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Flashcards in Oxidative Phosphorylation Deck (81)
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31

Atractyloside Bongkrekic Acid MOA?

Inhibits ADP/ATP transport. ATR. prevents binding
of ADP. B.A. prevents release of ADP

32

Atractyloside Bongkrekic Acid sx? 

Convulsions of a hypoglycemic nature (logical, isn't it?), collapse, death

33

Uncouplers uncouple ____ from phosphorylation

oxidation

34

The effect of uncouplers on respiratory control. Uncouplers stimulate ____ in the absence of ADP.

oxygen consumption

35

Uncouplers dissipate the proton gradient by providing an 

alternate route for proton re- entry into the matrix

36

what happens in absence of a graident? 

the synthase runs in reverse hydrolyzing ATP.

37

Properties of uncouplers? 

weak acids, hydrophobic, delocalized charge

38

A natural ____  present in mitochondria of brown adipose tissue is involved in non-shivering thermogenesis  and weight regulation

uncoupler

39

structure of the uncoupler protein in the mitocondria of brown adipose tissue. what regulates it? 

The uncoupler protein contains a proton pore which is under careful hormonal regulation

40

Oligomycin blocks ___

ADP

41

Oligomycin blocks ADP- but not 

uncoupler- stimulated respiration.

42

Oligomycin blocks proton movement through ___

FoF1

43

why does respiration slow with olgiomycin? 

 protons no longer reenter the matrix through FoF1.

44

Uncouplers stimulate respiration, but ____. 

no ATP is made.

45

A natural phosphorylation inhibitor (the inhibitor protein) protects against

 rapid ATP hydrolysis during ischemia

46

when does the natural phosphorylation inhibitor bind to FoF1? how?

 in the absence of O2, the pH of the matrix space drops and the inhibitor protein is protonated changing its conformation to a form that binds tightly to FoF1.

47

 Oxygen consumption measurement showing effect of cyanide 

what is blocked? 

ADP- and uncoupler-stimulated respiration are blocked.

48

 In heart mitochondria, the response to cyanide is

 the inhibitor protein will bind to the ATP synthase to inhibit ATP hydrolysis.

(like with ischemia)

49

 Cyanide acts by competing with O2 for binding to(3)

 the heme a3 iron and CuB. 

50

Unlike O2, CN- cannot accept ___

electrons

51

The basic premise of the chemiosmotic theory is that a ____ gradient is a required intermediate in coupling the exergonic redox reactions to the endergonic synthesis of ATP

delocalized electrochemical

52

Mitchell proposed a ___ mechanism for generating the gradient called: “Mitchell’s Loops”.

direct coupling

53

the net result of a mitchells loops like Q 

two protons have been transported out of the mitochondrion against an electrochemical gradient.

54

Mitchell’s proposed Loops cannot function in 

cytochrome oxidase, since tehre is no hyodrgen donor/acceptor

55

The principle of pumps is that proton transport is coupled to ____ indirectly through protein conformational changes

exergonic redox reactions

56

The FoF1-ATP synthase is now recognized to be a tiny molecular motor. Instead of being driven by a current of electrons it is driven by

current of protons

57

Shuttles of reducing equivalents from glycolytic NADH to the Respiratory Chain.

(1) Glycerol phosphate shuttle

(2) Malate/aspartate shuttle

58

ADP/ATP and Pi Translocases

involves One ADP moves in and one ATP moves out with the net exit of 

one negative charge (electrogenic).

 

One P - and one H+ move in with a net loss of one H+ 

59

2 predictions by mitchell 

predictions
1. membranes impermeable to protons
2. electrochemical gradient exists

60

2 things are needed for mitchells loops to work (q cycle)

alternate between electron donors
and hydrogen donor acceptors

and you are going to alter which
side of the membrane reduction and
oxidation occur