4. Etc And Oxidative Phosphorylation

Front 1

What are the components of the ETC?

Back 1

-FMN
-Fe-S centers
-Coenzyme Q
-Cytochromes B, c1, c, and aa3

Front 2

What do the electron carriers that make up the ETC DO?

Back 2

Pass electrons from NADH and FADH2 to Oxygen

Front 3

What is generated as a result of the energy produced by electrons passing thru the ETC?

Back 3

ATP

Front 4

How exactly is ATP production linked to electron flow thru the ETC?

Back 4

Energy is produced which drives protons from the mito matrix across the inner membrane to the cytosolic side.

Front 5

What does the increased H+ conc in the mitochondrial intermembrane space set up?

Back 5

A proton motive force - membrane potential

Front 6

What does the PMF drive?

Back 6

Flow of protons from the intermembrane space THROUGH ATP pumps, back into the mito matrix

Front 7

What happens as protons move thru the ATP synthase complex?

Back 7

ATP gets made from ADP and Pi

Front 8

How does the newly made ATP get from the mitochondrial matrix back out to the cytosol?

Back 8

By ATP/ADP antiport

Front 9

How much ATP gets generated by the oxidation of:
-1 NADH
-1 FADH2

Back 9

NADH = 3ATP
FADH2 = 2 ATP

Front 10

How are the ETC and ATP production related?

Back 10

-Occur simultaneously
-Tightly coupled

Front 11

What is the overall process of ETC oxidation and ATP production called?

Back 11

Oxidative phosphorylation

Front 12

What is ESSENTIAL to the ability for NADH and FADH2 to be oxidized?

Back 12

ADP must be available!

Front 13

What are NADH and FADH2 generated from?

Back 13

Oxidative reactions like
-glycolysis
-B-oxidation of FA's
-TCA cycle

Front 14

Where are the components of the ETC located?

Back 14

On the inner mitochondrial membrane

Front 15

What is the major difference between location of NADH and FAHD2?

Back 15

NADH diffuses freely from the mitochondrial matrix to the inner membrane; FADH2 is bound to it by Succinate dehydrogenase

Front 16

What are cristae?

Back 16

Infoldings of the inner mitochondrial membrane

Front 17

What are the structures that pass electrons along the ETC?

Back 17

Large protein complexes

Front 18

What happens as energy is given off at each protein complex of the ETC?

Back 18

Protons are pumped from the matrix to the intermembrane space

Front 19

What is generated by this pumping of protons?

Back 19

PMF - an electrochemical potential

Front 20

What are the 2 constituents of the PMF?

Back 20

-Membrane potential
-pH gradient (concentration)

Front 21

How is it that a pH gradient can be established across the inner mitochondrial membrane?

Back 21

It is impermeable to protons

Front 22

What is the only way that protons can get from the intermembrane space back into the mitochondrial matrix?

Back 22

Via ATP synthase complex

Front 23

What proteins on ATP synthase form the channel thru which H+ can flow?

Back 23

Fo

Front 24

What is the stalk that is attached to the ATP-synthesizing head that projects into the matrix?

Back 24

F1

Front 25

Does ALL of the energy produced from e- flow thru the protein complexes get used in proton pumping?

Back 25

No, some gets lost as heat

Front 26

Why do electrons flow from NADH toward O2 in the ETC?

Back 26

It has a large negative free energy change

Front 27

What are the THREE major stages of electron transport in the ETC?

Back 27

1. Transfer of e- from NADH to coenzyme Q
2. Transfer of e- from CoQ to Cytochrome c
3. Transfer of e- from cyto c to oxygen

Front 28

How do electrons flow from NADH to Coenzyme Q?

Back 28

1. NADH to FMN
2. FMN to Fe-S complexes
3. Fe-S complexes to Ubiquinone

Front 29

What TCA cycle reactions produce NADH?

Back 29

3/4/8
-Isocitrate dehydrogenase
-a-KG dehydrogenase
-Malate dehydrogenase

Front 30

What are 2 other processes that produce NADH?

Back 30

-PDH conversion of Pyruvate to AcCoA
-B-oxidation of fatty acids

Front 31

How many ATP can be generated by the transfer of 1 NADH to complex 1 and CoQ?

Back 31

1ATP

Front 32

Where do electrons from Coenzyme Q flow?

Back 32

To cytochrome C

Front 33

What do electrons from CoQ have to flow through first to get to Cyto C?

Back 33

-Fe-S centers
-Cyto b
-Cyto c1

Front 34

What is the overall protein complex 2 that is involved in all these electron transfers?

Back 34

Cytochrome reductase

Front 35

How are cytochromes
-similar
-different

Back 35

Similar: all have heme prosthetic groups
Different: all have different apoproteins

Front 36

How many electrons is each cytochrome capable of carrying at a time?

Back 36

Only 1

Front 37

So how many molecules in each cytochrome complex has to be reduced for every molecule of NADH that is oxidized?

Back 37

2

Front 38

How many ATP get generated for every CoQH2 that transfers 2 electrons to cyto c?

Back 38

1 ATP

Front 39

At what level of the ETC do electrons from FADH2 enter?

Back 39

At the CoQ level

Front 40

What is the final complex in the ETC to which electrons are transferred from cytochrome c?

Back 40

Cytochrome aa3 complex

Front 41

What does Cyto aa3 do with its electrons?

Back 41

Transfers them to Oxygen

Front 42

What happens to oxygen as it receives electrons from cyto aa3?

Back 42

It gets reduced to water

Front 43

What enzyme catalyzes the transfer of electrons at cyto aa3?

Back 43

Cytochrome oxidase

Front 44

What elements are found in Cyto a and a3?

Back 44

-Heme iron
-Other proteins + copper

Front 45

How many e- are needed for the reduction of one O2 atom?

Back 45

2

Front 46

For every NADH that is oxidized by the ETC,
-How much O2 is reduced to H2O?
-How much ATP is made?

Back 46

1/2 O2
3 ATP

Front 47

For every FADH2 that is oxidized by the ETC, how much ATP is made?

Back 47

2 ATP

Front 48

How does ATP made in the matrix get transferred to the cytosol?

Back 48

By ATP/ADP antiport - a protein in the inner mito membrane.

Front 49

What are 3 inhibitors of the ETC?

Back 49

-Rotenone
-Antimycins
-Chemicals CO and CN

Front 50

What will happen to electron carrier proteins in the ETC if the chain is blocked?

Back 50

-Carriers before the block will accumulate in REDUCED form
-Carriers after the block will accumulate in OXIDIZED state

Front 51

What are 3 general results of a block in the ETC?

Back 51

-O2 won't be consumed
-ATP won't be generated
-TCA cycle will slow down

Front 52

What is Rotenone? What does it block?

Back 52

A fish poison - blocks NADH dehydrogenase (complex 1)

Front 53

Does Rotenone completely stop ATP production?

Back 53

No - it doesn't block FADH2 input to the ETC

Front 54

What are Antimycins? What do they block?

Back 54

Antibiotics - block e- transfer thru cytochromes b-c1

Front 55

What are Cyanide and Carbon monoxide commonly used for?

Back 55

Suicide

Front 56

What complex is inhibited by CN and CO?

Back 56

Cytochrome oxidase (complex III)

Front 57

What are 2 ways that ATP synthesis can be inhibited?

Back 57

-Direct inhibition of ATP synthase
-Not enough supply of ADP

Front 58

What 4 changes will result from inhibition of ATP synthesis?

Back 58

-ATP synthesis will slow down
-O2 won't be consumed
-ETC components will accumulate in REDUCED states
-TCA cycle will slow down

Front 59

What do uncoupling agents do?

Back 59

Diffuse the PMF by allowing proteins to re-enter the mito matrix w/OUT flowing thru ATP synthase

Front 60

So what is uncoupled by uncoupling agents?

Back 60

ETC is uncoupled from ATP production

Front 61

How do Uncoupling agents affect
-O2 consumption
-Electron transport
-TCA cycle
-CO2 production
-ATP production

Back 61

O2 consumption INCREASES
Electron Transport INCREASES
TCA cycle INCREASES
CO2 production INCREASES
ATP production DECREASES

Front 62

What happens to the energy generated by the ETC if it is uncoupled from ATP production?

Back 62

It is lost as heat