Photosynthesis
From Light to Life
Definition
• The process by
which plants use
CO2 and water,
along with the
sun’s energy to
create glucose, a
simple sugar,
oxygen and
water.
Where does photosynthesis occur?
Chloroplasts- Thylakoids- Stroma
Chlorophyll absorbs the violet, blue and red waves of sunlight
and uses it. It reflects the green wavelengths, which is why
we see leaves as green.
Chlorophyll is a truly amazing
substance!
It is present in all green plants and is
responsible for light absorption, which
provides energy for photosynthesis.
Photosynthesis generates oxygen—a
source of life for our planet. This flask
contains chlorophyll extracted from
spinach leaves. When a beam of light
passes through the extract, the
chlorophyll absorbs the energy, which
is the first step in photosynthesis.
Because the chlorophyll in this flask
has been isolated from the plant,
energy cannot be converted and
stored. Instead the energy is released
as heat and red fluorescence.
The Process of PhotosynthesisTwo Phases
Light Phase- takes place in the
thylakoids
Light Reactions-REQUIRE LIGHT
1. Light is absorbed by
chlorophyll and the
molecules become
energized
2. Adenosine diphosphate
becomes
adenosinetriphosphate
3. The energy splits the water
(photolysis)
4. The hydrogen from water
bonds with NADP (H)
Results of Light Phase
• ATP and NADPH are
produced for use as energy
during the dark phase
• Oxygen (from H2O)is
released into the
atmosphere
Dark Phase Takes Place in the Stroma
Dark ReactionsDO NOT REQUIRE LIGHT
1. Carbon dioxide
combines with RuBP
2. RuBP splits into two
molecules of PGA
3. The ATP and
hydrogen/electrons
from light phase
change PGA to PGAL (a
higher energy
molecule
Results of Dark Phase
• Some of the PGAL
molecules go on to
form glucose
• The rest will continue
through the cycle and
repeat the process
Dark Reactions also known asThe Calvin Cycle
Really Now- Don’t you
agree that
photosynthesis is an
amazing process?
Hebrews 11:3
By faith we understand that the universe
was formed at God's command, so that what
is seen was not made out of what was visible.
BE AMAZED!