lecture 33 - oxidative phosphorylation Flashcards

1
Q

What are the 2 energetic gradients across the inner mitochondrial membrane as a result of the proton gradient created by the ETC?

A

A chemical/pH gradient, an electrical gradient

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2
Q

What is the pH/chemical gradient across the inner mitochondrial membrane a result of?

A

Different H+ concentration on either side of the membrane due to the ETC

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3
Q

What is the electrical gradient across the inner mitochondrial membrane a result of?

A

A charge difference across the membrane - intermembrane space is positive, matrix if negative

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4
Q

What is the name for the electrochemical gradient across the inner mitochondrial membrane?

A

The proton-motive force (pmf)

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5
Q

What does the proton motive force drive?

A

ATP synthesis

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6
Q

What is the relative pH in the intermembrane space of the mitochondria?

A

low PH, due to increased [H+]

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7
Q

What is the relative pH in the mitochondrial matrix?

A

High pH, due to protons being pumped out and therefore a low [H+]

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8
Q

What is a bacteriorhodopsin?

A

A light induced proton pump that uses energy from light to make a proton gradient across a lipid vesicle. This facilities ATP synthase prodcution of ATP

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9
Q

What is the impact of DNP on oxidative phosphorylation?

A

Shuttles H+ back from inter-membrane space to the matrix, dissipating the proton gradient and preventing ATP synthesis. Energy builds up and is dissipated as heat

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10
Q

What are the 2 parts of ATP synthase?

A

F1 and FO

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11
Q

Where is F1 of F1FO-ATP synthase found?

A

In the mitochondrial matrix

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12
Q

Where is F1 of F1FO-ATP synthase found?

A

In the inner mitochondrial membrane

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13
Q

What are the 2 types of subunits in ATP synthase, as characteristed by their ability to turn?

A

Rotor and stator subunits

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14
Q

What components of ATP synthase are rotor subunits?

A

c subunits, gamma stalk, epsilon

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15
Q

What components of ATP synthase are stator subunits?

A

a,b, alpha and beta subunits

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16
Q

What drives rotor movement in ATP synthase?

A

Proton flow over the c subunits

17
Q

What does rotor movement cause in ATP synthase?

A

Conformational changes in the stator that drive ATP synthesis

18
Q

What are the 3 conformational positions of the alpha and beta subunits of F1 of ATP synthase?

A

O (open), L (loose), T (tight)

19
Q

What happens to alpha/beta subunits in the open (O) state in ATP synthase?

A

Release or binding of ADP and Pi

20
Q

What happens to alpha/beta subunits in the loose (L) state in ATP synthase?

A

Holds ADP and Pi in preparation for catalysis

21
Q

What happens to alpha/beta subunits in the tight (T) state in ATP synthase?

A

allows for ATP formation - catalysis of phosphorylation of ADP to ATP

22
Q

What causes conformational changes in each dimer of alpha and beta subunits in ATP synthase?

A

The turning of the rotor (via the gamma stalk)

23
Q

How many protons produce 1 ATP in ATP synthase?

A

4 protons

24
Q

How many ATP does an NADH entering the ETC lead to, by pumping 10 protons?

A

2.5 ATP

25
Q

How many ATP does an FADH2 entering the ETC lead to, by pumping 6 protons?

A

1.5 ATP