15 – Electron Transport chain Flashcards
role of respiratory chain
turnign glucose & other nutrients into ATP
-donors of electorn - NADH & FADH2 donate elctrons in order to rpoduce energy - to make ATP
In complex I:
- use NADH to get electrons
2.CoQ reduction to CoQH2 - goes in CoQH2 pool
Complex II
Transfer electron to CoQ from succinate to fumurate
-reduces FAD to FADH2
-give elctrons to CoQ to fill CoQH2 pool
CoQH2
transfer electrons to complex III
what is job for complex I,III,IV
to create proton gradient
-pushing protein from matrix to intermembrane space to create difference in concentration
complex I -push out 4 protons
complex III - push out 4 protons
complex IV - push out 2 protons & give elctrons to oxygen - END
what is between Complex III & Complex IV and what does it do
cytochrome-C, diffuse easily between them to transport electrons
Proton motive force
create concentration gradient from pushing protons from matrix to intermmebrane space
Uncouplers - can punch holes in membrane (there is leakage of current)
-regulate mitochondrial function
DNP
CCCP
FCCP
complex V
dissipation of gradient, roton motive force allow to make ATP
what can block complex V
oligomycin -stop electorn transport -dissipation
Activity of electron transport chain can be measured as
pH changes
Reduces over time – H+ pumped out over time
Seahorse OCR
oxygen consumption rate
-add oligomycin = oxygen consumption drops, bc proton can no longer be pushed out of intermembrane space bc gradient is too big
how to solve this? place some uncouplers
When electrons are part of chemical bond wih oxygen =
stable state
To pull them off oxygen =
need to spend more energy
When allow electron to be in bonds with oxygen
= energy released
Electrons moved to
higher reduction potential groups all the way to O2
what passes the electrons downhill
Iron clusters & other prosthetic groups
in complex I, what is separated
Electron transfer & proton translocation
CoQ reduction – coupled to
squeezing H+ out by complex intracomplex movements
Complex I passes electrons to
Coenzyme Q = ubiquinone
Lipid-like carrier
at complex III, there isa cycle called.. & how does it work?
Q cycle
1st half=
1. CoQH2 binds at Qo site
2. 2 electrons can revover from CoQH2
-first electron continues in respiratory chain. -eventuallyoges to Cyt-C — intermembrane space
-other elctron transported to reduce CoQ
2nd half= same thing happens agins, but, 2nd electron get reduced to CoQH2
both first electrons are then pumped out to create a gradient
Complex IV
Passes electrons from Cytochrome C to O2 & at same time 4 protons are pushed out
summary (improtant factors)
interaction between complexes = CoQ
CoQH2 pool
Respiratory chain – allow
energy release to be slow/stepwise & recoverable in form of ATP
