2. What is photosynthesis?
• the process that transforms the
vast energy of the sun into
chemical energy and is the basis
for most food chains on Earth.
3. The overwhelming majority of life
depends on the photosynthetic
ability of green plants and algae,
and without these producers, life
as is known today could not
survive.
4. Energy from the Sun
Sun
• source of electromagnetic radiation
The visible light is only a small
portion of the EM radiation
5.
6.
7. • 380nm to 760 nm: the
wavelengths most important to
living organisms
• Leaves of plants reflect the green
and yellow portions of the
spectrum
12. THERE ARE TWO PHASES IN
PHOTOSYNTHESIS
• THE “LIGHT REACTIONS”
– H2O is split
• 2 H2O O2 + 4 [H]
– NADPH and ATP ere generated
• THE “CALVIN CYCLE”
– NADPH and ATP from the light reaction drives CH2O
production from CO2 and [H] :
• 4 [H] + CO2 (CH2O) + H2 O
13. LIGHT REACTIONS
• Takes place on the thylakoid
membranes within the chloroplasts
• Composed of Photosystem I and
Photosystem II
14. NADPH
Z Scheme of the Light Reaction
PS-II
PS-I
NADP+
ATP
(P680)
(P700)
