ETC

Question 1

How to calculate the respiratory control ratio?

Answer 1

slope of a/slope of b on graph

Question 1

What is CoQ

Answer 1

lipid-soluble quinone

Question 2

shape of graph with inhibitor of ETC added, then ADP and DNP

Answer 2

Minimal change in O2 concentration
- ETC cannot function and use O2

Question 3

What’s an uncoupler?

Answer 3

Disconnects ATP synthase from the rest of the ETC, resulting in the rest of the ETC creating O2 and heat at a much higher rate

Question 4

Other name of Complex 1

Answer 4

NADH Dehydrogenase

Question 5

Steps of Complex 1

Answer 5

1) NADH -> NAD transfers 2e- and 2H+ to FMN -> FMNH2
2) e- move to iron of Fe-S then to CoQ
3) energy of e- used to pump 4H+ from matrix to inter membrane space

Question 6

Other name of Complex II

Answer 6

Succinate Dehydrogenase

Question 7

Steps of Complex II

Answer 7

1) electrons move from FADH2 to Fe-S then to CoQ

Question 8

Which complexes pump H+ and what are their non-complex names?

Answer 8

Complexes I, III, IV, V
I: NADH DH
III: QH2-cytochrome c reductase
IV: cytochrome oxidase
V: ATP Synthase

Question 9

Which carriers deliver electrons to CoQ?

Answer 9

Complex I, Complex II, ACD, GPDHm

Question 10

Steps of GDPHm

Answer 10

mitochondrial glycerol-3-P DH
moves electrons from cytosolic NADH -> FAD -> FADH2 -> CoQ

Question 11

Steps of ACD

Answer 11

Acyl-CoA DH
FAD -> FADH2 -> CoQ

Question 12

Inhibitors of Complex I

Answer 12

Rotenone, Amytal

Question 13

Inhibitors of Complex III

Answer 13

Antimycin A

Question 14

Inhibitors of Complex IV

Answer 14

HCN (cyanide), CO, H2S, N3- (azide)

Question 15

Which complex does CoQ transfer its electrons to?

Answer 15

Complex III (QH2-cytochrome c reductase)

Question 16

How may H+ pumped across the proton pumps?

Answer 16

10 total
4 Complex I
4 Complex III
2 Complex IV

Question 17

How do cytochromes change when they carry electrons?

Answer 17

The Fe in their heme ring readily converts from Fe2+ to Fe3+

Question 18

Role of cytochrome c

Answer 18

Picks up electrons from Complex III and brings them to Complex IV

Question 19

Other names Complex IV

Answer 19

cytochrome oxidase

Question 20

Complex IV reaction

Answer 20

reduces O2 to H2O

Question 21

Structure of ATP synthase

Answer 21

Fo spans inner membrane
F1 sticks into the matrix
- contains C ring
- 3 subunits

Question 22

Complex V steps

Answer 22

1) H+ enter Fo via proton channel, driving rotation of the c ring
2) c ring rotation causes conformational change in the 3 subunits on Fi
3) one rotation = 3 ATP

Question 23

Inhibitor of Complex V

Answer 23

Oligomycin

Question 24

What do the three subunits of Fi do?

Answer 24

1) bind ADP + Pi
2) phosphorylate ADP to ATP
3) release ATP

Question 25

What do the glycerol phosphate shuttle and malate aspartate shuttles do?

Answer 25

Oxidizes NADH to NAD for reuse in Glycolysis and transports the electrons to FAD in the ETC
(NADH cannot enter the mitochondria)

Question 26

Glycerol P shuttle mechanism

Answer 26

1) Glycerol-3P DH loads e- and H+ onto DHAP
2) DHAP -> Glycerol-3P -> enters mitochondrial matrix
3) G3P reduces FAD to FADH2
4) G3P becomes DHAP and reenters cytosol

Question 27

Malate-Aspartate shuttle mechanism

Answer 27

1) Malate DH(cyto) transfers H+ and e- to Oxaloacetate, creating Malate
2) Malate DH(mito) reduces NAD to NADH
3) Malate converted to Oxaloacetate
4) Oxalo. combined with Glutamate to create Aspartate and a-ketoglutarate
5) Aspartate antiport with glutamate
6) a-ketoglutarate antiport with malate
7) recombine into oxalo and glutamate
- this is all because oxaloacetate cannot cross the membrane

Question 28

Leber Hereditary Optic Neuropathy

Answer 28

• ETC complex subunit mutations
• results in nerve damage in eye bc no disable mitochondrial function
• maternally inherited

Question 29

Permeability of inner vs outer mitochondrial membranes

Answer 29

Inner: Impermeable to most small ions including H and others
Outer: contains special channels formed by porin protein, permeable to most ions and small molecules

Question 30

Electron flow from different Eo values

Answer 30

Electrons flow from more negative Eo to more positive Eo

Question 31

Oxidation of CoQ

Answer 31

CoQ -> 2H+2e- -> QH2

Question 32

UCP-1 mechanism

Answer 32

Creates pores in IMM, leading to dissolution of H+ gradient

Question 33

DNP mechanism

Answer 33

Shuttles H+ across IMM, dissipating gradient