1. CH21 part2
生科3A
B983B0002 翁梨馨
B983B0044 楊濟鴻

2. reaction center (P870)
Single Reaction Center
electron transfer
Purple bacteria
cytochrome bc1 electron transfer complex
Photosynthetic Units
ATP synthase
ATP
noncyclic
PSII
reaction center (P680)
double Reaction Center
electron transfer
oxigen
cytochrome b6f complex
cyclic
PSI
reaction center (P700)
light-harvesting complex (LHC)
NADPH

3. Photosynthetic Units :
Many Chlorophyll Molecules
Single Reaction Center
antenna chlorophylls :
Light is captured
Routed
Chl•+ :
electron acceptor

4. Chlorophyll funnels the absorbed energy to reaction centers by exciton transfer
a few chlorophyll molecules associated with the photochemical reaction center
other pigment :
light-harvesting
antenna molecules

5. Excitation and electron transfer

6. Transduction of Light Energy into Chemical Energy Involves Oxidation-Reduction
Basis : light energy into chemical energy
Photon absorption
Chl → Chl*→molecule A→Chl•+ & A-
Oxidation of A- →NADP+ to NADPH

7. Purple bacteria Pigments: 3 basic modules
Bacteriochlorophyll a or b, together with various carotenoids
3 basic modules
reaction center (P870),
cytochrome bc1 electron transfer complex,
ATP synthase.

9. The light-driven QH2 is >30% → flow of electron
→ provides the energy for proton pumping by cyt bc1 complex
→ Powered by the proton gradient, ATP synthase provides ATP.
QH2 is >30%

10. 綠硫細菌
裂解H2S使電子變成不循環的電子傳遞
不循環的電子傳遞 :
為了製造NADH
還原能力保留

11. 2H2O+2NADP++8 photons→O2+2NADPH+H+

12. Oxidation

13. PSⅡ （ photosystemⅡ）
>maximal red absorption at 680 nm
>quinones as terminal electron acceptors
>reaction center P680
proton
thylakoid membrane
P680
Cytochrome b6f e- e-
PSⅠ e-
oxidation

14. PSⅠ （ photosystemⅠ）
>maximal red absorption at 700 nm
> ferredoxins as terminal electron acceptors
>reaction center P700
Electrons carrier:
plastocyanin(soluble protein ), a one-electron carrier

15. Cyclic Photophosphorylation
Use PSI
Overcome the ATP deficit for CO2 fixation,
adjusts the ratio of ATP to NADPH produced

16. Quiz 1 Characteristics of chlorophyll include all EXCEPT:
1. iron-containing porphyrin. 2. planar conjugated porphyrin ring. 3. long-chain phytol tail. 4. delocalized 拍 electrons in the aromatic ring. 5. photoexcitable electrons.

17. Quiz 2
All are properties of both the P700 and P680 reaction centers EXCEPT:
1. contain chlorophyll dimers are electron donors are activated by visible light are involved in light-driven O2 evolution all are properties.