Dr. Agbas' Mitochondria lecture

Question 1

Electron only transfer

Answer 1

electrons are transferred between two metal ions

Question 2

Reducing Equivalent

Answer 2

Involves transfer of both proton and electron

Question 3

Eo =

Answer 3

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

Question 4

High Eo =

Answer 4

high affinity of a redox pair of electrons

Question 5

Low Eo =

Answer 5

low affinity of a redox pair of electrons

Question 6

OxPhos

Answer 6

oxidative phosphorylation

Question 7

Mechanism of OxPhos:

must do the following for key goals

Answer 7

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

Question 8

OxPhos is mediated by the

Answer 8

respiratory chain integral proteins

Question 9

Cytochrome C

Answer 9

PEripheral receives electrons from complex III and IV

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

Question 10

CoQ (ubiquinone)

Answer 10

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

Question 11

what is measuring cytochome C useful for?

Answer 11

a biomakrer of membrane well being

Question 12

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

Answer 12

O2

Question 13

Gibbs and redox potential are related how

Answer 13

G = -nF delta Eo direct

Question 14

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

Answer 14

a direct, but negative

Question 15

the higher the G the

Answer 15

more negative the E

Question 16

Redox pairs vs redox couples

Answer 16

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

Question 17

how many proteins are in the respiratory chain?

Answer 17

5

Question 18

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

Answer 18

1, 3, 4

Question 19

which protein complex pumps proteins back into the mito cytoplasm?

Answer 19

5

Question 20

SOD1:

Answer 20

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

Question 21

SOD2

Answer 21

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

Question 22

Free radicals: are they useful?

Answer 22

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

Question 23

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

What are symptoms?

Answer 23

Complex I, IV

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

onset: infancy to early childhood

Question 24

Kearns-Sayre syndrome: affected ETC complexes

symptoms?

Answer 24

All complexes

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

Question 25

Leber hereditary optic neuropathy

Answer 25

complexes I, III

degenerative optic nerve
continued loss of central vision
early adulthood onset

Question 26

Leigh syndrome

Answer 26

complex I and IV

Difficulty swallowing, weak motor skills, vomiting, lesions in basal ganglia and brainstem
onset: first year of life

Question 27

pmf

Answer 27

proton motive force

Question 28

what two factors constitute a proton motive force across Complex V?

Answer 28

Vm and pH

Question 29

What drives ATP synthesis across complex V?

Answer 29

membrane potential and pH

Question 30

chemiosmosis =

Answer 30

oxidation of substrates coupled to ADP phosphorylation

Question 31

O2 consumed depends on

Answer 31

ADP added

Question 32

Uncoupling, i.e. disruption of proton gradient

name 4 things that occur

Answer 32

TCA cycle is accelerated
electron transfer to O2 increases
heat generation

Question 33

Synthesis of ATP is accomplished by what complex?

Answer 33

ATP synthase

catalyzed by a large membrane bound protein

7.3 kcal/mol to form ATP

Question 34

inhibitors of ATP synthase

Answer 34

oligomycin disrupts proton transport through channe l

Question 35

high ATP/ADP ratio does what

Answer 35

inhibits ATP synthase
increases H gradient 
Decreases electron transport/ H pumping 
slows down TCA cycle 
decreases glycolysis

Question 36

Low ATP/ADP ratio

Answer 36

activates ATP synthase 
decreases H gradient 
increases electron transport H pumping 
accelerates TCA cycle 
increases glycolysis

Question 37

Ubiquinone receives electrons from complexes

Answer 37

I and II, and it delivers to II

Question 38

cytochrome C transfers electrons between

Answer 38

III and IV

Question 39

ROS production occurs at what points in the ECT?

Answer 39

between I and II, between III and IV

Question 40

ATP synthase =

Answer 40

ATP synthasome

Question 41

Malate asparatate shuttle

Answer 41

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

Question 42

Glycophosphate shuttle

Answer 42

operates in skeletal muscle and brain 
helps FADH(2) donate its electron to the ETC at CoQ

Question 43

What inhibitors block Complex I?

Answer 43

Amytal
Rotenone
Myoxthiazol
Piericidin A

Question 44

What inhibitors block complex II?

Answer 44

malonate

Question 45

What inhibitors block complex III?

Answer 45

antimycin

Question 46

what inhibitors block complex IV?

Answer 46

CO
Cyanide
H2(S)

Question 47

what inhibitors block complex V?

Answer 47

oligomycin

Question 48

where does FADH2 come into the ETC compared to NADH?

Answer 48

NADH - complex 1

FADH2 - complex 2

Question 49

which complex passes electrons to O2?

Answer 49

IV