2. Photosynthesis
How plants turn sunlight into energy
Fuels all living organisms either
directly or indirectly
Chlorophyll (and a few other
pigments)are in the thylakoid
membranes: this absorbs solar energy
Also uses carbon dioxide and water
3. Oxidation and reduction
Reduction: gaining hydrogen atoms
Oxidation: losing hydrogen atoms
Hydrogen has a +1 charge, it moves
with electrons from solar energy,
which have a -1 charge
The electrons are what carry the energy
4. The Reaction
H2O + CO2 CH2O + O2
CH20 - six used to make C6H12O6, glucose
5. Photosynthesis
Two reactions occuring:
Light reactions
ATP produced and NADPH
produced using solar energy
Calvin cycle
ATP and NADPH change carbon
dioxide into carbohydrate
6. Light reactions
Chlorophyll absorbs violet, blue and red
light (why leaves look green)
Carotenoids absorb violet, blue and green
light (why leaves look red or yellow in
fall)
7. LR:Photosystems I and II
Photosystem II splits water
Solar energy makes electrons so excited
they escape from reaction center, which then
takes electrons from water to replace them
Photosystem I produces NADPH from electrons
excited by solar energy
PS I takes electrons from the above system
to replace the ones it has lost
8. Electron Transport Chains
These are a series of molecules that pass
electrons (and H+) from one to the next
Basically a way for the energy stored in
these ions to be passed around from one
area to another, so it can be used for
things
10. H+ and potential energy
As water is split, two H+ remain in thylakoid
space, and energy from the electron transport
chain is used to move even more H+ into this
space
Creates POTENTIAL engery as the H+ want to
be evenly distributed
So they flow back into stroma at ATP synthase
complex - a membrane protein complex that uses
this energy to make ATP
12. Calvin Cycle
Occur in stroma
First, attach CO2 to RuBP: fixation
Then, CO2 is reduced using NADPH and
ATP from the light reactions
This makes G3P, the precursor to glucose
but also many other biological molecules
Finally , RuBP is reformed to be used again