chapter 8 light reactions. need to know how photosystems convert light energy into chemical energy....
TRANSCRIPT
Need To Know• How photosystems convert light energy into
chemical energy. (There will be more on this in the next couple of days.)
• How photosystems convert solar energy to chemical energy.
• How linear electron flow in the light reactions results in the formation of ATP, NADPH, and O2
• How the formation of a proton gradient in the light reactions is used to for ATP from ADP and inorganic phosphate by ATP synthase.
Figure 8.11
Photon(fluorescence)
Groundstate
(b) Fluorescence
Excitedstate
Chlorophyllmolecule
Photon
Heat
e−
(a) Excitation of isolated chlorophyll molecule
En
erg
y o
f el
ectr
on
Figure 8.14
Photosystem II Photosystem I
NADPH
Millmakes
ATP
Ph
oto
n
Ph
oto
n
Figure 8.UN02
CalvinCycle
NADPH
NADP
ATP
ADP
Light
CO2
[CH2O] (sugar)
LightReactions
O2
H2O
Figure 8.12a
(a) How a photosystem harvests light
STROMA
THYLAKOID SPACE(INTERIOR OF THYLAKOID)
PhotonPrimaryelectronacceptor
Special pair ofchlorophyll amolecules
Transferof energy
Pigmentmolecules
Th
ylak
oid
mem
bra
ne
e−
Photosystem
Light-harvestingcomplexes
Reaction-centercomplex
There are two reaction centers
P680 P700
Linear electron flow
Figure 8.13-2
Photosystem II(PS II)
P680
Pigmentmolecules
Light
1
Primaryacceptor
22 H
O2
H2O
2
1 3
e−
e−
e−
ATP
Pq
Electrontransportchain
Cytochromecomplex
Pc
4
5Light
6
Pc
Primaryacceptor
Photosystem I(PS I)
P700
Light
6
NADPH
HNADP
reductase
NADP8e−
Fd
Electrontransportchain
7
Figure 8.16
Photosystem II Photosystem I
ToCalvinCycle
H
THYLAKOID SPACE(high H concentration)
Thylakoidmembrane
STROMA(low H concentration)
ATPsynthase
NADPH
e−
LightNADP
ATPADP
NADP
reductase
FdH
Pq
Pc
Cytochromecomplex
4 H
Light
2 HO2
H2O21
4 H
e−
1
2
3
Pi