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Photosynthesis: Energy Capture.
My name is Robert
Blankenship from
the Departments of
Biology and Chemistry at
Washington University
in St. Louis.
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Photosynthesis is a
biological process
in which plants store
the sun's energy
in the form of chemical energy.
It is the source
of all of our food
and most of our
energy resources.
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The basic concept
of photosynthesis
is that light energy is
absorbed by a plant,
and chemical processes
take place in which
carbon dioxide and
water are converted
into the organic
matter of the plant
and oxygen is given
off as a byproduct.
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Photosynthesis takes
place on a global scale.
This diagram shows
a map of the Earth
in which the areas that do
photosynthesis are color-coded.
On land, it is coded in terms
of the vegetation index,
and you can see the areas with dark
green are the most productive.
Some areas,
like the Sahara desert and
the center of Australia,
have low productivity,
while much of the rest of the
landmass has high productivity.
The oceans are coded in terms
of chlorophyll concentration,
there the green color
indicates regions of the ocean
with high productivity.
Approximately equal primary production
occurs on land and in the ocean.
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Photosynthesis takes place in
plants, algae and bacteria.
While details differ in the
various types of organisms,
the basic chemical
mechanism of photosynthesis
is essentially the
same in all organisms
that do chlorophyll-based
photosynthesis.
This mechanism is light-driven
electron transfer.
We will explore how this works
and some of the basic
concepts involved
in this light energy transduction
process during this talk.
