BIOC192 Lecture 33 - Oxidative Phosphorylation

Question 1

what are the 2 energetic gradients that result from the proton gradient across the inner mitochondrial membrane?

Answer 1

1) a chemical gradient

2) an electrical gradient

Question 2

what is the chemical gradient/pH gradient a result of?

Answer 2

result of different H+ concentrations on either side of the membrane

Question 3

what is the electrical gradient a result of?

Answer 3

result of the charge difference across the membrane (positive in the inter membrane space, negative in the matrix)

Question 4

what is the electrochemical gradient known as?

Answer 4

known as the proton motive force

Question 5

what is bacteriorhodopsin?

Answer 5

a light inducible proton pump

Question 6

does ATP synthase make ATP when the light was switched on?

Answer 6

yes

Question 7

does ATP synthase make ATP when the light was switched off?

Answer 7

no

Question 8

what is DNP molecule ?

Answer 8

an uncoupler

Question 9

what is the function of DNP molecule?

Answer 9

shuttles H+ from the inter-membrane space to the matrix, thus dissipating the proton gradient

Question 10

what 2 things happen in the presence of DNP?

Answer 10

1) ETC functions

2) no ATP is made

Question 11

what happens to the energy stored in the proton gradient?

Answer 11

converts to heat

Question 12

what is average number of ATP-synthases per cell?

Answer 12

40,000

Question 13

what is immobilised ATP-synthase linked to?

Answer 13

linked to fluorescent actin

Question 14

what part of the F1Fo-ATP synthase turns?

Answer 14

rotor subunits

Question 15

where is F1 located?

Answer 15

in the matrix

Question 16

where is the Fo located?

Answer 16

in the membrane

Question 17

what part of the F1Fo-ATP synthase does not turn?

Answer 17

stator subunits

Question 18

what drives rotor movement?

Answer 18

proton flow

Question 19

what does rotor movement cause?

Answer 19

causes a conformational changes in the stator that drives ATP synthesis

Question 20

what are the 3 conformational changes?

Answer 20

1) O=open
2) T=tight
3) L=loose

Question 21

what does the open conformational change lead to?

Answer 21

leads to release/binding

Question 22

what does the tight conformational change lead to?

Answer 22

leads to ATP formation

Question 23

what does the loose conformational change lead to?

Answer 23

holds ADP and Pi in preparation fro catalysis

Question 24

how many protons does it take to make 1 ATP?

Answer 24

4 protons

Question 25

how many ATP are made from NADH (10 protons)?

Answer 25

2.5 ATP made

Question 26

how many ATP are made from FADH2 (6 protons)?

Answer 26

1.5 ATP made