Photosynthesis in action: Scientists capture moment plant converts energy
- Team led by Arizona State University observes photosynthesis in action
- They were able to take a freeze-frame of plant process that creates oxygen
- They observed the molecular changes using X-ray flashes at a lab
- This snapshot lasted just 30 quadrillionths of a second
- And the research could be used to make artificial leaves, the so-called 'holy grail' of biochemistry
Published:
16:03 GMT, 10 July 2014
|
Updated:
17:13 GMT, 10 July 2014
Scientists have announced they are closer than ever to the ‘holy grail’ of biochemistry: artificial photosynthesis.
By
observing the first stage of the process in action, they say they’ve
got a better understanding of how plans turn carbon dioxide into oxygen.
And
ultimately it may be an important step to a future where artificial
plants are created that are more efficient than their organic siblings.
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Scientists have observed the water splitting
process in plants that creates oxygen, known as photosystem II. The
cycle, illustrated here, has four steps. The largest change is between
steps S1 and S3, so this is the part the scientists 'zoomed in' on to
capture their freeze-frame
The
groundbreaking research published in Nature was carried out by an
international team led by Arizona State University (ASU) scientists.
PHOTOSYNTHESIS IN A NUTHSELL
The
process through which plants absorb light using chlorophyll to produce
chemical energy in the form of oxygen, glucose and more is called
photosynthesis.
During the
process glucose is used by the plants to breathe or is converted into
starch, while oxygen is released as a waste product – in turn giving us
the air we need to breathe.
The
rate of photosynthesis is altered by differing carbon dioxide levels
and light intensity. If either is increased then the process will also
increase, up to a limit.
Temperature also plays a part, with a higher temperature increasing the rate.
However if the temperature is too high, beyond 40C, the rate slows down.
Photosynthesis provides most of the energy necessary for life on Earth to exist.
But no way to artificially mimic the process has yet been created, leaving us dependent on plants to survive and thrive.
In the
study they were able to observe the first snapshots of photosynthesis in
action as it split water into protons, electrons and oxygen.
This
is the process that maintains Earth’s oxygen atmosphere and ensures air
is made up of the things we need to breathe it and survive.
‘This
study is the first step towards our ultimate goal of unraveling the
secrets of water splitting and obtaining molecular movies of
biomolecules,’ said Professor Petra Fromme, professor of chemistry and
biochemistry at ASU and leader of the research team.
Photosynthesis is one of the fundamental processes of life on Earth.
The
early Earth contained no oxygen and was only converted to the
oxygen-rich atmosphere we have today 2.5 billion years ago by the
‘invention’ of the water splitting process that occurs in
photosynthesis.
This
water splitting process is known as photosystem II (PSII), which
produces the oxygen we breathe and ultimately keeps us alive.
Revealing
the mechanism of this process is essential for the development of
artificial systems that mimic and surpass the efficiency of natural
systems.
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In the study they were able to observe the first
snapshots of photosynthesis in action as it split water into protons,
electrons and oxygen. This is the process that maintains Earth¿s oxygen
atmosphere and ensures air is made up of the things we need to breathe
it and survive
The
development of an ‘artificial leaf’ is one of the major goals of the
ASU Center for Bio-Inspired Solar Fuel Production, which was the main
supporter of this study.
Director
of the centre Professor Devens Gust explained that they are trying to
find a way to turn water into oxygen gas, hydrogen ions and electrons
just like plants do.
‘Photosynthetic
organisms already know how to do this, and we need to know the details
of how photosynthesis carries out the process using abundant manganese
and calcium,’ he said.
‘Once
the mechanism of photosynthetic water oxidation is understood, chemists
can begin to design artificial photosynthetic catalysts that will allow
them to produce useful fuels using sunlight.’
The
team, led by Professor Fromme, used the world's most powerful X-ray
flashlight at the US National Accelerator Laboratory to record still
frames of the molecule complex PSII as it splits water into hydrogen and
oxygen.
‘This
is the very first scene of a molecular movie showing light-driven water
splitting in photosystem II, the mechanism which makes all oxygen in
the atmosphere,’ said Fromme.
Co-author
Professor Henry Chapman from the Deutsches Elektronen-Synchrotron
(Desy) added: ‘A deeper understanding of photosynthesis could, for
instance, aid the development of better solar cells and might advance
the quest for biochemistry's holy grail, artificial photosynthesis.’
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The process through which plants absorb light
using chlorophyll to produce chemical energy in the form of oxygen,
glucose and more is called photosynthesis. Shown is a Cyanobacteria
cell, which was an early form of plant life that converted the Earth's
early atmosphere into a breathable one
To
observe photosystem II in action, the team grew tiny nano-crystals of
the photosystem II complex of bacteria that employ photosynthesis,
cyanobacteria called Thermosynechococcus elongatus.
These
crystals were illuminated with a visible laser to start the water
splitting process, which is otherwise driven by sunlight.
The
researchers used double light flashes to trigger the transition and,
with the short and intenses X-ray laser flashes, were able to monitor
how the molecular structure changed in the process.
This provided just enough time to freeze-frame the water splitting process for 30 quadrillionths of a second.
But
that was enough to glean the snapshot of the process in action - and
now they’ll be hoping to take the research further and see the rest of
the photosynthesis process.
Read more:
http://www.dailymail.co.uk/sciencetech/article-2687703/Photosynthesis-action-Scientists-capture-moment-plant-converts-energy-help-create-man-plants.html#ixzz376oxH09n
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