Ch. 13: ETC, Oxidative Phosphorylation, Other O2-Consuming Systems

Question 1

ETC: What is complex I?

Answer 1

NADH-ubiquinone (coenzyme Q) oxidoreductase

Question 2

ETC: What is complex II?

Answer 2

Succinate-ubiquinone (coenzyme Q) oxidoreductase

Question 3

ETC: What is complex III?

Answer 3

Ubiquinol (hydroquinone) - cytochrome c oxidoreductase

Question 4

ETC: What is complex IV?

Answer 4

Cytochrome c oxidase

Question 5

Which ETC complexes move H+ from mitochondrial matrix ➡️ intermembrane space? How many H+ are moved by each?

Answer 5

Complexes I, III, IV

4 H+

Question 6

Co-factors in complex I?

Answer 6

FMN

Fe-S

Question 7

Co-factors in complex II?

Answer 7

FAD

Fe-S

Question 8

Co-factors in complex III?

Answer 8

Cytochrome b
Fe-S
Cytochrome c1

Question 9

Co-factors in complex IV?

Answer 9

Cytochrome a (Cu)
Cytochrome a3 (Cu)
O2

Question 10

Role of Fe-S (iron-sulfur protein complex Fe4S4)?

Answer 10

Center of accepting & donating e- (complexes I, II, III)

Question 11

Inhibitors of complex I?

Answer 11

Rotenone
Piericidin A
Amytal

Question 12

Inhibitors of complex II?

Answer 12

Oxaloacetate
Malonate
Thenoyltrifluoroacetone
Carboxin

Question 13

Inhibitor of complex III?

Answer 13

Antimycin A

Question 14

Inhibitors of complex IV?

Answer 14

Cyanide (blocks ferric state iron of cyt a & a3)
CO
Sodium azide

Question 15

What enzyme complex does NADPH use?

Answer 15

Transdehydrogenase

Question 16

ATP Synthase: Location of F0 complex? Function?

Answer 16

Inner mitochondrial membrane

Contains H+ pore

Question 17

ATP Synthase: Location of F1 complex? Function?

Answer 17

Mitochondrial matrix

Contains catalytic activity (ADP + Pi ➡️ ATP)

Question 18

3 alpha-beta domains of ATP Synthase F1 complex?

Answer 18

Open conformation: ⬇️ affinity for [S] & [P], inactive
Loose conformation: binds loosely, catalytically inactive
Tight conformation: binds tightly, catalytically active

Question 19

What is the function of uncoupling agents of oxidative phosphorylation?

Answer 19

Create channel ➡️ H+ reenter mitochondrial matrix w/out capturing energy as ATP

Energy released as heat

Question 20

What are the uncoupling agents of oxidative phosphorylation?

Answer 20

Oligomycin
Brown adipocytes (UCP1, thermogenin)
2,4-dinitrophenol
⬆️ aspirin
Ionophores (valinomycin, nigericin, gramicidin A)

Question 21

Of the 2 shuttles moving NADH ➡️ mitochondria, which is principle?

Answer 21

Malate-aspartate shuttle

Question 22

G3P shuttle: NADH (cytosol) ➡️ FADH2 (MT)

Where does FADH2 go?

Answer 22

Coenzyme Q of ETC

Question 23

Malate Aspartate shuttle: NADH (cytosol) ➡️ NADH (MT)

Where does NADH go?

Answer 23

Complex I of ETC

Question 24

Regulation of apoptosis at MT?

Answer 24

➕: Bax, free radicals, ⬆️Ca2+

➖: Bcl2

Question 25

release of cyt c ➡️ steps to apoptosis?

Answer 25

Cyt c + Apaf-1 + Procaspase 9 ➡️ Apoptosome Apoptosome + ATP ➡️ activate Caspase 9 Caspase 9 ➡️ activates caspases ➡️ cell death

Question 26

mtDNA mutations: Nucleotide substitutions Mildly deleterious base substitutions ➡️ clinical examples?

Answer 26

Familial deafness Alzheimer's Parkinson's

Question 27

mtDNA mutations: Nucleotide substitutions Moderately deleterious base substitutions ➡️ clinical examples?

Answer 27

Leber's hereditary optic neuropathy (LHON) | Myoclonic epilepsy & ragged-red fiber disease (MERRF)

Question 28

mtDNA mutations: Nucleotide substitutions Severe deleterious base substitutions ➡️ clinical examples?

Answer 28

Leigh's syndrome dystonia

Question 29

mtDNA mutations: rearrangements Milder rearrangements (duplications) ➡️ clinical examples?

Answer 29

Maternally inherited adult-onset diabetes & deafness

Question 30

mtDNA mutations: rearrangements Severe rearrangements (deletions) ➡️ clinical examples?

Answer 30

chronic progressive external ophthalmoplegia (CPEO) Kearns-Sayre syndrome (KSS) lethal childhood disorders Pearson marrow/pancreas syndrome

Question 31

Other O2 consuming systems: Hypoxanthine ➡️ 2 products? (separate rxns w/water & O2 ➡️ also makes ROS)

Answer 31

Xanthine Uric acid

Question 32

Other O2 consuming systems: D-amino acid ➡️ ? (+ H2O2)

Answer 32

Keto acids

Question 33

Fxn of NADPH producing ROS?

Answer 33

Kills germs

Question 34

Fxn of glutathione?

Answer 34

Reacts with ROS (protects against O2 toxicity) Oxidized glutathione (GSSG) reacts with NADPH