Please wait while the transcript is being prepared...
0:00
Plastid structure: Development
and Differentiation.
Dr. Kevin Pyke
Plant Sciences Division,
School of Biosciences,
University of
Nottingham in the UK.
0:11
Chloroplasts define plants.
Green pigmented chloroplast
containing chlorophyll
are one of
the defining aspects of
higher plants and also
of all lower plants.
They are the cellular
organelles which create
a green planet by virtue of
their presence in leaves,
stems and all green
parts of plants.
One only has to look around you
at the outside world to see that
the influence which chloroplasts
in green parts of plants
have upon the planet.
In fact, chlorophyll is one of
the few molecules that
can be seen from space
and any visitor from
outer space would
certainly see the planet
Earth as a green planet.
Chloroplasts are the site of
photosynthetic
carbon fixation and
the photolysis of water.
They are absolutely central
to fixing carbon
dioxide from the air,
splitting water using
light energy and
releasing the waste product
which essentially is oxygen.
This oxygen supports life forms
on the planet carrying
out respiration.
As a result, chloroplasts
are absolutely
fundamental to the way that
the biosphere and
the planet work.
In this lecture,
we will consider
some of the basic aspects of
the chloroplast
structure and some of
their more interesting cell
biology characteristics.
1:22
Chloroplasts are
abundant in leaf cells.
Here you see a scanning
electron micrograph
of a piece of leaf
which has been
pseudo-colored to show you
where the green chloroplasts
are inside the mesophyll cells
which are long and thin.
In this case, they're called
palisade mesophyll cells
and they reside just below
the upper epidermis,
which you can see at the
top of the photograph.
You can see very clearly that
these palisade cells are
absolutely stuffed full of
chloroplasts and in fact
in leaves, there are millions
and millions of chloroplasts
in both these cells and
also the spongy mesophyll cells
which are slightly
lower in the leaf.
Here you see a chloroplast in
