Class 2: OX Phos I Flashcards
Mitochondria membrane systems:
Outer membrane: permeable d.t porin VDAC
Inner membrane: impermeable, folded in cristae.
2 compartments of the mito. :
Intermembrane space
Matrix: TCA and FA oxidation
WHere does ox phos occur?
Inner membrane of mito.
Semi-autonomous organelles.
HAVE THEIR OWN DNA, MAKE PROTEINS AND RNAs.
All mito. Derived from rickettsia prowazekii by endosymbiotic event.
Human DNA has 16,569 bp and encodes 13 respiratory chain proteins, rRNAs, tRNAs.
Mitochondrial genome.
TCA cycle generates :
Electron carriers. NADH and FADH2
Electrons reduce->
O2 to water
Which 3 complexes pump H+ into the intermembrane space?
1,3, and 4
How do H+s return to the matrix from intermembrane space?
ATP synthase - powers synthesis of ATP
NADH Q oxidoreductase
Complex 1
Succinct Q reductase
Complex 2
Q cytochrome c oxidoreductase
Complex 3
Cytochrome c oxidase
Complex 4
Electron flow is ________
Exergonic
Succincte Q reductase generates FADH2 and has what enzyme from TCA in it?
Succinate dehydrogenase
Which complex doesnt pump electrons across membrane to intermembrane space?
Succinate Q reductase
Or
Complex 2
Complex 1,3,4 collectively are called
Respirasome
Transfers e- from NADH Q oxidoreductase and then succinate Q reductase to Q cytochrome c oxidoreductase
Coenzyme Q
Or
Ubiquinone
Shuttles e- from Q cytochrome c oxidoreductase(3) to cytochrome c oxidase (4)
Final component of ETC
Catalyzes the reduction of O2
Cytochrome c
Prosthetic groups for complex 1:
FMN
Fe-S
Complex 2 prosthetic groups:
FAD
Fe-S
Complex 3 prosthetic groups:
Heme b and c
Fe-S
Complex 4 prosthetic groups:
heme a
Cu
Play a role in reduction reactions.
Oxidation-reduction reactions but the H+’s never leave the protein.
Fe-S clusters
Rare inherited RECESSIVE disease.
Caused by mutation in the protein FRATAXIN.
Issue: synthesis of Fe-S clusters.
Affects CNS, PNS, heart, and skeletal system –excitable cells.
Common mutation is trinucleotide expansion in fraxtaxin gene.
Friedreich’s ataxia
First point of entry of electrons from NADH.
Pumps 4 protons into intermembrane space.
Complex 1
FADH2 enters ETC and doesnt leave through:
Leave ATP synthesized from oxidation of FADH2
Complex 2
Electrons from QH2 are passed on to cytochrome c by:
2 protons pumped into intermembrane space
Complex 3
Solves problem of cyt c only carrying 1 e- from CoQ
Q cycle
Catalyzes transfer of e-‘s from reduced cyt c to molecular O2, the final acceptor
Makes these reactions aerobic, makes ppl breath.
4 e-s funneled to O2 to reduce it to water
Complex 4
4 protons are pumped and 4 protons are used to form 2 molecules of water :
Peroxide bridge
Complete reduction of O2 forms water.
Partial reduction forms dangerous species.
Can form superoxide anion or hydrogen peroxide.
Hydroxyl radical formed from both
Free radicals
Dz asso. W/ free radicals:
Parkinson’s Dz
Ischemia; reperfusion injury
Enzymes for antioxidants:
- Superoxide dismutase (SOD) uses selenium. To turn superoxide anion to H2O2
- Catalase converted H2O2 to 2 molecules of water.
This protein has been conserved throughout nearly all of evo.
Cytochrome c
