Electron transport chain

Question 1

Redox potential symbol and units:

Answer 1

E*, volts

Question 2

higher E* corresponds to

Answer 2

higher electron affinity (acceptor activity)

Question 3

list redox pairs in order of increasing redox potential

Answer 3

NAD+/NADH
FMN/FMNH2
FAD/FADH2
pyruvate/lactate
Cytochrome C F3+/F2+
Oxygen/water

Question 4

what are the 5 electron carriers?

Answer 4

Metabolic carriers - NADH, FADH2

Electron transport chain components, cytochromes, Fe-S proteins, ubiquinone

Question 5

what are the 4 protein complexes?

Answer 5

NADH dehydrogenase
Succinate dehydrogenase
Ubiquinone: cytochrome C oxidoreductase
Cytochrome oxidase

Question 6

what happens at NADH dehydrogenase

Answer 6

NADH oxidised. Electrons and H+ transferred to Q, forming QH2 which goes to complex 3.
4 H+ are pumped into intermembrane space.

Question 7

what happens at succinate dehydrogenase

Answer 7

FADH2 formed from succinate reaction is oxidised, H+ and e- transferred to Q to form QH2 which goes to complex 3

Question 8

what happens at ubiquinone cytochrome C oxidoreductase

Answer 8

QH2 oxidised to Q, H+ and electrons
2H+ from oxidation goes to intermembrane space, also 2+ from matrix goes to intermembrane space.
Electrons go to cytochrome C, which is transported to cytochrome C oxidase

Question 9

what happens at cytochorme C oxidase

Answer 9

Electrons react with O2 and H+ to form water.

2H+ goes to the intermembrane space.

Question 10

what is chemiosmotic theory

Answer 10

Energy from electron transfer reactions is temporarility stored as a transmembrane difference in charge and pH. This is used to drive ATP production

Question 11

why the term oxidative phosphorylation?

Answer 11

ATP synthesis (phosphorylation) and oxidation are linked/coupled

Question 12

describe artificial/mechanical damage to the inner mito membrane

Answer 12

H+ gradient is abolised. Oxidation occurs, but not phosphorylation

Question 13

ddescribe chemical reagants in uncoupling ATP synthesis and electron transport

Answer 13

some chemical reagents can take up H+ in intermembrane space and then transport H+ to matrix, causing the H+ gradient to be abolised

Question 14

describe the natrual uncoupler thermogenin

Answer 14

integrin of inner mito memb
provides an alternative route for H+. so that the energy that would have been used as proton motive force is used to heat the baby.

Question 15

role of venturician

Answer 15

binds to and inhibits catalytic site of ATP synthase

Question 16

role of oligomycin and DCCD

Answer 16

bind to and block H+ channel

Question 17

describe ATP synthase

Answer 17

has protein pump (F0) and enzyme (F1) components.