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

Medical Biochemistry > Ch. 13: ETC, Oxidative Phosphorylation, Other O2-Consuming Systems > Flashcards

Flashcards in Ch. 13: ETC, Oxidative Phosphorylation, Other O2-Consuming Systems Deck (34):
1

ETC: What is complex I?

NADH-ubiquinone (coenzyme Q) oxidoreductase

2

ETC: What is complex II?

Succinate-ubiquinone (coenzyme Q) oxidoreductase

3

ETC: What is complex III?

Ubiquinol (hydroquinone) - cytochrome c oxidoreductase

4

ETC: What is complex IV?

Cytochrome c oxidase

5

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

Complexes I, III, IV

4 H+

6

Co-factors in complex I?

FMN
Fe-S

7

Co-factors in complex II?

FAD
Fe-S

8

Co-factors in complex III?

Cytochrome b
Fe-S
Cytochrome c1

9

Co-factors in complex IV?

Cytochrome a (Cu)
Cytochrome a3 (Cu)
O2

10

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

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

11

Inhibitors of complex I?

Rotenone
Piericidin A
Amytal

12

Inhibitors of complex II?

Oxaloacetate
Malonate
Thenoyltrifluoroacetone
Carboxin

13

Inhibitor of complex III?

Antimycin A

14

Inhibitors of complex IV?

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

15

What enzyme complex does NADPH use?

Transdehydrogenase

16

ATP Synthase: Location of F0 complex? Function?

Inner mitochondrial membrane

Contains H+ pore

17

ATP Synthase: Location of F1 complex? Function?

Mitochondrial matrix

Contains catalytic activity (ADP + Pi ➡️ ATP)

18

3 alpha-beta domains of ATP Synthase F1 complex?

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

19

What is the function of uncoupling agents of oxidative phosphorylation?

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

Energy released as heat

20

What are the uncoupling agents of oxidative phosphorylation?

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

21

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

Malate-aspartate shuttle

22

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

Where does FADH2 go?

Coenzyme Q of ETC

23

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

Where does NADH go?

Complex I of ETC

24

Regulation of apoptosis at MT?

➕: Bax, free radicals, ⬆️Ca2+

➖: Bcl2

25

release of cyt c ➡️ steps to apoptosis?

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

26

mtDNA mutations: Nucleotide substitutions

Mildly deleterious base substitutions ➡️ clinical examples?

Familial deafness
Alzheimer's
Parkinson's

27

mtDNA mutations: Nucleotide substitutions

Moderately deleterious base substitutions ➡️ clinical examples?

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

28

mtDNA mutations: Nucleotide substitutions

Severe deleterious base substitutions ➡️ clinical examples?

Leigh's syndrome dystonia

29

mtDNA mutations: rearrangements

Milder rearrangements (duplications) ➡️ clinical examples?

Maternally inherited adult-onset diabetes & deafness

30

mtDNA mutations: rearrangements

Severe rearrangements (deletions) ➡️ clinical examples?

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

31

Other O2 consuming systems:

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

Xanthine

Uric acid

32

Other O2 consuming systems:

D-amino acid ➡️ ? (+ H2O2)

Keto acids

33

Fxn of NADPH producing ROS?

Kills germs

34

Fxn of glutathione?

Reacts with ROS (protects against O2 toxicity)

Oxidized glutathione (GSSG) reacts with NADPH