2.2.2. Phosphorylation Flashcards Preview

MSK Week 2 > 2.2.2. Phosphorylation > Flashcards

Flashcards in 2.2.2. Phosphorylation Deck (24)
1

Oxidative Phosphorylation Poisons: Electron Transport Inhibitors (there are four)

1) Rotenone
2) Cyanide
3) Antimycin A
4) Carbon Monoxide

2

Oxidative Phosphorylation Poisons: ATP Synthase Inhibitors (there is one)

1) Oligomycin

Explanation: directly inhibits mitochondrial ATP synthase causing an increased proton gradient

3

Oxidative Phosphorylation Posions: Uncoupling Agents

1) 2,4-dinitrophenol
2) aspiring overdose
3) thermogenin (brown fat)

Explanation: results in increased permeability of the membrane, causing decreased proton gradient and increased O2 consumption. ATP synthesis stops, but electron transport continues; produces heat.

4

What is the final electron acceptor in the
ETC?

O2

5

Complex I

NADH dehydrogenase

6

Complex II

succinate dehydrogenase

7

Complex III

cytochrome b-c1 complex or CoQ:C1 oxidoreductase

8

Complex IV

cytochrome oxidase (O2--> H2O)

9

Complex V

(F0F1 ATPase) ATP Synthase; couples the movement of H+ across the inner mito membrane to ATP synthesis from ADP + Pi

10

Where does NADH pass its electrons to?

FMN (flavin mononucleotide)

11

Where does FMN pass electrons to?

through a series of Fe-S centers to Coenzyme Q: accepts e- one at a time forming semiquinone, then ubiquinol (energy produced by e- transfers pumps H+ into cytosolic side of inner mito membrane)

12

CoQ passes electrons to...

Cytochrome b and c1 through Fe-S centers

13

Cytochrome c1 passes electrons to

cytochrome c; energy of e- transfers pumps H+ across the membrane

14

Oxygen is reduced to water by...

electrons transferred from cytochrome aa3, which receives electrons from cytochrome c

15

Where do the electrons from FADH2 enter the ETC?

Complex II; transfers election to CoQ without associated proton pumping across inner mito membrane

16

ATP synthase conformations:
Loose

ADP + Pi

17

ATP synthase conformations:
Tight

ATP

18

ATP synthase conformations:
Open

release ATP

19

__ ATP/NADH

2.5 ATP

20

__ ATP/FADH2

1.5 ATP

21

Why is cyanide poisonous?

CN blocks oxygen at the aa3 complex, so the ETC has no final electron acceptor

22

MERRF

myotonic epilepsy & ragged red fibers
- faulty tRNA for leucine
- proliferation and aggregation of mitochondria
- progressive muscle weakness

23

LHON: Leber Hereditary Optic neuropathy

90% caused by mutation of Complex I subunit
- maternally inherited
- acute optic atrophy with late onset, sudden presentation with blindness (15-35 yoa)

24

MELAS

mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes
- faulty tRNA for lysine
- also ragged red fibers