Transcript Photosynthesis I

AP Biology
Photosynthesis
Part 1
Autotroph - Plants
Autotroph - Algae
Autotroph - Phytoplankton
Autotroph - Bacteria
Heterotroph - Animal
Heterotroph - Fungus
Chloroplasts in plant leaf cells
Chloroplast
Photosynthesis chemical reaction
(Remember… conservation of matter.)
6 CO2 + 6 H2O  C6H12O6 + 6 O2 + Heat
Photosynthesis Light Dependent
Reactions
Light Dependent
Reactions
These reactions
start the process of
photosynthesis by
using energy from
sunlight to create
ATP and NADPH.
Energy from
excited electrons is
used to later create
glucose.
Photosynthesis Calvin Cycle – Light
Independent Reactions
Light Independent
Reactions
These reactions
follow the light
dependent
reactions and use
the energy from the
stored electrons to
create glucose.
Electromagnetic Spectrum
Absorption vs. Reflection
As we know from Sophomore Biology,
chloroplasts absorb all wavelengths of
light except for green light. This light
is reflected away from the
chloroplasts, thus causing most plants
to appear green.
How do we know that chloroplasts
absorb all wavelengths of light except
for green? Are there any experiments
that could be done to show this
phenomenon?
Chloroplasts REFLECTING
Green Light
White
light
Refracting
prism
Chlorophyll
solution
Photoelectric
tube
Galvanometer
0
Slit moves to
pass light
of selected
wavelength
Green
light
100
The high transmittance
(low absorption)
reading indicates that
chlorophyll absorbs
very little green light.
Chlorophyll ABSORBING
Blue light to power
photosynthesis
White
light
Refracting
prism
Chlorophyll
solution
Photoelectric
tube
0
Slit moves to
pass light
of selected
wavelength
Blue
light
100
The low transmittance
(high absorption)
reading indicates that
chlorophyll absorbs
most blue light.
Chloroplasts absorbing the blue
and the red light waves. The green
is NOT being absorbed.
Chlorophyll Molecule
(How many electrons are in Mg’s outer shell?)
Hint: Look at the Periodic Table.
Answer: 2
These 2 electrons will be important!
Photosystem and collecting
sunlight energy.
Photosystems 1 and 2
Where are the photosystems
located?