Animations
Movies
Words
Appendix
Summary
Art
Art
Chapter
10
Quizzes:
Self
Activities
Chapter
Cum.
Unit 2: The Cell
Photosynthesis
Review
Plants and other
are the
of
ecosystems.
Most
autotrophs
are
and use the process called
to convert
energy
into the
energy in food.
Heterotrophs are
(including decomposers), in the ecosystem, and obtain their energy from
other
organisms.
Photosynthesis
is a
process where water is
and carbon dioxide is
to
. This is the reverse of
respiration,
where
is oxidized and
is reduced.
In plants, photosynthesis occurs in organelles called
which
contain membranous sacs called
folded into stacks called
, and surrounded by a
fluid-filled
.
There are two
major
stages:
the light reactions and the Calvin cycle (light-independent reactions).
The light reactions occur in the
.
Pigment
molecules such as
and
are clustered in
complexes
where they
absorb
portions of the light spectrum and reach an
state.
The excited electron is passed through a series of
reactions
including
and
transport chains
(ETCs),
where the captured energy is used to produce
and reduce NADP
+
to
, an electron acceptor. This
process
consumes
and
releases
.
The
Calvin
cycle occurs in the
and can proceed without light. The
and
from the light reactions drive the synthesis of
from carbon
.
C4
plants minimize the cost of
by incorporating CO
2
into
-carbon compounds in
cells, then exported to bundle
cells, where they release CO
2
used in the Calvin
cycle.
The production of
carbon
compounds from
CO
2
is called
fixation.
These organic compounds provide the
and
material for
ecosystems.
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Oct 6, 2006
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