Flashcards in bcm34 Deck (22):
simple chemiosmotic system
3 neccessary components of chemiosmotic system
f type atpase
change in pmf (mV) = membrane potential (mV) -59 * change in ph
how many H+/atp
1 turn = 3 atp
1 c= 1 proton
octameric c rotor
how many c subunits?
8 in mammals
14 is in plastids with 2H+/atp
why is H+ amount quoted sometimes as 4/3
as proton consumed by translocase bringing atp
how do we know proton gradient is neccessary
uncoupling agents prevent atp synthesis
give examples of uncoupling agents
valinomycin - transport K+ ions from inner membrane to matrix
dinitrophenol transports h+ through the membrane
brown fat in babies
deliberate uncoupling of lipid oxidation from atp synthesis
uncoupler = thermogenin = heat generator
uncouple mitochondira to generate inflorescences
vapourise amines to attract flies via uncoupling to produce heat
uncouples to melt snow
how are many chemiosmostic systems driven?
what is the standard reduction potential of a half reaction?
free energy of a reduction expressed in volts
how do you calculate voltage generated by 2 coupled half cells
change in e^o = E^0 red - E^0 ox
how are voltage differences related to free energy?
delta g = zf delta E
E = E^0 + RT/zF ln [x]ox/[x]red
what do electrons flow spontaneously from?
more negative redox potential to more positive
what is redox potential?
measure of tendency of chemical species to aquire electrons and be reduced measured in volts
what is chemiosmosis?
coupling of spontaneous flow of H+ down gradient to non spontaneous atp synthess
how does uncoupling produce heat?
energy from proton motive force is disspitated as heat
what do ab and delta subunits of atpase do?
they are stators
prevent head from rotating