Photosynthesis occurs in four steps: (1) Carbon dioxide and water enter leaves through stomata where chloroplasts absorb sunlight using chlorophyll. (2) The light-dependent reaction uses sunlight to make ATP and NADPH by transferring electrons. (3) The light-independent reaction uses ATP and NADPH to produce glucose through the Calvin Cycle. (4) Overall, photosynthesis uses carbon dioxide, water, and sunlight to produce oxygen and glucose as an energy source for plants.

1. PHOTOSYNTHESIS

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7. PHOTOSYNTHESIS
FOUR
IN
STEPSAnne Marie Helmenstine, Ph.D.
(chemistry.about.com)
Updated: July 1, 2016

8. PHOTOSYNTHESIS
FOUR
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1. In plants, photosynthesis usually occurs in
the leaves. This is where plants can get the
raw materials for photosynthesis all in one
convenient location. Carbon dioxide and
oxygen enter/exit the leaves through pores
called stomata. Water is delivered to the
leaves from the roots through a vascular
system. The chlorophyll in the
chloroplasts inside leaf cells absorbs
sunlight.

10. PHOTOSYNTHESIS
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IN
STEPS
2. The process of photosynthesis is divided into
two main parts: light dependent reactions
and light independent or dark reactions.
The light dependent reaction happens when solar
energy is captured to make a molecule called
ATP (adenosine triphosphate). The dark reaction
happens when the ATP is used to make glucose
(the Calvin Cycle).

11. PHOTOSYNTHESIS
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STEPS
3. Antenna complexes transfer light energy to one of two
types of photochemical reaction centers. The photochemical
reaction centers are located on the thylakoid membrane
of the chloroplast. Excited electrons are transferred to
electron acceptors, leaving the reaction center in an
oxidized state.

12. PHOTOSYNTHESIS
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4. The light-independent reactions produce
carbohydrates by using ATP and NADPH that
was formed from the light-dependent reactions.