Baker Electron Transport Chains Flashcards
A positive electrochemical potential is equal to what kind of gibbs?
+E = -G
How many protons and electrons do flavins carry?
2H+, 2e-
How many protons and electrons do FeS carry?
one e- per Fe
How many protons and electrons do quinones carry?
2e-, 2H+
What is the redox chain of mitochondrial complex 1?
FMN-3x 4Fe4S
How many protons does complex 1 mitochondrial pump?
4
How many protons does mitochondrial complex 2 pump?
0
What prosthetic groups does complex 2 have?
FeS-cytB
Are complexes 3 bc1 and bf6 analogous or homologous?
analogous- same function, different origin
what is the ISP?
2Fe-2His in complex 3
how many protons does the Q cycle pump?
4
what is the structure of cytochromes?
porphyrin rings with varying sidechains. double bonds for electron transport. Fe/haem centre
What is the mitochondrial complex 4 equation?
4CytCr + 8Hm + O2 -> 4CytCo + 4Hi + 2H2O
What is the redox pathway of mitochondrial complex 4?
CuA:CuA - cyt a- cyt a3 - CuB. 2e- to CuB and a3. O2 peroxide bridge 2e-, 2H+ for hydroxyls 2H+ releases
How many H does ATP synthase pump?
3H+ for F0/c subunit repulsion through y stalk to alpha-beta dimers for beta-catalysis by binding change mechanism
What is the P:O ratio?
NADH 2.5, FADH 1.5
what is the structure of chlorophyll?
cyclic tetrapyrolles with Mg centre. double bonds for electron transport
what wavelengths are absorbed by chlorophyll?
red 600-700, blue 400-500
what chlorophyll molecules are in the reaction centre?
special pair of chla
which bacterium has cyclic electron transport?
rhodopseudomonas viridis
What is the structure of the P960?
L&M structural TM helices, 2 other peptides
what structure is pheophytin?
chlorophyll without the Mg
What is the redox cycle of P960?
Bchl- BPh- Qa- Qb- Q pool- Cyt bc1- Cytc2 permanment subunit
What is the PS11 wavelength?
680
What is the PS11 redox groups?
Mn4 OEC P680 Pheo PQa PQb PQ pool cyt b6f PC
What is the redox system of PS1?
PC P700 ChlA0 PQA1 3x 4Fe4S Fd-Q oxidoreductase 2Fe2S of Fd Fd-NADP oxidoreductase + FAD NADPH
what is the pathway of chloroplast cyclic electron transport?
Fd to Fd-PC oxidoreductase
what is the structure of PC?
analogous to cytochrome C with Copper centre
what wavelength do caroteniods absorb?
green-blue
what structure do caroteniods have?
C20 isoprene with double bounds
what wavelengths do phycobilosomes absorb?
yellow/green 600-400
what organisms have phycobilisomes?
algae, cyanobacteria
Which direction does cytb6f translocate protons?
stroma into thylakiod lumen
how do antenna pigments transfer energy?
resonance energy transfer
what structure is the phycobilisome?
phycoerthyrin and phycocyanin attached to photosystem membrane surface
what antenna do yeast and fungi use?
phycoerthyrin and phycocyanin
what structure is the LHC11?
trimeric antenna complex
each monomer has 12chla/b + carotenoids
surronds PS11 reaction centre/special pair
which chlorophyll is found in reaction centres?
a
which protein complexes are in stacked region of thylakiod?
PS11 and cyt b6f
how does the LHC11 kinase reduce energy absorption?
PS11>PS1 then reduced PQ activates LHC11 kinase to phosphorylate LHC11 to reduce resonance transfer
how does the photosynthetic ETC change reduction potential?
decreases
what is the complex 3 Q cycle?
e- to ISP to cytC/F
e- to bL to bH
Do flavins always carry 2H?
No, can carry 1
What are the 3 forms of Plasto/ubiquinone?
Q
Q-
QH2
How are cytochromes bound to proteins?
Through cysteines or non-covalently
How can the movement of ATPase be observed?
Linking actin filament through streptavidin/biotin to F0 when F1 is membrane bound
How does the P:O ratio differ in bacteria and yeast?
Lower as more c subunits
What are the inhibitors of mETC?
1: rotenome, amytal 2: 3: antimycin 4: cyanide ATPase: oligomycin uncoupler
What reducing power does photophosphorylation produce?
NADPH
Which is the slow step of PSII?
QH2 pool
How many photons are required to evolve the first oxygen?
3
What is the structure of the OEC?
4Mn, 3 in coordination and 1 for O2 binding
What type of tetrapyrolle are the phycobilins?
linear
Is the a defined number of LHC per PS?
No
Is cytochrome b6f isolated in the stacked region?
No, found in stacked and unstacked region of thylakoid membrane