ETC Flashcards

1
Q

complex 1

A

NADH dehydrogenase

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2
Q

what molecule brings e- to the complex in complex I

A

NADH

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3
Q

what molecule in the complex accepts the electrons in NADH DH

A

FMN

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4
Q

which two complexes move e- through NADH DH

A

2Fe-2S & 4Fe-4S

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5
Q

how many e- are moved at a time through NADH DH

A

2e-

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6
Q

what is the final e- acceptor for complex I

A

Q

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7
Q

how many H+ are transported across the membrane via NADH DH

A

4

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8
Q

what inhibits complex I

A

rotenone

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9
Q

complex II

A

succinate DH

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10
Q

what molecule accepts e- in succinate DH

A

FAD

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11
Q

what accepts e- after transport through succinate DH

A

Q

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12
Q

what inhibits the formation of Q

A

statin

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13
Q

how many H+ are transported across the membrane via succinate DH

A

0

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14
Q

complex III

A

cytochrome bc (cytc reductase)

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15
Q

what is the e- source for cytochrome bc

A

QH2

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16
Q

how many e- flow through cytochrome bc at a time

A

1 e- per pathway

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17
Q

where does the first e- from QH2 travel in cytochrome bc

A

Rieske Fe/S complex, CytC1, CytC shuttle

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18
Q

where does the second e- from QH2 travel in cytochrome bc

A

CytbL, CytbH, Q (or seiquinone), QH2 diffuses into inner membrane (Q recycling)

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19
Q

what inhibits cytochrome bc

A

antimycin

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20
Q

where does QH2 bind on cytochrom bc

A

at the Q0 binding site (specific for QH2)

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21
Q

where does Q bind in cytochrome bc

A

Q1 binding site (specific for Q and semiquinone, releases QH2)

22
Q

how many H+ does cytochrom bc move through the membrane

A

4 (2 per QH2)

23
Q

how many QH2 molecules deliver e- to cytochrome bc

A

2

24
Q

complex IV

A

CytC oxidase

25
Q

what delivers e- to complex IV

A

CytC shuttle

26
Q

how many e- are moved at a time through CytC oxidase

A

1

27
Q

how do e- move through CytC oxidase

A

CytC shuttle, CuA/CuA, Cyta, Cytca3-CuB, O2

28
Q

what is the final e- acceptor of the ETC

A

O2

29
Q

what inhibits CytC oxidase

A

CN-, azide, CO

30
Q

how many H+ are moved through the membrane via CytC oxidase

A

2

31
Q

what is the goal of ETC complexes I-IV

A

to create a proton gradient that allows for ATP synthesis via ATP synthase

32
Q

how many total H+ are moved into the intermembrane space via complexes I-IV

A

10

33
Q

what inhibits ATP synthase

A

oligomycin

34
Q

what is oxidative phosphorylation

A

process by which NADH and QH2 are oxidized to form ATP

35
Q

what is the chemiosmotic theory

A

the proton gradient is the driving force behind ATP synthesis

36
Q

what is an uncoupler/does an uncoupler do

A
  • stimulates the oxidation of substrates in the absence of ADP
  • lipid soluble weak acid
  • deplete the proton gradient by transporting protons across the membrane
  • ex: 2,4 dinitrophenol
37
Q

what is the protonmotive force (delta p)

A

the energy of the proton concentration gradient

38
Q

what is the equation for protonmotive force

A

chemical contribution: deltaG = -2.302nRT (delta pH)
electrical contribution: deltaG = nFpsi
total force: deltaG = nFdelta p

39
Q

what is a standard reduction potential

A

the amount of energy require to convert a molecule in its oxidized state to its reduced state

40
Q

how to calculate the standard reduction potential of a reaction

A
  1. write out half rxns for all reductions and oxidations
  2. flip the sign for all oxidative rxns
  3. add all reduction potentials
41
Q

which cofactor donates 2e- at a time

A

NADH

42
Q

which coenzymes donate 1e- at a time

A

flavins (FMN and FAD)

43
Q

what forms the rotor of ATP synthase

A

c - ε - γ

44
Q

which domain has the ADP + Pi binding site and converts ADP to ATP

A

beta subunits

45
Q

how are ATP and ADP moved in/out of the mitochondria

A

ATP is moved into the cytosol and ADP is moved into the matrix via an antiporter

46
Q

how are H+ and Pi- moved into the matrix

A

a symporter

47
Q

what is the P:O ratio

A

P:O ratio = molecules of ADP phosphorylated/ atoms of oxygen reduced
ex: NADH
10H+ translocated/ 4H+ required for ATP synthesis (2Ox2e-) = 2.5 ATP/O

48
Q

how many H+ are transported for each ATP synthesized by ATP synthase

A

4 (3 required by ATP synthase for every 1ATP made and 1 for transport of Pi, ADP, and ATP)

49
Q

what are the two ways NADH is moved into the mitochondrial matrix

A

1) glycerol phosphate shuttle (common in insect flight muscles)
2) malate-aspartate shuttle (predominant in liver/mammalian tissues)

50
Q

how does the glycerol phosphate shuttle work

A

NADH (cytosol) -> glycerol 3 P -> FADH2 (in G3PDH complex) -> Q (inner mitochondrial membrane)

51
Q

how does the malate-aspartate shuttle work

A

oxaloacetate -NADH-> malate (diffuses into matrix) -> malate (generates NADH) -> oxaloacetate -> aspartate (diffuses out of matrix) -> oxaloacetate (via transaminase)