Dr. Agbas' Mitochondria lecture Flashcards

1
Q

Electron only transfer

A

electrons are transferred between two metal ions

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2
Q

Reducing Equivalent

A

Involves transfer of both proton and electron

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3
Q

Eo =

A

Redox potential, measure of affinity of a redox pair of electrons

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4
Q

High Eo =

A

high affinity of a redox pair of electrons

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5
Q

Low Eo =

A

low affinity of a redox pair of electrons

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6
Q

OxPhos

A

oxidative phosphorylation

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7
Q

Mechanism of OxPhos:

must do the following for key goals

A

1) transfer electrons from NADH and FADH2 to O2
2) To establish a proton gradient across the inner mitochondrial membrane
3) to synthesize ATP

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8
Q

OxPhos is mediated by the

A

respiratory chain integral proteins

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9
Q

Cytochrome C

A

PEripheral receives electrons from complex III and IV

important because if mito becomes leaky, CytoC in the cytosol will signify apoptosis

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10
Q

CoQ (ubiquinone)

A

freely mobile a lipophilic molecule, not a prosthetic group-complex III

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11
Q

what is measuring cytochome C useful for?

A

a biomakrer of membrane well being

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12
Q

Which has a higher redox potential: O2 or NAD+?

A

O2

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13
Q

Gibbs and redox potential are related how

A

G = -nF delta Eo direct

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14
Q

what kind of ratio/relationship does Gibbs free energy have to redox potential?

A

a direct, but negative

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15
Q

the higher the G the

A

more negative the E

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16
Q

Redox pairs vs redox couples

A

pairs are molecule that can exchange electrons and protons (two molecules)
couples are metals than can just exchange electrons

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17
Q

how many proteins are in the respiratory chain?

A

5

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18
Q

Which proteins in the respiratory chain pump protons into the inner membrane space?

A

1, 3, 4

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19
Q

which protein complex pumps proteins back into the mito cytoplasm?

A

5

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20
Q

SOD1:

A

superoxide dismutase 1, found in cytoplasm and has Mn as a prosthetic group

21
Q

SOD2

A

superoxide dismutase 2, found in innermembrane space and has ZnCu as prosthetic groups

22
Q

Free radicals: are they useful?

A

yes, some serve as signaling molecules (For example, in the mitochondrial fusion)

23
Q

Mitochondrial encephalopathy, lactic acidosis, and stroke is connected to defects in complexes….

What are symptoms?

A

Complex I, IV

Muscle weakness and pain
acumulation of lactic acid, vomiting, loss of appetite, seizures, strokelike episodes

onset: infancy to early childhood

24
Q

Kearns-Sayre syndrome: affected ETC complexes

symptoms?

A

All complexes

eye pain, retinopathy, apthalmoplegia, ptosis, ragged red fibers. onset before 20. cardiac conduction,

25
Leber hereditary optic neuropathy
complexes I, III degenerative optic nerve continued loss of central vision early adulthood onset
26
Leigh syndrome
complex I and IV Difficulty swallowing, weak motor skills, vomiting, lesions in basal ganglia and brainstem onset: first year of life
27
pmf
proton motive force
28
what two factors constitute a proton motive force across Complex V?
Vm and pH
29
What drives ATP synthesis across complex V?
membrane potential and pH
30
chemiosmosis =
oxidation of substrates coupled to ADP phosphorylation
31
O2 consumed depends on
ADP added
32
Uncoupling, i.e. disruption of proton gradient name 4 things that occur
TCA cycle is accelerated electron transfer to O2 increases heat generation
33
Synthesis of ATP is accomplished by what complex?
ATP synthase catalyzed by a large membrane bound protein 7.3 kcal/mol to form ATP
34
inhibitors of ATP synthase
oligomycin disrupts proton transport through channe l
35
high ATP/ADP ratio does what
``` inhibits ATP synthase increases H gradient Decreases electron transport/ H pumping slows down TCA cycle decreases glycolysis ```
36
Low ATP/ADP ratio
``` activates ATP synthase decreases H gradient increases electron transport H pumping accelerates TCA cycle increases glycolysis ```
37
Ubiquinone receives electrons from complexes
I and II, and it delivers to II
38
cytochrome C transfers electrons between
III and IV
39
ROS production occurs at what points in the ECT?
between I and II, between III and IV
40
ATP synthase =
ATP synthasome
41
Malate asparatate shuttle
operates in the heart, liver, and kidney helps NADH enter the ETC at Complex 1 malate is oxidized while reducing NAH--> NADH the oxidized malate (oxaloacetate) is reduced by glutamate to alpha-ketogluterate
42
Glycophosphate shuttle
``` operates in skeletal muscle and brain helps FADH(2) donate its electron to the ETC at CoQ ```
43
What inhibitors block Complex I?
Amytal Rotenone Myoxthiazol Piericidin A
44
What inhibitors block complex II?
malonate
45
What inhibitors block complex III?
antimycin
46
what inhibitors block complex IV?
CO Cyanide H2(S)
47
what inhibitors block complex V?
oligomycin
48
where does FADH2 come into the ETC compared to NADH?
NADH - complex 1 | FADH2 - complex 2
49
which complex passes electrons to O2?
IV