Lecture 21: Electron Transport Flashcards
what pigment does PS2 use
P680+
what is P680+
a very strong oxidant that is strong enough to pull electrons from H2O
what pigment does PS1 use
P700
what is P700
a very strong reductant that is strong enough to donate electrons to NADP+
reductants _______ electrons to other species
donate
oxidizers ______ electrons from other species
remove
what does the electron transport chain generate to drive ATP production
proton-motive force
which photosystem takes electron from water
PS2
which photosystem donates to NADP+
PS1
where are photosystems embeded
in thylakoid membranes
plastoquinone
small molecule and mobile electron carrier that is used between PS2 and cytochrome b
plastocyanin
small protein and mobile electron carrier used between cytochrome b and PS1
what direction does the linear electron transport go
PS2 - Cyt b6f - PS1
how are some chlorophylls, B-carotenes, and other small molecules held in position
PS2
process of the oxygen-evolving complex
exciton of P680 is followed by withdrawal of one electron from Mn cluster that stores the residual positive charge. When Mn charges accumulate, the complex oxidizes 2H2O molecules and releases O2
Electron transfer steps in PS2
- light converts reaction center chlorophyll to excited form P680 - P680+
- electron transferred to pheophytin (Pheo), forming pheo-
- Pheo- passes electron to QA to prodcue QA-
- passed to Qb to make Qb-
how is the electron transferred to Q in PS2
Pheophytin
electrons move from ______ to ______ side in the electron transfer of PS2
luminal to stromal
first half of Q cycle in the cytochromeb6f complex
PQH2 delivers 2 protons to lumen and 1 electron to PC. PQ returns to PS2
secon half of Q cycle in the cytochromeb6f complex
another PQH2 delivers 2 protons to lumen, and 1 electron to PC. PQ, 2 electrons, and 2 protons regenerate PQH2, which cycles again
ferredoxin
a soluble electron carrier to transfer electrons to NADP+
how does ferredoxin transfer electrons
ferredoxin:NADP+ reductase
how does ATP synthase work
moves protons from inside of lumen to the stroma and use the movement to synthesis ATP from ADP and Pi
where are PS2, PS1, ATP synthase, and Cyt b6f found in regions of the thylakoids
PS2 = appressed regions
PS1 and ATP synthase = non-appressed regions
Cyt - uniformly distributed throughout