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M1 > The Electron Transport Chain, ATP Synthesis, and Mitochondrial Shuttles > Flashcards

The Electron Transport Chain, ATP Synthesis, and Mitochondrial Shuttles Flashcards

1
Q

Complex I:

A

NADH-Q oxidoreductase (it pumps 4 protons from NADH donates to Q) Contains FMN and two kinds of Fe-S clusters (2Fe-2S and 4Fe-4S) in which the iron cycles between +2 and +3 oxidation states

Source of NADH: : TCA cycle, fatty acid b-oxidation, amino acid catabolism

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2
Q

Complex III

A

Q-cytochrome c oxidoreductase (it pumps 4 protons) Receives electrons from complexes I and II via QH2

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3
Q

Complex IV:

A

cytochrome c oxidase

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4
Q

Complex II:

A

succinate-Q reductase (does not pump protons)

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5
Q

A supramolecular complex involving complexes I, II, and III

A

respirasome

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6
Q

Consist of different oxidized states of Coenzyme Q (Q and QH2)

A

Q-pool

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7
Q

The first electron accepter in Complex I

A

FMN (flavin mononucleotide)

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8
Q

Contains TCA cycle flavoprotein succinate dehydrogenase

A

Complex II

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9
Q

Electron pair from FADH2 can generate only ____ ATPs vs _____ for NADH

A

1.5; 2.5

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10
Q

Complex III contains three ______groups

A

heme (bL, bH, c1)

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11
Q

Contains 2 heme a groups (a and a3) and 2 copper centers (CuA CuB)

A

Complex IV Oxygen binds between heme a3 and CuB. It forms a peroxide bridge, and is reduced to the peroxyl derivative and then converted to water using four “substrate” protons

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12
Q

Contains catalytic activity of ATP Synthase

A

F1

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13
Q

Part of F1 that rotates and contains long helical coiled-coil that extends into hexamer and breaks it symmetry

A

gamma subunit connected to the C-ring of the F<span>0</span> subunits

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14
Q

Asymmetric distribution of protons provides a

A

“proton-motive force”

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15
Q

Each proton pump give about _____ of free energy

A

20 kJ/mol

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16
Q

At ATP synthase ATP and ADP are at _______

A

equilibrium

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17
Q

Only _____ subunits of F1 are catalytically active

A

ß

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18
Q

How many ATPs are made per 360 degree rotation of gamma subunit

A

3 ATPs

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19
Q

The Glycerol 3-Phosphate (glycerol-3-phosphate dehydrogenase) shuttle is prevalent in _____

A

muscle

uses FADH2 and is present on the outer (cytoplasmic) surface of inner membrane and donates to electrons to Q

Allows transport against [NADH] gradient

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20
Q

How many moles of ATP made per mole of glucose?

A

30 moles of ATP

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21
Q

Last electron acceptor

A

Oxygen

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22
Q

Blocks flow through complex III.

A

Antimycin A

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23
Q

Block e-flow through complex I

A

Rotenone, amytal

24
Q

Inhibition of ATP synthase

A

Oligomycin, dicyclohexylcarbodiimide

25
Q

genetic mutation in genes of one of the subunits of Complex 1 (ND1, ND4, ND6). Can lead to blindness in middle age

A

Leber’s Hereditary Optic Neuropathy (LHON) Diagnosis can be confirmed by a genetic test. Mutation effects nervous system; cause death of optic nerve

26
Q

How many subunits of Complex 1 are encoded by mitochondrial genes?

27
Q

How many people worldwide are affected by low vision due to LHON

A

About 3500

28
Q

largely permeable membrane with many copies of VDAC

A

outer membrane

29
Q

largely impermeable membrane that has various shuttles or transporters

A

inner membrane

30
Q

Mitochondrion arose during endosymbiotic event involving _____.

A

alpha-proteobacterium

31
Q

Hydrophobic molecule that diffuses rapidly within membrane (long tail contains ten 5-carbon isoprene units)

A

Ubiquinone (Coenzyme Q) Accepts e-‘s from complexes I & II; shuttles back and forth between thes donors and acceptors

32
Q

Sources of NADH

A

TCA cycle, fatty acid Beta-oxidation, amino acid catabolism

33
Q

Electron carriers of the ETC

A

Coenzyme Q and cytochrome c

34
Q

Contains heme group (heme b) that does not receive electrons, but protects against formation of ROS

A

Complex II

35
Q

Contains two types of cytochromes (b and c1) with three hemes (bL, bH, and c1- all protoporphyrin IX type and a Rieske 2Fe-2S center)

A

Q-Cytochrome c oxidoreductase (Complex III, Cytochrome reductase)

36
Q

Contains 13 subunits, but only 3 are critical for e- flow

A

Complex IV

37
Q

ATP Synthase

A

F1F0 ATPase

38
Q

F1 subunits

A

alpha3, beta3, gamma, delta, and sigma

39
Q

Coupling between respiratory chain and ATP Synthesis is ________.

A

“obligatory” —-can’t have one without the other

40
Q

T, O, and L configurations of beta subunits in F1

A

T: tight (binds ATP very tightly O: open (can bind or release ADP or ATP) L: loose (binds ADP, Pi)

41
Q

Chemical uncouplers

A

2,4-dinitrophenol

e- transport can proceed, but ATP synthesis cannot

42
Q

Inhibition of ATP-ADP tranlocase

A

Atractyloside, bongkrekic acid

43
Q

Inhibits cytochrome oxidase

A

CN-, N3- (azide), CO

44
Q

The F0 ____ subunit is stationary (stator) while the “c” subunits for a membrane- spanning ring that can rotate (rotator)

A

a subunit

contains two hydrophobic half-channels that do not span the membrane (each channel interacts with one “c” subunit)

45
Q

________(AA) is in the center of “c” subunit

A

Aspartic acid residue (Asp-61)

46
Q

How many “c” subunits are present in F0?

47
Q

No direct transporters for:

A

NADH, acetyl-CoA and oxaloacetate

48
Q

Phosphate carrier and ATP-ADP translocase and synthase together form large ____

A

ATP synthasome

49
Q

Shuttle mainly present in heart and liver

A

malate-aspartate shuttle

Another way of getting electrons from cytosolic NADH into mitochondrial matrix

Involves transport of malate/alpha-ketoglutarate and aspartate/glutamate across membrane

50
Q

Other shuttles (carriers):

  • Dicarboxylate
  • Tricarboxylate
  • Pyruvate
A
  • phosphate/malate
  • malate/citrate
  • pyruvate/OH-
51
Q

Some organisms can uncouple e- transport from ATP synthesis to generate ____

A

heat

ex. Brown adipose tissue (contains lots of uncoupling protein, UCP-1 (thermogenin))

“nonshivering theromogenesis

52
Q

Electrons passed down chain in order of

A

increasing reduction potential – highly exergonic process

53
Q

Energy released from ETC ultimately fuels

A

synthesis of ATP

54
Q

Three large complexes that pump electrons

A
  • Complex I: NADH-Q oxidoreductase
  • Complex III: Q-cytochrome c oxidoreductase
  • Complex IV: cytochrome c oxidase
55
Q

Hydrophobic molecule that diffuses rapidly within membrane (long tail contains ten 5-carbon isoprene units)

A

Ubiquinone

M1 (48 decks)

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