Similarities between photophosphorylation and oxidative phosphorylation e-e- Proton pump ATP...
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Transcript of Similarities between photophosphorylation and oxidative phosphorylation e-e- Proton pump ATP...
Similarities between photophosphorylation and oxidative phosphorylation
e-
Proton pump
ATP synthase
H+
H+ H+ H+ H+
H+
ADP+Pi
ATP
e-e-
Energy from electrons is used
for H+ translocation
ATP synthesis is driven by H+
gradient
H+ gradient formation
Differences between photophosphorylation and oxidative phosphorylation
e-Proton pump
ATP synthase
H+
H+ H+ H+ H+ H+
H+ADP+Pi
ATP
NADHFADH2
NADP+
NADPH
O2
H2O
Energy source: light
Energy source: electrons
By-product: electrons
By-product: water
Chlorophyll (or other pigments) absorbs light energy and conserve it as ATP and NADPH.
Not all photosynthetic organisms use H2O as electron donor in photosynthesis; thus not all of them produce O2 while they produce ATP and NADPH.
There are two types of photosynthesis: oxygenic (producing oxygen) photosynthesis and anoxygenic (not producing oxygen) photosynthesis. Only organisms with two photosystems can do oxygenic photosynthesis.
At lease half of the photosynthsis in this world is done by microorganisms (algae, photosynthetic eukaryotes and photosynthetic bacteria).
p727
Cyanobacteria & red algae also contain similar structures called phycobilisome to facilitate light absorption
p726
Alternating single and double bonds give strong absorption in the visible light
The major light absorbing pigment in higher plants
p731(PSII) (PSI)
Anoxygenic photosynthesis
(pheophytin)
(ferredoxin)
(restore RC to original state)
(restore RC to original state)
p733
The Z scheme of oxygenic photosynthesis
Purple bacteria type
Green bacteria type
(pheophytin)
(plastoquinone)
(special form of chlorophyll)
(phylloquinone)
p736
LHCII holds grana together
PSI and PSII on thylakoid membrane are separated to prevent Excition Larceny
-Thr- P
Granal stacking by LHCII is regulated by light intensity
-Thr-OH
LHCIIProtein kinase
ATP
ADP
Protein PPase
Pi
High light [PQH2] [PQ]
Low light [PQH2] [PQ]
appressednonappressed
ee
ee
eeeeTyr
p739
Oxygen-evolving complex(water-splitting complex)
Mn
Mn
Mn
Mn
P680
D1D2
Pheo Pheo
QA QBFe
eeee
2H2O
eeeeO24H+
p1062
Chloroplast from higher plants is probably evolved from endosymbiotic bacteria (prochlorophytes)Chloroplast from red algae is probably evolved from cyanobacteria