Photosynth (don't forget to study diagrams) Flashcards
What are all four lineages of photosynthetic organisms?
Cyanobacteria, green algae, eukaryotic algae, plants
What is the great oxygenation event?
When oxygen-fixing, photosynthetic bacteria started to fix oxygen into the atmosphere
Where is photosystem I found, where is photosystem II found ?
PS I: stoma thylakoid membranes
PS II: mostly inner grana space, some stroma thlakoid membrane
What are the the six protein involved photosynthesis in order?
PSII, plastoquinone (PQ), cytochrome b/f6, plastocyanin PC, and ferredoxin Fd, PS I
What does light absorbtion do to the PS complexes?
It makes the redox potential more negative
What is the ultimate electron donor? how about acceptor?
Donor: H2O
acceptor: NADP+
What is more energetic: blue or red light?
Blue light
What type of light can the PS rxn center absorb? (red or blue)? What about carotenoids?
PS: Red light (low energy so wont damage components)
carotenoids: high energy blue light
How many oxidation states does the mangesium core have? What does it decays to in the dark?
Five states. Decays to state 1.
What is the quantum yeild of O2 (photons needed per an O2 released)? How about Chl needed? How about electrons?
four electrons
2400 chlorophylls
9 -> 10 hv (photons)
What is the average size of the antenna for the PS’s ?
300 chl per a photosystem
how many photons does it take to fix one carbon?
9 to 10 photons
What is required from the light rxn to run the CBC/dark rxn cycle?
2NADPH and 3 ATP
How many photons per a 2 NADPH and 3 ATP?
9 or 10 photons (8 for linear + 1 for cyclic)
What is the electron to ATP ratio in photosynthesis
2:1 e-: ATP
what electron carrier does cyclic electron transport?
Ferridoxin (Fd)
Which PS is in the stromal membranes? Which PS is in the grana stacks? Where does ATPase and Cytob6f lie?
PS II: thylakoid
PSI: stromal
ATPase: stromal
cytob6f : everywhere
How many mV across the membrane is needed to make ATP? Where do these energies come from (pH or delta psi) in the thylakoid, mitocondria, and bacterial membranes
180 mV
Thylakoids like high pH difference and low psi
mitochondria like lo delta pH and high delta psi
bacteria go either or
What are the exact units for an Einstein and what does it measure?
Units are kJ/mol of photons. Used to measure light
What is the chemiosmotic hypothesis?
the protonmotive force forces is made up of both pH and psi
What are the 5 ways plants/algae can concentrate CO2
Carboxysomes, pyrenoids, C2, C4, and CAM
What are the major nutrients of life?
C, H, N, O, P, S
What is fluorescence’s relation to photochemistry
it is 1-photochemistry. When there is a charged molecule, it can either use the charge to do photochemistry or dissipate the energy as fluorescence
Why is there two photosystems instead of just one?
Stops electrons from backsliding in the wrong direction or from releasing their energy as heat/light
what does one Einstein equal?
Kj/mol of photons
The photosystems go from a uncharged state with a ___ redox potential, to an charged state with a ___ redox potential
uncharged = possitive
charged = negative
how many chlorophyll molecules per a rxn center on avg?
around 300 Chl
Organize the molecules from high energy absorbing to low energy absorbing: carotenoids, P680, Chl a, Chl b
Carotenoids, Chl b, Chl a, P680
What is the equation for the protonmotive force?
pmf = (delta mu/F) =60 (delta pH) + delta psi [mV]
How efficient is photosynethsis?
31% energy conversion
What is Mitchell’s Chemiosmotic Coupling hypothesis?
The energy used to make ATP across membranes is stored an electro-chemical graident
What is the photosynthetic equation (fixation of one carbon from the air)?
CO2 + 2H2O +n(hv) –> CH2O +H2O +O2
What is the difference between the F0 subunit and the F1 subunit.
F0: proton channel with multiple subunits. This is the embedded part of the protein
F1:ATPase with 9 total subunits
