ETC Flashcards

1
Q

What are the two major roles of the electron transport chain/oxidative phosphorylation?

A

re-oxidize cofactors from TCA cycle, produce ATP

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2
Q

Through the electron transport chain, ________ from NADH and FADH2 are eventually transferred to ________, forming water.

A

electrons and O2

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3
Q

Where is the electron transport chain located in the mitochondria?

A

inner membrane

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4
Q

What makes up the electron transport chain?

A

series of electron-transfer carriers bound to proteins embedded in inner mitochondrial membrane

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5
Q

The principle of the electron transport chain is movement from most negative to most positive _______ potentials.

A

redox

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6
Q

How many complexes are there is the electron transport chain?

A

4

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7
Q

At what complex of the electron transport chain do NADH/H+ molecules begin?

A

Complex I

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8
Q

At what complex of the electron transport chain do FADH2 molecules being?

A

Complex II

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9
Q

Complex I of the electron transport chain is known by which two enzyme names?

A

NADH dehydrogenase (NADH oxidized), NADH-CoQ reductase (NADH oxidized, CoQ reduced)

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10
Q

Complex II of the electron transport chain is known by which two enzyme names?

A

succinate dehydrogenase (succinate oxidized), succinate-CoQ reductase (succinate oxidized, CoQ reduced)

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11
Q

Co-enzyme Q of the electron transport chain is known by which two names?

A

CoQ, ubiquinone

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12
Q

What is the role of Cytochrome C in the electron transport chain?

A

shuttle between Complex III and Complex IV

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13
Q

Complex IV of the electron transport chain is known by which three names?

A

cytochrome oxidase (cytochrome oxidized), cytochrome a-a3, cytochrome c oxidase

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14
Q

Cytochromes only contain ______-iron complexes.

A

heme

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15
Q

What is responsible for the modification of the Fe2+/Fe3+ redox potential?

A

different environment

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16
Q

What is the only electron transport chain carrier that is not a protein-bound co-factor?

A

coenzyme Q

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17
Q

Is Coenzyme Q lipophillic? Why or why not?

A

yes, because it has a long isoprene side chain

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18
Q

Heme-iron complexes have what shape?

A

octahedral

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19
Q

What is the only complex of the electron transport chain that has both heme-iron and iron-sulfur complexes?

A

Complex III

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20
Q

Which complex of the electron transport chain contains the binding site for oxygen?

A

complex IV

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21
Q

What is the only complex of the electron transport chain that has copper complexes?

A

complex IV

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22
Q

Oxidation of reduced cytochrome c by cytochrome c oxidase (complex IV) is coupled to __________.

A

proton transport

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23
Q

In the proton transport needed for the oxidation of reduced cytochrome c by cytochrome c oxidase (complex IV), are protons being pumped in or out of the liposome, and how many are being pumped?

A

2 protons pumped out (pH in liposome increases, pH outside decreases)

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24
Q

Besides protons being pumped out of the cytochrome c oxidase liposome (in oxidizing cytochrome c), what else contributes to decreased proton concentration inside the liposome?

A

formation of water

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25
Q

The reduction of oxygen to water in cytochrome c oxidase (complex IV) is a result of the interaction between what two kinds of complexes?

A

Fe, Cu

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26
Q

In complex I and III, how many protons does 1 NADH cause to be transported out (into intermembrane space of mitochondria)?

A

4

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27
Q

In complex IV, how many protons does 1 NADH cause to be transported out (into intermembrane space of mitochondria)?

A

2

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28
Q

If something is said to have a higher redox potential, is its numerical value more positive or more negative?

A

more negative

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29
Q

In oxidative phosphorylation, the reduction of oxygen to water and the oxidation of the cofactors is coupled to what?

A

phosphorylation of ADP to ATP

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30
Q

The energy for ATP synthesis arises from a proton gradient across the _______ mitochondrial membrane.

A

inner

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31
Q

Is the matrix side of the mitochondria positive or negative relative to the intermembrane side?

A

negative (helps drive proton gradient)

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32
Q

Which F subunit of ATP synthase is responsible for making ATP?

A

F1

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33
Q

What are the two F subunits of ATP synthase?

A

F0, F1

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34
Q

Of the subunits of the F1 subunit of ATP synthase, which is responsible for making ATP?

A

beta subunit

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35
Q

Which subunit of the F1 subunit of ATP synthase rotates to change the shape of the beta subunits?

A

gamma subunit

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36
Q

What are the three different conformations F1 beta sites undergo in ATP synthesis?

A

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

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37
Q

What is going on in the F1 beta site when it’s in the open (O) conformation?

A

ATP leaves, ADP + phosphate come in

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38
Q

What is going on in the F1 beta site when it’s in the loose (L) conformation?

A

ADP + phosphate bind

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39
Q

What is going on in the F1 beta site when it’s in the tight (T) conformation?

A

ADP + phosphate reacts to form ATP

40
Q

One of the reasons for anion-transporters in the inner mitochondrial membrane is for continuous import of ___________ and _______.

A

ADP, phosphate

41
Q

Which complexes in the electron transport chain have iron-sulfur complexes?

A

I, II, III

42
Q

What is dinitrophenol and what does it do?

A

lipophillic compound (pKa ~7) that transports protons back and forth across the mitochondrial membrane (between matrix and intermembrane space) based on the pH (protonated in acidic conditions in intermembrane space, gives up protons once in matrix), preventing ATPsynthase from working (no ATP produced, toxic)

43
Q

DNP =

A

dinitrophenol

44
Q

Is the dinitrophenol uncoupling process good for the cell?

A

no

45
Q

What is thermogenin?

A

transmembrane protein in inner mitochondrial membrane of brown adipose cell

46
Q

What does thermogenin do?

A

uncouples electron transport chain from ATPsynthase by pumping protons from intermembrane space into the matrix (energy normally used for ATP synthesis released as heat instead)

47
Q

What do OXPHOS diseases affect?

A

oxidative phosphorylation process

48
Q

What often causes OXPHOS diseases?

A

mutations of mitochondrial DNA (so electron transport chain/oxidative phosphorylation not made right)

49
Q

What are two places where creatine phosphate commonly occurs?

A

brain, heart

50
Q

What is the role of creatine phosphate?

A

allows for fast ATP generation (can undergo substrate level phosphorylation if energy suddenly needed)

51
Q

all fuels are broken down to _____

A

acetyl-CoA

52
Q

acetyl-CoA is the source of the _____

A

TCA cycle

53
Q

the _____ portion of acetyl-CoA is _____ , and ______ are generated

A

the acetyl portion of acetyl-CoA is oxidized to CO2, and reduced cofactors are generated

54
Q

the electron transport chain and oxidative phosphorylation finishes the energy provision process by ______ and ______

A

re-oxidizing the cofactors and by ATP production through ATP synthase

55
Q

electron transport: most of the energy released during oxidation of glucose to CO2 is retained in _____ and _____

A

NADH and FADH2

56
Q

electron transport: during respiration, electrons are _____ from ______ and eventually are transferred to ____ through and electron transport chain

A

electrons are released from NADH and FADH2 and eventually are transferred to O2 (forming H2O) through an ETC

57
Q

electron transport: the step-by-step transfer of electrons via the ETC allows the large amount of free energy produced by ______ to be released in ______

A

free energy produced by the transfer of electrons to O2 to be released in small increments

58
Q

oxidative phosphorylation: several ETC components convert small increments of free energy into a ______ and a ______ across the _____ membrane

A

proton gradient and a voltage gradient across the inner mitochondrial membrane

59
Q

oxidative phosphorylation: the movement of protons down their electrochemical gradient back into the mitochondrial matrix drives ______

A

the synthesis of ATP from ADP and Pi

60
Q

oxidative phosphorylation occurs in _____

A

the mitochondria

61
Q

the ETC sits in the _____

A

inner mitochondrial membrane

62
Q

ATP is released into _____

A

the mitochondrial matrix

63
Q

the ETC consists of a series of _____, which are bound to _____ embedded in the inner mitochondrial membrane

A

series of electron transfer carriers, which are bound to proteins

64
Q

the ETC is a stepwise process, in which electrons are carried from _____ to _____

A

from reduced co-factors (NADH/H+ and FADH2) to O2

65
Q

principle redox components of the ETC:

A

H2/2H+

66
Q

redox potential of H2/2H+

A

-0.42 V

67
Q

redox potential of Cu+/Cu2+

A

+0.15 V

68
Q

redox potential of hydroquinone/quinone

A

+0.28 V

69
Q

redox potential of Fe2+/Fe3+

A

+0.75 V

70
Q

redox potential of H2O/O2

A

+0.82 V

71
Q

components (complexes) of the ETC

A

complex I (NADH dehydrogenase; NADH-CoQ-reductase)

72
Q

complex II (succinate dehydrogenase) is part of _____

A

the TCA cycle

73
Q

the complexes contain many sub-components such as…

A

Fe-S complexes, other iron complexes (cytochromes), and Cu complexes

74
Q

the redox centers are _____

A

co-enzymes (co-factors and prosthetic groups, such as FMN, Fe-S, and heme)

75
Q

why are only 2 H+ channeled out at complex IV?

A

the other 2 are used to generate H2O

76
Q

electrons flow through how many complexes?

A

3

77
Q

_____ is responsible for the modification of the Fe2+/Fe3+ redox potential

A

the different biochemical environment of Fe

78
Q

Fe-S complexes are _____ in protein structure

A

covalently anchored

79
Q

CoQ10: the 10 refers to…

A

the number of isoprene units in the side chain

80
Q

CoQ is an essential part of our body’s _____

A

energy producing process

81
Q

CoQ is the only electron transfer carrier that is not a ______

A

protein-bound co-factor

82
Q

because of CoQ’s _____ residues, especially the _____ side chain, CoQ is very _____ and ______

A

CoQ’s lipophilic residues, especially the isoprene side chain, CoQ is very lipophilic and dissolves well in the membrane

83
Q

different forms of CoQ

A

ubiquinone (oxidized form)

84
Q

the _____ isomer of CoQ10 is found naturally in the human body

A

trans isomer

85
Q

good forms of supplemental CoQ10 are produced by _____

A

yeast

86
Q

two forms of natural supplemental CoQ10 are offered:

A

ubiquinone and ubiquinol

87
Q

is ubiquinol better/worse than ubiquinone?

A

no, the body converts ubiquinone to ubiquinol quite efficiently

88
Q

CoQ10 is found throughout the body, but is most highly concentrated in ______ because of _____

A

most highly concentrated in heart muscles because of the high energy demands there

89
Q

CoQ10 transports protons through the _____ into the _____ of the ______

A

through the inner membrane into the intermembrane space of the mitochondria

90
Q

CoQ10 deficiency

A

affects many people >50yr

91
Q

the term ubiquinone comes from ubiquitous since you can find it throughout your body and in ______

A

all living organisms, including obligatory anaerobic bacteria

92
Q

anaerobic bacteria ETC uses _____ to absorb electrons at the end

A

sulfur or carbon

93
Q

anaerobic bacteria that use sulfur as the final electron acceptor are responsible for…

A

the smell in sewers or mud at the bottom of ponds

94
Q

anaerobic bacteria that use carbon as the final electron acceptor are _____ and occur in ______

A

methanogenic bacteria and occur in coal mines (explosions, coal fires, etc.)

95
Q

heme prosthetic groups of ETC cytochromes in mitochondria are _____ in shape

A

octahedral

96
Q

_____ contains the binding site for oxygen

A

cytochrome c oxidase (complex IV)

97
Q

cytochrome c oxidase is the only component of the ETC with ______

A

Cu complexes