Northern tip of Africa. Birds are able to navigate using a wide variety
of very clever tricks. It turns out, after many years of study, that the European robin navigates
by sensing the Earth’s magnetic field; it’s a very, very weak field,
but it [can] sense it. And it doesn’t sense it like a compass. It doesn’t, somehow,
have a built-in GPS compass system that sort of tells him, you know,
which direction it should be going. It turns out it’s sensitive
to much subtler changes in the magnetic field. And no-one could really understand
how that happens. It turns out the most likely scenario
is one based on quantum mechanics. That inside the retina
of the robin’s right eye – not left eye, they ruled that out
with experiments – inside the retina of the robin’s right eye are tiny proteins, tiny molecules
called cryptochrome that are sensitive to light – because that’s why
they’re in the bird’s eye – and particular,
light with blue wavelength, the sunlight has all colours
of the rainbow, all wavelengths, but particularly blue light
has a particular energy, and what that does is knock
an electron from one of the atoms inside this cryptochrome protein. And that electron will jump far away from its partner
that it was spinning with. Now, these electrons – their fates are intertwined,
they’re entagled. And yet, when they move far apart, they remain, over distance, somehow, in instantaneous communication
with each other. And it’s when they move apart
that that distance means, the action of these atoms is sensitive to the changes
in the Earth’s magnetic field. And any changes will change
the different chemical reactions that these proteins will produce, sending signals to the brain
allowing the bird to know where it is and which direction to move in. So, even something as non-quantumy
as how the European robin navigates would appear to require quantum mechanics. But I want to end with the idea of Löwdin and the suggestion that DNA
mutations might take place. That’s something that we’re now
becoming more interested in again. We just need to find out how we can prove
that quantum tunneling, the same process that drives
the energy of the Sun, might also drive mutations
and evolution in life. Biologists are getting very clever
with their experiments, and they can isolate the DNA,
and they can look at these processes. At the moment we’re at the stage where physicists are trying to develop
very sophisticated models, organic chemists develop
very sophisticated computer programs that can model hundreds
of thousands of molecules, and how they all jiggle about and move, and they make a prediction that the biologists then carry out
experiments to test. If it turns out that quantum physics
does play a role in mutations, we really don’t know where that will lead, what applications it will have. Just one hugely speculative
example, for instance, which researchers
in America are interested in, is whether we can understand
those mutations responsible for cancer. So how a cell becomes cancerous tends to rely on several
highly unlikely mutations. And yet, cancer is everywhere, it will affect one in three of us
at some point in our lives. If quantum mechanics
is responsible for mutations, then we might be able
to control those mutations. Now, I’m not suggesting that quantum mechanics
is going to be the cure for cancer. But this is a new, young,
speculative area of research where physicists, chemists
and biologists are coming together, and who knows where
it may lead in the future. Thank you very much. (Applause)