DR. RICHARD ALLEY: This
is the simplest version
of photosynthesis
and respiration
that we can come up with.
This is a plant.
It stands in for all
the green plants.
And it takes CO2 from the
air, and it takes water,
and it puts those together.
But that requires
energy from the sun
to make the chemical
bonds which give us
plant, shown here as CH2O.
They're just sort of
the formula of plant.
And it releases
oxygen to the air.
Now, animals and
bacteria and fungi
and all these other things take
plant, and they take oxygen,
and they burn them
to get energy so they
can run around and do things.
And that releases
the CO2 and H2O.
Fires also do this,
but they don't do it
in quite so controlled a manner.
