bcm34

Question 1

simple chemiosmotic system

Answer 1

bacteriorhodopsin

Question 2

3 neccessary components of chemiosmotic system

Answer 2

proton pump
two compartments
f type atpase

Question 3

pmf equation

Answer 3

change in pmf (mV) = membrane potential (mV) -59 * change in ph

Question 4

how many H+/atp

Answer 4

1 turn = 3 atp
1 c= 1 proton
octameric c rotor 
= 8H+/3Atp
=2.7H+

Question 5

how many c subunits?

Answer 5

8 in mammals
8-14 observed
14 is in plastids with 2H+/atp

Question 6

why is H+ amount quoted sometimes as 4/3

Answer 6

as proton consumed by translocase bringing atp

Question 7

how do we know proton gradient is neccessary

Answer 7

uncoupling agents prevent atp synthesis

Question 8

give examples of uncoupling agents

Answer 8

salicyclic acid
valinomycin - transport K+ ions from inner membrane to matrix
dinitrophenol transports h+ through the membrane

Question 9

brown fat in babies

Answer 9

deliberate uncoupling of lipid oxidation from atp synthesis

uncoupler = thermogenin = heat generator

Question 10

arum lilies

Answer 10

uncouple mitochondira to generate inflorescences

Question 11

titan arum

Answer 11

vapourise amines to attract flies via uncoupling to produce heat

Question 12

skunk cabbage

Answer 12

symplocarpud foetidus

uncouples to melt snow

Question 13

how are many chemiosmostic systems driven?

Answer 13

by redox

Question 14

what is the standard reduction potential of a half reaction?

Answer 14

E^0

free energy of a reduction expressed in volts

Question 15

how do you calculate voltage generated by 2 coupled half cells

Answer 15

change in e^o = E^0 red - E^0 ox

Question 16

how are voltage differences related to free energy?

Answer 16

delta g = zf delta E

E = E^0 + RT/zF ln [x]ox/[x]red

Question 17

what do electrons flow spontaneously from?

Answer 17

more negative redox potential to more positive

Question 18

what is redox potential?

Answer 18

measure of tendency of chemical species to aquire electrons and be reduced measured in volts

Question 19

what is chemiosmosis?

Answer 19

coupling of spontaneous flow of H+ down gradient to non spontaneous atp synthess

Question 20

how does uncoupling produce heat?

Answer 20

energy from proton motive force is disspitated as heat

Question 21

what do ab and delta subunits of atpase do?

Answer 21

they are stators

prevent head from rotating

Question 22

describe the process of atp production

Answer 22

1. H+ enter rotor at c subunits
2. turning of f0 is coupled to rotation of lambda axis
3. causes a conformational change in alpha and beta of f1
4. beta = catalytic alternate between, open, tight, lose
5. open adp and pi bind
6. loose - adp phosphorylated to atp
7. atp protein stabilised tightly bound
8. energy rellease provided by motion of axle which pops freshly synthesized atp from active site converting back to open